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Drug overview for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
Generic name: efavirenz/lamivudine/tenofovir disoproxil fumarate (EF-a-VIR-enz/la-MIV-ue-deen/ten-OF-oh-vir)
Drug class: Antiviral-HIV (Antiretroviral) Nonnucleoside RT Inhibitor
Therapeutic class: Anti-Infective Agents
Efavirenz, an antiretroviral agent, is a human immunodeficiency virus (HIV) Lamivudine, an antiretroviral agent, is a human immunodeficiency virus Tenofovir disoproxil fumarate (tenofovir DF), an antiretroviral agent, is a (HIV) nucleoside reverse transcriptase inhibitor (NRTI) that is active human immunodeficiency virus (HIV) nucleotide reverse transcriptase nonnucleoside reverse transcriptase inhibitor (NNRTI). against HIV and hepatitis B virus (HBV). inhibitor that is active against HIV and hepatitis B virus (HBV).
No enhanced Uses information available for this drug.
Generic name: efavirenz/lamivudine/tenofovir disoproxil fumarate (EF-a-VIR-enz/la-MIV-ue-deen/ten-OF-oh-vir)
Drug class: Antiviral-HIV (Antiretroviral) Nonnucleoside RT Inhibitor
Therapeutic class: Anti-Infective Agents
Efavirenz, an antiretroviral agent, is a human immunodeficiency virus (HIV) Lamivudine, an antiretroviral agent, is a human immunodeficiency virus Tenofovir disoproxil fumarate (tenofovir DF), an antiretroviral agent, is a (HIV) nucleoside reverse transcriptase inhibitor (NRTI) that is active human immunodeficiency virus (HIV) nucleotide reverse transcriptase nonnucleoside reverse transcriptase inhibitor (NNRTI). against HIV and hepatitis B virus (HBV). inhibitor that is active against HIV and hepatitis B virus (HBV).
No enhanced Uses information available for this drug.
DRUG IMAGES
SYMFI LO 400-300-300 MG TABLET
The following indications for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate) have been approved by the FDA:
Indications:
HIV infection
Professional Synonyms:
Human immunodeficiency virus disease
Human immunodeficiency virus infection
Indications:
HIV infection
Professional Synonyms:
Human immunodeficiency virus disease
Human immunodeficiency virus infection
The following dosing information is available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
Although tenofovir DF is a prodrug that requires metabolism for activation, If efavirenz is used for treatment of HIV-1 infection in patients receiving dosage of the drug is expressed in terms of the prodrug diester (i.e., voriconazole, the voriconazole dosage should be increased to 400 mg every tenofovir DF). 12 hours and the efavirenz dosage should be reduced to 300 mg daily using
the capsule formulation. Dosage of tenofovir DF oral powder containing 40 mg/g is expressed as the
number of scoops of powder.
If efavirenz is used for treatment of HIV-1 infection in patients receiving rifampin, those weighing >=50 kg should receive an increased efavirenz dosage of 800 mg daily.
The usual dosage of lamivudine for the treatment of HIV-1 infection in adults is 150 mg twice daily or 300 mg once daily.
When lamivudine oral solution containing 10 mg/mL is used for the treatment of HIV-1 infection in pediatric patients 3 months of age or older, the recommended dosage is 5 mg/kg twice daily or 10 mg/kg once daily (up to 300 mg maximum daily dosage). Consider HIV-1 viral load and CD4+ cell count/percentage when selecting the dosing interval for patients initiating treatment with oral solution.
When lamivudine 150-mg scored tablets are used in pediatric patients 3 months of age or older who weigh 14 kg or more and are able to swallow tablets, the recommended dosage is based on weight (see Table 1and Table 2). Data regarding efficacy of the once-daily regimen of lamivudine given as 150-mg scored tablets in pediatric patients 3 months of age or older is limited to those who transitioned from a twice-daily regimen to a once-daily regimen after 36 weeks of treatment.
Table 1. Twice-daily Lamivudine for Treatment of HIV-1 Infection in Pediatric Patients Weighing at least 14 kg (150-mg Tablets)
Weight (kg) AM Dose PM Dose 14 to <20 75 mg (half of 150-mg 75 mg (half of 150-mg tablet) tablet) 20 to <25 75 mg (half of 150-mg 150 mg (one 150-mg tablet) tablet) >=25 150 mg (one 150-mg 150 mg (one 150-mg tablet) tablet)
Table 2. Once-daily Lamivudine for Treatment of HIV-1 Infection in Pediatric Patients Weighing at least 14 kg (150-mg Tablets)
Weight (kg) Once-daily Dose 14 to <20 150 mg (one 150-mg tablet) 20 to <25 225 mg (one and one-half 150-mg tablets) >=25 300 mg (two 150-mg tablets or one 300-mg tablet)
Although safety and efficacy of lamivudine in infants younger than 3 months of age have not been established, some experts suggest that neonates younger than 4 weeks of age+ can receive lamivudine in a dosage of 2 mg/kg twice daily and infants 4 weeks of age or older+ can receive a dosage of 4 mg/kg (up to 150 mg) twice daily.
When empiric HIV therapy+ is used for prevention of perinatal HIV transmission + in neonates at highest risk of HIV acquisition, a 3-drug antiretroviral regimen of zidovudine, lamivudine, and nevirapine is recommended and should be initiated as soon as possible after birth (within 6-12 hours).
For empiric HIV therapy+ in HIV-exposed neonates, experts recommend that lamivudine be given in a dosage of 2 mg/kg twice daily from birth to 4 weeks of age followed by 4 mg/kg twice daily from 4-6 weeks of age.
The optimal duration of empiric HIV therapy+ in HIV-exposed neonates at highest risk of HIV acquisition is unknown. Many experts recommend that the 3-drug regimen be continued for 6 weeks; others discontinue nevirapine and/or lamivudine if the result of the neonate's HIV nucleic acid amplification test (NAAT) is negative, but recommend continuing zidovudine for 6 weeks.
Clinicians can consult the National Perinatal HIV Hotline at 888-448-8765 for information regarding selection of antiretrovirals, including dosage considerations, for the prevention of perinatal HIV transmission.
When lamivudine (100-mg tablets or oral solution containing 5 mg/mL) is used for the treatment of chronic HBV infection in adults, the recommended dosage is 100 mg once daily.
The recommended oral dosage of lamivudine for the treatment of chronic HBV infection in pediatric patients 2-17 years of age is 3 mg/kg once daily up to a maximum daily dosage of 100 mg. The oral solution formulation should be prescribed for patients requiring a dosage less than 100 mg or unable to swallow tablets.
the capsule formulation. Dosage of tenofovir DF oral powder containing 40 mg/g is expressed as the
number of scoops of powder.
If efavirenz is used for treatment of HIV-1 infection in patients receiving rifampin, those weighing >=50 kg should receive an increased efavirenz dosage of 800 mg daily.
The usual dosage of lamivudine for the treatment of HIV-1 infection in adults is 150 mg twice daily or 300 mg once daily.
When lamivudine oral solution containing 10 mg/mL is used for the treatment of HIV-1 infection in pediatric patients 3 months of age or older, the recommended dosage is 5 mg/kg twice daily or 10 mg/kg once daily (up to 300 mg maximum daily dosage). Consider HIV-1 viral load and CD4+ cell count/percentage when selecting the dosing interval for patients initiating treatment with oral solution.
When lamivudine 150-mg scored tablets are used in pediatric patients 3 months of age or older who weigh 14 kg or more and are able to swallow tablets, the recommended dosage is based on weight (see Table 1and Table 2). Data regarding efficacy of the once-daily regimen of lamivudine given as 150-mg scored tablets in pediatric patients 3 months of age or older is limited to those who transitioned from a twice-daily regimen to a once-daily regimen after 36 weeks of treatment.
Table 1. Twice-daily Lamivudine for Treatment of HIV-1 Infection in Pediatric Patients Weighing at least 14 kg (150-mg Tablets)
Weight (kg) AM Dose PM Dose 14 to <20 75 mg (half of 150-mg 75 mg (half of 150-mg tablet) tablet) 20 to <25 75 mg (half of 150-mg 150 mg (one 150-mg tablet) tablet) >=25 150 mg (one 150-mg 150 mg (one 150-mg tablet) tablet)
Table 2. Once-daily Lamivudine for Treatment of HIV-1 Infection in Pediatric Patients Weighing at least 14 kg (150-mg Tablets)
Weight (kg) Once-daily Dose 14 to <20 150 mg (one 150-mg tablet) 20 to <25 225 mg (one and one-half 150-mg tablets) >=25 300 mg (two 150-mg tablets or one 300-mg tablet)
Although safety and efficacy of lamivudine in infants younger than 3 months of age have not been established, some experts suggest that neonates younger than 4 weeks of age+ can receive lamivudine in a dosage of 2 mg/kg twice daily and infants 4 weeks of age or older+ can receive a dosage of 4 mg/kg (up to 150 mg) twice daily.
When empiric HIV therapy+ is used for prevention of perinatal HIV transmission + in neonates at highest risk of HIV acquisition, a 3-drug antiretroviral regimen of zidovudine, lamivudine, and nevirapine is recommended and should be initiated as soon as possible after birth (within 6-12 hours).
For empiric HIV therapy+ in HIV-exposed neonates, experts recommend that lamivudine be given in a dosage of 2 mg/kg twice daily from birth to 4 weeks of age followed by 4 mg/kg twice daily from 4-6 weeks of age.
The optimal duration of empiric HIV therapy+ in HIV-exposed neonates at highest risk of HIV acquisition is unknown. Many experts recommend that the 3-drug regimen be continued for 6 weeks; others discontinue nevirapine and/or lamivudine if the result of the neonate's HIV nucleic acid amplification test (NAAT) is negative, but recommend continuing zidovudine for 6 weeks.
Clinicians can consult the National Perinatal HIV Hotline at 888-448-8765 for information regarding selection of antiretrovirals, including dosage considerations, for the prevention of perinatal HIV transmission.
When lamivudine (100-mg tablets or oral solution containing 5 mg/mL) is used for the treatment of chronic HBV infection in adults, the recommended dosage is 100 mg once daily.
The recommended oral dosage of lamivudine for the treatment of chronic HBV infection in pediatric patients 2-17 years of age is 3 mg/kg once daily up to a maximum daily dosage of 100 mg. The oral solution formulation should be prescribed for patients requiring a dosage less than 100 mg or unable to swallow tablets.
Single-entity efavirenz is commercially available as capsules or tablets. Efavirenz capsules and tablets are administered orally once daily on an empty stomach, preferably at bedtime. Because administration with food increases plasma efavirenz concentrations and may increase the incidence of adverse effects, the drug should be taken on an empty stomach.
Administration of efavirenz at bedtime may make adverse CNS effects (e.g., dizziness, insomnia, impaired concentration, somnolence, abnormal dreams) more tolerable. Efavirenz is used in conjunction with other antiretrovirals. Single-entity efavirenz should not be used concomitantly with efavirenz/emtricitabine/tenofovir disoproxil fumarate (tenofovir DF; e.g., Atripla(R)), unless needed for adjustment of efavirenz dosage (e.g., when the fixed combination is used concomitantly with rifampin).
Single-entity tenofovir DF is commercially available as tablets or oral powder. Tenofovir DF tablet is administered orally once daily without regard to meals. Tenofovir DF oral powder is administered once daily.
Measure the appropriate dosage of the oral powder using only the scoop provided by the manufacturer. One level scoop delivers 1 g of powder, which contains 40 mg of tenofovir DF. Mix the required number of scoops of the powder with 2-4 ounces of soft food that can be swallowed without chewing (e.g., applesauce, baby food, yogurt), and ingest the entire mixture immediately to avoid a bitter taste.
Do not administer the oral powder in a liquid since the powder may float to the top of the liquid, even after stirring. Store tenofovir DF oral power and tablets at 25oC (excursions permitted to 15-30oC). Dispense in the original container, and keep the container tightly closed.
Lamivudine is administered orally once or twice daily without regard to meals. For the treatment of HIV-1 infection, lamivudine is commercially available as an oral solution containing 10 mg/mL or tablets containing 150 or 300 mg of the drug (Epivir(R), generic). The 150-mg scored tablets are the preferred preparation in pediatric patients who weigh 14 kg or more and can swallow tablets.
The oral solution should be used in those unable to safely and reliably swallow tablets. Lamivudine is used in conjunction with other antiretrovirals for the treatment of HIV-1 infection. For the treatment of chronic HBV infection, lamivudine is commercially available as an oral solution containing 5 mg/mL or film-coated tablets containing 100 mg of the drug (Epivir-HBV(R), generic).
The 5-mg/mL oral solution should be used in patients requiring a dosage less than 100 mg and in children unable to reliably swallow tablets. Lamivudine preparations labeled by FDA for treatment of chronic HBV infection should not be used in HIV-infected patients because they contain a lower dosage of the drug than that required for treatment of HIV-1 infection. If such preparations are used for the management of chronic HBV infection in a patient with unrecognized or untreated HIV infection, rapid emergence of HIV resistance is likely to result because of the subtherapeutic dose and the inappropriateness of monotherapy for HIV-infected individuals.
Store lamivudine 100-mg, 150-mg, and 300-mg tablets at 25degreesC (excursions permitted between 15-30degreesC). Store lamivudine 5-mg/mL oral solution at 20-25degreesC and store lamivudine 10-mg/mL oral solution at 25degreesC.
Administration of efavirenz at bedtime may make adverse CNS effects (e.g., dizziness, insomnia, impaired concentration, somnolence, abnormal dreams) more tolerable. Efavirenz is used in conjunction with other antiretrovirals. Single-entity efavirenz should not be used concomitantly with efavirenz/emtricitabine/tenofovir disoproxil fumarate (tenofovir DF; e.g., Atripla(R)), unless needed for adjustment of efavirenz dosage (e.g., when the fixed combination is used concomitantly with rifampin).
Single-entity tenofovir DF is commercially available as tablets or oral powder. Tenofovir DF tablet is administered orally once daily without regard to meals. Tenofovir DF oral powder is administered once daily.
Measure the appropriate dosage of the oral powder using only the scoop provided by the manufacturer. One level scoop delivers 1 g of powder, which contains 40 mg of tenofovir DF. Mix the required number of scoops of the powder with 2-4 ounces of soft food that can be swallowed without chewing (e.g., applesauce, baby food, yogurt), and ingest the entire mixture immediately to avoid a bitter taste.
Do not administer the oral powder in a liquid since the powder may float to the top of the liquid, even after stirring. Store tenofovir DF oral power and tablets at 25oC (excursions permitted to 15-30oC). Dispense in the original container, and keep the container tightly closed.
Lamivudine is administered orally once or twice daily without regard to meals. For the treatment of HIV-1 infection, lamivudine is commercially available as an oral solution containing 10 mg/mL or tablets containing 150 or 300 mg of the drug (Epivir(R), generic). The 150-mg scored tablets are the preferred preparation in pediatric patients who weigh 14 kg or more and can swallow tablets.
The oral solution should be used in those unable to safely and reliably swallow tablets. Lamivudine is used in conjunction with other antiretrovirals for the treatment of HIV-1 infection. For the treatment of chronic HBV infection, lamivudine is commercially available as an oral solution containing 5 mg/mL or film-coated tablets containing 100 mg of the drug (Epivir-HBV(R), generic).
The 5-mg/mL oral solution should be used in patients requiring a dosage less than 100 mg and in children unable to reliably swallow tablets. Lamivudine preparations labeled by FDA for treatment of chronic HBV infection should not be used in HIV-infected patients because they contain a lower dosage of the drug than that required for treatment of HIV-1 infection. If such preparations are used for the management of chronic HBV infection in a patient with unrecognized or untreated HIV infection, rapid emergence of HIV resistance is likely to result because of the subtherapeutic dose and the inappropriateness of monotherapy for HIV-infected individuals.
Store lamivudine 100-mg, 150-mg, and 300-mg tablets at 25degreesC (excursions permitted between 15-30degreesC). Store lamivudine 5-mg/mL oral solution at 20-25degreesC and store lamivudine 10-mg/mL oral solution at 25degreesC.
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| SYMFI LO 400-300-300 MG TABLET | Maintenance | Adults take 1 tablet by oral route once daily at bedtime |
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| EFAVIR-LAMIV-TENOF 400-300-300 | Maintenance | Adults take 1 tablet by oral route once daily at bedtime |
The following drug interaction information is available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
There are 9 contraindications.
These drug combinations generally should not be dispensed or administered to the same patient. A manufacturer label warning that indicates the contraindication warrants inclusion of a drug combination in this category, regardless of clinical evidence or lack of clinical evidence to support the contraindication.
| Drug Interaction | Drug Names |
|---|---|
| Selected Nephrotoxic Agents/Cidofovir SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Cidofovir is nephrotoxic. Concurrent administration of other nephrotoxic agents may result in additive or synergistic effects on renal function.(1-3) CLINICAL EFFECTS: Concurrent use of cidofovir with nephrotoxic agents such as adefovir, intravenous aminoglycosides, amphotericin B, foscarnet, intravenous pentamidine, tenofovir, vancomycin, voclosporin and non-steroidal anti-inflammatory agents may result in renal toxicity.(1-3) Other nephrotoxic agents include capreomycin, cisplatin, gallium nitrate, high-dose methotrexate, and streptozocin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The Australian,(1) UK,(2) and US(3) manufacturers of cidofovir state that concurrent administration of potentially nephrotoxic agents such as adefovir, intravenous aminoglycosides, amphotericin B, foscarnet, intravenous pentamidine, tenofovir, vancomycin, voclosporin and non-steroidal anti-inflammatory agents may result in renal toxicity.(1-3) Other nephrotoxic agents include capreomycin, cisplatin, gallium nitrate, high-dose methotrexate, and streptozocin. These agents should be discontinued at least 7 days before the administration of cidofovir. DISCUSSION: The safety of cidofovir has not been studied in patients receiving other known potentially nephrotoxic agents. Renal impairment is the major toxicity of cidofovir.(1-3) |
CIDOFOVIR |
| Adefovir/Tenofovir SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: The mechanism involves competition for active tubular secretion sites in the kidney.(1-4) CLINICAL EFFECTS: Concurrent use of adefovir and tenofovir in the treatment of hepatitis B may result in elevated levels of tenofovir or adefovir. PREDISPOSING FACTORS: Renal impairment or use of concurrent renally excreted drugs. PATIENT MANAGEMENT: The US manufacturer of adefovir(1) and the UK(2) and US(3) manufacturers of tenofovir state that adefovir and tenofovir should be not be administered together. DISCUSSION: Tenofovir is eliminated principally by renal tubular secretion and any competitive inhibition of excretion of tenofovir by adefovir increases the likelihood of increased serum concentrations of tenofovir and resultant toxicity.(1-4) |
ADEFOVIR DIPIVOXIL, HEPSERA |
| Cobicistat-Elvitegravir/NNRTIs SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Cobicistat inhibits CYP2D6, CYP3A4, BCRP, OATP1B1 and OATP1B3. Elvitegravir induces CYP2C9. Efavirenz may induce the metabolism of cobicistat via CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of cobicistat-elvitegravir with non-nucleoside reverse transcriptase inhibitors (NNRTIs) may result in altered and/or suboptimal pharmacokinetics of cobicistat, elvitegravir, and/or the NNRTI.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The combination product containing cobicistat-elvitegravir-emtricitabine-tenofovir should not be used with non-nucleoside reverse transcriptase inhibitors.(1) DISCUSSION: Concurrent use of cobicistat-elvitegravir with non-nucleoside reverse transcriptase inhibitors may result in altered and/or suboptimal pharmacokinetics of cobicistat, elvitegravir, and/or the NNRTI.(1) |
GENVOYA, STRIBILD |
| Elbasvir-Grazoprevir/Strong CYP3A4 Inducers SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Inducers of CYP3A4 may induce the metabolism of elbasvir and grazoprevir.(1,2) CLINICAL EFFECTS: Concurrent use of a strong inducer of CYP3A4 may result in decreased levels and effectiveness of elbasvir and grazoprevir.(1,2) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Concurrent use of elbasvir-grazoprevir and strong CYP3A4 inducers is contraindicated.(1,2) If concurrent use is deemed medically necessary, monitor the patient for potential treatment failure and decreased elbasvir and grazoprevir levels. DISCUSSION: In single dose studies, rifampin increased levels of both elbasvir and grazoprevir. In a study in 14 subjects, rifampin (600 mg single IV dose) increased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of a single dose of elbasvir (50 mg) by 41%, 22%, and 31%, respectively. In a study in 14 subjects, rifampin (600 mg single oral dose) increased the Cmax, AUC, and Cmin of a single dose of elbasvir (50 mg) by 29%, 17%, and 21%, respectively. In a study in 12 subjects, rifampin (600 mg single IV dose) increased the Cmax, AUC, and Cmin of a single dose of grazoprevir (200 mg) by 10.94-fold, 10.21-fold, and 1.77-fold, respectively. In a study in 12 subjects, rifampin (600 mg single oral dose) increased the Cmax, AUC, and Cmin of a single dose of grazoprevir (200 mg) by 6.52-fold, 8.35-fold, and 1.61-fold, respectively.(1) However, multiple dose studies with rifampin showed decreased grazoprevir levels. In a study in 12 subjects, rifampin (600 mg orally) decreased the AUC and Cmin of grazoprevir (200 mg daily) by 7% and 90%, respectively. Cmax increased 16%.(1) In a study in 12 subjects, efavirenz (600 mg daily) decreased the Cmax, AUC, and Cmin of elbasvir (50 mg daily) by 45%, 34%, and 59%, respectively.(1) In a study in 12 subjects, efavirenz (600 mg daily) decreased the Cmax, AUC, and Cmin of grazoprevir (200 mg daily) by 87%, 82%, and 69%, respectively.(1) Strong inducers of CYP3A4 include apalutamide, barbiturates, carbamazepine, efavirenz, encorafenib, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, primidone, phenytoin, and St. John's wort.(1-4) |
ZEPATIER |
| Cilostazol (Greater Than 50 mg BID)/Strong & Moderate CYP2C19 Inhibitors that Prolong QT SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP2C19 may inhibit the metabolism of cilostazol.(1-4) Both agents have been shown to prolong the QT interval.(1,5) CLINICAL EFFECTS: Concurrent use of strong or moderate inhibitors of CYP2C19 may result in elevated levels of 3,4-dehydro-cilostazol, a metabolite of cilostazol that is 4-7 times as active as cilostazol.(1) Concurrent use may also result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(6) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of cilostazol should be limited to 50 mg twice daily in patients receiving concurrent therapy with strong and moderate inhibitors of CYP2C19.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study in 20 subjects examined the effects of omeprazole (40 mg daily) on a single dose of cilostazol (100 mg). Concurrent omeprazole increased the cilostazol maximum concentration (Cmax) and area-under-curve (AUC) by 18% and 26%, respectively. The Cmax and AUC of the 3,4-dehydro-cilostazol metabolite of cilostazol increased 29% and 69%, respectively. The Cmax and AUC of the OPC-13213 metabolite of cilostazol decreased by 22% and 31%, respectively.(4) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology. |
CILOSTAZOL |
| Selected Nephrotoxic Agents/Bacitracin SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Bacitracin may cause renal failure due to glomerular and tubular necrosis. Concurrent administration of other nephrotoxic agents may result in additive renal toxicity.(1-3) CLINICAL EFFECTS: Concurrent use of bacitracin with other potentially nephrotoxic agents may result in renal toxicity.(1-3) PREDISPOSING FACTORS: Dehydration and high-dose bacitracin may predispose to adverse renal effects.(1) PATIENT MANAGEMENT: Health Canada states that bacitracin is contraindicated in patients with renal impairment, including those taking other nephrotoxic drugs.(1) The Canadian and US manufacturers of bacitracin state that concomitant use of bacitracin with other potentially nephrotoxic agents should be avoided.(2,3) DISCUSSION: Renal impairment is a major toxicity of bacitracin. Cases of nephrotoxicity have been reported when bacitracin was used off-label.(1-3) |
BACITRACIN, BACITRACIN MICRONIZED, BACITRACIN ZINC |
| Cabotegravir-Rilpivirine/Strong CYP3A4 & UGT1A1 Inducers SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Apalutamide, barbiturates, carbamazepine, dexamethasone, efavirenz, encorafenib, enzalutamide, eslicarbazepine, fosphenytoin, ivosidenib, lumacaftor, mitotane, natisedine, oxcarbazepine, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, ritonavir, or St. John's wort may induce the metabolism of cabotegravir-rilpivirine by CYP3A4 and uridine diphosphate (UDP)-glucuronosyl transferase 1A1 (UGT1A1).(1) CLINICAL EFFECTS: Concurrent or recent use of apalutamide, barbiturates, carbamazepine, dexamethasone, efavirenz, encorafenib, enzalutamide, eslicarbazepine, fosphenytoin, ivosidenib, lumacaftor, mitotane, natisedine, oxcarbazepine, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, ritonavir, or St. John's wort may result in decreased levels and effectiveness of cabotegravir-rilpivirine, as well as the development of resistance.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of cabotegravir-rilpivirine states that concurrent use of CYP3A4 inducers and/or UGT1A1 inducers is contraindicated.(1) It may take several weeks after the discontinuation of an enzyme inducer for enzyme activity to return to normal.(1) DISCUSSION: In a study in 16 subjects, rifampin (600 mg daily) decreased the concentration maximum (Cmax), area-under-curve (AUC), and concentration minimum (Cmin) of rilpivirine (150 mg daily) by 69%, 80%, and 89%, respectively. There were no significant effects on the Cmax or AUC of rifampin or 25-desacetylrifampin.(1) In a study in 15 subjects, rifampin (600 mg daily) decreased the Cmax, AUC, and Cmin of cabotegravir by 6%, 59%, and 50%, respectively.(1) Strong CYP3A4 inducers linked include: apalutamide, barbiturates, carbamazepine, dexamethasone, encorafenib, enzalutamide, eslicarbazepine, fosphenytoin, ivosidenib, lumacaftor, mitotane, natisedine, oxcarbazepine, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, or St. John's wort.(1,2) UGT1A1 inducers linked include: carbamazepine, efavirenz, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone, rifapentine, rifampin, and ritonavir.(1,2) |
CABENUVA |
| Cabotegravir/UGT1A1 Inducers SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Carbamazepine, efavirenz, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone, rifapentine, rifampin, and ritonavir may induce the metabolism of cabotegravir by uridine diphosphate (UDP)-glucuronosyl transferase 1A1 (UGT1A1).(1) CLINICAL EFFECTS: Concurrent or recent use of carbamazepine, efavirenz, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone, rifapentine, rifampin, or ritonavir may result in decreased levels and effectiveness of cabotegravir, as well as the development of resistance.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of cabotegravir states that concurrent use of UGT1A1 inducers such as carbamazepine, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone, rifapentine, rifampin, and ritonavir is contraindicated.(1) It may take several weeks after the discontinuation of an enzyme inducer for enzyme activity to return to normal.(1) DISCUSSION: In a study in 15 subjects, rifampin (600 mg daily) decreased the concentration maximum (Cmax), area-under-curve (AUC), and concentration minimum (Cmin) of cabotegravir by 6%, 59%, and 50%, respectively.(1) UGT1A1 inducers linked include: carbamazepine, efavirenz, fosphenytoin, oxcarbazepine, phenobarbital, phenytoin, primidone, rifapentine, rifampin, and ritonavir.(1,2) |
APRETUDE, CABOTEGRAVIR ER (CABENUVA), VOCABRIA |
| Lonafarnib/Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate CYP3A4 inducers that prolong the QTc interval may increase the metabolism of lonafarnib. Concurrent use may result in an additive risk of QT prolongation.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers that prolong QT may decrease the serum levels and effectiveness of lonafarnib and have additive effects on the QTc interval, which may result in potentially life-threatening arrhythmias including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The use of moderate CYP3A4 inducers with lonafarnib is contraindicated. If concurrent use is warranted, monitor ECG prior to initiation, during concurrent therapy, and as clinically indicated with other agents known to prolong the QTc interval.(1) DISCUSSION: With coadministration of a single oral dose of 50 mg lonafarnib (combined with a single oral dose of 100 mg ritonavir) following 600 mg rifampin (a strong CYP3A4 inducer) for 8 days, the area-under-curve (AUC) was reduced by 98% and the maximum concentration (Cmax) was reduced by 92%.(1) In a thorough QT study, lonafarnib 200 mg twice daily for 9 consecutive days and a single 200 mg dose on day 10 increased the mean QTc interval by 19 msec (upper bound of 90% confidence interval = 27 msec) on day 10 at 48 hours after administration of the morning dose of lonafarnib 200 mg. The maximum concentration (Cmax) on Day 10 was 2233 ng/ml, which is similar to the mean Cmax of 2695 ng/ml observed in the Hutchinson-Gilford Progeria Syndrome patient population.(1) Moderate inducers of CYP3A4 that prolong QT include: efavirenz and thioridazine.(3,4) |
ZOKINVY |
There are 112 severe interactions.
These drug interactions can produce serious consequences in most patients. Actions required for severe interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration scheduling, and providing additional patient monitoring. Review the full interaction monograph for more information.
| Drug Interaction | Drug Names |
|---|---|
| Hormonal Contraceptive Agents/Efavirenz; Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz(1) and nevirapine(2,3) may induce the metabolism of hormonal contraceptives via CYP3A4. CLINICAL EFFECTS: Concurrent administration of efavirenz(1) or nevirapine(2,3) with a hormonal contraceptive agent may result in decreased plasma concentrations and clinical effectiveness of the contraceptive agent. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of efavirenz(1) and nevirapine(2) state that hormonal contraceptives should not be used as the sole method of contraception in women taking these agents. A reliable method of barrier contraception must be used in addition to hormonal contraception in women taking efavirenz.(1) Alternative or additional methods of contraception should be considered in women taking nevirapine.(2) Because of the long half-life of efavirenz, women should continue to use a barrier method of contraception in addition to hormonal contraception for 12 weeks after discontinuing efavirenz.(1) For emergency contraception, the UK's Medicines & Healthcare Products Regulatory Agency (MHRA) recommends that women who have used a CYP3A4 inducer in the previous 4 weeks should consider a non-hormonal emergency contraceptive (ie a copper IUD). If a non-hormonal emergency contraceptive is not an option, double the usual dose of levonorgestrel from 1.5 to 3 mg.(4) Advise the patient to have a pregnancy test to exclude pregnancy after use and to seek medical advice if they do become pregnant. DISCUSSION: In a study in 21 subjects, concurrent efavirenz (600 mg daily for 14 days) and ethinyl estradiol/norgestimate (0.035/0.25 mg for 14 days) had no effect on ethinyl estradiol levels. The maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of norelgestromin decreased by 46%, 64%, and 82%, respectively. The Cmax, AUC, and Cmin of levonorgestrel decreased by 80%, 83%, and 86%, respectively.(1) There have been reports of contraceptive failure in patients with etonogestrel implants who were receiving efavirenz.(1) In a study in 10 subjects taking Ortho-Novum 1/35, nevirapine decreased the AUC of ethinyl estradiol by 20% and the AUC and Cmax of norethindrone by 19% and 16%, respectively.(2) In a study in 16 HIV-positive females, concurrent nevirapine (200 mg daily, Days 2-15; 200 mg twice daily, Days 16-29) and ethinyl estradiol with norethindrone decreased the AUCs of ethinyl estradiol and norethindrone by 29% and 18%, respectively.(3) A study of 118 HIV-positive females compared levonorgestrel pharmacokinetics and safety between the following groups: 1. levonorgestrel 1.5 mg with dolutegravir-based antiretrovirals (ART)(control group), 2. levonorgestrel 1.5 mg with efavirenz-based ART, 3. levonorgestrel 3 mg with efavirenz-based ART, and 4. levonorgestrel 3 mg with rifampin. While both levonorgestrel 3 mg groups had Cmax and AUC(0-8h) similar to the control group, the half life of levonorgestrel was shorter, resulting in an AUC(inf) that was 53% lower in the efavirenz group and 37% lower in the rifampin group than the control group. Tolerability was similar between groups. No pregnancies were reported but it is unknown whether the correction of levonorgestrel levels early in the dosing period is sufficient to maintain overall emergency contraceptive effectiveness.(5) |
2-METHOXYESTRADIOL, AFIRMELLE, ALTAVERA, ALYACEN, AMETHIA, AMETHYST, ANNOVERA, APRI, ARANELLE, ASHLYNA, AUBRA, AUBRA EQ, AUROVELA, AUROVELA 24 FE, AUROVELA FE, AVIANE, AYUNA, AZURETTE, BALCOLTRA, BALZIVA, BEYAZ, BLISOVI 24 FE, BLISOVI FE, BRIELLYN, CAMILA, CAMRESE, CAMRESE LO, CAZIANT, CHARLOTTE 24 FE, CHATEAL EQ, CRYSELLE, CYRED, CYRED EQ, DASETTA, DAYSEE, DEBLITANE, DEPO-PROVERA, DEPO-SUBQ PROVERA 104, DESOGESTR-ETH ESTRAD ETH ESTRA, DIETHYLSTILBESTROL, DOLISHALE, DROSPIRENONE-ETH ESTRA-LEVOMEF, DROSPIRENONE-ETHINYL ESTRADIOL, ELINEST, ELLA, ELURYNG, EMZAHH, ENILLORING, ENPRESSE, ENSKYCE, ERRIN, ESTARYLLA, ESTRADIOL, ESTRADIOL BENZOATE, ESTRADIOL CYPIONATE, ESTRADIOL HEMIHYDRATE, ESTRADIOL HEMIHYDRATE MICRO, ESTRADIOL MICRONIZED, ESTRADIOL VALERATE, ESTRIOL, ESTRIOL MICRONIZED, ESTRONE, ETHINYL ESTRADIOL, ETHYNODIOL-ETHINYL ESTRADIOL, ETONOGESTREL-ETHINYL ESTRADIOL, FALMINA, FEIRZA, FEMLYV, FINZALA, GEMMILY, HAILEY, HAILEY 24 FE, HAILEY FE, HALOETTE, HEATHER, ICLEVIA, INCASSIA, ISIBLOOM, JAIMIESS, JASMIEL, JENCYCLA, JOLESSA, JOYEAUX, JULEBER, JUNEL, JUNEL FE, JUNEL FE 24, KAITLIB FE, KALLIGA, KARIVA, KELNOR 1-35, KELNOR 1-50, KURVELO, LARIN, LARIN 24 FE, LARIN FE, LAYOLIS FE, LEENA, LESSINA, LEVONEST, LEVONORG-ETH ESTRAD ETH ESTRAD, LEVONORG-ETH ESTRAD-FE BISGLYC, LEVONORGESTREL-ETH ESTRADIOL, LEVORA-28, LO LOESTRIN FE, LO-ZUMANDIMINE, LOESTRIN, LOESTRIN FE, LOJAIMIESS, LORYNA, LOW-OGESTREL, LUTERA, LYLEQ, LYZA, MARLISSA, MEDROXYPROGESTERONE ACETATE, MERZEE, MIBELAS 24 FE, MICROGESTIN, MICROGESTIN FE, MILI, MINZOYA, MONO-LINYAH, NATAZIA, NECON, NEXPLANON, NEXTSTELLIS, NIKKI, NORA-BE, NORELGESTROMIN-ETH ESTRADIOL, NORETHIN-ETH ESTRA-FERROUS FUM, NORETHINDRON-ETHINYL ESTRADIOL, NORETHINDRONE, NORETHINDRONE-E.ESTRADIOL-IRON, NORGESTIMATE-ETHINYL ESTRADIOL, NORTREL, NUVARING, NYLIA, OCELLA, ORTHO TRI-CYCLEN, ORTHO-NOVUM, PHILITH, PIMTREA, PORTIA, RECLIPSEN, RIVELSA, SAFYRAL, SETLAKIN, SHAROBEL, SIMLIYA, SIMPESSE, SLYND, SPRINTEC, SRONYX, SYEDA, TARINA 24 FE, TARINA FE, TARINA FE 1-20 EQ, TAYTULLA, TILIA FE, TRI-ESTARYLLA, TRI-LEGEST FE, TRI-LINYAH, TRI-LO-ESTARYLLA, TRI-LO-MARZIA, TRI-LO-MILI, TRI-LO-SPRINTEC, TRI-MILI, TRI-SPRINTEC, TRI-VYLIBRA, TRI-VYLIBRA LO, TRIVORA-28, TULANA, TURQOZ, TWIRLA, TYBLUME, VALTYA, VELIVET, VESTURA, VIENVA, VIORELE, VOLNEA, VYFEMLA, VYLIBRA, WERA, WYMZYA FE, XARAH FE, XELRIA FE, XULANE, YASMIN 28, YAZ, ZAFEMY, ZARAH, ZOVIA 1-35, ZUMANDIMINE |
| Fosamprenavir; Saquinavir/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of fosamprenavir,(1-3) and saquinavir (1,2,4) via CYP3A4. CLINICAL EFFECTS: Concurrent use of fosamprenavir and efavirenz without the correct amount of concurrent ritonavir may result in decreased levels of amprenavir.(1-3) Concurrent use of saquinavir as the sole protease inhibitor with efavirenz may result in decreased saquinavir levels and effectiveness.(1,2,4) Saquinavir may decrease efavirenz levels.(1,4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: An additional 100 mg/day (300 mg total) of ritonavir is recommended when efavirenz is administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when efavirenz is administered with fosamprenavir/ritonavir twice daily. Appropriate doses of fosamprenavir and efavirenz administered without ritonavir have not been established.(1-3) Saquinavir should not be used as the sole protease inhibitor in patients receiving efavirenz.(1,2) Appropriate doses of the combination of efavirenz and saquinavir mesylate/ritonavir have not been determined.(4) DISCUSSION: In a study in 16 subjects, concurrent use of efavirenz (600 mg daily) with fosamprenavir (1400 mg daily) with ritonavir (200 mg daily) decreased the amprenavir AUC and minimum concentration (Cmin) by 13% and 36%, respectively. Administration of an additional 100 mg of ritonavir daily increased amprenavir Cmax and AUC by 18% and 11%, respectively.(3) In a study in 16 subjects, concurrent use of efavirenz (600 mg daily) with fosamprenavir (700 mg twice daily) with ritonavir (100 mg twice daily) decreased amprenavir Cmin by 17% but had no effect on amprenavir AUC or Cmax.(3) In a study in 12 subjects, concurrent use of efavirenz (600 mg daily) with saquinavir (1200 mg every 8 hours) decreased the saquinavir AUC, Cmax, and Cmin by 62%, 50%, and 56%, respectively. Efavirenz AUC, Cmax, and Cmin were decreased by 12%, 13%, and 14%, respectively.(1,4) |
FOSAMPRENAVIR CALCIUM |
| Voriconazole/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of voriconazole by CYP3A4. Voriconazole may inhibit the metabolism of efavirenz by CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent use of efavirenz and voriconazole may result in decreased levels of voriconazole, therapeutic failure of voriconazole, elevated levels of efavirenz, and efavirenz toxicity.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of efavirenz(1) and voriconazole (2) state that concurrent use of standard doses of voriconazole and efavirenz are contraindicated. When coadministered, the dose of voriconazole should be increased to 400 mg every 12 hours and the dose of efavirenz should be decreased to 300 mg daily(1,2) using the capsule formulation.(1) Efavirenz tablets should not be broken.(1) The UK and US manufacturers of the combination product containing efavirenz/emtricitabine/tenofovir disoproxil fumarate states that this product should not be used with voriconazole because it is a fixed dose of efavirenz that cannot be adjusted.(3,4) DISCUSSION: In a study in healthy subjects, efavirenz (400 mg daily) decreased voriconazole (400 mg twice daily for 1 day, then 200 mg twice daily) maximum concentration (Cmax) and area-under-curve (AUC) by 61% and by 77%, respectively. Efavirenz Cmax and AUC increased by 38% and by 44%, respectively.(1,2) In a study in healthy males, concurrent administration of voriconazole (300 mg twice daily) with efavirenz (300 mg daily) decreased voriconazole AUC and Cmax by 55% and 36%, when compared to levels achieved with voriconazole 200 mg twice daily. When compared to levels achieved with efavirenz 600 mg daily, efavirenz AUC was equivalent and Cmax decreased by 14%.(1,2) In a study in healthy males, concurrent administration of voriconazole (400 mg twice daily) with efavirenz (300 mg daily) decreased voriconazole AUC by 7% and increased voriconazole Cmax by 23%, when compared to levels achieved with voriconazole 200 mg twice daily. When compared to levels achieved with efavirenz 600 mg daily, efavirenz Cmax was equivalent and AUC increased by 17%.(1,2) |
VFEND, VFEND IV, VORICONAZOLE |
| Ziprasidone/Selected QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ziprasidone has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ziprasidone with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(1,3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The manufacturer of ziprasidone states under contraindications that ziprasidone should not be used with other drugs that prolong the QT interval such as dofetilide, sotalol, quinidine, other Class Ia and III anti-arrhythmics, mesoridazine, thioridazine, chlorpromazine, droperidol, pimozide, sparfloxacin, gatifloxacin, moxifloxacin, halofantrine, mefloquine, pentamidine, arsenic trioxide, levomethadyl acetate, dolasetron mesylate, probucol or tacrolimus.(1) It would be prudent to avoid the use of ziprasidone with medicines suspected of prolonging the QT interval. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2) |
GEODON, ZIPRASIDONE HCL, ZIPRASIDONE MESYLATE |
| Colistimethate/Selected Nephrotoxic Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Colistimethate can cause nephrotoxicity.(1,2) Concurrent administration of other nephrotoxic agents may result in an increased risk of nephrotoxicity.(1) It is suspected that cephalothin interferes with the excretion of colistimethate resulting in enhanced nephrotoxicity.(2,3) CLINICAL EFFECTS: Concurrent use of colistimethate with other nephrotoxic agents may result in additive nephrotoxic effects. PREDISPOSING FACTORS: Factors predisposing to nephrotoxicity include higher cumulative doses of colistimethate, longer treatment duration, hypovolemia, and critical illness. PATIENT MANAGEMENT: Concurrent use of potentially nephrotoxic agents with colistimethate should be avoided.(1,2) If concurrent use is necessary, it should be undertaken with great caution.(1) DISCUSSION: In a case control study of 42 patients on intravenous colistimethate sodium, NSAIDs were identified as an independent risk factor for nephrotoxicity (OR 40.105, p=0.044).(4) In 4 case reports, patients developed elevated serum creatinine and blood urea nitrogen following concurrent colistimethate and cephalothin (3 patients) or when colistimethate followed cephalothin therapy (1 patient).(3) A literature review found that individual nephrotoxic agents, including aminoglycosides, vancomycin, amphotericin, IV contrast, diuretics, ACE inhibitors, ARBs, NSAIDs, and calcineurin inhibitors, were not consistently associated with additive nephrotoxicity when used with colistimethate. However, when multiple agents (at least 2 additional potential nephrotoxins) were used concurrently, there was a significant correlation to colistimethate nephrotoxicity.(5) |
COLISTIMETHATE, COLISTIMETHATE SODIUM, COLY-MYCIN M PARENTERAL |
| Itraconazole; Ketoconazole; Posaconazole/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of itraconazole,(1-4) ketoconazole,(1-5) and posaconazole (1,6) via CYP3A4. CLINICAL EFFECTS: Concurrent use of efavirenz may result in decreased levels and effectiveness of itraconazole,(1-4) ketoconazole,(1-5) and posaconazole.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Consider alternatives to itraconazole,(1-4) ketoconazole,(1-5) and posaconazole,(1,6) such as fluconazole, in patients receiving efavirenz unless the benefits of therapy outweigh the risks. If concurrent therapy is necessary, monitor patients closely for decreased therapeutic effects. The US manufacturer of itraconazole states that concurrent use with efavirenz is not recommended two weeks before and during itraconazole treatment. DISCUSSION: In a study in 18 subjects, concurrent efavirenz (600 mg daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of itraconazole (200 mg twice daily) by 37%, 39%, and 44%, respectively. The Cmax, AUC, and Cmin of hydroxyitraconazole decreased by 35%, 37%, and 43%, respectively.(1-3) There were no effects on efavirenz levels.(3,4) In a study in 12 HIV-positive subjects, efavirenz (600 mg daily) decreased the Cmax, AUC, and half-life (T1/2) of a single dose of ketoconazole (400 mg) by 44%, 72%, and 58%, respectively.(5) In a study in 11 subjects, efavirenz (400 mg daily) decreased the Cmax and AUC of posaconazole (400 mg twice daily) by 45% and 50%, respectively.(5,6) In a study in 10 subjects, efavirenz (400 mg daily) had no effect on the pharmacokinetics of fluconazole (200 mg daily).(1-3) The AUC and Cmin of fluconazole increased by 16% and 22%, respectively.(1) |
ITRACONAZOLE, ITRACONAZOLE MICRONIZED, KETOCONAZOLE, NOXAFIL, POSACONAZOLE, SPORANOX, TOLSURA |
| Maraviroc/Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong CYP3A4 inducers may increase the metabolism of maraviroc.(1) CLINICAL EFFECTS: Concurrent use of strong inducers of CYP3A4 in the absence of an inhibitor of CYP3A4 and without a dosage adjustment of maraviroc may result in decreased levels and effectiveness of maraviroc.(1) PREDISPOSING FACTORS: This interaction may be more severe in patients with renal impairment.(1) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of maraviroc states that adult patients receiving therapy with inducers of CYP3A4 who are not also receiving an inhibitor of CYP3A4 should receive a dose of 600 mg maraviroc twice daily.(1) The US manufacturer of maraviroc states that adult patients receiving therapy with inducers of CYP3A4 who are also receiving a strong inhibitor of CYP3A4 should receive a dose of 150 mg maraviroc twice daily.(1) In adults, maraviroc should not be used with a strong CYP3A4 inducer in patients with a creatinine clearance less than 30 ml/min or end-stage renal disease.(1) In children aged 2 years and older weighing at least 10 kg, patients receiving therapy with strong CYP3A4 inducers who are not also receiving an inhibitor of CYP3A4 is not recommended.(1) In children aged 2 years and older weighing at least 10 kg, patients receiving therapy with a strong CYP3A4 inducer and a strong CYP3A4 inhibitor should receive the following maraviroc dose based on tablet or oral solution (20 mg/ml): - 10 - <20 kg: 50 mg twice daily or 50 mg (2.5ml) twice daily - 20 - <30 kg: 75 mg twice daily or 80 mg (4 ml) twice daily - 30 - <40 kg: 100 mg twice daily or 100 mg (5 ml) twice daily - >= 40 kg: 150 mg twice daily or 150 mg (7.5 ml) twice daily In pediatric patients aged 2 years and older weighing at least 10 kg, no dose recommendations are available with mild to moderate renal impairment. Maraviroc is contraindicated in pediatric patients with severe renal impairment or end-stage renal disease who are on concurrent therapy with strong CYP3A4 inhibitors.(1) DISCUSSION: In a study in 12 subjects, concurrent efavirenz (600 mg daily) decreased the minimum concentration (Cmin), area-under-curve (AUC), and maximum concentration (Cmax) of maraviroc (100 mg twice daily) by 45%, 44.8%, and 51.4%, respectively.(1) In a study in 12 subjects, concurrent efavirenz (600 mg daily) increased the Cmin, AUC, and Cmax of maraviroc (200 mg twice daily) by 9%, 15%, and 16%, respectively, when compared to the administration of maraviroc (100 mg twice daily) alone.(1) In a study in 12 subjects, concurrent rifampin (600 mg daily) decreased the Cmin, AUC, and Cmax of maraviroc (100 mg twice daily) by 78%, 63%, and 66%, respectively.(1) In a study in 12 subjects, concurrent rifampin (600 mg daily) decreased the Cmin and Cmax of maraviroc (200 mg twice daily) by 34% and 4%, respectively, when compared to the administration of maraviroc (100 mg twice daily) alone. The AUC of maraviroc increased by 3%.(1) Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, efavirenz, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, natisedine, phenobarbital, phenytoin, primidone, rifampin, and rifapentine. |
MARAVIROC, SELZENTRY |
| Atazanavir/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of atazanavir via CYP3A4.(1-4) CLINICAL EFFECTS: Concurrent use of atazanavir and efavirenz without concurrent ritonavir may result in decreased levels and effectiveness of atazanavir.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturers of atazanavir(1,2), cobicistat,(3) and efavirenz(4) state that if atazanavir is to be used concurrently with efavirenz in treatment naive patients, patients should receive 400 mg atazanavir with 100 mg ritonavir or 150 mg cobicistat as a single daily dose with food, and 600 mg of efavirenz should be administered once a day on an empty stomach, preferably at bedtime.(1,3) Atazanavir should not be administered with efavirenz without ritonavir or cobicistat.(2) Atazanavir and efavirenz should not be coadministered in treatment-experienced patients.(1-3) The combination product containing efavirenz/emtricitabine/tenofovir is not recommended for use in patients receiving atazanavir.(5) DISCUSSION: In a study in 27 subjects, the administration of atazanavir and efavirenz without ritonavir decreased the atazanavir area-under-curve (AUC), maximum concentration (Cmax), and minimum concentration (Cmin) by 74%, 59%, and 93% respectively.(1,2) In a study in 13 subjects, concurrent atazanavir/ritonavir (300/100 mg daily) with efavirenz (600 mg daily) increased atazanavir AUC, Cmax, and Cmin by 39%, 14%, and 48%, when compared to atazanavir 400 mg daily alone.(1,2) In a study in 14 subjects, concurrent atazanavir/ritonavir (400/100 mg daily) with efavirenz (600 mg daily) increased atazanavir Cmax by 17%. Atazanavir Cmin decreased by 42%.(1) Because both efavirenz and tenofovir decrease atazanavir concentrations and the effect of taking both on atazanavir pharmacokinetics has not been studied, the use of atazanavir with the combination product efavirenz/emtricitabine/tenofovir is not recommended.(5) |
ATAZANAVIR SULFATE, EVOTAZ, REYATAZ |
| Deferasirox/Strong UGT Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of UDP-glucuronosyltransferase (UGT) may induce the metabolism of deferasirox.(1) CLINICAL EFFECTS: Concurrent use of carbamazepine, efavirenz, etravirine, fosphenytoin, phenobarbital, phenytoin, primidone, rifampin, or ritonavir may result in decreased levels and effectiveness of deferasirox.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the use of strong UGT inducers with deferasirox. If concurrent therapy is warranted, consider increasing the initial dose of deferasirox by 50%. Further dosage adjustments should be made based upon serum ferritin levels and clinical response. Doses above 40 mg/kg are not recommended.(1) DISCUSSION: In a study in healthy subjects, administration of rifampin (600 mg/day for 9 days) decreased the area-under-curve (AUC) of a single dose of deferasirox (30 mg/kg) by 44%.(1) Other strong inducers of UGT, such as carbamazepine, efavirenz, etravirine, fosphenytoin, phenobarbital, phenytoin, primidone, and ritonavir are expected to produce similar results.(1) |
DEFERASIROX, EXJADE, JADENU, JADENU SPRINKLE |
| Efavirenz/Carbamazepine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of carbamazepine via CYP3A4. Carbamazepine may induce the metabolism of efavirenz by CYP3A4 and CYP2B6.(1) CLINICAL EFFECTS: Concurrent use may result in decreased levels of and effectiveness of both carbamazepine and efavirenz.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of efavirenz states that alternative agents to carbamazepine should be used in patients receiving efavirenz.(1) If concurrent use is warranted, monitor levels of both efavirenz and carbamazepine. DISCUSSION: In a study in 12 healthy subjects, administration of efavirenz (600 mg daily for 14 days) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of carbamazepine (200 mg daily for 3 days, 200 mg twice daily for 3 days, then 400 mg daily for 29 days) by 20%, 27%, and 35%, respectively. The Cmin of the epoxide metabolite of carbamazepine decreased by 13%. The Cmax, AUC, and Cmin of efavirenz decreased by 21%, 36%, and 47%, respectively.(1,2) |
CARBAMAZEPINE, CARBAMAZEPINE ER, CARBATROL, EPITOL, EQUETRO, TEGRETOL, TEGRETOL XR |
| Clopidogrel/Efavirenz; Etravirine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Clopidogrel is a prodrug and is converted to its active metabolite via a 2 step process. The first conversion step is mediated by CYP2C19, CYP1A2 and CYP2B6, while the second step is mediated by CYP3A4, CYP2B6 and CYP2C19.(1,2) CYP2C19 contributes to both steps and is thought to be the more important enzyme involved in formation of the pharmacologically active metabolite.(1) Efavirenz and etravirine may inhibit the metabolism of clopidogrel to its active form by CYP2C19.(1-4) CLINICAL EFFECTS: Concurrent use of efavirenz or etravirine may result in decreased clopidogrel effectiveness, resulting in increased risk of adverse cardiac events.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of clopidogrel states that concurrent use of inhibitors of CYP2C19, such as efavirenz or etravirine should be avoided.(1) HIV treatment guidelines from the US Department of Health and Human Services and the University of Liverpool HIV Drug Interactions database recommend not to coadminister clopidogrel with efavirenz or etravirine. Consider alternative antiretroviral or antiplatelet therapy.(4,5) The US manufacturer of etravirine recommends alternative to clopidogrel in patients maintained on etravirine.(2) The US manufacturer of clopidogrel states that alternatives to clopidogrel should be considered in patients who are poor metabolizers of CYP2C19.(1) It would be prudent to assume that patients taking strong inhibitors of CYP2C19 are poor metabolizers of this isoenzyme. Moderate CYP2C19 inhibitors, such as efavirenz or etravirine, may also affect this interaction. Consider alternatives to etravirine in patients stabilized on clopidogrel and alternatives to clopidogrel in patients stabilized on etravirine. If concurrent therapy is warranted, consider appropriate testing to assure adequate inhibition of platelet reactivity. DISCUSSION: In a randomized, cross-over study in healthy subjects, ketoconazole (another CYP2C19 inhibitor, 400 mg daily) decreased the maximum concentration (Cmax) of the active metabolite of clopidogrel (300 mg loading dose, followed by 75 mg daily) by 61%. The area-under-curve (AUC) of the active metabolite of clopidogrel was decreased by 22% following the loading dose and by 29% during maintenance dosing. Clopidogrel-induced inhibition of platelet aggregation was decreased by 28% following the loading dose and by 33% during the maintenance dose.(6) In a cross-over study in 72 healthy subjects, simultaneous administration of omeprazole (another CYP2C19 inhibitor, 80 mg daily) and clopidogrel (300 mg loading dose, followed by 75 mg daily) decreased the AUC of the active metabolite of clopidogrel by 46% following the loading dose and by 42% during maintenance dosing. Clopidogrel-induced inhibition of platelet aggregation was decreased by 47% following the loading dose and by 30% during the maintenance dose. In a cross-over study in 72 healthy subjects, administration of omeprazole (another CYP2C19 inhibitor, 80 mg daily) 12 hours after clopidogrel (300 mg loading dose, followed by 75 mg daily) produced similar effects.(1) |
CLOPIDOGREL, CLOPIDOGREL BISULFATE, PLAVIX |
| Linagliptin/Strong P-gp or CYP3A4 Inducer SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong P-gp or CYP3A4 inducers may increase the metabolism of linagliptin.(1) CLINICAL EFFECTS: Concurrent or recent use of strong P-gp or CYP3A4 inducers may result in decreased levels and effectiveness of linagliptin.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: If possible, use an alternative agent to strong P-gp or CYP3A4 inducers in patients maintained on linagliptin. If concurrent therapy is required, patients may need adjustment to their diabetes therapy, including replacement of linagliptin.(1) DISCUSSION: Concurrent rifampin (600 mg daily) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of linagliptin (5 mg daily) by 40% and 44%, respectively.(1) Strong P-gp or CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, efavirenz, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lorlatinib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(2) |
GLYXAMBI, JENTADUETO, JENTADUETO XR, TRADJENTA, TRIJARDY XR |
| Apixaban;Rivaroxaban/P-gp & Strong 3A4 Inducers;Efavirenz;PB SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Apalutamide, carbamazepine, efavirenz, fosphenytoin, phenytoin, rifampin, rifapentine, and St. John's wort may induce the metabolism of apixaban(1-4) and rivaroxaban(5) by both P-gp and CYP3A4. Phenobarbital and primidone may also induce the metabolism of apixaban and rivaroxaban.(1-5) CLINICAL EFFECTS: Concurrent or recent use of apalutamide, carbamazepine, efavirenz, fosphenytoin, phenobarbital, phenytoin, primidone, rifapentine, rifampin, or St. John's wort may result in decreased levels and effectiveness of apixaban(1-4) or rivaroxaban.(5) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of apixaban and rivaroxaban states to avoid the concurrent use of agents that are combined P-gp and strong CYP3A4 inducers (such as apalutamide, carbamazepine, efavirenz, fosphenytoin, phenytoin, rifampin, rifapentine, and St. John's wort), phenobarbital, and primidone in patients receiving apixaban or rivaroxaban. DISCUSSION: Concurrent rifampin decreased the area-under-curve (AUC) and maximum concentration (Cmax) of apixaban by 54% and 42%, respectively.(1-4) In a clinical trial, rifampin (600 mg daily) decreased the AUC and Cmax of a single dose of rivaroxaban (20 mg with food) by 50% and 22%,respectively. Similar decreases in pharmacodynamic effects were seen.(5) A self-controlled case study of 1,622 oral anticoagulant-precipitant drug pairs were reviewed and found 14% of drug pairs were associated with a statistically significant elevated risk of thromboembolism. Concurrent use of rivaroxaban and phenytoin resulted in a ratio of rate ratios (95% CI) of 2.39 (1.33-3.29).(6) |
ELIQUIS, RIVAROXABAN, XARELTO |
| Cobimetinib/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of cobimetinib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of cobimetinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with cobimetinib.(1) Consider the use of alternatives with little to no induction potential. DISCUSSION: Based upon simulations, coadministration of cobimetinib with a strong CYP3A4 inducer may decrease cobimetinib exposure by 83%, with a moderate CYP3A4 inducer by 73%, leading to a reduction in efficacy.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, cenobamate, encorafenib, enzalutamide, ivosidenib, lorlatinib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: bosentan, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(1-3) |
COTELLIC |
| Selected Hepatitis C Agents/Efavirenz; Etravirine;Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz, etravirine, and nevirapine may induce the metabolism of boceprevir,(1,2) telaprevir,(2,3) simeprevir,(4) velpatasvir(5,6) voxilaprevir, glecaprevir(7), and pibrentasvir(7) via CYP3A4. Efavirenz may also decrease absorption of these agents through the P-glycoprotein (P-gp) transporter. CLINICAL EFFECTS: Concurrent use of efavirenz, etravirine, or nevirapine(1,2) may result in decreased levels and effectiveness of boceprevir,(3,4) telaprevir,(4,5) simeprevir,(6) velpatasvir,(6,7) voxilaprevir,(8) glecaprevir,(9) and pibrentasvir(9). PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the concurrent use of boceprevir and efavirenz.(3,4) The concurrent use of efavirenz, etravirine, or nevirapine(1,2) with simeprevir,(6) velpatasvir,(6,7) voxilaprevir,(8) glecaprevir,(9) and pibrentasvir(9) is not recommended. If concurrent therapy is warranted, monitor patients for decreased response to boceprevir,(3,4) telaprevir,(4,5) simeprevir,(6) velpatasvir,(6,7) voxilaprevir,(8) glecaprevir,(9) and pibrentasvir(9). The Swedish manufacturer of telaprevir recommends that the dose of telaprevir be increased to 1125 mg every 8 hours when used concurrently with efavirenz.(10) DISCUSSION: In a study, concurrent efavirenz (600 mg daily for 16 days) decreased the the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of boceprevir (800 mg 3 times daily for 6 days) by 8%, 19%, and 44%, respectively. Efavirenz Cmax and AUC increased by 11% and 20%, respectively.(3,4) In a study in 21 subjects, efavirenz (600 mg daily for 20 days) decreased the Cmax, AUC, and Cmin of telaprevir (750 mg every 8 hours for 10 days) by 9%, 26%, and 47%, respectively. The Cmax, AUC, and Cmin of efavirenz decreased by 16%, 7%, and 2%, respectively.(4,5) In a study in 15 subjects, concurrent telaprevir (1125 mg every 8 hours for 7 days), tenofovir (300 mg daily for 7 days), and efavirenz (600 mg daily for 7 days) decreased telaprevir Cmax, AUC, and Cmin by 14%, 18%, and 25%, respectively. Efavirenz Cmax, AUC, and Cmin decreased by 24%, 18%, and 10%, respectively.(5) In a study in 16 subjects, concurrent telaprevir (1500 mg every 8 hours for 7 days), tenofovir (300 mg daily for 7 days), and efavirenz (600 mg daily for 7 days) decreased telaprevir Cmax, AUC, and Cmin by 3%, 20%, and 48%, respectively. Efavirenz Cmax, AUC, and Cmin decreased by 20%, 15%, and 11%, respectively.(5) In a study in 23 subjects, efavirenz (600 mg daily for 14 days) decreased the Cmax, AUC, and Cmin of simeprevir (150 mg daily for 14 days) by 51%, 71%, and 91%, respectively.(4,6) In a study in 23 subjects, simeprevir (150 mg daily for 14 days) decreased the AUC and Cmin of efavirenz (600 mg daily for 14 days) by 10% and 13%, respectively.(4) In an interaction study, efavirenz 600 mg daily (in combination with emtricitabine-tenofovir DF) decreased velpatasvir Cmax, AUC, and Cmin 47%, 53% and 57% respectively.(7,8) |
EPCLUSA, MAVYRET, SOFOSBUVIR-VELPATASVIR, VOSEVI |
| Canagliflozin/UGT Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: UGT inducers may induce the metabolism of canagliflozin, which is glucuronidated by UGT1A9 and UGT2B4.(1) CLINICAL EFFECTS: Concurrent use of an inducer of UGT may result in decreased levels and effectiveness of canagliflozin.(1) PREDISPOSING FACTORS: This interaction may be more severe in patients who have a eGFR of less than 60 ml/min/1.73m2.(1) PATIENT MANAGEMENT: In patients with a eGFR of 60 ml/min/1.73m2 or more who are currently tolerating canagliflozin 100 mg daily and require therapy with an inducer of UGT, the manufacturer of canagliflozin recommends increasing the dose of canagliflozin to 200 mg daily. Patients currently tolerating canagliflozin 200 mg daily and require additional glycemic control may have their dose increased to 300 mg daily.(1) In patients with a eGFR of less than 60 ml/min/1.73m2 who are currently tolerating canagliflozin 100 mg daily and receiving therapy with a UGT inducer, increase the dose of canagliflozin to 200 mg daily. Consider other antihyperglycemic agents in patients who require additional glycemic control.(1) DISCUSSION: Pretreatment with rifampin (600 mg daily for 8 days) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of a single dose of canagliflozin (300 mg) by 51% and 28%, respectively.(1) Inducers of UGT include: carbamazepine, efavirenz, etravirine, fosphenytoin, lorlatinib, phenobarbital, phenytoin, primidone, rifampin, and ritonavir.(1) |
INVOKAMET, INVOKAMET XR, INVOKANA |
| Dolutegravir/Etravirine; Efavirenz; Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Etravirine, efavirenz, and nevirapine may induce the metabolism of dolutegravir via CYP3A4.(1,2) Efavirenz may also induce dolutegravir metabolism via UGT enzymes. CLINICAL EFFECTS: Concurrent use of etravirine, efavirenz, or nevirapine and dolutegravir may result in decreased levels of and clinical effectiveness of dolutegravir.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of dolutegravir states that dolutegravir should not be used with etravirine without atazanavir/ritonavir (ATVr), darunavir/ritonavir (DRVr), or lopinavir/ritonavir (LPVr).(1) The Canadian(3) and UK(4) manufacturers of dolutegravir state that INSTI-naive patients may use etravirine concurrently with dolutegravir at an increased dose of 50 mg twice daily. In pediatric patients, the weight-based once daily dose should be given twice daily. No dose adjustment for dolutegravir is needed when used with etravirine along with concurrent ATVr, DRVr, or LPVr.(1,3-5) When used with efavirenz, the dosage of dolutegravir should be 50 mg twice daily.(1,2) When using the combination abacavir-dolutegravir-lamivudine product, an additional 50 mg dolutegravir table should be taken 12 hours apart from the combination product.(2) Alternative combinations that do not induce metabolic inducers should be considered when possible for INSTI-experience patients with certain INSTI-associated resistance substitutions or clinically suspected INSTI resistance. In pediatric patients, increase the weight-based dose to twice daily. Refer to the current labeling for the specific dosing recommendation.(1) Although the US(1) and Canadian(3) manufacturers of dolutegravir recommend avoiding concurrent use of nevirapine, the US Department of Health and Human Services HIV guidelines recommend standard doses of dolutegravir when administered concurrently with nevirapine.(5) The UK manufacturer of dolutegravir recommends increasing the dose of dolutegravir to 50 mg twice daily when used concurrently with nevirapine.(4) DISCUSSION: In a study in 12 subjects, the administration of efavirenz with dolutegravir (50 mg daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of dolutegravir by 39%, 57%, and 75%, respectively.(1) In a study in 16 subjects, the administration of etravirine with dolutegravir (50 mg daily) decreased the Cmax, AUC, and Cmin of dolutegravir by 52%, 71%, and 88%, respectively.(1) In a study in 9 subjects, the administration of etravirine and darunavir/ritonavir (200 mg and 600/100 mg BID) with dolutegravir (50 mg daily) decreased the Cmax, AUC, and Cmin of dolutegravir by 12%, 25%, and 37%, respectively.(1) In a study in 8 subjects, the administration of efavirenz and lopinavir/ritonavir (200 mg and 400/100 mg BID) with dolutegravir (50 mg daily) increased the Cmax, AUC, and Cmin of dolutegravir by 7%, 11%, and 28%, respectively.(1) |
DOVATO, JULUCA, TIVICAY, TIVICAY PD, TRIUMEQ, TRIUMEQ PD |
| Guanfacine/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate inducers of CYP3A4 may induce the metabolism of guanfacine.(1) CLINICAL EFFECTS: The concurrent administration of a strong or moderate CYP3A4 inducer may result in decreased levels and effectiveness of guanfacine.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Patients maintained on guanfacine may need dosage adjustments if strong or moderate inducers of CYP3A4 are initiated or discontinued. The manufacturer of extended-release guanfacine recommends a starting dose of extended-release guanfacine initiated at up to double the recommended level of the weight based dosing in patients receiving strong or moderate inducers of CYP3A4. If a patient has been maintained on extended-release guanfacine and is started on a strong or moderate CYP3A4 inducer, the dose of extended-release guanfacine should be increased up to double the recommended weight based dose over 1 to 2 weeks. If a patient has been maintained on extended-release guanfacine and a strong or moderate CYP3A4 inducer, and the strong or moderate CYP3A4 inducer is discontinued, the dose of extended-release guanfacine may need to be decreased to the recommended weight based dose over 1 to 2 weeks. Extended-release guanfacine target dose range for attention deficit hyperactivity disorder is 0.05-0.12 mg/kg/day. Doses above 4 mg/day have not been evaluated in children ages 6-12 years and doses above 7 mg/day have not been evaluated in adolescents ages 13-17 years.(1) DISCUSSION: Rifampin (dosage not stated), a strong inducer of CYP3A4, decreased the maximum concentration (Cmax) and area-under-curve (AUC) of guanfacine (dosage not stated) by approximately 50%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(1-3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat, thioridazine, and tovorafenib.(1-3) |
GUANFACINE HCL, GUANFACINE HCL ER, INTUNIV |
| Esomeprazole; Omeprazole/Select CYP2C19 and CYP3A4 Inducer SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Proton pump inhibitors are primarily metabolized by CYP2C19, while CYP3A4 also plays a role in metabolism.(1,2) Enzalutamide, rifampin, and St. John's wort are moderate inducers of CYP2C19 and strong inducers of CYP3A4.(3,4) Apalutamide is a strong inducer of CYP2C19 and CYP3A4.(5) Efavirenz and pacritinib are moderate inducers of CYP2C19 and CYP3A4.(3,6) CLINICAL EFFECTS: Concurrent use of agents which induce both CYP2C19 and CYP3A4 decrease systemic exposure and may result in decreased effectiveness of proton pump inhibitors.(1-7) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concurrent use of esomeprazole or omeprazole with CYP2C19 or CYP3A4 inducers.(1,2) Monitor patients receiving concurrent therapy for reduced proton pump inhibitor (PPI) effectiveness. Although specific dosing recommendations are not available, a higher dose of the proton pump inhibitor may be considered to maintain PPI efficacy. DISCUSSION: In an interaction study, subjects with prostate cancer received omeprazole before and after enzalutamide 160 mg daily for at least 55 days. Enzalutamide decreased omeprazole area-under-curve (AUC) by 70.5%.(3,4) In an interaction study, rifampin 600 mg daily for 7 days decreased omeprazole AUC by 89.5%.(3,7) In an interaction study, pacritinib 200 mg twice daily at steady state decreased the maximum concentration (Cmax) and AUC of a single dose of omeprazole (20 mg) by 27% and 51%, respectively. In an interaction study, St. John's wort decreased the maximum concentration (Cmax) and AUC of omeprazole by 37.5% and 49.6%, respectively. The Cmax and AUC of omeprazole sulfone (via CYP2C19) increased by 160.3% and 136.6%, respectively. The Cmax and AUC of 5-hydroxyomeprazole (via CYP3A4) increased by 38.1% and 37.2%, respectively.(8,9) |
ESOMEPRAZOLE MAGNESIUM, ESOMEPRAZOLE SODIUM, KONVOMEP, NAPROXEN-ESOMEPRAZOLE MAG, NEXIUM, OMECLAMOX-PAK, OMEPRAZOLE, OMEPRAZOLE-SODIUM BICARBONATE, PRILOSEC, TALICIA, VIMOVO, YOSPRALA |
| Artemether; Lumefantrine/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of artemether and lumefantrine via CYP3A4. Both artemether-lumefantrine and efavirenz can prolong the QT interval and may result in additive risk of QT prolongation.(1-3) CLINICAL EFFECTS: Concurrent use of CYP3A4 inducers with artemether and lumefantrine may result in decreased levels and effectiveness of the antimalarial agents and treatment failure. Concurrent use may also cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturers of artemether-lumefantrine and Atripla (efavirenz/tenofovir/emtricitabine) state that caution should be used with concurrent use of artemether-lumefantrine because decreased artemether, dihydroartemisinin, and lumefantrine concentrations may result in decreased antimalarial efficacy of artemether-lumefantrine.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study in 6 subjects, administration of rifampin (600 mg daily, a potent inducer of CYP3A4) with artemether-lumefantrine (6 dose regimen over 3 days) decreased the area-under-curve (AUC) of artemether, dihydroartemisinin (DHA), and lumefantrine by 89%, 85%, and 68%, respectively.(1) In a study in 12 subjects, administration of efavirenz (600 mg daily for 26 days) with artemether-lumefantrine (6 dose regimen over 3 days) decreased the AUC of artemether, dihydroartemisinin, and lumefantrine by 51%, 46%, and 21%, respectively.(2) |
COARTEM |
| Cobicistat-Boosted Darunavir/Efavirenz;Etravirine;Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz, etravirine, and nevirapine may induce the metabolism of darunavir and cobicistat via CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent use of efavirenz, etravirine, or nevirapine may may result in altered and/or suboptimal pharmacokinetics of cobicistat, resulting in subtherapeutic levels of darunavir.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Cobicistat boosted darunavir should not be coadministered with efavirenz, etravirine, or nevirapine.(1,2) Note that there is no clinically significant interaction between ritonavir-boosted darunavir and efavirenz, etravirine, or nevirapine, and no dose adjustments are recommended.(2,3) DISCUSSION: Concurrent use of efavirenz, etravirine, or nevirapine with cobicistat boosted darunavir may result in altered and/or suboptimal pharmacokinetics of cobicistat(1,2) In a study of 30 HIV-positive patients, darunavir 800 mg once daily and cobicistat 150 mg once daily administered with etravirine 400 mg once daily resulted in no change to darunavir AUC and Cmax but a 56 % decrease in Cmin. Cobicistat AUC, Cmax, and Cmin decreased 30 %, 14 % and 66 %, respectively.(4) |
DARUNAVIR, PREZCOBIX, PREZISTA, SYMTUZA |
| Selected Nephrotoxic Agents/Foscarnet SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Foscarnet is nephrotoxic. Concurrent administration of other nephrotoxic agents may result in additive or synergistic effects on renal function.(1) Concurrent intravenous pentamidine may also result in hypocalcemia.(1) CLINICAL EFFECTS: Concurrent use of foscarnet with nephrotoxic agents such as acyclovir, adefovir, intravenous aminoglycosides, amphotericin B, cyclosporine, methotrexate, non-steroidal anti-inflammatory agents, intravenous pentamidine, tacrolimus, tenofovir, vancomycin and voclosporin may result in renal toxicity.(1) Other nephrotoxic agents include capreomycin, cisplatin, gallium nitrate, high-dose methotrexate, and streptozocin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of foscarnet state that concurrent administration of potentially nephrotoxic agents such as acyclovir, intravenous aminoglycosides, amphotericin B, cyclosporine, methotrexate, tacrolimus, and intravenous pentamidine should be avoided.(1) Other nephrotoxic agents include adefovir, capreomycin, cisplatin, gallium nitrate, high-dose methotrexate, non-steroidal anti-inflammatory agents, streptozocin, tenofovir, vancomycin and voclosporin. If concurrent therapy is warranted, monitor renal function closely. In patients receiving concurrent foscarnet and pentamidine, also monitor serum calcium levels and instruct patients to report severe muscle spasms, mental/mood changes, and/or seizures.(1) DISCUSSION: The safety of foscarnet has not been studied in patients receiving other known potentially nephrotoxic agents. Renal impairment is the major toxicity of foscarnet.(1) |
FOSCARNET SODIUM, FOSCAVIR |
| Atovaquone; Proguanil/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The mechanism of interaction between atovaquone and efavirenz is unknown. Efavirenz, an inducer of CYP2C19, may induce the metabolism of proguanil.(1,2) CLINICAL EFFECTS: Concurrent use of CYP2C19 inducers with atovaquone and proguanil may result in decreased levels and effectiveness of the antimalarial agents and treatment failure.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concomitant administration of atovaquone/proguanil with efavirenz is not recommended and may result in decreased levels of atovaquone and proguanil.(1) Monitor patients for signs of treatment failure. DISCUSSION: In a study of 30 human immunodeficiency virus (HIV)-infected subjects enrolled in three treatment arms (10 taking no antiretroviral therapy, 10 taking combination antiretroviral therapy including efavirenz, and 10 taking combination antiretroviral therapy with atazanavir/ritonavir) received atovaquone 750 mg BID for 14 days followed by atovaquone 1500 mg BID for 14 days, or vice-versa, with a washout period in between. The subjects on a combination antiretroviral regimen including efavirenz had a 47% and 44% lower atovaquone area-under-curve (AUC) on both dosing regimens, 750 mg BID and 1500 mg BID, respectively (p<0.01). Concentrations of atovaquone required to successfully treat Pneumocystis jiroveci pneumonia (average Concentration > 15 mcg/ml) were achieved in 50% of the subjects receiving an efavirenz based regimen. Concentrations of atovaquone required to successfully treat Toxoplasma encephalitis (average Concentration > 18.5 mcg/ml) were achieved in 20% of the subjects receiving an efavirenz based regimen with atovaquone 750 mg BID.(3) In a study of 76 HIV-infected patients, 18 healthy volunteers, 20 patients with efavirenz, 19 patients with lopinavir/ritonavir, or 19 patients with atazanavir/ritonavir received a single dose of atovaquone/proguanil 250/100 mg dose. The geometric mean ration (GMR) [95% confidence interval] AUC and maximum concentration (Cmax) for atovaquone, respectively, were 0.25 and 0.56 for patients on efavirenz, 0.26 and 0.56 for patients on lopinavir/ritonavir, and 0.54 and 0.51 for patients on atazanavir/ritonavir. Proguanil concentrations after adjustment for confounders including CYP2C19 genotype resulted in the GMR AUC of 0.57 for patients on efavirenz, 0.62 for patients on lopinavir/ritonavir, and 0.59 for patients on atazanavir/ritonavir. The Cmax for proguanil was unchanged in all three groups compared to healthy controls.(4) |
ATOVAQUONE, ATOVAQUONE-PROGUANIL HCL, MALARONE, MEPRON |
| Cobicistat/Tenofovir disoproxil SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. CLINICAL EFFECTS: Coadministration of cobicistat with tenofovir disoproxil increases the risk of new onset or worsening renal impairment including acute renal failure and Fanconi syndrome.(1-10) PREDISPOSING FACTORS: Patients with impaired baseline renal function or who are receiving concomitant nephrotoxic agents may have an increased risk of renal-related adverse events.(1-10) PATIENT MANAGEMENT: The Canadian, UK, and US manufacturers of atazanavir/cobicistat, cobicistat and darunavir/cobicistat do not recommend coadministration with tenofovir disoproxil fumarate (DF) in patents with a creatinine clearance (CrCl) below 70 ml/min or with concomitant or recent use of an additional nephrotoxic agent.(2-10) In patients receiving concurrent therapy, check glucose and urine protein at baseline and routinely monitor CrCl, urine glucose, urine protein, and serum phosphorus. Discontinue concurrent therapy if CrCl decreases below 70 ml/min.(2-10) DISCUSSION: Renal toxicity has been documented with coadministration of cobicistat with tenofovir disoproxil fumarate (DF) but not tenofovir alafenamide (AF). Monitoring of renal function is prudent and discontinuation is recommended when CrCl decreases below 70 ml/min to avoid renal impairment.(1-10) |
EVOTAZ, PREZCOBIX, TYBOST |
| Orlistat/Selected Antiretrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. Orlistat may reduce the absorption of lipophilic antiretroviral HIV drugs by retention in the gastrointestinal tract or reduced gastrointestinal tract transit time. CLINICAL EFFECTS: The concurrent administration of orlistat and atazanavir, efavirenz, emtricitabine, maraviroc, ritonavir, or tenofovir may result in a decrease in the levels and clinical effects of the antiretroviral, including loss of virological control.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: HIV RNA levels should be frequently monitored in patients taking orlistat while being treated for HIV infection. If there is a confirmed increase in HIV viral load, orlistat should be discontinued.(1) DISCUSSION: Loss of virological control has been reported in HIV-infected patients taking orlistat concomitantly with lipophilic antiretroviral drugs.(1) There are three case reports of patients having an increased HIV viral load after taking orlistat concomitantly with their HIV therapy.(2-4) Antiretrovirals included in this monograph are atazanavir, efavirenz, emtricitabine, maraviroc, ritonavir, and tenofovir. |
ORLISTAT, XENICAL |
| Venetoclax/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of venetoclax.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of venetoclax.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of venetoclax states that the concurrent use of CYP3A4 inducers should be avoided, and that alternative treatments with less CYP3A4 induction should be considered.(1) DISCUSSION: In a study with 10 healthy subjects, co-administration of rifampin (600 mg daily for 13 days), decreased venetoclax area-under-curve (AUC) by 71% and maximum concentration (Cmax) by 42%.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, telotristat, thioridazine, tipranavir/ritonavir, and tovorafenib.(2-3) |
VENCLEXTA, VENCLEXTA STARTING PACK |
| Deoxycytidine Kinase Substrates/Cladribine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Clofarabine, cytarabine, emtricitabine, fludarabine, gemcitabine, lamivudine, molnupiravir, nelarabine and zalcitabine may inhibit the intracellular phosphorylation of cladribine by deoxycytidine kinase (dCK). CLINICAL EFFECTS: Concurrent administration of clofarabine, cytarabine, emtricitabine, fludarabine, gemcitabine, lamivudine, molnupiravir, nelarabine, or zalcitabine with cladribine may result in decreased clinical efficacy of cladribine. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lamivudine states that the concurrent use of lamivudine and cladribine is not recommended.(1) The manufacturer of cladribine states that concurrent use of compounds that require activation by intracellular phosphorylation should be avoided.(2) DISCUSSION: Cladribine undergoes a series of phosphorylations to its active metabolites. In a case report, a patient on lamivudine who received cladribine concurrently did not experience a decrease in his lymphocyte count. After discontinuation of lamivudine and readministration of cladribine, his lymphocytes dropped as expected.(3) It is expected that other compounds phosphorylated by dCK would also decrease cladribine's efficacy.(4) Compounds phosphorylated by dCK include: clofarabine, cytarabine, emtricitabine, fludarabine, gemcitabine, lamivudine, molnupiravir, nelarabine and zalcitabine. |
CLADRIBINE, MAVENCLAD |
| Etoposide/P-glycoprotein (P-gp) Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Etoposide is a substrate of the efflux transporter P-glycoprotein (P-gp).(1-5) P-gp induction may decrease cellular concentrations of etoposide, increase biliary or renal elimination of etoposide, and decrease systemic absorption of oral etoposide. CLINICAL EFFECTS: Concurrent or recent use of P-glycoprotein inducers may result in decreased levels and effectiveness of etoposide. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concurrent use of an inducer of P-gp such as apalutamide, carbamazepine, lorlatinib, phenytoin, rifampin, rifapentine, or St. John's wort in patients treated with etoposide and consider use of alternative agents when possible. If therapy with a P-gp inducer is required, consider therapeutic drug monitoring of etoposide to assure treatment efficacy. The time to maximal induction may be delayed 1-2 weeks depending upon the half-life and dose of the inducer. After discontinuation of the inducer the offset of induction is also gradual. DISCUSSION: This monograph is based upon the relatively recent understanding of the role of transporters in the absorption, distribution and elimination of etoposide.(1-3) Apalutamide, carbamazepine, efavirenz, fosphenytoin, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, and St. John's wort induce production of P-gp which may lead to decreased systemic or cellular exposure to etoposide. |
ETOPOPHOS, ETOPOSIDE |
| Neratinib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inducers of CYP3A4 may induce the metabolism of neratinib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may result in decreased effectiveness of neratinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of neratinib with strong or moderate inducers of CYP3A4.(1) If concurrent use is warranted, monitor patients closely for decreased neratinib effectiveness. DISCUSSION: Rifampin, a strong CYP3A4 inducer, decreased maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of neratinib (240 mg) by 76% and 87%, respectively.(1) Strong CYP3A4 inducers include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine and St. John's wort.(1,2) Moderate CYP3A4 inducers include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat, thioridazine, and tovorafenib.(1,2) |
NERLYNX |
| Sorbitol/Lamivudine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Sorbitol increases the osmotic pressure in the intestine, resulting in accelerated small intestinal transit time and decreased absorption and bioavailability of lamivudine. CLINICAL EFFECTS: Concurrent administration of sorbitol and lamivudine may result in decreased clinical efficacy of lamivudine.(1) Reduction in lamivudine exposure is sorbitol dose-dependent. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lamivudine states that the concurrent use of lamivudine and sorbitol should be avoided.(1) Consider more frequent monitoring of HBV viral load when chronic coadministration cannot be avoided. DISCUSSION: In an open label, randomized sequence, 4-period, crossover trial in 16 healthy adults, coadministration of a single dose of lamivudine (300 mg) with sorbitol (3.2 grams) resulted in a dose-dependent decrease of lamivudine's area-under-the-curve (AUC(0-24), AUC infinity) and maximum concentration (Cmax) of 20%, 28%, and 28%. A single dose of lamivudine with sorbitol (10.2 grams) resulted in a decrease of lamivudine's AUC and Cmax of 39%, 52%, and 52%. A single dose of lamivudine with sorbitol (13.4 grams) resulted in a decrease of lamivudine's AUC and Cmax of 36%, 55%, and 55%.(1) |
KIONEX, SPS |
| Slt Proton Pump Inhibitors/Strong 2C19 and 3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong CYP2C19 and CYP3A4 inducers may induce the metabolism of dexlansoprazole, lansoprazole, or pantoprazole.(1-3) CLINICAL EFFECTS: Concurrent use of strong CYP2C19 and CYP3A4 inducers may decrease systemic levels and effectiveness of lansoprazole, dexlansoprazole, or pantoprazole.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturers of lansoprazole and dexlansoprazole recommend avoiding concurrent use of CYP2C19 or CYP3A4 inducers.(1,2) Although the manufacturer of pantoprazole does not mention an interaction with CYP2C19 inducers, pantoprazole is also a substrate of CYP2C19 and CYP3A4.(3) If concurrent therapy is warranted, monitor closely for loss of efficacy. Although specific dosing recommendations are not available, a higher dose of the proton pump inhibitor may be considered to maintain PPI efficacy. DISCUSSION: Decreased exposure of lansoprazole, dexlansoprazole, or pantoprazole is expected when used concomitantly with strong CYP2C19 and CYP3A4 inducers. Strong CYP2C19 and CYP3A4 inducers linked to this monograph include: apalutamide, efavirenz, enzalutamide, fosphenytoin, phenytoin, rifampin, and St. John's Wort.(4,5) |
DEXILANT, DEXLANSOPRAZOLE DR, LANSOPRAZOL-AMOXICIL-CLARITHRO, LANSOPRAZOLE, PANTOPRAZOLE SODIUM, PANTOPRAZOLE SODIUM-0.9% NACL, PREVACID, PROTONIX, PROTONIX IV |
| Abemaciclib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Abemaciclib is a substrate of CYP3A4. Moderate inducers of CYP3A4 may induce the metabolism of abemaciclib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of abemaciclib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of abemaciclib states to avoid concurrent administration with moderate CYP3A4 inducers and consider alternative agents.(1) DISCUSSION: Abemaciclib is a substrate of CYP3A4.(1) Concurrent administration of rifampin (600 mg once daily, a strong CYP3A4 inducer) with a single 200 mg dose of abemaciclib decreased the relative potency adjusted unbound area-under-curve (AUC) of abemaciclib and its active metabolites (M2, M18, and M20) by 70% in healthy subjects.(1) Concurrent administration of efavirenz, bosentan, and modafinil (moderate CYP3A4 inducers) are predicted to decrease the relative potency adjusted unbound AUC of abemaciclib and its active metabolites (M2, M18, and M20) by 53%, 41%, and 29%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, tipranavir/ritonavir and tovorafenib.(2,3) |
VERZENIO |
| Doravirine/Efavirenz;Etravirine;Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz, etravirine, and nevirapine may induce the metabolism of doravirine via CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of efavirenz, etravirine, or nevirapine may result in subtherapeutic levels of doravirine.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Coadministration of doravirine with efavirenz, etravirine, or nevirapine is not recommended.(1) DISCUSSION: In a study in 17 healthy subjects, coadministration of efavirenz (600 mg daily) with a single dose of doravirine (100 mg) decreased doravirine's area-under-curve (AUC), maximum concentration (Cmax), and 24 hour concentration (C24) by 62%, 35%, and 85%, respectively.(1) |
DELSTRIGO, PIFELTRO |
| Lorlatinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 are expected to increase the metabolism of lorlatinib.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate inducers of CYP3A4 may result in decreased levels and effectiveness of lorlatinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concurrent administration of moderate inducers of CYP3A4 with lorlatinib.(1) If concurrent use of lorlatinib and moderate CYP3A4 inducers cannot be avoided, increase the dose of lorlatinib to 125 mg daily.(1) DISCUSSION: Modafinil (a moderate CYP3A4 inducer) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of a single 100 mg dose of lorlatinib by 23% and 22%, respectively.(1) Moderate inducers of CYP3A4 include belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, modafinil, nafcillin, pacritinib, pexidartinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(1) |
LORBRENA |
| Brigatinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Brigatinib is a substrate of CYP3A4. Moderate inducers of CYP3A4 may induce the metabolism of brigatinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of brigatinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of brigatinib states to avoid concurrent administration with moderate CYP3A4 inducers. If concurrent use cannot be avoided, increase the daily dose of brigatinib in 30 mg increments every 7 days, as tolerated, to a maximum of twice the brigatinib dose that was tolerated prior to initiation of the moderate CYP3A4 inducer. After discontinuation of a moderate CYP3A4 inducer, resume the brigatinib dose that was tolerated prior to initiation of the inducer.(1) DISCUSSION: Brigatinib is a substrate of CYP3A4.(1) Concurrent administration of rifampin (600 mg daily, a strong CYP3A4 inducer) with a single 180 mg dose of brigatinib decreased the brigatinib maximum concentration (Cmax) by 60% and area-under-curve (AUC) by 80% compared to brigatinib alone. Moderate CYP3A4 inducers are expected to decrease the AUC of brigatinib by 50%.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat ethyl, thioridazine, tipranavir/ritonavir and tovorafenib.(2-3) |
ALUNBRIG |
| Erdafitinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Erdafitinib is a substrate of CYP2C9 and CYP3A4. Moderate inducers of CYP3A4 may induce the metabolism of erdafitinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of erdafitinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of erdafitinib states that if a moderate CYP3A4 inducer must be co-administered, increase the erdafitinib dose to 9 mg daily. If a moderate CYP3A4 inducer is discontinued, continue erdafitinib at the same dose in the absence of drug-related toxicity.(1) DISCUSSION: Carbamazepine (a strong CYP3A4 inducer and weak CYP2C9 inducer) decreased the mean maximum concentration (Cmax) and area-under-curve (AUC) of erdafitinib by 78% and 45%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
BALVERSA |
| Darolutamide/P-gp and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that are combined P-gp and moderate CYP3A4 inducers may induce the metabolism of darolutamide by both pathways.(1) CLINICAL EFFECTS: Concurrent or recent use of inducers of both P-gp and CYP3A4 may result in decreased levels and effectiveness of darolutamide.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: If possible, avoid the concurrent use of agents that are combined P-gp and moderate CYP3A4 inducers in patients receiving darolutamide.(1) DISCUSSION: Concurrent rifampin (combined P-gp and strong CYP3A4 inducer) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of darolutamide by 72% and 52%, respectively. Combined P-gp and moderate CYP3A4 inducers are expected to decrease the AUC by 36-58%.(1) Agents that are combined P-gp and moderate CYP3A4 inducers linked to this monograph include: efavirenz, lorlatinib and rifabutin.(2) |
NUBEQA |
| Pretomanid/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may induce the metabolism of pretomanid by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and pretomanid may result in decreased levels and clinical effectiveness of pretomanid.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of pretomanid recommends avoiding concurrent use with strong or moderate CYP3A4 inducers during pretomanid therapy.(1) Patients receiving concurrent therapy with strong and moderate CYP3A4 inducers and pretomanid should be observed for decreased levels and clinical effectiveness. DISCUSSION: In a clinical study, concurrent use of pretomanid 200 mg with efavirenz 600 mg for 7 days resulted in decreased mean area-under-curve (AUC) by 35% and maximum concentration (Cmax) by 28%.(1) In a clinical study, concurrent use of pretomanid 200 mg with rifampin 600 mg for 7 days resulted in decreased mean AUC by 66% and Cmax by 53%.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(1,2) |
PRETOMANID |
| Fedratinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Fedratinib is a substrate of CYP3A4. Moderate inducers of CYP3A4 may induce the metabolism of fedratinib.(1) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of fedratinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of fedratinib states that concurrent use with moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Coadministration of efavirenz (moderate CYP3A4 inducer: 600 mg once daily) with a single dose of fedratinib (500 mg; 1.25 times the recommended dose) decreased the area-under-curve (AUC) of fedratinib by approximately 47%.(1) Moderate inducers of CYP3A4 include: belzutifan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(2-3) |
INREBIC |
| Letermovir/P-glycoprotein (P-gp) or UGT Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Letermovir is a substrate of the efflux transporter P-glycoprotein (P-gp) and of UDP-glucuronosyltransferase (UGT) 1A1/3 enzymes. P-gp induction may decrease systemic absorption of letermovir, while UGT1A1/3 induction may increase the metabolism of letermovir.(1) CLINICAL EFFECTS: Concurrent or recent use of P-glycoprotein or UGT1A1/3 inducers may result in decreased levels and loss of effectiveness of letermovir. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of letermovir states that coadministration of P-gp inducers or UGT1A1/3 inducers is not recommended. DISCUSSION: In a study, at 24 hours after the last dose of rifampin (600 mg daily), the AUC of letermovir was decreased by 85 %, compared to letermovir when taken alone.(1) Inducers of P-glycoprotein or of UGT1A1/3 linked to this monograph include: apalutamide, efavirenz, etravirine, fosphenytoin, lorlatinib, phenobarbital, phenytoin, primidone, rifampin, rifapentine, ritonavir, and St. John's wort.(2) |
PREVYMIS |
| Daridorexant/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Daridorexant is a substrate of CYP3A4. Strong or moderate inducers of CYP3A4 may induce the metabolism of daridorexant.(1) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of daridorexant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of daridorexant states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Concomitant use of rifampin, a strong CYP3A4 inducer, with daridorexant 50 mg decreased daridorexant area-under-curve (AUC) by more than 50%. Efavirenz 600 mg, a moderate CYP3A4 inducer, decreased daridorexant AUC and maximum concentration (Cmax) by 60% and 40%, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
QUVIVIQ |
| Lumateperone/CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lumateperone is a substrate of CYP3A4. Inducers of CYP3A4 may induce the metabolism of lumateperone.(1) CLINICAL EFFECTS: The concurrent administration of a CYP3A4 inducer may decrease the exposure to lumateperone.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of lumateperone states that concurrent use with CYP3A4 inducers should be avoided.(1) DISCUSSION: Coadministration of lumateperone with rifampin, a strong CYP3A4 inducer, resulted in a 98% reduction in area-under-curve (AUC) and a 90% reduction in concentration maximum (Cmax).(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, repotrectinib, rifabutin, telotristat, thioridazine, and tovorafenib.(2,3) Weak inducers of CYP3A4 include: amprenavir, armodafinil, bexarotene, brivaracetam, clobazam, danshen, darolutamide, dexamethasone, dicloxacillin, echinacea, eslicarbazepine, garlic, genistein, gingko, ginseng, glycyrrhizin, nevirapine, omaveloxolone, oxcarbazepine, pioglitazone, quercetin, rufinamide, sotorasib, sulfinpyrazone, tecovirimat, terbinafine, ticlopidine, troglitazone, vemurafenib, and vinblastine.(2,3) |
CAPLYTA |
| Avapritinib/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate CYP3A4 inducers may induce the metabolism of avapritinib. CLINICAL EFFECTS: Coadministration of avapritinib with a strong or moderate CYP3A4 inducer decreases avapritinib plasma concentrations, which may decrease efficacy of avapritinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of avapritinib states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Coadministration of avapritinib 400 mg as a single dose with rifampin 600 mg daily, a strong CYP3A4 inducer, decreased avapritinib concentration maximum (Cmax) by 74% and area-under-curve (AUC) by 92%.(1) Coadministration of avapritinib 300 mg once daily with efavirenz 600 mg once daily, a moderate CYP3A4 inducer, is predicted to decrease avapritinib Cmax by 55% and AUC by 62% at steady state.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine and tovorafenib.(2,3) |
AYVAKIT |
| Ibrutinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of ibrutinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may decrease the levels and effectiveness of ibrutinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of moderate CYP3A4 inducers in patients receiving therapy with ibrutinib.(1) Consider the use of alternative agents with less enzyme induction potential.(1) DISCUSSION: The coadministration of rifampin decreased the maximum concentration (Cmax) and area-under-curve (AUC) of ibrutinib by more than 13-fold and 10-fold.(1) In a pharmacokinetic model, efavirenz (600 mg daily), a moderate CYP3A4 inducer, was predicted to decrease the Cmax and AUC of ibrutinib (560 mg) by 2.4-fold and 2.5-fold, respectively.(2) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(4) |
IMBRUVICA |
| Tazemetostat/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate CYP3A4 inducers may induce the metabolism of tazemetostat.(1) CLINICAL EFFECTS: Coadministration of tazemetostat with a strong or moderate CYP3A4 inducer may decrease tazemetostat plasma concentrations, which may decrease the efficacy of tazemetostat.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of tazemetostat says to avoid coadministration of strong or moderate CYP3A4 inducers with tazemetostat.(1) DISCUSSION: Tazemetostat is a known substrate of CYP3A4. According to the manufacturer, coadministration with a strong or moderate CYP3A4 inducer may decrease tazemetostat plasma concentrations which may decrease the efficacy of tazemetostat. No clinical studies have been conducted.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
TAZVERIK |
| Rimegepant/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of rimegepant by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and rimegepant may result in decreased levels and clinical effectiveness of rimegepant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of rimegepant recommends avoiding concurrent use with strong or moderate CYP3A4 inducers due to potential decrease in exposure to rimegepant and loss of efficacy.(1) Patients receiving concurrent therapy with strong and moderate CYP3A4 inducers and rimegepant should be observed for decreased clinical effectiveness. DISCUSSION: In a drug interaction study, rifampin, a strong CYP3A4 inducer, decreased the area-under-curve (AUC) and maximum concentration (Cmax) of rimegepant (75 mg) by 80% and 64%, respectively.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(1,2) |
NURTEC ODT |
| Selumetinib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of selumetinib by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and selumetinib may result in decreased levels and clinical effectiveness of selumetinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of selumetinib recommends avoiding concurrent use with strong or moderate CYP3A4 inducers due to potential decrease in exposure to selumetinib and loss of efficacy.(1) Patients receiving concurrent therapy with strong and moderate CYP3A4 inducers and selumetinib should be observed for decreased clinical effectiveness. DISCUSSION: In a study of 22 healthy subjects, rifampin 600 mg daily (a strong CYP3A4 inducer) decreased selumetinib area-under-curve (AUC) and maximum concentration (Cmax) by 51% and 26%, respectively.(2) Concomitant use of efavirenz, a moderate CYP3A4 inducer, is predicted to decrease selumetinib AUC and Cmax by 38% and 22%, respectively.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(3) |
KOSELUGO |
| Pemigatinib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of pemigatinib by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and pemigatinib may result in decreased levels and clinical effectiveness of pemigatinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of strong and moderate CYP3A4 inducers with pemigatinib.(1) DISCUSSION: Rifampin, a strong CYP3A4 inducer, decreased pemigatinib maximum concentration (Cmax) by 62% and area-under-curve (AUC) by 85% following a single pemigatinib oral dose of 13.5 mg. Concomitant use of a moderate CYP3A4 inducer is predicted to decrease pemigatinib exposure by more than 50%. Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, mavacamten, lumacaftor, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(3) |
PEMAZYRE |
| Sacituzumab Govitecan/UGT1A1 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inducers of UGT1A1 may increase the metabolism of SN-38, the topoisomerase inhibitor which is the antineoplastic component of sacituzumab govitecan.(1) CLINICAL EFFECTS: Concurrent use of UGT1A1 inducers may result in decreased exposure to sacituzumab govitecan and therapeutic failure.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the use of UGT1A1 inducers in patients receiving sacituzumab govitecan.(1) DISCUSSION: SN-38, the small molecule moiety of sacituzumab govitecan, is metabolized by UGT1A1, and inducers of UGT1A1 are expected to decrease SN-38 levels and effectiveness.(1) In a clinical trial, patients homozygous for decreased function UGT1A1*28 allele had a 26% incidence of Grade 4 neutropenia, compared to 13% of patients heterozygous for the UGT1A1*28 allele and 11% of patients homozygous for the wild type allele.(1) UGT1A1 inducers linked to this monograph include: carbamazepine, efavirenz, etravirine, fosphenytoin, lorlatinib, phenobarbital, phenytoin, primidone, rifampin, ritonavir. |
TRODELVY |
| Capmatinib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of capmatinib by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and capmatinib may result in decreased exposure to capmatinib and decreased anti-tumor activity.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of strong and moderate CYP3A4 inducers with capmatinib.(1) DISCUSSION: Coadministration with rifampin (a strong CYP3A4 inducer) decreased capmatinib area-under-curve (AUC) by 67% and maximum concentration (Cmax) by 56%. Coadministration with efavirenz (a moderate CYP3A4 inducer) was predicted to decrease capmatinib AUC by 44% and Cmax by 34%.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(2) |
TABRECTA |
| Berotralstat/Selected P-gp Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Berotralstat is a substrate of the intestinal efflux transporter P-glycoprotein (P-gp). Inducers of P-gp may decrease systemic absorption of berotralstat.(1) CLINICAL EFFECTS: Concurrent or recent use of P-gp inducers may result in decreased systemic levels and effectiveness of berotralstat.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of berotralstat states concurrent use is not recommended with P-gp inducers.(1) DISCUSSION: Berotralstat is a substrate P-gp. Concomitant administration with a P-gp inducer may decrease berotralstat plasma concentration leading to reduced efficacy of berotralstat.(1) Selected P-gp inducers linked to this monograph include: apalutamide, carbamazepine, efavirenz, fosphenytoin, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, and St. John's wort.(1) |
ORLADEYO |
| Idelalisib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of idelalisib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may decrease the levels and effectiveness of idelalisib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of moderate CYP3A4 inducers in patients receiving therapy with idelalisib.(1) Consider the use of alternative agents with less enzyme induction potential.(1) DISCUSSION: In a study in healthy subjects, rifampin (600 mg daily for 8 days) decreased the concentration maximum (Cmax) and area-under-curve (AUC) of idelalisib (150 mg single dose) by 58% and 75%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, cenobamate, dipyrone, efavirenz, etravirine, lesinurad, modafinil, nafcillin, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2) |
ZYDELIG |
| Voclosporin/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of voclosporin.(1) CLINICAL EFFECTS: Concurrent use of strong and moderate CYP3A4 inducers may decrease the serum levels and effectiveness of voclosporin.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The use of strong or moderate CYP3A4 inducers with voclosporin should be avoided.(1) DISCUSSION: Concurrent use of voclosporin with rifampin 600 mg daily for 10 days (strong CYP3A4 inducer) decreased the concentration maximum (Cmax) and area-under-curve (AUC) by 0.32-fold and 0.13-fold, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
LUPKYNIS |
| Crizotinib/Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz and thioridazine, moderate CYP3A4 inducers, may induce the CYP3A4 isoenzyme and increase the metabolism of crizotinib.(1) Crizotinib as well as efavirenz and thioridazine have all been observed to prolong the QTc interval. Concurrent use of agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: Concurrent use of crizotinib with efavirenz or thioridazine may decrease the levels and effectiveness of crizotinib(1) and increase the risk of potentially life-threatening arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) CYP2B6 genotype may also increase the risk of this interaction. Patients who are most susceptible to this interaction are patients who are CYP2B6 poor metabolizers with CYP2B6 *6/*6 allele.(4) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of moderate CYP3A4 inducers, including efavirenz and thioridazine, in patients receiving therapy with crizotinib. Consider the use of alternative agents with less enzyme induction potential and less potential to affect the QTc interval.(1,2) If concurrent use is necessary, consider electrocardiogram (ECG) and electrolyte monitoring (calcium, magnesium, and potassium levels) at baseline and regular intervals.(1) Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. In patients who develop a QTc greater than 500 ms on at least 2 separate ECGs, withhold crizotinib until recovery to baseline or to a QTc less than 481 ms, then resume crizotinib at reduced dose.(1) In patients who develop a QTc greater than 500 ms or greater than or equal to 60 ms change from baseline with Torsade de pointes or polymorphic ventricular tachycardia or signs/symptoms of serious arrhythmia, permanently discontinue crizotinib.(1) DISCUSSION: Rifampin (600 mg daily), a strong CYP3A4 inducer, decreased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of crizotinib (250 mg) by 69% and 82%, respectively.(1) Crizotinib is associated with concentration-dependent QTc interval prolongation. In a clinical trial 2.1% of patients were found to have a QTcF greater than or equal to 500 msec and 5% of patients had an increase in QTcF by greater than or equal to 60 msec.(1) A retrospective review of 618 cancer patients treated with 902 administrations of tyrosine kinase inhibitors were evaluated for rate and incidence of QTc prolongation. In patients who received crizotinib, QTc prolongation was identified in 1 (50%) with 1 (100%) having Grade 1 (QTc 450-480 ms). No patients had a QTc change greater than or equal to 60 ms, ventricular tachycardia, sudden cardiac death, or TdP.(5) A thorough QT study was conducted in the general population in 120 healthy subjects receiving efavirenz 600 mg daily. Time-matched differences in QTc with efavirenz compared to placebo was evaluated on day 11, at 6 hours post dose. The mean change in QTc was 5.2 msec and no change in QTc was greater than 10 msec.(6) In addition to the thorough QT study, the effect of efavirenz on the QTc interval was evaluated in 58 healthy subjects based on CYP2B6 genotype. CYP2B6 polymorphism was evaluated for each patient and results were the following: 65% with *1/*1 or *1/*4 allele (wild-type metabolizers), 26% with *1/*6 allele (intermediate metabolizers) and 9% with *6/*6 allele (slow metabolizers). Subjects with 2 copies of the CYP2B6*6 allele had significantly higher efavirenz exposure at steady-state (p<0.05). At steady-state concentrations of efavirenz, patients with CYP2B6 *1/*1 or *1/*6 alleles had no change in the QTc interval (p>0.05). However, patients with CYP2B6 *6/*6 allele had an increase in QTc mean +/- SD from 406 +/- 16.4 to 423 +/- 11.8 msec (p=0.02).(4) |
XALKORI |
| Efavirenz/Phenytoin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of phenytoin via CYP2C19 or inhibit the metabolism of phenytoin via CYP2C9 and/or CYP2C19. Phenytoin may induce the metabolism of efavirenz by CYP3A4 and CYP2B6.(1) CLINICAL EFFECTS: Concurrent use may result in decreased levels of and effectiveness of efavirenz. Concurrent use may also result in decreased levels of phenytoin or elevated levels of and toxicity from phenytoin. Phenytoin has a narrow therapeutic range. Early symptoms of phenytoin toxicity may include nystagmus, ataxia, dysarthria, tremor, hyperreflexia, lethargy, slurred speech, blurred vision, nausea, and vomiting. Severe toxicity may produce organ dysfunction (e.g. coma, irreversible cerebellar dysfunction and atrophy, hypotension, bradycardia, seizures, and cardiac arrest) and may be fatal.(1) PREDISPOSING FACTORS: Renal impairment, hepatic impairment, or hypoalbuminemia. PATIENT MANAGEMENT: Efavirenz levels should be monitored if phenytoin is initiated or discontinued or if phenytoin dosage adjustments are made. The dosage of efavirenz may need to be adjusted.(1,2) Phenytoin levels should be monitored if efavirenz is initiated or discontinued or if efavirenz dosage adjustments are made. The dosage of phenytoin may need to be adjusted.(1,2) Monitor the patient for signs of hydantoin toxicity (e.g. nystagmus, ataxia, dysarthria, tremor, hyperreflexia, lethargy, slurred speech, blurred vision, nausea, and vomiting). The US HIV guidelines state an alternative antiretroviral or anticonvulsant should be considered. If coadministration is necessary, monitor anticonvulsant and efavirenz concentrations.(4) DISCUSSION: In one case report, an HIV+ patient stable on phenytoin (200 mg twice daily) was started on efavirenz (800 mg once daily) and emtricitabine/tenofovir (200/300 mg once daily). Efavirenz concentrations at Day 5 and 15 were undetectable. Efavirenz concentrations increased after increasing the efavirenz dose (600 mg twice daily) and stopping phenytoin.(5) In another case report, a man stable on phenytoin (300 mg twice daily) was started on efavirenz (600 mg once daily). One week later efavirenz concentration (340 ng/ml) was found to be below the target concentration of 1000 ng/ml. The phenytoin dosage was rapidly tapered and efavirenz dosage was increased (800 mg once daily). Eighteen days after initiating efavirenz, the efavirenz concentration was still reduced. Phenytoin concentrations were also measured while receiving efavirenz (600 mg once daily). A gradual increase was seen over three weeks (11 mcg/ml to 23.5 mcg/ml).(6) |
CEREBYX, DILANTIN, DILANTIN-125, FOSPHENYTOIN SODIUM, PHENYTEK, PHENYTOIN, PHENYTOIN SODIUM, PHENYTOIN SODIUM EXTENDED |
| Glasdegib/Strong and Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Glasdegib is a substrate of CYP3A4. Strong and moderate inducers of CYP3A4 that prolong the QTc interval may induce the metabolism of glasdegib and result in additive risk of QT prolongation.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 that prolongs QT may result in decreased levels and effectiveness of glasdegib and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of glasdegib states to avoid concurrent administration with strong or moderate CYP3A4 inducers. If concurrent use with a moderate CYP3A4 inducer cannot be avoided, increase the daily dose of glasdegib as tolerated as follows: - If current dose of glasdegib is 100 mg once daily, increase to 200 mg once daily - If current dose of glasdegib is 50 mg once daily, increase to 100 mg once daily After the moderate CYP3A4 inducer has been discontinued for 7 days, resume the glasdegib dose that was tolerated prior to initiation of the inducer.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: A population-based pharmacokinetic model predicts that efavirenz would decrease glasdegib area-under-curve (AUC) by 55% and maximum concentration (Cmax) by 25%.(1) Strong and moderate CYP3A4 inducers that prolong QT linked to this monograph include: efavirenz, encorafenib, ivosidenib, pacritinib, and thioridazine.(3,4) |
DAURISMO |
| Entrectinib/Strong and Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Entrectinib is a substrate of CYP3A4. Strong and moderate inducers of CYP3A4 that prolong QT may induce the metabolism of entrectinib and result in additive risk of QT prolongation.(1,2) CLINICAL EFFECTS: The concurrent administration of a strong or moderate CYP3A4 inducer that prolongs QT may result in decreased levels and effectiveness of entrectinib and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de points.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of entrectinib states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Concomitant administration of rifampin (strong CYP3A4 inducer) with a single 600 mg entrectinib dose decreased entrectinib maximum concentration (Cmax) and area-under-the-curve (AUC) by 56% and 77%.(1) Coadministration with a moderate CYP3A4 inducer is predicted to decrease entrectinib's AUC and Cmax by 56% and 43%.(1) Strong and moderate inducers of CYP3A4 that prolong QT include: efavirenz, encorafenib, ivosidenib, pacritinib, and thioridazine.(3,4) |
ROZLYTREK |
| Intravenous and Oral Lefamulin/Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lefamulin is a substrate of CYP3A4. Moderate CYP3A4 inducers that prolong the QTc interval may result in additive risk of QT prolongation.(1,2) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inducer that prolongs QT may result in decreased levels and effectiveness of lefamulin and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of lefamulin states that concurrent use with moderate CYP3A4 inducers should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study, concurrent administration of rifampin (strong inducer) with lefamulin injection decreased lefamulin area-under-the-curve (AUC) and maximum concentration (Cmax) by 28% and 8%.(1) In a study, concurrent administration of rifampin (strong inducer) with oral lefamulin (tablets) decreased lefamulin AUC and Cmax by 72% and 57%.(1) Moderate inducers of CYP3A4 that prolong QT include: efavirenz and thioridazine.(3,4) |
XENLETA |
| Selpercatinib/Strong and Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of selpercatinib.(1) Selpercatinib prolongs the QTc interval.(1) Some CYP3A4 inducers (e.g., efavirenz, encorafenib, ivosidenib, thioridazine) can also prolong the QTc interval.(2) CLINICAL EFFECTS: Coadministration of selpercatinib with a strong or moderate CYP3A4 inducer decreases selpercatinib plasma concentrations, which may decrease the efficacy of selpercatinib.(1) It is unknown how decreased levels of selpercatinib affects the risk of QTc interval prolongation when selpercatinib is used concurrently with QT prolonging CYP3A4 inducers. The concurrent use of selpercatinib with other QT prolonging agents may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(3) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of selpercatinib states that concurrent use with strong and moderate CYP3A4 inducers should be avoided.(1) When concurrent therapy with QT prolonging CYP3A4 inducers is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(3) DISCUSSION: In a study, multiple doses of rifampin (a strong CYP3A inducer) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of selpercatinib by 87% and 70%, respectively.(1) Coadministration of multiple doses of bosentan or efavirenz (moderate CYP3A inducers) is predicted to decrease the AUC and Cmax of selpercatinib 40-70% and 34-57%, respectively.(1) Strong and moderate CYP3A4 inducers that prolong QT include: efavirenz, encorafenib, ivosidenib, pacritinib, and thioridazine.(4,5) |
RETEVMO |
| Bedaquiline/Strong & Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers that prolong the QTc interval may induce the metabolism of bedaquiline and result in additive risk of QT prolongation.(1,2) CLINICAL EFFECTS: Concurrent or recent use of strong or moderate CYP3A4 inducers that prolong the QTc interval may result in decreased levels and effectiveness of bedaquiline and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The concurrent administration of strong or moderate CYP3A4 inducers and bedaquiline should be avoided.(1) Bedaquiline should be used with caution in patients receiving therapy with agents that prolong the QT interval. Patients should receive a baseline electrocardiogram (ECG) before initiation, 2 weeks after initiation, during treatment as clinically indicated, and at the expected time of maximum increase of the QT interval when receiving concurrent agents that prolong the QT interval. Bedaquiline and other QT prolonging agents should be discontinued if the patient develops a clinically significant ventricular arrhythmia or a QTcF of greater than 500 msec confirmed by repeat ECGs. If a patient develops syncope, perform an ECG.(1) Also consider obtaining serum calcium, magnesium, and potassium levels at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study in healthy subjects, concurrent administration of rifampin (600 mg daily) and bedaquiline (300 mg daily) for 21 days decreased the area-under-curve (AUC) of bedaquiline by 52%.(1) In a study in healthy subjects, pretreatment with efavirenz (600 mg daily for 27 days) decreased the AUC of a single dose of bedaquiline by 20%. There was no effect on bedaquiline Cmax. The AUC and Cmax of the primary metabolite of bedaquiline increased by 70% and 80%, respectively.(1) In a clinical trial, mean increases in QTc were greater in patients treated with bedaquiline than with placebo. At Week 1, bedaquiline increased QTc by an average of 9.9 msec, compared with 2.5 msec for placebo. At Week 24, bedaquiline increased QTc by an average of 15.7 msec, compared with 6.2 msec for placebo. In another clinical trial in which patients received bedaquiline with other QT prolonging agents, QT prolongation was additive and proportional to the number of QT prolonging drugs used. Patients receiving bedaquiline alone averaged a QTc increase of 23.7 msec over baseline, while patients receiving bedaquiline with at least one other QT prolonging agent averaged a QTc increase of 30.7 msec.(1) In a study, bedaquiline was coadministered with QTc prolonging agents clofazimine and levofloxacin. In the study, 5% of patients had a QTc >= 500 ms and 43% of patients had an increase in QTc >= 60 ms from baseline.(1) Strong and moderate inducers of CYP3A4 that prolong QT include: efavirenz, encorafenib, ivosidenib, pacritinib, and thioridazine.(3,4) |
SIRTURO |
| Pimavanserin/Strong and Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate inducers of CYP3A4 that prolong the QTc interval may induce the metabolism of pimavanserin and result in additive risk of QT prolongation.(1,2) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 that prolongs the QTc interval may result in decreased levels and effectiveness of pimavanserin and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of pimavanserin recommends avoiding concomitant use of strong or moderate CYP3A4 inducers.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Pimavanserin is primarily metabolized by CYP3A4 while other metabolic enzymes CYP2J2, CYP2D6 and FMO play a lesser role.(1) In a study of subjects pretreated with 7 days of rifampin (600 mg daily, a strong CYP3A4 inducer), a single dose of pimavanserin (34 mg) produced an area-under-curve (AUC) and maximum concentration (Cmax) that was 91 % and 71 % lower, respectively, than when pimavanserin is given without rifampin.(1) A physiology-based pharmacokinetic model predicted that efavirenz (a moderate CYP3A4 inducer) would decrease pimavanserin AUC and Cmax by 70 % and 60 %, respectively.(1) Strong and moderate inducers of CYP3A4 that prolong QT include: efavirenz, encorafenib, ivosidenib, pacritinib, and thioridazine.(4,5) |
NUPLAZID |
| Ibrexafungerp/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of ibrexafungerp by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong or moderate CYP3A4 inducers with ibrexafungerp may result in decreased levels and clinical effectiveness of ibrexafungerp.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of strong and moderate CYP3A4 inducers with ibrexafungerp.(1) DISCUSSION: Ibrexafungerp is a substrate of CYP3A4. The manufacturer of ibrexafungerp states that concurrent use of strong or moderate CYP3A4 inducers are likely to significantly reduce ibrexafungerp exposure, but this interaction has not been studied.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(2,3) |
BREXAFEMME |
| Ripretinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of ripretinib via this pathway.(1) Ripretinib and the active metabolite DP-5439 contribute to anticancer activity. CYP3A4 is the primary metabolism pathway for both ripretinib and the active metabolite DP-5439.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may alter the clinical effectiveness of ripretinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of ripretinib with moderate CYP3A4 inducers.(1) When possible, select alternative agents in place of the moderate CYP3A4 inducer. If the moderate CYP3A4 inducer cannot be avoided, increase the dose of ripretinib from 150 mg once daily to 150 mg twice daily during concurrent therapy. Monitor patients receiving concurrent therapy for reduced efficacy.(1) If the moderate CYP3A4 inducer is discontinued, reduce the dose of ripretinib back to 150 mg once daily 14 days after discontinuation of the moderate CYP3A4 inducer.(1) If a dose of ripretinib is missed (in patients taking twice daily dosing): -If less than 4 hours have passed since missed dose, patient should take the dose as soon as possible and then take the next dose at the regularly scheduled time. -If more than 4 hours have passed since missed dose, patient should skip the missed dose and then take the next dose at the regularly scheduled time.(1) DISCUSSION: The primary metabolism pathway for ripretinib and DP-5439 is via CYP3A4.(1) In an interaction study of rifampin (a strong CYP3A inducer) and ripretinib, concurrent use decreased ripretinib concentration maximum (Cmax) by 18% and area-under-curve (AUC) by 61%, as well as decreased the active metabolite DP-5439 AUC by 57% and increased Cmax by 37%.(1) In a pharmacokinetic model of efavirenz (a moderate CYP3A inducer), concurrent use was predicted to decrease ripretinib Cmax by 24% and decrease AUC by 56%.(1) In an interaction study of itraconazole (a strong CYP3A4 inhibitor) and ripretinib, concurrent use increased ripretinib Cmax by 36% and AUC by 99%. Concurrent use increased the AUC of DP-5439 by 99% with no change in Cmax.(1) Moderate CYP3A4 inducers linked to this monograph are: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
QINLOCK |
| Finerenone/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of finerenone by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong or moderate CYP3A4 inducers with finerenone may result in decreased levels and clinical effectiveness of finerenone.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of strong or moderate CYP3A4 inducers with finerenone.(1) DISCUSSION: Finerenone is a substrate of CYP3A4. Concurrent use of efavirenz (a moderate CYP3A4 inducer) and rifampicin (a strong CYP3A4 inducer) decreased finerenone area-under-curve (AUC) by 80% and 90%, respectively.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(2,3) |
KERENDIA |
| Siponimod/Strong & Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Drugs that are moderate or strong inducers of CYP3A4 may increase the metabolism of siponimod.(1) Patients with a CYP2C9*1/*3 or *2/*3 genotype who are more dependent on CYP3A4 for the metabolism of siponimod would experience a greater effect of CYP3A4 induction. Initiation of siponimod has a negative chronotropic effect and may cause bradycardia. Concurrent use with CYP3A4 inducers that prolong the QT interval may increase the risk of bradycardia and QT prolongation.(1,2) CLINICAL EFFECTS: Concurrent use of a siponimod with a moderate or strong CYP3A4 inducer in patients with a CYP2C9*1/*3 or *2/*3 genotype may result in decreased levels and effectiveness of siponimod.(1) The heart rate lowering effect of siponimod starts within an hour, and the Day 1 decline is maximal at approximately 3-4 hours. This leads to a mean decrease in heart rate of 5-6 beats per minute after the first dose. The first dose has also been associated with heart block. With continued up-titration, further heart rate decreases are seen on subsequent days, with maximal decrease from Day 1-baseline reached on Day 5-6. Symptomatic bradycardia has been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1,2) PREDISPOSING FACTORS: Patients with a CYP2C9*1/*3 or *2/*3 genotype who are more dependent on CYP3A4 for the metabolism of siponimod would experience a greater effect of CYP3A4 induction. Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to siponimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to siponimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of siponimod says that the combination of siponimod with a moderate or strong CYP3A4 inducer is not recommended for patients with a CYP2C9*1/*3 or *2/*3 genotype.(1) Agents that are both moderate CYP3A4 inducers and moderate CYP2C9 inducers (e.g., lorlatinib) should be used with caution regardless of the patient's CYP2C9 genotype.(1) Patients receiving concurrent treatment with a QT prolonging agent at the time siponimod is initiated or resumed should be referred to a cardiologist. Consult the prescribing information for recommendations regarding cardiac monitoring.(1) DISCUSSION: In a study, efavirenz (a moderate CYP3A4 inducer) decreased the area-under-curve (AUC) of siponimod by up to 52% across CYP2C9 genotypes. After the first dose of siponimod, heart rate decrease may begin within an hour. Decline is usually maximal at approximately 3-4 hours. With continued, chronic dosing, heart rate gradually returns to baseline in about 10 days.(1,2) A transient, dose-dependent decrease in heart rate was observed during the initial dosing phase of siponimod, which plateaued at doses greater than or equal to 5 mg, and bradyarrhythmic events (AV blocks and sinus pauses) were detected at a higher incidence under siponimod treatment than placebo. AV blocks and sinus pauses occurred above the recommended dose of 2 mg, with notably higher incidence under non-titrated conditions compared to dose titration conditions.(1) Drugs that are moderate or strong CYP3A4 inducers linked to this monograph include: efavirenz, ivosidenib, pacritinib and thioridazine.(4,5) |
MAYZENT |
| Atogepant/CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong, moderate, and weak CYP3A4 inducers may increase the metabolism of atogepant by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong, moderate, or weak CYP3A4 inducers with atogepant may result in decreased levels and clinical effectiveness of atogepant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of atogepant recommends that patients on concomitant strong, moderate, or weak CYP3A4 inducers receive atogepant 30 mg or 60 mg once daily for prevention of episodic migraines and avoid use of atogepant for prevention of chronic migraines.(1) Patients receiving concurrent therapy with CYP3A4 inducers and atogepant should be observed for decreased clinical effectiveness. DISCUSSION: In a study of healthy subjects, rifampin, a strong CYP3A4 inducer, decreased the area-under-curve (AUC) and maximum concentration (Cmax) of atogepant by 60% and 30%, respectively. Topiramate, a weak CYP3A4 inducer, decreased atogepant AUC and Cmax by 25% and 24%, respectively.(1) Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine and tovorafenib. Weak CYP3A4 inducers linked to this monograph include: armodafinil, bexarotene, brigatinib, brivaracetam, clobazam, danshen, darolutamide, dexamethasone, dicloxacillin, echinacea, eslicarbazepine, floxacillin, garlic, genistein, ginseng, glycyrrhizin, methylprednisolone, mobocertinib, nevirapine, omaveloxolone, oritavancin, oxcarbazepine, pioglitazone, pitolisant, quercetin, relugolix, rufinamide, sarilumab, sulfinpyrazone, tazemetostat, tecovirimat, terbinafine, ticlopidine, topiramate, troglitazone, vemurafenib, vinblastine, and zanubrutinib.(1,2) |
QULIPTA |
| Avacopan/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Avacopan is a substrate of CYP3A4. Strong or moderate inducers of CYP3A4 may induce the metabolism of avacopan.(1) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of avacopan.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of avacopan states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) The Australian manufacturer of avacopan states that patients anticipated to require long-term administration of a CYP3A4 inducer should not be treated with avacopan. If short term co-administration cannot be avoided in a patient already on avacopan, closely monitor for reoccurrence of disease activity.(4) DISCUSSION: Co-administration of rifampin 600 mg once daily for 11 days, a strong CYP3A4 inducer, decreased the avacopan concentration maximum (Cmax) by 79% and area-under-curve (AUC) by 93%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: belzutifan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, rifabutin, sotorasib, telotristat ethyl, thioridazine and tovorafenib.(2-3) |
TAVNEOS |
| Duvelisib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may accelerate the metabolism of duvelisib.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may alter the clinical effectiveness of duvelisib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of duvelisib with moderate CYP3A4 inducers.(1) When possible, select alternative agents in place of the moderate CYP3A4 inducer. If the moderate CYP3A4 inducer cannot be avoided, increase the dose of duvelisib on day 12 of concurrent therapy as follows: - If the initial dose of duvelisib is 25 mg twice daily, increase the duvelisib dose to 40 mg twice daily. - If the initial dose of duvelisib is 15 mg twice daily, increase the duvelisib dose to 25 mg twice daily. Monitor patients receiving concurrent therapy for reduced efficacy.(1) If the moderate CYP3A4 inducer is discontinued, reduce the dose of duvelisib back to the initial dose 14 days after discontinuation of the moderate CYP3A4 inducer.(1) DISCUSSION: The primary metabolism pathway for duvelisib is CYP3A4.(1) In an interaction study, etravirine (a moderate CYP3A inducer) 200 mg twice daily decreased the maximum concentration (Cmax) and area-under-curve (AUC) of single dose duvelisib 25 mg by 16% and 35%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-4) |
COPIKTRA |
| Levoketoconazole/Possible QT Prolonging Agents SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Levoketoconazole has been observed to prolong the QTc interval in a dose-dependent manner. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of levoketoconazole with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of levoketoconazole states that levoketoconazole is contraindicated with other agents that prolong the QT interval.(1) Levoketoconazole is also contraindicated in patients with a prolonged QTcF interval of greater than 470 msec at baseline, history of torsades de pointes, ventricular tachycardia, ventricular fibrillation, or long QT syndrome (including first-degree family history). Use caution in patients with other risk factors for QT prolongation including congestive heart failure, bradyarrhythmias, and uncorrected electrolyte abnormalities. Consider more frequent ECG monitoring. Prior to starting levoketoconazole, obtain a baseline ECG and correct hypokalemia or hypomagnesemia. If a patient develops QT prolongation with a QTc interval greater than 500 msec, temporarily discontinue levoketoconazole. After resolution of prolonged QTc interval, levoketoconazole may be resumed at a lower dose. If QTc interval prolongation recurs, permanently discontinue levoketoconazole.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: During phase 1 and 2 studies, which excluded patients with baseline QTcF interval greater than 470 msec, 4 (2.4%) patients experienced QTcF > 500 msec, and 23 (14.7%) patients experienced change-from-baseline QTcF > 60 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) |
RECORLEV |
| Mitapivat/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may increase the metabolism of mitapivat.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of mitapivat.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Consider alternative therapies that are not moderate CYP3A4 inducers in patients who are on mitapivat. If concurrent use is necessary, monitor hemoglobin closely and titrate mitapivat dose, not to exceed a maximum dose of 100 mg twice daily.(1) DISCUSSION: Mitapivat is a CYP3A4 substrate. In a pharmacokinetic study with 5 or 20 mg twice daily of mitapivat, efavirenz decreased area-under-curve (AUC) and concentration maximum (Cmax) by 60% and 30%, respectively. After mitapivat doses of 50 mg twice daily, efavirenz decreased AUC and Cmax by 55% and 24%, respectively.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, modafinil, nafcillin, pacritinib, pexidartinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
PYRUKYND |
| Ganaxolone/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ganaxolone is a substrate of CYP3A4. Strong or moderate inducers of CYP3A4 may induce the metabolism of ganaxolone.(1) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of ganaxolone.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of ganaxolone states that concurrent use with strong or moderate CYP3A4 inducers should be avoided. If concurrent use is unavoidable, consider increasing the dose of ganaxolone. Do not exceed the recommended maximum daily dose.(1) In patients who are stable on ganaxolone and are initiated on anticonvulsants that are CYP3A4 inducers, consider increasing the dose of ganaxolone. Do not exceed the recommended maximum daily dose.(1) DISCUSSION: Co-administration of rifampin, a strong CYP3A4 inducer, decreased the ganaxolone concentration maximum (Cmax) by 57% and area-under-curve (AUC) by 68%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
ZTALMY |
| Vonoprazan/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Vonoprazan is a substrate of CYP3A4. Strong or moderate inducers of CYP3A4 may increase the metabolism of vonoprazan.(1) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of vonoprazan.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of vonoprazan states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Strong CYP3A4 inducers like rifampin are predicted to decrease the area-under-curve (AUC) of vonoprazan by 80%, and moderate CYP3A4 inducers like efavirenz are predicted to decrease vonoprazan AUC by 50%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
VOQUEZNA, VOQUEZNA DUAL PAK |
| Vonoprazan-Clarithromycin-Amoxicillin/Strong or Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate inducers of CYP3A4 that prolong the QTc interval may accelerate the metabolism of vonoprazan and clarithromycin.(1) Clarithromycin prolongs the QTc interval.(1) Some CYP3A4 inducers (e.g., efavirenz, thioridazine) can also prolong the QTc interval.(2) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of vonoprazan and clarithromycin.(1) Additive QTc prolongation may occur and result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of vonoprazan states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Increase the frequency of ECG monitoring in patients with risk factors for QTc prolongation, including congenital long QT syndrome, heart disease, or electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Vonoprazan and clarithromycin are CYP3A4 substrates. Strong CYP3A4 inducers like rifampin are predicted to decrease the area-under-curve (AUC) of vonoprazan by 80%, and moderate CYP3A4 inducers like efavirenz are predicted to decrease vonoprazan AUC by 50%.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2) Strong or moderate inducers of CYP3A4 that prolong the QTc interval include: efavirenz and thioridazine.(4,5) |
VOQUEZNA TRIPLE PAK |
| Betibeglogene Autotemcel/Anti-Retrovirals; Hydroxyurea SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Betibeglogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. Hydroxyurea may interfere with hematopoietic stem cell (HSC) mobilization of CD34+ cells.(1) CLINICAL EFFECTS: Use of hydroxyurea before mobilization may result in unsuccessful stem cell mobilization. Use of antiretrovirals before mobilization and apheresis may interfere with the production of betibeglogene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals and hydroxyurea for at least one month prior to mobilization and until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications and hydroxyurea may interfere with the manufacturing of betibeglogene autotemcel therapy.(1) |
ZYNTEGLO |
| Elivaldogene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Elivaldogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of elivaldogene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization and until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications may interfere with the manufacturing of elivaldogene autotemcel therapy.(1) |
SKYSONA |
| Olutasidenib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may increase the metabolism of olutasidenib by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and olutasidenib may result in decreased levels and clinical effectiveness of olutasidenib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of strong and moderate CYP3A4 inducers with olutasidenib.(1) DISCUSSION: Coadministration of multiple doses of rifampin (a strong CYP3A4 inducer) decreased olutasidenib area-under-curve (AUC) and maximum concentration (Cmax) by 80% and 43%, respectively.(1) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, carbamazepine, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, encorafenib, enzalutamide, etravirine, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's wort, sotorasib, telotristat, thioridazine, and tovorafenib.(2) |
REZLIDHIA |
| Lenacapavir/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may accelerate the metabolism of lenacapavir.(1-3) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may decrease the levels and effectiveness of lenacapavir.(1-3) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of lenacapavir states that concurrent use of moderate CYP3A4 inducers is not recommended.(1-3) DISCUSSION: In a study, efavirenz 600 mg once daily (inducer of CYP3A4 [moderate] and P-glycoprotein) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of lenacapavir by 36% and 56%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: barbiturates, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, nevirapine, oxcarbazepine, phenobarbital, primidone, rifabutin, sotorasib, telotristat ethyl, thioridazine, tipranavir-ritonavir, and tovorafenib.(4,5) |
SUNLENCA |
| Cariprazine/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Cariprazine and its major active metabolite DDCAR are metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may accelerate the metabolism of cariprazine.(1-4) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of cariprazine.(1-4) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of cariprazine does not recommend concurrent use of strong CYP3A4 inducers.(1) The Australian, Canadian, and UK manufacturers of cariprazine state that concurrent use of strong and moderate CYP3A4 inducers is contraindicated.(2-4) DISCUSSION: Cariprazine and its active metabolites are primarily metabolized by CYP3A4. Coadministration with CYP3A4 inducers has not been studied and the net effect is unclear. Due to the long half life of the active metabolites, it takes several weeks for cariprazine to reach steady state after dosage changes.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(5-6) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(5-6) |
VRAYLAR |
| Elacestrant/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Elacestrant is metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may increase the metabolism of elacestrant.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of elacestrant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of elacestrant with strong or moderate CYP3A4 inducers.(1) DISCUSSION: Coadministration of 200 mg dose of elacestrant with rifampin (a strong CYP3A inducer) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of elacestrant by 73% and 86%, respectively.(1) Efavirenz is predicted to decrease the Cmax and AUC of elacestrant by 44 to 63% and 55% to 73%, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(2,3) |
ORSERDU |
| Pirtobrutinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Pirtobrutinib is metabolized by CYP3A4. Moderate inducers of CYP3A4 may increase the metabolism of pirtobrutinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of pirtobrutinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of pirtobrutinib with moderate CYP3A4 inducers.(1) If concomitant use of moderate CYP3A4 inducers is unavoidable, and the current dose of pirtobrutinib is 200 mg daily, increase the dose to 300 mg daily. If the current pirtobrutinib dosage is 50 mg or 100 mg once daily, increase the dose by 50 mg.(1) DISCUSSION: Efavirenz and bosentan (moderate CYP3A inducers) are predicted to decrease the area-under-curve (AUC) of pirtobrutinib by 49% and 27%, respectively.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, and thioridazine.(2,3) |
JAYPIRCA |
| Omaveloxolone/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Omaveloxolone is metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may increase the metabolism of omaveloxolone.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of omaveloxolone.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of omaveloxolone with strong or moderate CYP3A4 inducers.(1) DISCUSSION: Omaveloxolone is a substrate of CYP3A4. The effect of concomitant use with strong CYP3A4 inducers is unknown. Concurrent administration of a single dose of efavirenz (moderate CYP3A4 inducer) with omaveloxolone decreased the maximum concentration (Cmax) and area-under-the-curve (AUC) of omaveloxolone by 38% and 48%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(2,3) |
SKYCLARYS |
| Leniolisib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Leniolisib is metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may increase the metabolism of leniolisib.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of leniolisib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of leniolisib with strong or moderate CYP3A4 inducers.(1) DISCUSSION: PBPK model-based simulations predicted a maximum decrease of 78% and 58% in leniolisib area-under-curve (AUC) with rifampin (strong CYP3A4 inducer) and efavirenz (moderate CYP3A4 inducer), respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(2,3) |
JOENJA |
| Zanubrutinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Zanubrutinib is a substrate of CYP3A4. Moderate inducers of CYP3A4 may induce the metabolism of zanubrutinib.(1) CLINICAL EFFECTS: The concurrent administration of moderate CYP3A4 inducers may result in decreased levels and effectiveness of zanubrutinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of zanubrutinib states that concurrent use with moderate CYP3A4 inducers should be avoided. If concurrent use cannot be avoided, increase zanubrutinib dosage to 320 mg twice daily.(1) DISCUSSION: Co-administration of multiple doses of efavirenz, a moderate CYP3A4 inducer, is predicted to decrease zanubrutinib Cmax by 58% and AUC by 60%.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
BRUKINSA |
| Axitinib/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of axitinib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of axitinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with axitinib.(1) Consider the use of alternatives with little to no induction potential.(1) DISCUSSION: Rifampin (600 mg daily for 9 days), a strong CYP3A4 inducer, decreased the maximum concentration (Cmax) and area-under-curve (AUC) of axitinib to less than half and less than 25% of levels seen without concurrent rifampin.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, dexamethasone, encorafenib, enzalutamide, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat ethyl, thioridazine and tovorafenib.(1-3) |
INLYTA |
| Palovarotene/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Palovarotene is extensively metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may increase the metabolism of palovarotene.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of palovarotene.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of palovarotene with strong and moderate CYP3A4 inducers.(1) DISCUSSION: In a clinical trial, rifampin, a strong CYP3A4 inducer, decreased the maximum concentration (Cmax) and area-under-curve (AUC) of palovarotene by 81% and 89%, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2) |
SOHONOS |
| Erlotinib/CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inducers of CYP3A4 may induce the metabolism of erlotinib.(1) CLINICAL EFFECTS: Concurrent or recent use of a CYP3A4 inducer may result in decreased levels and effectiveness of erlotinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of CYP3A4 inducers in patients receiving therapy with erlotinib. Consider the use of alternative agents with less enzyme induction potential.(1) Consider increasing the dosage of erlotinib by 50 mg increments as tolerated at two week intervals (to a maximum of 450 mg) while closely monitoring the patient. The highest dosage studied with concurrent rifampin is 450 mg. If the dosage of erlotinib is increased, it will need to be decreased when the inducer is discontinued.(1) DISCUSSION: Pretreatment and concurrent therapy with rifampin increased erlotinib clearance by 3-fold and decreased the erlotinib area-under-curve (AUC) by 66% to 80%. This is equivalent to a dose of about 30 mg to 50 mg in NSCLC.(1) In a study, pretreatment with rifampin for 11 days decreased the AUC of a single 450 mg dose of erlotinib to 57.6% of the AUC observed with a single 150 mg dose of erlotinib.(1) In a case report, coadministration of phenytoin (180mg daily) and erlotinib (150mg daily) increased the phenytoin concentration from 8.2mcg/ml to 24.2mcg/ml and decreased the erlotinib concentration 12-fold (from 1.77mcg/ml to 0.15mcg/ml) and increased the erlotinib clearance by 10-fold (from 3.53 L/h to 41.7 L/h).(2) In a study, concurrent use of sorafenib (400 mg twice daily) and erlotinib (150 mg daily) decreased the concentration minimum (Cmin), concentration maximum (Cmax), and AUC of erlotinib.(3) In an animal study, concurrent use of dexamethasone and erlotinib decreased the AUC of erlotinib by 0.6-fold.(4) Strong inducers of CYP3A4 include: barbiturates, encorafenib, enzalutamide, fosphenytoin, ivosidenib, mitotane, phenobarbital, phenytoin, primidone, rifampin, and rifapentine.(5,6) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat, thioridazine, and tovorafenib.(5,6) Weak inducers of CYP3A4 include: amprenavir, armodafinil, bexarotene, brigatinib, brivaracetam, clobazam, danshen, darolutamide, dicloxacillin, echinacea, eslicarbazepine, flucloxacillin, garlic, genistein, ginkgo, ginseng, glycyrrhizin, mobocertinib, nevirapine, omaveloxolone, oritavancin, oxcarbazepine, pioglitazone, pitolisant, quercetin, relugolix, rufinamide, sarilumab, sulfinpyrazone, tazemetostat, tecovirimat, terbinafine, ticlopidine, topiramate, troglitazone, vemurafenib, vinblastine, and zanubrutinib.(5,6) |
ERLOTINIB HCL |
| Olaparib/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of olaparib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of olaparib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with olaparib.(1) Consider the use of alternatives with little to no induction potential. DISCUSSION: In a drug interaction trial, olaparib area-under-curve (AUC) and maximum concentration (Cmax) decreased 87% and 71% respectively when olaparib was administered with rifampin. Based upon simulated models, a moderate CYP3A4 inducer is predicted to decrease olaparib AUC by 50-60% and Cmax by 20-30%.(1-3) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(4-5) |
LYNPARZA |
| Palbociclib/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of palbociclib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of palbociclib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with palbociclib.(1) Consider the use of alternatives with little to no induction potential. DISCUSSION: In a study in 14 healthy subjects, rifampin (600 mg daily) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of palbociclib by 70% and 85%, respectively.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
IBRANCE |
| Sonidegib/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that induce the CYP3A4 isoenzyme may induce the metabolism of sonidegib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of sonidegib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with sonidegib.(1) Consider the use of alternatives with little to no induction potential. DISCUSSION: In an interaction study, 16 healthy subjects received a single dose of sonidegib 800mg alone or 5 days after receiving rifampin 600 mg daily for 14 days. Mean sonidegib area-under-curve (AUC) was decreased by 75% and maximum concentration (Cmax) decreased 54% when taken with rifampin. Based upon population based pharmacokinetic (PBPK) simulations, a moderate CYP3A4 inducer such as efavirenz given for 14 days is predicted to decrease sonidegib AUC 56% in cancer patients taking sonidegib 200 mg daily. Coadministration with a moderate CYP3A4 inducer for 4 months is predicted to decrease sonidegib exposure (AUC) by 69%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate inducers of CYP3A4 include: bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
ODOMZO |
| Valoctocogene Roxaparvovec/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The mechanism of this interaction has not been established.(1) CLINICAL EFFECTS: Co-administration of valoctocogene roxaparvovec with efavirenz was poorly tolerated and resulted in elevations of liver enzymes with subsequent decreased factor VIII levels and increased risk of bleeding.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of valoctocogene roxaparvovec states that co-administration with efavirenz is not recommended.(1) DISCUSSION: In an HIV positive patient who had been stable on his antiretroviral regimen for over 10 years, treatment with valoctocogene roxaparvovec and the antiretroviral regimen of efavirenz, lamivudine, and tenofovir resulted in elevations of liver enzymes. The patient developed asymptomatic elevations in ALT, AST, and GGT (> 5 x ULN (upper limit of normal)) and serum bilirubin (> ULN and up to 1.5 x ULN). The liver enzyme elevations resolved after efavirenz was stopped, worsened with rechallenge of efavirenz, and resolved again after replacing efavirenz with raltegravir. In addition, the patient did not maintain detectable FVIII levels after gene therapy, experiencing 21 bleeding events and eventually reverting to prophylactic FVIII therapy.(1,2) In vitro studies indicate efavirenz suppresses factor VIII transcription independent of hepatotoxicity, and expression was not restored upon discontinuation.(1) In efavirenz HIV trials, 20% of hepatitis B or C coinfected patients who received efavirenz had ALT elevations > 5 times the upper limit of normal versus 7% of patients in the control arm.(3) |
ROCTAVIAN |
| Quizartinib/Strong & Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate inducers of CYP3A4 that prolong the QTc interval may accelerate the metabolism of quizartinib.(1) Quizartinib prolongs the QTc interval.(1) Some CYP3A4 inducers (e.g., efavirenz, thioridazine) can also prolong the QTc interval.(3,4) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of quizartinib.(1) Additive QTc prolongation may occur and result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of quizartinib states that the concurrent use of QT prolonging agents should be avoided.(1) Avoid the concurrent use of strong or moderate CYP3A4 inducers in patients receiving therapy with quizartinib.(1) Quizartinib is only available through a restricted REMS program due to the serious risk of QT prolongation, torsades de pointes, and cardiac arrest. The manufacturer recommends monitoring as follows: -Initiate quizartinib only if the QTcF is less than or equal to 450 ms. -During induction and consolidation, monitor ECGs prior to initiation and then at minimum once weekly during treatment. -During maintenance, monitor ECGs prior to initiation and then at minimum once weekly for the first month following dose initiation and escalation and clinically therafter. Dose escalation may occur only if the QTcF is less than or equal to 450 ms. The manufacturer recommends the following dose modifications for adverse reactions: -If the QTcF is 450 ms to 480 ms (Grade 1) - Continue quizartinib dose. -If the QTcF is 481 ms to 500 ms (Grade 2) - Reduce the dose of quizartinib without interruption based on prescribing information. Resume the previous dose in the next cycle if the QTcF has decreased to less than 450 ms. -If the QTcF is greater than 500 ms (Grade 3) - Interrupt quizartinib. Resume at a reduced dose based on prescribing information when the QTcF is less than 450 ms. Maintain the dose of 26.5 mg once daily during maintenance if the QTcF is greater than 500 ms during induction or consolidation. -If recurrent QTcF is greater than 500 ms (Grade 3) - Permanently discontinue quizartinib if QTcF is greater than 500 ms despite dose reduction and correction/elimination of other risk factors. -If TdP, polymorphic ventricular tachycardia, or signs/symptoms of life-threatening arrythmia occur (Grade 4) - Permanently discontinue quizartinib. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: The area-under-curve (AUC) of quizartinib decreased by 90% and maximum concentration (Cmax) by 45% following concomitant use of a single 53 mg dose of quizartinib with efavirenz (a moderate CYP3A inducer). The AUC of active metabolite AC886 decreased by 96% and the Cmax by 68%. The effect of concomitant use with a strong CYP3A inducer may result in even greater effect on quizartinib pharmacokinetics based on mechanistic understanding of the drugs involved.(1) Quizartinib has been associated with QTc interval prolongation, Torsades de Pointes, ventricular arrhythmias, cardiac arrest, and sudden death. Quizartinib increased QTc in a dose- and concentration-dependent manner.(1) In an exposure-response analysis, quizartinib had a predicted concentration-dependent QTc prolongation of 18 to 24 ms (upper bound of 2-sided 90% CI: 21 and 27 ms) at a median steady-state Cmax dose of 26.5 mg and 53 mg during maintenance therapy.(1) In patients administered quizartinib, 2.3% of 265 patients had a QTcF greater than 500 msec and 10% of patients had a increase from baseline QTcF greater than 60 msec.(1) In patients administered quizartinib during the induction phase, torsades de pointes occurred in approximately 0.2% of patients, cardiac arrest occurred in 0.6%, including 0.4% with a fatal outcome, and 0.1% of patients experienced ventricular fibrillation.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(2) Strong inducers of CYP3A4 include: encorafenib and ivosidenib. Moderate inducers of CYP3A4 include: efavirenz, pacritinib, and thioridazine.(3,4) |
VANFLYTA |
| Pralsetinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of pralsetinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inducer may result in a loss of pralsetinib efficacy.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of pralsetinib with moderate CYP3A4 inducers.(1) If coadministration with a moderate CYP3A4 inducer cannot be avoided, increase the dose of pralsetinib on day 7 of coadministration with pralsetinib as follows: -If the current dose is 400 mg once daily, increase the dose to 600 mg daily. -If the current dose is 300 mg once daily, increase the dose to 500 mg daily. -If the current dose is 200 mg once daily, increase the dose to 300 mg daily. After discontinuation of a moderate CYP3A4 inducer for at least 14 days, resume the previous pralsetinib dose prior to initiating the moderate CYP3A4 inducer.(1) Monitor patients receiving concurrent therapy for reduced efficacy. DISCUSSION: Coadministration of efavirenz 600 mg once daily is expected to decrease pralsetinib concentration maximum (Cmax) by 18% and area-under-curve (AUC) by 45%.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2-3) |
GAVRETO |
| Zuranolone/CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inducers of CYP3A4 may induce the metabolism of zuranolone.(1) CLINICAL EFFECTS: Concurrent use of a CYP3A4 inducer may result in a loss of zuranolone efficacy.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid the concurrent use of zuranolone with CYP3A4 inducers.(1) DISCUSSION: Coadministration of zuranolone with rifampin decreased the maximum concentration (Cmax) by 0.31-fold and area-under-curve (AUC) by 0.15-fold.(1) Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort. Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib. Weak CYP3A4 inducers linked to this monograph include: armodafinil, bexarotene, brigatinib, brivaracetam, clobazam, danshen, darolutamide, dexamethasone, dicloxacillin, echinacea, eslicarbazepine, flucloxacillin, garlic, genistein, ginseng, glycyrrhizin, methylprednisolone, mobocertinib, nevirapine, omaveloxolone, oritavancin, oxcarbazepine, pioglitazone, pitolisant, quercetin, relugolix, rufinamide, sarilumab, sulfinpyrazone, tazemetostat, tecovirimat, terbinafine, ticlopidine, topiramate, troglitazone, vemurafenib, vinblastine, and zanubrutinib.(2,3) |
ZURZUVAE |
| Fruquintinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of fruquintinib.(1) CLINICAL EFFECTS: Concurrent or recent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of fruquintinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: If possible, avoid concurrent use of moderate inducers of CYP3A4 with fruquintinib. If concurrent use cannot be avoided, continue to administer fruquintinib at the recommended dosage.(1) DISCUSSION: Concomitant use with efavirenz (moderate CYP3A4 inducer) is predicted to decrease the fruquintinib maximum concentration (Cmax) by 4% and the area-under-curve (AUC) by 32%.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
FRUZAQLA |
| Capivasertib/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate inducers of CYP3A4 may increase the metabolism of capivasertib.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of capivasertib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of capivasertib with strong and moderate CYP3A4 inducers.(1) DISCUSSION: Rifampin (strong CYP3A4 inducer) is predicted to decrease capivasertib area-under-curve (AUC) by 70% and maximum concentration (Cmax) by 60%.(1) Efavirenz (moderate CYP3A4 inducer) is predicted to decrease capivasertib AUC by 60% and Cmax by 50%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2,3) |
TRUQAP |
| Repotrectinib/Strong or Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate CYP3A4 inducers may induce the metabolism of repotrectinib.(1) CLINICAL EFFECTS: Coadministration of repotrectinib with a strong or moderate CYP3A4 inducer decreases repotrectinib plasma concentrations, which may decrease efficacy of repotrectinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of repotrectinib states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Coadministration of repotrectinib with rifampin, a strong CYP3A4 and P-glycoprotein inducer, decreased concentration maximum (Cmax) by 79% and area-under-curve (AUC) by 92%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, encorafenib, etravirine, lesinurad, modafinil, nafcillin, pacritinib, pexidartinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
AUGTYRO |
| Nirogacestat/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate CYP3A4 inducers may induce the metabolism of nirogacestat.(1) CLINICAL EFFECTS: Coadministration of nirogacestat with a strong or moderate CYP3A4 inducer decreases nirogacestat plasma concentrations, which may decrease efficacy of nirogacestat.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of nirogacestat states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: In a PKPB model, coadministration of rifampin, a strong CYP3A4 inducer, following multiple doses of nirogacestat (150 mg BID) is predicted to decrease the area-under-curve (AUC) of nirogacestat by 85%.(1) In a PKPB model, coadministration of efavirenz, a moderate CYP3A4 inducer, following multiple doses of nirogacestat (150 mg BID) is predicted to decrease the AUC of nirogacestat by 67%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, modafinil, nafcillin, pacritinib, pexidartinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
OGSIVEO |
| Lovotibeglogene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lovotibeglogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of lovotibeglogene autotemcel.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization and until all cycles of apheresis are completed.(1) There are some long-acting antiretroviral medications that may require a longer duration of discontinuation for elimination of the medication. If a patient is taking anti-retrovirals for HIV prophylaxis, confirm a negative test for HIV before beginning mobilization and apheresis of CD34+ cells.(1) DISCUSSION: Antiretroviral medications may interfere with the manufacturing of lovotibeglogene autotemcel therapy.(1) |
LYFGENIA |
| Vincristine/P-glycoprotein (P-gp) Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inducers of P-glycoprotein (P-gp) may reduce systemic exposure to vincristine.(1) CLINICAL EFFECTS: Concurrent or recent use of P-gp inducers may result in decreased effectiveness of vincristine.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of vincristine states that concurrent use of P-gp inducers should be avoided.(1) Consider the use of agents with no or minimal induction potential if possible. Monitor patients for decreased response to therapy. DISCUSSION: Vincristine is transported by P-gp and inducers of this transporter are expected to decrease levels of vincristine.(1) Inducers of P-gp include linked to this monograph include: efavirenz, green tea, and lorlatinib.(2,3) |
VINCASAR PFS, VINCRISTINE SULFATE |
| Lemborexant/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lemborexant is a substrate of CYP3A4. Efavirenz is a moderate inducer of CYP3A4 and may increase the metabolism of lemborexant.(1,2) Efavirenz is a substrate of CYP2B6. Lemborexant is an inducer of CYP2B6 and may increase the metabolism of efavirenz.(1,2) CLINICAL EFFECTS: Concurrent use may result in decreased levels and effectiveness of both lemborexant and efavirenz.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lemborexant states that concurrent use with moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: A pharmacokinetic model predicted that co-administration of rifampin, a strong CYP3A4 inducer, would decrease the AUC of lemborexant by 90%.(1) In a study, lemborexant (10 mg dose) decreased the concentration maximum (Cmax) and area-under-curve (AUC) of a S-bupropion (a CYP2B6 substrate) by 49.9% and 45.5%, respectively.(1) |
DAYVIGO |
| Efavirenz/Barbiturates SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of barbiturates via CYP2C19. Barbiturates may induce the metabolism of efavirenz by CYP3A4.(1-2) CLINICAL EFFECTS: Concurrent use may result in decreased levels and effectiveness of both efavirenz and phenobarbital.(1-2) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US HIV guidelines state an alternative antiretroviral or anticonvulsant should be considered. If coadministration is necessary, monitor anticonvulsant and efavirenz concentrations.(2) DISCUSSION: No specific interaction studies have been performed. In a case report, an HIV+ patient stable on phenytoin (another strong CYP3A4 inducer) (200 mg twice daily) was started on efavirenz (800 mg once daily) and emtricitabine/tenofovir (200/300 mg once daily). Efavirenz concentrations at Day 5 and 15 were undetectable. Efavirenz concentrations increased after increasing the efavirenz dose (600 mg twice daily) and stopping phenytoin.(3) In another case report, a man stable on phenytoin (300 mg twice daily) was started on efavirenz (600 mg once daily). One week later efavirenz concentration (340 ng/ml) was found to be below the target concentration of 1000 ng/ml. The phenytoin dosage was rapidly tapered and efavirenz dosage was increased (800 mg once daily). Eighteen days after initiating efavirenz, the efavirenz concentration was still reduced. Phenytoin concentrations were also measured while receiving efavirenz (600 mg once daily). A gradual increase was seen over three weeks (11 mcg/ml to 23.5 mcg/ml).(4) |
ASA-BUTALB-CAFFEINE-CODEINE, ASCOMP WITH CODEINE, BUTALB-ACETAMINOPH-CAFF-CODEIN, BUTALBITAL, BUTALBITAL-ACETAMINOPHEN, BUTALBITAL-ACETAMINOPHEN-CAFFE, BUTALBITAL-ASPIRIN-CAFFEINE, DONNATAL, FIORICET, FIORICET WITH CODEINE, MYSOLINE, PENTOBARBITAL SODIUM, PHENOBARBITAL, PHENOBARBITAL SODIUM, PHENOBARBITAL-BELLADONNA, PHENOBARBITAL-HYOSC-ATROP-SCOP, PHENOHYTRO, PRIMIDONE, SEZABY, TENCON |
| Praziquantel/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of praziquantel.(1,2) CLINICAL EFFECTS: Concurrent or recent use of a moderate inducer of CYP3A4 may decrease the levels and effectiveness of praziquantel.(1,2) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of praziquantel recommends avoiding concomitant administration with moderate CYP3A4 inducers due to the risk of a clinically significant decrease in praziquantel plasma concentration which may lead to reduced therapeutic effect of praziquantel.(2) In patients receiving a clinically significant CYP3A4 inducer drug who need immediate treatment for schistosomiasis, alternative agents for schistosomiasis should be considered, where possible. If praziquantel treatment is necessary immediately, increase monitoring for reduced anthelmintic efficacy associated with praziquantel, when used in combination with a moderate CYP3A4 inducer.(2) In patients receiving a clinically significant CYP3A4 inducer drug whose treatment could be delayed, discontinue the CYP3A4 inducer drug at least 2 to 4 weeks before administration of praziquantel and, where possible, consider starting alternative medications that are not CYP3A4 inducers. The CYP3A4 inducer drug can be restarted 1 day after completion of praziquantel treatment, if needed.(2) DISCUSSION: In a crossover study, 20 healthy subjects ingested a single 40 mg/kg oral dose of praziquantel following pre-treatment with oral efavirenz (400 mg daily for 13 days). Oral efavirenz reduced the mean praziquantel area-under-curve (AUC) by 77% and maximum concentration (Cmax) by 79%, when coadministered with praziquantel compared to praziquantel given alone.(2) Moderate CYP3A4 inducers include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(3-4) |
BILTRICIDE, PRAZIQUANTEL |
| Atidarsagene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Atidarsagene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of atidarsagene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization (or the expected duration of time needed for elimination of the medication) until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications may interfere with the manufacturing of atidarsagene autotemcel therapy.(1) |
LENMELDY |
| Lazertinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of lazertinib via this pathway.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may reduce the clinical effectiveness of lazertinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of lazertinib states that concurrent use of moderate CYP3A4 inducers should be avoided. Consider an alternative concomitant medication with no potential to induce CYP3A4.(1) DISCUSSION: In a pharmacokinetic modelling study, concomitant use of efavirenz (moderate CYP3A4 inducer) is predicted to decrease lazertinib steady state concentration maximum (Cmax) and area-under-curve (AUC) by at least 32% and 44%, respectively.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
LAZCLUZE |
| Revumenib/Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inducers may induce the metabolism of revumenib by CYP3A4 and increase formation of the M1 metabolite which contributes to revumenib's effects on the QTc interval.(1) Concurrent use of agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may result in decreased levels and effectiveness of revumenib and increased risk of QT prolongation due to increased exposure to revumenib's M1 metabolite. The risk of potentially life-threatening arrhythmias including torsades de pointes may be increased.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of revumenib states that concomitant use of other drugs that may prolong the QTc interval should be avoided. In addition, concomitant use of moderate CYP3A4 inducers should be avoided. If concurrent use cannot be avoided, obtain ECGs prior to initiating revumenib, during concomitant use, and as clinically indicated.(1) If the QTc interval is greater than 480 ms, withhold revumenib therapy. Resume revumenib after the QTc interval drops to 480 msec or less.(1) If coadministration with another agent that prolongs QT is unavoidable, monitor for prolongation of the QTc interval.(1) When concurrent therapy is warranted: consider obtaining serum calcium, magnesium, and potassium levels and monitoring EKG at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Revumenib is primarily metabolized by CYP3A4. Concomitant use of a moderate CYP3A4 inducer may decrease revumenib concentrations and increase M1 systemic exposure, resulting in decreased revumenib efficacy or increased risk of QT prolongation.(1) In clinical trials, QTc interval prolongation was reported as an adverse event in 29% of 135 patients treated with the recommended dosage of revumenib; 12% of patients had Grade 3 QTc prolongation. Revumenib increased the QTc interval in a concentration-dependent manner. At the mean steady-state Cmax using the highest approved recommended dosage of revumenib without CYP3A4 inhibitors, QTc increase was predicted to be 27 msec (upper bound of 90% confidence interval = 30 msec). At the steady-state Cmax using the highest approved recommended dosage of revumenib with CYP3A4 inhibitors, QTc increase was predicted to be 19 msec (upper bound of 90% confidence interval = 22 msec).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) Moderate CYP3A4 inducers that prolong QT linked to this monograph include: efavirenz, pacritinib, and thioridazine.(4) |
REVUFORJ |
| Acoramidis/UGT and Selected CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: UGT and selected CYP3A4 inducers may induce the metabolism of acoramidis, which is glucuronidated by UGT1A9, UGT1A1, and UGT2B7.(1) CLINICAL EFFECTS: Concurrent use of UGT and selected CYP3A4 inducers may result in decreased levels and effectiveness of acoramidis.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of acoramidis states to avoid concomitant use of acoramidis with UGT inducers and strong CYP3A inducers.(1) DISCUSSION: UGT and selected CYP3A4 inducers linked to this monograph include: carbamazepine, efavirenz, etravirine, fosphenytoin, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and ritonavir. |
ATTRUBY |
| Vanzacaftor-Tezacaftor-Deutivacaftor/Moderate CYP3A4 Inducer SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of vanzacaftor, tezacaftor, and deutivacaftor.(1) CLINICAL EFFECTS: Concurrent or recent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of vanzacaftor, tezacaftor, and deutivacaftor.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Concurrent use of moderate CYP3A4 inducers in patients maintained on vanzacaftor- tezacaftor-deutivacaftor is not recommended.(1) DISCUSSION: Concurrent administration with efavirenz (a moderate inducer of CYP3A4) is predicted to decrease vanzacaftor and deutivacaftor area-under-curve (AUC) by 69% and 73%, respectively, and maximum concentration (Cmax) by 65% and 56%, respectively.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
ALYFTREK |
| Bictegravir/Efavirenz; Etravirine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz and etravirine may induce the metabolism of bictegravir via CYP3A4 and UGT1A1.(1-3) Efavirenz and etravirine are moderate CYP3A4 and UGT1A1 inducers.(2) CLINICAL EFFECTS: The concurrent use of bictegravir and efavirenz or etravirine may lead to decreased levels of bictegravir, which may result in the loss of therapeutic effect and development of resistance to bictegravir.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The HIV guidelines state that bictegravir and efavirenz or etravirine should not be coadministered.(3) DISCUSSION: In a single dose study, rifampin (a strong CYP3A4 and UGT1A1 inducer) decreased the maximum concentration (Cmax) and area-under-curve (AUC) levels of bictegravir by 28% and 75%, respectively.(1) |
BIKTARVY |
| Suzetrigine/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of suzetrigine.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may reduce the clinical effectiveness of suzetrigine.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of suzetrigine states that concurrent use of moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Concomitant administration of efavirenz (moderate CYP3A inducer) with suzetrigine is predicted to decrease suzetrigine and active metabolite M6-SUZ area-under-curve (AUC) by 63% and 60%, respectively, while suzetrigine maximum concentration (Cmax) is predicted to decrease by 29% and M6-SUZ Cmax is predicted to increase by 1.3-fold, respectively.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
JOURNAVX |
| Ranolazine/Moderate CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of ranolazine.(1,2) Concurrent use of agents that prolong the QTc interval may result in additive effects on the QTc interval.(1,2) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of ranolazine and increased risk of QT prolongation. The risk of potentially life-threatening arrhythmias including torsades de pointes may be increased.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of ranolazine states that the concurrent use of CYP3A4 inducers such as rifampin, rifabutin, rifapentine, phenobarbital, phenytoin, carbamazepine, and St. John's wort is contraindicated. Concurrent use of moderate CYP3A4 inducers should be avoided.(1) The UK manufacturer of ranolazine states that ranolazine should not be used in patients receiving CYP3A4 inducers.(2) If coadministration with another agent that prolongs QT is unavoidable, monitor for prolongation of the QTc interval. When concurrent therapy is warranted: consider obtaining serum calcium, magnesium, and potassium levels and monitoring EKG at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Concurrent rifampin (600 mg daily), strong inducer of CYP3A4, decreased ranolazine plasma concentrations by 95%.(1,2) The effects of a moderate CYP3A4 inducer on ranolazine concentrations has not been studied. Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(4) Moderate CYP3A4 inducers that prolong QT linked to this monograph include: efavirenz, pacritinib, and thioridazine.(5,6) |
ASPRUZYO SPRINKLE, RANOLAZINE ER |
| Atrasentan/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of atrasentan.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may reduce the clinical effectiveness of atrasentan.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of atrasentan states that concurrent use of moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: In a study, atrasentan trough concentration (Ctrough) decreased by 90% following coadministration of a single dose of 10 mg of atrasentan with rifampin (strong CYP3A4 inducer).(1) The effects of a moderate CYP3A4 inducer on atrasentan concentrations has not been studied. Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
VANRAFIA |
| Mavacamten/Moderate CYP2C19 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP2C19 inhibitors may decrease the metabolism of mavacamten.(1-3) CLINICAL EFFECTS: Concurrent use of a moderate CYP2C19 inhibitor increases plasma exposure of mavacamten which may increase the incidence and severity of adverse reactions of mavacamten.(1-3) PREDISPOSING FACTORS: CYP2C19 rapid and ultrarapid metabolizers may experience an increased incidence or severity of adverse effects.(1-3) PATIENT MANAGEMENT: The US manufacturer of mavacamten recommends initiating mavacamten at the recommended starting dosage of 2.5 mg orally once daily in patients who are on stable therapy with a moderate CYP2C19 inhibitor. Reduce dose by one level (i.e., 15 to 10 mg, 10 to 5 mg, or 5 to 2.5 mg) in patients who are on mavacamten treatment and intend to initiate a moderate CYP2C19 inhibitor. Schedule clinical and echocardiographic assessment 4 weeks after inhibitor initiation, and do not up-titrate mavacamten until 12 weeks after inhibitor initiation.(1) Avoid initiation of concomitant moderate CYP2C19 inhibitors in patients who are on stable treatment with 2.5 mg of mavacamten because a lower dose is not available.(1) For short-term use (e.g. 1 week), interrupt mavacamten therapy for the duration of the moderate CYP2C19 inhibitor. After therapy with the moderate CYP2C19 inhibitor is discontinued, mavacamten may be reinitiated at the previous dose immediately upon discontinuation.(1) The Canadian manufacturer of mavacamten states concomitant use with moderate CYP2C19 inhibitors is contraindicated.(2) The UK manufacturer of mavacamten states concomitant use with moderate CYP2C19 inhibitors is dependent on CYP2C19 phenotype. Labeling recommends: -In patients who are CYP2C19 poor metabolizers, moderate CYP2C19 inhibitors may be used concurrently without dose adjustment of mavacamten. Monitor left ventricular ejection fraction (LVEF) in 4 weeks then resume usual monitoring schedule. -In patient who are CYP2C19 intermediate, normal, rapid, or ultrarapid metabolizers: Moderate CYP2C19 inhibitors may be used concurrently without dose adjustment of mavacamten starting dose of 5 mg daily. If starting a moderate CYP2C19 inhibitor, reduce mavacamten dose by one dose level or discontinue 2.5 mg. Monitor LVEF in 4 weeks then resume usual monitoring schedule. -If CYP2C19 phenotype is unknown, consider a mavacamten starting dose of 2.5 mg daily. If starting a moderate CYP2C19 inhibitor, reduce mavacamten dose from 5 mg to 2.5 mg or discontinue mavacamten if on 2.5 mg. Monitor LVEF in 4 weeks then resume usual monitoring schedule.(3) DISCUSSION: Concomitant use of mavacamten (15 mg) with omeprazole (20 mg), a weak CYP2C19 inhibitor, once daily increased mavacamten area-under-curve (AUC) by 48% with no effect on maximum concentration (Cmax) in healthy CYP2C19 normal metabolizers and rapid metabolizers.(1) Moderate CYP2C19 inhibitors linked to this monograph include: abrocitinib, cannabidiol, efavirenz, esomeprazole, etravirine, moclobemide, omeprazole, stiripentol, triclabendazole.(4,5) |
CAMZYOS |
There are 42 moderate interactions.
The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.
| Drug Interaction | Drug Names |
|---|---|
| Cilostazol (Less Than or Equal To 50 mg BID)/Strong & Moderate CYP2C19 Inhibitors that Prolong QT SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP2C19 may inhibit the metabolism of cilostazol.(1-4) Both agents have been shown to prolong the QT interval.(1,5) CLINICAL EFFECTS: Concurrent use of strong or moderate inhibitors of CYP2C19 may result in elevated levels of 3,4-dehydro-cilostazol, a metabolite of cilostazol that is 4-7 times as active as cilostazol.(1) Concurrent use may also result in potentially life-threatening cardiac arrhythmias, including torsades de pointes(TdP).(6) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of cilostazol should be limited to 50 mg twice daily in patients receiving concurrent therapy with strong and moderate inhibitors of CYP2C19.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study in 20 subjects examined the effects of omeprazole (40 mg daily) on a single dose of cilostazol (100 mg). Concurrent omeprazole increased the cilostazol maximum concentration (Cmax) and area-under-curve (AUC) by 18% and 26%, respectively. The Cmax and AUC of the 3,4-dehydro-cilostazol metabolite of cilostazol increased 29% and 69%, respectively. The Cmax and AUC of the OPC-13213 metabolite of cilostazol decreased by 22% and 31%, respectively.(4) One or more of the drug pairs linked to this monograph have been included in a list of interactions that should be considered "high-priority" for inclusion and should not be inactivated in EHR systems. This DDI subset was vetted by an expert panel commissioned by the U.S. Office of the National Coordinator (ONC) for Health Information Technology. |
CILOSTAZOL |
| Lopinavir/Efavirenz; Nevirapine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz(1-3) and nevirapine(1,2,4) may induce the metabolism of lopinavir via CYP3A4. CLINICAL EFFECTS: The concurrent administration of efavirenz(1-3) or nevirapine(1,2,4) with lopinavir may result in decreased levels and clinical effectiveness of lopinavir. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Lopinavir/ritonavir should not be administered once daily in combination with either efavirenz or nevirapine. Administration of lopinavir/ritonavir with either efavirenz or nevirapine in patients less than 6 months of age is not recommended.(1) The US manufacturer of lopinavir/ritonavir states that the dose of lopinavir/ritonavir tablets should be 500/125 mg (two 200/50 mg tablets and one 100/25 mg tablet) twice daily in adults receiving concurrent efavirenz.(1) The US manufacturer of efavirenz states that a dosage increase to 600/150 mg of lopinavir/ritonavir twice daily may be considered in treatment-experienced patients receiving combination therapy in whom decreased susceptibility to lopinavir is suspected.(3) The US manufacturers of lopinavir/ritonavir(1) and nevirapine(4) states that the dose of lopinavir/ritonavir tablets should be 500/125 mg (two 200/50 mg tablets and one 100/25 mg tablet) twice daily in adults receiving concurrent nevirapine. The dose of lopinavir/ritonavir oral solution should be 520/130 mg (6.5 ml) twice daily in adults receiving concurrent efavirenz or nevirapine.(1,4) The US manufacturer of lopinavir/ritonavir states that pediatric patients aged 6 months to 18 years receiving efavirenz or nevirapine require a dosage increase to 300/75 mg/m2 of oral solution twice daily (not to exceed the recommended adult dose).(1) If weight-based dosing is preferred, patients weighing less than 15 kg should receive 13/3.25 mg/kg of lopinavir/ritonavir oral solution twice daily with food and patients weighing 15 kg to 45 kg should receive 11/2.75 mg/kg of lopinavir/ritonavir oral solution twice daily with food.(1,4) Refer to the current Kaletra tablet labeling for information on dosing Kaletra tablets in pediatric patients who can swallow tablets.(1) DISCUSSION: A study in 11 subjects examined the effects of concurrent administration of efavirenz (600 mg daily) with lopinavir/ritonavir (400/100 mg twice daily). When compared to 7 controls, concurrent administration resulted in decreases in the area-under-curve (AUC) and and minimum concentration (Cmin) lopinavir by 19% and 39%, respectively. Efavirenz AUC and Cmin decreased 16% and 16%, respectively.(1-3) There was no effect on ritonavir levels.(3) In a study in 19 subjects, concurrent efavirenz (600 mg daily) with lopinavir/ritonavir (500/125 mg twice daily) increased lopinavir maximum concentration (Cmax) and AUC by 12% and 6%, respectively, and decreased lopinavir Cmin by 10% when compared to lopinavir/ritonavir 400/100 mg twice daily alone.(1) In a study in 23 subjects, concurrent efavirenz (600 mg daily) with lopinavir/ritonavir (600/150 mg twice daily) increased lopinavir Cmax, AUC, and Cmin by 36%, 36%, and 32%, respectively, when compared to lopinavir/ritonavir (400/100 mg twice daily) without concurrent efavirenz.(1) A study compared 22 subjects taking concurrent nevirapine (200 mg twice daily) with lopinavir/ritonavir (400/100 mg twice daily) with 19 subjects taking lopinavir/ritonavir alone. Concurrent therapy decreased lopinavir Cmax, AUC, and Cmin by 19%, 27%, and 51%, respectively. Another study compared 12 subjects taking concurrent nevirapine (7 mg/kg or 4 mg/kg daily for 2 weeks, twice daily for 1 week) and lopinavir/ritonavir (300/75 mg/m2) with 15 subjects taking lopinavir/ritonavir alone. Concurrent therapy decreased lopinavir Cmax, AUC, and Cmin by 14%, 22%, and 55%, respectively.(4) Another study compared 5 subjects taking concurrent nevirapine (200 mg daily for 14 days, twice daily for 6 days) with 6 subjects taking lopinavir/ ritonavir alone. Concurrent therapy increased nevirapine Cmax, AUC, and Cmin by 5%, 8%, and 15% respectively.(1-3) In pediatric patients aged 6 months to 12 years, administration of 230/57.5 mg/m2 twice daily of lopinavir/ritonavir without nevirapine and 300/73 mg/m2 twice daily of lopinavir/ritonavir with nevirapine provided similar lopinavir plasma concentrations.(1) |
KALETRA, LOPINAVIR-RITONAVIR |
| Caspofungin/Efavirenz; Nevirapine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz and nevirapine may induce the metabolism of caspofungin via induction of unspecified hepatic CYP enzymes.(1) CLINICAL EFFECTS: The concurrent administration of caspofungin with either efavirenz or nevirapine may result in decreased levels and clinical effectiveness of caspofungin.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: In adult patients receiving concurrent therapy with efavirenz or nevirapine, the US manufacturer of caspofungin recommends that an increase in the daily dose of caspofungin to 70 mg (following the usual 70 mg loading dose) be considered.(1) In pediatric patients receiving concurrent therapy with efavirenz or nevirapine, the US manufacturer of caspofungin recommends that an increase in the daily dose of caspofungin to 70 mg/m2 (to a maximum of 70 mg daily, following the usual 70 mg/m2 loading dose) be considered.(1) DISCUSSION: Regression analyses of patient pharmacokinetic data suggests that administration of caspofungin with inducers and or mixed inducers/ inhibitors of drug clearance may result in clinically significant decreases in caspofungin concentrations. Therefore, the manufacturer of caspofungin recommends that an increase in the daily dose of caspofungin to 70 mg (following the usual 70 mg loading dose) be considered in patients receiving concurrent therapy with efavirenz or nevirapine. The efficacy of a 70 mg daily dose in patients who are not responding to the 50 mg daily dose is not known, but limited safety data suggests that it is well tolerated.(1) |
CANCIDAS, CASPOFUNGIN ACETATE |
| Rifabutin/Efavirenz SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz may induce the metabolism of rifabutin via CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent use of efavirenz may result in decreased levels and therapeutic failure of rifabutin.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of efavirenz recommends increasing the dose of rifabutin by 50% in patients receiving concurrent efavirenz. In regimens when rifabutin is only given 2 or 3 times per week, the manufacturer of efavirenz recommends doubling the dose of rifabutin.(1,2) DISCUSSION: In a study in 9 subjects, concurrent efavirenz (600 mg daily) and rifabutin (300 mg daily) decreased the rifabutin maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) by 32%, 38%, and by 45%, respectively. The efavirenz Cmin decreased by 12%.(1,2) In a study in 21 patients with tuberculosis and HIV infection, administration of twice weekly rifabutin (600 mg) with isoniazid (15 mg/kg) with efavirenz produced levels that adequately compensated for the efavirenz interaction. Efavirenz levels were 10% higher than in historical controls.(3) In a case report, a patient receiving efavirenz (600 mg daily, increased to 800 mg daily) had subtherapeutic efavirenz levels during concomitant use of rifabutin (450 mg daily). Expected clinical outcomes of efavirenz were seen 12 days after discontinuation of rifabutin.(4) In another case report, a patient receiving efavirenz experienced treatment failure with rifabutin.(5) |
RIFABUTIN, TALICIA |
| Atazanavir/Tenofovir disoproxil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tenofovir disoproxil may induce the metabolism of atazanavir.(1) It is unknown how atazanavir increases tenofovir disoproxil levels.(2) CLINICAL EFFECTS: Concurrent use of atazanavir and tenofovir disoproxil without concurrent ritonavir or cobicistat may result in decreased levels and effectiveness of atazanavir.(1-3) Concurrent use of atazanavir may result in increased levels and toxicity from tenofovir disoproxil.(2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of atazanavir states that patients on concurrent tenofovir disoproxil 300 mg daily should receive atazanavir 300 mg and ritonavir 100 mg once daily all as a single daily dose with food. Treatment-experienced patients on both tenofovir disoproxil and a H-2 antagonist should have their atazanavir dose increased to 400 mg with ritonavir 100 mg daily. Treatment-experienced pregnant patients in the second or third trimester on concurrent tenofovir disoproxil should also have their atazanavir dose increased to 400 mg with ritonavir 100 mg daily.(1) Atazanavir should not be administered with tenofovir disoproxil without concurrent ritonavir in adults or pediatric patients of at least 13 years of age and weighing at least 40 kg.(1-3) There are no data to recommend a dose of atazanavir with tenofovir disoproxil in pediatric patients weighing less than 40 kg.(1) Patients receiving concurrent therapy should be monitored for tenofovir associated adverse events and tenofovir should be discontinued in patients who experience adverse events.(1-2) The combination product containing efavirenz/emtricitabine/tenofovir disoproxil is not recommended for use in patients receiving atazanavir.(4) No dosage adjustment is required with the use of tenofovir alafenamide.(5) DISCUSSION: In a study in healthy subjects, concurrent atazanavir (400 mg daily) with tenofovir disoproxil fumarate (300 mg daily) decreased atazanavir area-under-curve (AUC), maximum concentration (Cmax), and minimum concentration (Cmin) by 25%, 21%, and 40%, respectively. The AUC, Cmax, and Cmin of tenofovir increased by 24%, 14%, and 22%, respectively.(1,2) In another study, atazanavir AUC, Cmax, and Cmin decreased by 25%, 28%, and 23%, respectively, when atazanavir (300 mg daily), ritonavir (100 mg daily), and tenofovir disoproxil fumarate (300 mg daily) were coadministered, when compared to the administration of atazanavir and ritonavir alone. However, these decreased levels were approximately 2.3-fold and 4-fold higher that the respective values for atazanavir (400 mg daily) alone.(1,2) Interim data suggests that rate of moderate or severe adverse effects is similar between atazanavir-treated patients and unboosted atazanavir-treated patients.(1) In a study of 12 subjects, the AUC, Cmax and Cmin of tenofovir disoproxil fumarate (300 mg daily) increased 37%, 34% and 29% respectively, when given with atazanavir (300 mg daily) and ritonavir (100 mg daily).(1) Because both efavirenz and tenofovir disoproxil decrease atazanavir concentrations and the effect of taking both on atazanavir pharmacokinetics has not been studied, the use of atazanavir with the combination product efavirenz/emtricitabine/tenofovir disoproxil is not recommended.(4) |
ATAZANAVIR SULFATE, REYATAZ |
| Levomethadone; Methadone/Efavirenz; Nevirapine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz(1-4) and nevirapine(4-6) may induce the metabolism of methadone by CYP2B6. Levomethadone is an enantiomer of methadone.(7) CLINICAL EFFECTS: Concurrent use of efavirenz or nevirapine may result in decreased levels and effectiveness of methadone and withdrawal symptoms. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving efavirenz or nevirapine should be monitored for decreased effectiveness of methadone and symptoms of methadone withdrawal. The dosage of methadone may need to be adjusted. DISCUSSION: In a study, efavirenz (600 mg daily) given for 3 weeks led to a decrease of levomethadone maximum concentration (Cmax) and area-under-curve (AUC) of 48 % and 57 %, respectively.(7) In a study of 11 patients receiving methadone maintenance therapy, the addition of efavirenz to their regimen decreased methadone Cmax and AUC by 45% and by 52%, respectively. Nine patients experienced withdrawal symptoms beginning at Day 8 of concurrent therapy.(1) The manufacturer of efavirenz states that concurrent use resulted in decreased methadone levels and signs of withdrawal. Subjects required an average methadone dosage increase of 22% to relieve symptoms.(2) There are case reports of methadone withdrawal symptoms in patients receiving efavirenz.(8,9) In a study in 20 HIV-positive patients receiving methadone maintenance therapy, the addition of nevirapine to their regimen decreased methadone AUC by 41%. Reductions in AUC were similar for racemic methadone (37%) and (R)-methadone (44%). Changes in AUC ranged from mild increases in three patients to decreases of up to 70%. Fourteen subjects experienced withdrawal symptoms and required methadone dosage adjustments. The median dosage adjustment was 15%.(5) In a study in 8 HIV-positive patients receiving methadone maintenance therapy, the addition of nevirapine resulted in withdrawal symptoms after 5-10 days of concurrent therapy.(6) In a study in 9 patients receiving methadone, the addition of nevirapine (200 mg daily for 14 days, then 200 mg twice daily for at least 7 days) increased the clearance of methadone by 3-fold and withdrawal symptoms. Dosage adjustments were required in 7 patients.(10) There are several case reports of methadone withdrawal following the addition of nevirapine.(11-15) |
DISKETS, METHADONE HCL, METHADONE HCL-0.9% NACL, METHADONE HCL-NACL, METHADONE INTENSOL, METHADOSE |
| Tenofovir/Selected Nephrotoxic Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tenofovir and other nephrotoxic agents may result in additive or synergistic effects on renal function and increase nephrotoxicity risk.(1) CLINICAL EFFECTS: Concurrent use of tenofovir and other nephrotoxic agents may result in renal toxicity and acute renal failure.(1) Reports of acute renal failure and Fanconi syndrome have been reported with tenofovir use.(2,3) However, this has been reported in 3 case reports and the renal failure may have been complicated by other pre-existing conditions.(2) PREDISPOSING FACTORS: Pre-existing renal dysfunction, long duration of use, low body weight, concomitant use of drugs that may increase tenofovir levels may increase the risk of nephrotoxicity.(1) PATIENT MANAGEMENT: The US prescribing information for tenofovir recommends avoiding concurrent or recent use of a nephrotoxic agent.(3) Evaluate renal function prior to initiation of concurrent therapy and continue renal function monitoring during therapy. Dose adjustments may be required for impaired renal function. Tenofovir should be avoided with high-dose or multiple NSAIDs. Alternatives to NSAIDs should be considered in patients at risk for renal dysfunction.(3) Patients receiving concurrent NSAIDs with tenofovir should be monitored for possible renal toxicity.(1,2) The dosing interval should be adjusted in patients with a baseline creatinine clearance of less than 50 ml/min.(1-3) DISCUSSION: From March 18, 2003 to December 1, 2005, Health Canada received 10 reports of nephrotoxic reactions with tenofovir. Three of these occurred following the addition of a NSAID to tenofovir therapy. In the first report, a patient maintained on tenofovir for 29 months developed acute renal failure and acute tubular necrosis requiring dialysis 5 days after beginning indomethacin (100 mg rectally twice daily). In the second report, a patient maintained on tenofovir for 7 months developed acute renal failure and acute tubular necrosis after taking 90 tablets of naproxen (375 mg) over 2 months. The patient died. In the third report, a patient maintained on tenofovir for over a year developed acute renal failure and nephrotic syndrome after 2 months of valdecoxib (20 mg daily) therapy. Symptoms subsided following discontinuation of valdecoxib.(1) |
ABELCET, ACYCLOVIR, ACYCLOVIR SODIUM, ACYCLOVIR SODIUM-0.9% NACL, AFINITOR, AFINITOR DISPERZ, AMBISOME, AMIKACIN SULFATE, AMPHOTERICIN B, AMPHOTERICIN B LIPOSOME, ANAPROX DS, ANJESO, ARTHROTEC 50, ARTHROTEC 75, ASTAGRAF XL, BROMFENAC SODIUM, BUPIVACAINE-KETOROLAC-KETAMINE, CALDOLOR, CAMBIA, CELEBREX, CELECOXIB, CISPLATIN, COMBOGESIC, COMBOGESIC IV, CONSENSI, COXANTO, CYCLOSPORINE, CYCLOSPORINE MODIFIED, DAYPRO, DICLOFENAC, DICLOFENAC POTASSIUM, DICLOFENAC SODIUM, DICLOFENAC SODIUM ER, DICLOFENAC SODIUM MICRONIZED, DICLOFENAC SODIUM-MISOPROSTOL, EC-NAPROSYN, ELYXYB, ENVARSUS XR, ETODOLAC, ETODOLAC ER, EVEROLIMUS, FELDENE, FENOPROFEN CALCIUM, FENOPRON, FLURBIPROFEN, FYARRO, GANCICLOVIR SODIUM, GENGRAF, GENTAMICIN SULFATE, GENTAMICIN SULFATE IN NS, HYDROCODONE-IBUPROFEN, IBU, IBUPAK, IBUPROFEN, IBUPROFEN LYSINE, IBUPROFEN-FAMOTIDINE, INDOCIN, INDOMETHACIN, INDOMETHACIN ER, INFLAMMACIN, INFLATHERM(DICLOFENAC-MENTHOL), KANAMYCIN SULFATE, KEMOPLAT, KETOPROFEN, KETOPROFEN MICRONIZED, KETOROLAC TROMETHAMINE, KIPROFEN, LODINE, LOFENA, LUPKYNIS, LURBIPR, MECLOFENAMATE SODIUM, MEFENAMIC ACID, MELOXICAM, METHOTREXATE, METHOTREXATE SODIUM, NABUMETONE, NABUMETONE MICRONIZED, NALFON, NAPRELAN, NAPROSYN, NAPROTIN, NAPROXEN, NAPROXEN SODIUM, NAPROXEN SODIUM CR, NAPROXEN SODIUM ER, NAPROXEN-ESOMEPRAZOLE MAG, NEOMYCIN SULFATE, NEOPROFEN, NEORAL, OXAPROZIN, PENTAM 300, PENTAMIDINE ISETHIONATE, PHENYLBUTAZONE, PIROXICAM, PROGRAF, R.E.C.K.(ROPIV-EPI-CLON-KETOR), RELAFEN DS, ROPIVACAINE-CLONIDINE-KETOROLC, ROPIVACAINE-KETOROLAC-KETAMINE, SANDIMMUNE, SIROLIMUS, SPRIX, STREPTOMYCIN SULFATE, SULINDAC, SUMATRIPTAN SUCC-NAPROXEN SOD, SYMBRAVO, TACROLIMUS, TACROLIMUS XL, TEMSIROLIMUS, TOBRAMYCIN, TOBRAMYCIN SULFATE, TOLECTIN 600, TOLMETIN SODIUM, TORISEL, TORONOVA II SUIK, TORONOVA SUIK, TORPENZ, TOXICOLOGY SALIVA COLLECTION, TRESNI, TREXIMET, VALACYCLOVIR, VALACYCLOVIR HCL, VALCYTE, VALGANCICLOVIR HCL, VALTREX, VANCOMYCIN, VANCOMYCIN HCL, VANCOMYCIN HCL-0.9% NACL, VANCOMYCIN HCL-D5W, VIMOVO, VIVLODEX, ZIPSOR, ZORTRESS, ZORVOLEX, ZOVIRAX, ZYNRELEF |
| Clarithromycin/NNRTIs SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz, etravirine, and nevirapine may induce the metabolism of clarithromycin via CYP3A4. Clarithromycin may inhibit the metabolism of etravirine by CYP3A4. Also, delavirdine may inhibit the metabolism of clarithromycin by CYP3A4. CLINICAL EFFECTS: Concurrent use of clarithromycin with efavirenz, etravirine, or nevirapine may alter blood levels of clarithromycin and its active metabolite, 14-OH-clarithromycin, resulting in decreased effectiveness and/or toxicity. Concurrent use of clarithromycin may increase etravirine levels. Concurrent use of clarithromycin with delavirdine may increase the levels and toxicities of clarithromycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of efavirenz,(1,2) etravirine,(3) and nevirapine(4) state that concurrent use with clarithromycin is not recommended and that alternative antibiotic agents, such as azithromycin, should be considered. If concurrent therapy is warranted, monitor patients closely for efficacy and adverse effects. No dosage adjustment of efavirenz(2) or the combination of efavirenz/emtricitabine/tenofovir(3) is recommended. The US manufacturer of delavirdine recommends that the dose of clarithromycin be reduced by 50% in patients with a CrCl of 30 ml/min to 60 ml/min. For patients with a CrCl of less than 30 ml/min, the dose of clarithromycin should be reduced by 75%. No adjustment is necessary in patients with normal renal function.(5) DISCUSSION: In a study in 11 subjects, concurrent efavirenz (400 mg) and clarithromycin (500 mg twice daily) decreased the maximum concentration (Cmax), AUC, and minimum concentration (Cmin) by 26%, 39%, and 53%, respectively. The Cmax, AUC, and Cmin of 14-OH-clarithromycin increased by 49%, 34%, and 26%, respectively. The Cmax of efavirenz increased by 11%. In uninfected subjects, 46% developed a rash during concurrent therapy.(1,2) In a study in 15 subjects, concurrent clarithromycin (500 mg twice daily) increased the Cmax, AUC, and Cmin of etravirine (dosage not stated) by 46%, 42%, and 46%, respectively. The Cmax, AUC, and Cmin of clarithromycin decreased by 34%, 39%, and 53%, respectively. The Cmax, AUC, and Cmin of 14-OH-clarithromycin increased by 33%, 21%, and 5%, respectively.(3) In a study in 15 subjects, concurrent nevirapine (200 mg daily for 14 days, then 200 mg twice daily for 14 days) and clarithromycin (500 mg twice daily) decreased the Cmax, AUC, and Cmin of clarithromycin by 23%, 31%, and 56%, respectively. The Cmax and AUC of 14-OH-clarithromycin increased by 47% and 42 %, respectively.(4) Although 14-OH-clarithromycin is an active metabolite, it has reduced activity against Mycobacterium avium-intracellulare complex.(4) In a study in 6 subjects, concurrent delavirdine (300 mg 3 times daily) with clarithromycin (500 mg 3 times daily) increased the area-under-curve (AUC) of clarithromycin by 100%. There was no effect on delavirdine levels.(5) |
CLARITHROMYCIN, CLARITHROMYCIN ER, LANSOPRAZOL-AMOXICIL-CLARITHRO, OMECLAMOX-PAK |
| Quetiapine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The use of quetiapine in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The US manufacturer of quetiapine states that concurrent use with agents known to prolong the QT interval should be avoided.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Although quetiapine was not associated with QT or QTc changes in clinical trials, QT prolongation has been reported in post-marketing reports in conjunction with the use of other agents known to prolong the QT interval.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(2) |
QUETIAPINE FUMARATE, QUETIAPINE FUMARATE ER, SEROQUEL, SEROQUEL XR |
| Bupropion/Moderate CYP2B6 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP2B6 inducers may induce the metabolism of bupropion.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP2B6 inducers may decrease the effectiveness of bupropion.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Consider the use of alternative agents in patients maintained on bupropion for psychiatric indications and inform patients that bupropion may not be effective for smoking cessation during concurrent moderate CYP2B6 inducers. If concurrent use is warranted, monitor patients for decreased levels and effectiveness if moderate CYP2B6 inducers are initiated. The dosage of bupropion may need to be increased; however, the maximum recommended dose of bupropion should not be exceed.(2) DISCUSSION: In a study in 16 healthy subjects, rifampin (600 mg/day, a moderate CYP2B6 inducer) increased bupropion (150 mg single dose) apparent clearance 2-fold and decreased the bupropion half-life by 48%. In addition, concurrent rifampin increased the maximum concentration (Cmax) of hydroxybupropion by 43% and decreased the hydroxybupropion area-under-curve (AUC) by 38%.(2) In a study with 34 subjects, the effects of 150 mg of bupropion alone and 150 mg of bupropion with carbamazepine (a strong CYP2B6 inducer) were compared. Carbamazepine decreased bupropion AUC by 90% and peak Cmax by 87%. In addition, hydroxybupropion peak concentration Cmax by 71% and AUC by 50%.(3) Moderate CYP2B6 inducers linked include: dipyrone, efavirenz, rifampin, and ritonavir.(4,5) |
APLENZIN, BUPROPION HCL, BUPROPION HCL SR, BUPROPION XL, FORFIVO XL, WELLBUTRIN SR, WELLBUTRIN XL |
| Fingolimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Fingolimod is a sphingosine 1-phosphate (S1P) receptor modulator. Initiation of fingolimod has a negative chronotropic effect leading to a mean decrease in heart rate of 13 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1-3) Fingolimod blocks the capacity of lymphocytes to egress from lymph nodes, reducing the number of lymphocytes in peripheral blood. The mechanism by which fingolimod exerts therapeutic effects in multiple sclerosis is unknown but may involve the reduction of lymphocyte migration into the central nervous system.(1-3) CLINICAL EFFECTS: The heart rate lowering effect of fingolimod is biphasic with an initial decrease usually within 6 hours, followed by a second decrease 12 to 24 hours after the first dose. Symptomatic bradycardia and heart block, including third degree block, have been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes. There is no consistent signal of increased incidence of QTc outliers, either absolute or change from baseline, associated with fingolimod treatment.(1-3) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to fingolimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to fingolimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: Patients with a baseline QTc interval greater than or equal to 500 milliseconds should not be started on fingolimod. Patients with pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, or a prolonged QTc interval prior to fingolimod initiation should receive cardiologist consultation to evaluate the risks of fingolimod therapy. In all patients, first dose monitoring is recommended to monitor for bradycardia for the first 6 hours. Check blood pressure and pulse hourly. ECG monitoring is recommended prior to dosing and at the end of the observation period. US monitoring recommendations include additional monitoring for the following patients:(1) If heart rate (HR) is less than 45 beats per minute (bpm), the heart rate 6 hours postdose is at the lowest value postdose, or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. Continuous overnight ECG monitoring is recommended in patients requiring pharmacologic intervention for symptomatic bradycardia, some preexisting heart and cerebrovascular conditions, prolonged QTc before dosing or during 6 hours observation, concurrent therapy with QT prolonging drugs, or concurrent therapy with drugs that slow heart rate or AV conduction. Consult the prescribing information for full monitoring recommendations. United Kingdom recommendations:(3) Obtain a 12-lead ECG prior to initiating fingolimod therapy. Consult a cardiologist for pretreatment risk-benefit assessment if patient has a resting heart rate less than 55 bpm, history of syncope, second degree or greater AV block, sick-sinus syndrome, concurrent therapy with beta-blockers, Class Ia, or Class III antiarrhythmics, heart failure or other significant cardiovascular disease. Perform continuous ECG monitoring, measure blood pressure and heart rate every hour, and perform a 12-lead ECG 6 hours after the first dose. Monitoring should be extended beyond 6 hours if symptomatic bradycardia or new onset of second degree AV block, Mobitz Type II or third degree AV block has occurred at any time during the monitoring period. If heart rate 6 hours after the first dose is less than 40 bpm, has decreased more than 20 bpm compared with baseline, or if a new onset second degree AV block, Mobitz Type I (Wenckebach) persists, then monitoring should also be continued. If fingolimod treatment is discontinued for more than two weeks, the effects on heart rate and conduction could recur. Thus, first dose monitoring precautions should be followed upon reintroduction of fingolimod. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: After the first dose of fingolimod, heart rate decrease may begin within an hour. Decline is usually maximal at approximately 6 hours followed by a second decrease 12 to 24 hours after the first dose. The second dose may further decrease heart rate, but the magnitude of change is smaller than the first dose. With continued, chronic dosing, heart rate gradually returns to baseline in about one month.(1,2) In a thorough QT interval study of doses of 1.25 or 2.5 mg fingolimod at steady-state, when a negative chronotropic effect of fingolimod was still present, fingolimod treatment resulted in a prolongation of QTc, with the upper boundary of the 90% confidence interval (CI) of 14.0 msec. The cause of death in a patient who died within 24 hour after taking the first dose of fingolimod was not conclusive; however a link to fingolimod or a drug interaction with fingolimod could not be ruled out.(1) |
FINGOLIMOD, GILENYA, TASCENSO ODT |
| Afatinib/P-glycoprotein (P-gp) Inducers; Phenobarbital SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Afatinib is a substrate of the intestinal efflux transporter P-glycoprotein (P-gp). Apalutamide, carbamazepine, efavirenz, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, and St. John's wort induce production of P-gp which may lead to decreased exposure to afatinib.(1,2) Phenobarbital may also induce the metabolism of afatinib.(1) Primidone is metabolized to phenobarbital. CLINICAL EFFECTS: Concurrent or recent use of P-glycoprotein inducers (apalutamide, carbamazepine, efavirenz, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, or St. John's wort), phenobarbital, or primidone may result in decreased levels and effectiveness of afatinib. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of afatinib recommends an increase of afatinib dose by 10 mg per day as tolerated in patients receiving chronic therapy with a P-gp inducer or phenobarbital.(1) Onset of induction is gradual and maximal induction may be delayed for many days or longer, depending upon the inducing agent and dose. If the P-gp inducer, phenobarbital, or primidone is stopped, the manufacturer of afatinib recommends resumption of previous afatinib dose 2 to 3 days after discontinuation of the inducing agent.(1) DISCUSSION: In a drug interaction study, co-administration of rifampin 600 mg once daily for 7 days decreased afatinib exposure 34%.(1) P-gp inducers include apalutamide, carbamazepine, efavirenz, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, and St. John's wort.(1,2) Based on 2 case reports(3,4) and in vitro studies,(5,6) the manufacturer of afatinib also includes phenobarbital as a P-gp inducer.(1) |
GILOTRIF |
| Exemestane/Selected Moderate-Weak CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: CYP3A4 inducers may induce the metabolism of exemestane.(1) CLINICAL EFFECTS: Concurrent use of a CYP3A4 inducer may result in decreased levels and effectiveness of exemestane.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of exemestane recommends that patients receiving concurrent therapy with a strong CYP3A4 inducer receive 50 mg of exemestane daily after a meal.(1) It may be prudent to consider a dosage increase for patients receiving weaker CYP3A4 inducers. DISCUSSION: In a study in 10 healthy postmenopausal subjects, pretreatment with rifampin (a strong CYP3A4 inducer, 600 mg daily for 14 days) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of a single dose of exemestane (25 mg) by 54% and 41%, respectively.(1) Strong inducers of CYP3A4 would be expected to decrease the AUC of a sensitive 3A4 substrate by 80% or more and include: carbamazepine, enzalutamide, mitotane, phenobarbital, phenytoin, rifabutin, rifampin, and St. John's wort.(1-3) Moderate inducers of CYP3A4 would be expected to decrease the AUC of a sensitive 3A4 substrate by 50-80% and include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) Weak inducers of CYP3A4 would be expected to decrease the AUC of a sensitive 3A4 substrate by 20-50% and include: armodafinil, bexarotene, brigatinib, brivaracetam, clobazam, danshen, darolutamide, dexamethasone, dicloxacillin, echinacea, elafibranor, enasidenib, eslicarbazepine, floxacillin, garlic, gingko, ginseng, glycyrrhizin, lorlatinib, meropenem-vaborbactam, methylprednisolone, nevirapine, omaveloxolone, oritavancin, oxcarbazepine, pioglitazone, pitolisant, quercetin, relugolix, rufinamide, sarilumab, sulfinpyrazone, suzetrigine, tazemetostat, tecovirimat, terbinafine, ticlopidine, topiramate, troglitazone, vemurafenib, vinblastine, and zanubrutinib.(2,3) |
AROMASIN, EXEMESTANE |
| Efavirenz/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Efavirenz has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of efavirenz with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) CYP2B6 genotype may also increase the risk of this interaction. Patients who are most susceptible to this interaction are patients who are CYP2B6 poor metabolizers with CYP2B6 *6/*6 allele.(3) PATIENT MANAGEMENT: The US manufacturer of efavirenz states alternatives should be considered when concurrent administration with a drug with a known risk of Torsade de Pointes or when administered to patients at higher risk of Torsade de Pointes. Limited information is available on the potential pharmacodynamic interaction between efavirenz and drugs that prolong the QT interval; however, QT prolongation has been observed with efavirenz.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A thorough QT study was conducted in the general population in 120 healthy subjects receiving efavirenz 600 mg daily. Time-matched differences in QTc with efavirenz compared to placebo was evaluated on day 11, at 6 hours post dose. The mean change in QTc was 5.2 msec and no change in QTc was greater than 10 msec.(4) In addition to the thorough QT study, the effect of efavirenz on the QTc interval was evaluated in 58 healthy subjects based on CYP2B6 genotype. CYP2B6 polymorphism was evaluated for each patient and results were the following: 65% with *1/*1 or *1/*4 allele (wild-type metabolizers), 26% with *1/*6 allele (intermediate metabolizers) and 9% with *6/*6 allele (slow metabolizers). Subjects with 2 copies of the CYP2B6*6 allele had significantly higher efavirenz exposure at steady-state (p<0.05). At steady-state concentrations of efavirenz, patients with CYP2B6 *1/*1 or *1/*6 alleles had no change in the QTc interval (p>0.05). However, patients with CYP2B6 *6/*6 allele had an increase in QTc mean +/- SD from 406 +/- 16.4 to 423 +/- 11.8 msec (p=0.02).(3) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(5) |
ADLARITY, AGRYLIN, ALFUZOSIN HCL ER, AMIODARONE HCL, AMIODARONE HCL-D5W, ANAGRELIDE HCL, APOKYN, APOMORPHINE HCL, ARICEPT, ARSENIC TRIOXIDE, ATOMOXETINE HCL, AVELOX IV, AZITHROMYCIN, BETAPACE, BETAPACE AF, CAPRELSA, CESIUM CHLORIDE, CHLOROQUINE PHOSPHATE, CHLORPROMAZINE HCL, CIPRO, CIPROFLOXACIN, CIPROFLOXACIN HCL, CIPROFLOXACIN-D5W, CLOZAPINE, CLOZAPINE ODT, CLOZARIL, CORVERT, DANZITEN, DASATINIB, DIFLUCAN, DIPRIVAN, DISOPYRAMIDE PHOSPHATE, DOFETILIDE, DONEPEZIL HCL, DONEPEZIL HCL ODT, DROPERIDOL, E.E.S. 200, E.E.S. 400, ELLENCE, EPIRUBICIN HCL, ERIBULIN MESYLATE, ERY-TAB, ERYPED 200, ERYPED 400, ERYTHROCIN LACTOBIONATE, ERYTHROCIN STEARATE, ERYTHROMYCIN, ERYTHROMYCIN ESTOLATE, ERYTHROMYCIN ETHYLSUCCINATE, ERYTHROMYCIN LACTOBIONATE, ERZOFRI, FANAPT, FARESTON, FLECAINIDE ACETATE, FLUCONAZOLE, FLUCONAZOLE-NACL, GATIFLOXACIN SESQUIHYDRATE, GRANISETRON HCL, HALAVEN, HALDOL DECANOATE 100, HALDOL DECANOATE 50, HALOPERIDOL, HALOPERIDOL DECANOATE, HALOPERIDOL DECANOATE 100, HALOPERIDOL LACTATE, IBUTILIDE FUMARATE, INVEGA, INVEGA HAFYERA, INVEGA SUSTENNA, INVEGA TRINZA, ISRADIPINE, LAPATINIB, LEVOFLOXACIN, LEVOFLOXACIN HEMIHYDRATE, LEVOFLOXACIN-D5W, MEMANTINE HCL-DONEPEZIL HCL ER, MOXIFLOXACIN, MOXIFLOXACIN HCL, MULTAQ, NAMZARIC, NEXAVAR, NEXTERONE, NILOTINIB HCL, NORPACE, NORPACE CR, NUEDEXTA, OFLOXACIN, ONAPGO, ONDANSETRON HCL, ONDANSETRON HCL-0.9% NACL, OXALIPLATIN, PACERONE, PALIPERIDONE ER, PAZOPANIB HCL, PENTAM 300, PENTAMIDINE ISETHIONATE, PIMOZIDE, PROCAINAMIDE HCL, PROPOFOL, QUINIDINE GLUCONATE, QUINIDINE SULFATE, RUBRACA, SANCUSO, SEVOFLURANE, SIGNIFOR, SIGNIFOR LAR, SORAFENIB, SOTALOL, SOTALOL AF, SOTALOL HCL, SOTYLIZE, SPRYCEL, STRATTERA, SUNITINIB MALATE, SUSTOL, SUTENT, TASIGNA, THIORIDAZINE HCL, THIORIDAZINE HYDROCHLORIDE, TIKOSYN, TOLTERODINE TARTRATE, TOLTERODINE TARTRATE ER, TOREMIFENE CITRATE, TRISENOX, TYKERB, ULTANE, UROXATRAL, VERSACLOZ, VIBATIV, VOTRIENT, ZELBORAF, ZITHROMAX, ZITHROMAX TRI-PAK, ZYKADIA |
| Ribociclib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of ribociclib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of ribociclib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid concurrent use of ribociclib with agents known to prolong the QT interval.(1) If concurrent therapy is deemed medically necessary, monitor patients closely. Obtain serum calcium, magnesium, and potassium levels and correct any electrolyte abnormalities at the beginning of each ribociclib cycle. Monitor ECG at baseline, Day 14 of the first cycle, at the beginning of the second cycle, and as necessary. If a prolonged QTc is noted, refer to ribociclib prescribing information for current dose modification and management instructions. Ribociclib may need to be interrupted, reduced, or discontinued.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Ribociclib has been shown to prolong the QTc interval in a concentration-dependent manner. At steady state, the mean increase in QTc interval exceeded 20 msec.(1) In MONALEESA-7, an increase of greater than 60 ms from baseline in the QTcF interval was observed in 14/87 (16%) of patients in the ribociclib and tamoxifen combination group.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
KISQALI |
| Selected Nephrotoxic Agents/Immune Globulin IV (IGIV) SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Immune Globulin Intravenous (IGIV) products, particularly those containing sucrose, can cause renal dysfunction, acute renal failure, osmotic nephrosis, and/or death. Concurrent administration of other nephrotoxic agents may result in additive or synergistic effects on renal function.(1-4) CLINICAL EFFECTS: Concurrent use of Immune Globulin Intravenous (IGIV) products with nephrotoxic agents such as adefovir, intravenous aminoglycosides, amphotericin B, non-steroidal anti-inflammatory agents, tenofovir, and vancomycin may result in renal toxicity.(1-4) Other nephrotoxic agents include capreomycin, gallium nitrate, and streptozocin. PREDISPOSING FACTORS: Patients at risk of acute renal failure include those with any degree of pre-existing renal insufficiency, diabetes mellitus, advanced age (above 65 years of age), volume depletion, sepsis, paraproteinemia, or receiving known nephrotoxic drugs.(1-4) Renal dysfunction and acute renal failure occur more commonly in patients receiving IGIV products containing sucrose.(3-4) PATIENT MANAGEMENT: For patients at risk of renal dysfunction or renal failure, the US manufacturers of Immune Globulin Intravenous (IGIV) products recommends administration at the minimum dose and infusion rate practicable; ensure adequate hydration in patients before administration; and monitor renal function and urine output with assessment of blood urea nitrogen (BUN) and serum creatinine before initial infusion and at regular intervals during therapy.(1-3) Concurrent administration of potentially nephrotoxic agents should be avoided.(1) Review prescribing information for IGIV product to be administered for sucrose content. If concurrent therapy is warranted, monitor renal function closely. In high risk patients, consider selecting an IGIV product that does not contain sucrose. DISCUSSION: The safety of Immune Globulin Intravenous (IGIV) has not been studied in patients receiving other known potentially nephrotoxic agents. Renal impairment is a major toxicity of IGIV products.(1-3) A review of the FDA renal adverse events (RAEs) (i.e. acute renal failure or insufficiency) from June 1985 to November 1998 identified 120 reports worldwide associated with IGIV administration. In the US, the FDA received 88 reports of cases with clinical and/or laboratory findings consistent with RAE (i.e. increased serum creatinine, oliguria, and acute renal failure). Patient cases involved a median age of 60.5 years and 55% were male. Of the 54 patients who developed acute renal failure, 65% were greater than 65 years, 56% had diabetes, and 26% had prior renal insufficiency; 59% had one, 35% had two, and 6% had three of these conditions. Upon review of the IGIV product received, 90% of cases received sucrose-containing IGIV products with the remaining patients receiving either maltose- or glucose-containing products. Approximately 40% of affected patients required dialysis and RAE may have contributed to death in 15% of patients.(4) |
ALYGLO, BIVIGAM, CUTAQUIG, CUVITRU, FLEBOGAMMA DIF, GAMMAGARD LIQUID, GAMMAGARD S-D, GAMMAKED, GAMMAPLEX, GAMUNEX-C, HIZENTRA, HYQVIA, HYQVIA IG COMPONENT, OCTAGAM, PANZYGA, PRIVIGEN, XEMBIFY |
| Perampanel/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong and moderate CYP3A4 inducers may induce the metabolism of perampanel by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of strong and moderate CYP3A4 inducers and perampanel may result in decreased levels and clinical effectiveness of perampanel.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Patients receiving concurrent therapy with strong and moderate CYP3A4 inducers and perampanel should be observed for decreased anticonvulsant levels and clinical effectiveness. The manufacturer of perampanel recommends a starting dose of 4 mg once daily at bedtime in patients receiving concurrent therapy with CYP3A4 inducers. Dose increases are recommended by 2 mg increments once daily based on clinical response and tolerability, no more frequently than at weekly intervals. The highest studied dose with concurrent enzyme-inducing antiepileptic drugs was 12 mg once daily.(1) The dose of the anticonvulsant may need to be adjusted if a strong or moderate CYP3A4 inducer is added to or removed from therapy.(1) DISCUSSION: In a study in healthy subjects, carbamazepine 300 mg BID decreased the maximum concentration (Cmax) and area-under-curve (AUC) of a single 2 mg tablet dose of perampanel by 26% and 67%, respectively. The half-life (t1/2) of perampanel was shortened from 56.8 hours to 25 hours. In clinical studies examining partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 64% in patients on carbamazepine compared to the AUC in patients not on enzyme-inducing antiepileptic drugs.(1) In a study in partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 48% in patients on oxcarbazepine compared to patients not on enzyme-inducing antiepileptic drugs.(1) In a study in partial-onset and primary generalized tonic-clonic seizures, a population pharmacokinetic analysis showed that perampanel AUC was reduced by 43% in patients on phenytoin compared to patients not on enzyme-inducing antiepileptic drugs.(1) In a study in partial-onset and primary generalized tonic-clonic seizures in clinical trials (40 patients co-administered phenobarbital and 9 patients co-administered primidone), no significant effect on perampanel AUC was found. A modest effect of phenobarbital and primidone on perampanel concentrations cannot be excluded.(1) In a study in 76 patients, concentration-to-dose (CD) ratio of perampanel was assessed with and without concurrent antiepileptic agents. In patients only on perampanel the mean CD ratio was 3963 ng/mL/mg/kg (range: 1793-13,299) compared to the mean CD ratio in patients using enzyme-inducing AEDs [1760 (range: 892-3090), 2256 (range: 700-4703), and 1120 (range: 473-1853) ng/mL/mg/kg in patients taking phenytoin, phenobarbital, and carbamazepine, respectively], and carbamazepine had a significantly greater reduction in the CD ratio compared with phenytoin or phenobarbital (P < 0.001).(3) Strong and moderate CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, bosentan, carbamazepine, cenobamate, dabrafenib, efavirenz, elagolix, encorafenib, enzalutamide, eslicarbazepine, etravirine, fosphenytoin, ivosidenib, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, oxcarbazepine, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(1,2) |
FYCOMPA |
| Encorafenib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Concurrent use of encorafenib with agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of encorafenib with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Avoid the concurrent use of encorafenib with medications that prolong the QT interval.(1) Recommended dosage modifications for encorafenib and QTc prolongation adverse reactions include: - QTcF greater than 500 ms and less than or equal to 60 ms increase from baseline: Withhold encorafenib until QTcF less than or equal to 500 ms. Resume at reduced dose. If more than one recurrence, permanently discontinue encorafenib. - QTcF greater than 500 ms and greater than 60 ms increase from baseline: Permanently discontinue encorafenib.(1) See prescribing information for additional information regarding dose reductions.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Encorafenib has been associated with a dose-dependent QTc interval prolongation. Following administration of encorafenib in combination with binimetinib, the largest mean (90% CI) QTcF change from baseline was 18 ms (14-22 ms), based on central tendency analysis.(1) Following administration of encorafenib in combination with cetuximab and mFOLFOX6, an increase of QTcF >500 ms was measured in 3.6% (8/222) of patients.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
BRAFTOVI |
| Oxcarbazepine/Selected UGT and Strong CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Oxcarbazepine is metabolized by CYP3A4 to the active metabolite, eslicarbazepine, which is conjugated by UDP-glucuronosyltransferase (UGT) enzymes. Strong CYP3A4 inducers and UGT inducers decrease exposure to eslicarbazepine.(3) CLINICAL EFFECTS: Concurrent use of oxcarbazepine with UGT inducers and strong CYP3A4 inducers may lead to decreased levels and effectiveness of oxcarbazepine, e.g loss of seizure control.(3) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: For patients stabilized on UGT or strong CYP3A4 inducers, the US manufacturer of extended release oxcarbazepine recommends initiating extended release oxcarbazepine at 900 mg once daily in adults and 12-15 mg/kg once daily (not to exceed 900 mg per day in the first week) in pediatric patients.(3) If a strong CYP3A4 inducer or UGT inducer is added in a patient stabilized on oxcarbazepine, the dose of oxcarbazepine may need to be increased. Onset of induction is gradual and may not be maximal for days or weeks. If a strong CYP3A4 inducer or UGT inducer is discontinued in a patient stabilized on oxcarbazepine, the concentration of oxcarbazepine will increase over 1 to 4 weeks. Monitor serum levels and adjust dosages as needed. DISCUSSION: In interaction studies, phenytoin doses of 250 mg to 500 mg daily decreased the concentration of oxcarbazepine's active metabolite (eslicarbazepine) by approximately 30%.(3) Similarly, phenobarbital doses of 100 mg to 150 mg daily decreased the mean concentration of eslicarbazepine by 25%.(3) UGT and strong CYP3A inducers linked to this monograph include: apalutamide, carbamazepine, efavirenz, encorafenib, enzalutamide, etravirine, ivosidenib, lorlatinib, lumacaftor, mitotane, rifampin, rifapentine, and St. John's wort.(1-2) |
OXCARBAZEPINE, OXCARBAZEPINE ER, OXTELLAR XR, TRILEPTAL |
| Hydroxychloroquine/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Hydroxychloroquine has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of hydroxychloroquine with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of hydroxychloroquine states that hydroxychloroquine should not be administered with other agents that prolong the QT interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: The manufacturer states that hydroxychloroquine has been shown to prolong the QT interval;(1) however, conditions that hydroxychloroquine treats have also been associated with QT prolongation. Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) |
HYDROXYCHLOROQUINE SULFATE, PLAQUENIL, SOVUNA |
| Ubrogepant/Moderate and Weak CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate or weak CYP3A4 inducers may induce the metabolism of ubrogepant.(1) CLINICAL EFFECTS: Concurrent use of a moderate or weak CYP3A4 inducer may result in decreased levels and effectiveness of ubrogepant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer recommends a dosage adjustment of ubrogepant when coadministered with moderate or weak CYP3A4 inducers. Initial dose of ubrogepant should be 100 mg. If a second dose is needed, the dose of ubrogepant should be 100 mg.(1) DISCUSSION: Coadministration of ubrogepant with rifampin, a strong CYP3A4 inducer, resulted in an 80% reduction in ubrogepant exposure. No dedicated drug interaction studies were conducted to assess concomitant use with moderate or weak CYP3A4 inducers. Dose adjustment for concomitant use of ubrogepant with moderate or weak CYP3A4 inducers is recommended based on a conservative prediction of 50% reduction in exposure of ubrogepant.(1) Moderate inducers of CYP3A4 would be expected to decrease the AUC of a sensitive 3A4 substrate by 50-80% and include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, rifabutin, telotristat, thioridazine, and tovorafenib.(2,3) Weak inducers of CYP3A4 would be expected to decrease the AUC of a sensitive 3A4 substrate by 20-50% and include: armodafinil, bexarotene, brigatinib, brivaracetam, clobazam, danshen, dexamethasone, dicloxacillin, echinacea, elafibranor, enasidenib, eslicarbazepine, floxacillin, garlic, genistein, ginseng, glycyrrhizin, meropenem-vaborbactam, methylprednisolone, nevirapine, omaveloxolone, oritavancin, oxcarbazepine, pioglitazone, pitolisant, relugolix, repotrectinib, rufinamide, sarilumab, sulfinpyrazone,suzetrigine, tazemetostat, tecovirimat, terbinafine, ticlopidine, topiramate, troglitazone, vemurafenib, vinblastine, and zanubrutinib.(2,3) |
UBRELVY |
| Rolapitant/Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rolapitant is metabolized primarily by CYP3A4. Moderate inducers of CYP3A4 may increase the metabolism and clearance of rolapitant via CYP3A4.(1) CLINICAL EFFECTS: Concurrent use with moderate inducers of CYP3A4 may result in significantly decreased levels and effectiveness of rolapitant.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The UK manufacturer of rolapitant states that rolapitant is not recommended in patients already taking moderate CYP3A4 inducers.(1) If concomitant use is warranted, monitor the patient for decreased antiemetic efficacy. When possible and clinically appropriate, consider use of an alternative antiemetic or alternatives to the moderate CYP3A4 inducer. DISCUSSION: The effect of moderate CYP3A4 inducers on rolapitant has not been studied. The UK manufacturer of rolapitant does not recommend the concurrent use of rolapitant with moderate CYP3A4 inducers. Rifampin (600 mg daily for 14 days), a strong CYP3A4 inducer, decreased the Cmax and AUC of a single dose of rolapitant (180 mg on Day 7) by 30% and 85%, respectively. The half-life of rolapitant decreased from 176 hours to 41 hours.(3) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
VARUBI |
| Amisulpride/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Amisulpride has been shown to prolong the QT interval. Concurrent use with QT prolonging agents may result in additive effects on the QT interval.(1) CLINICAL EFFECTS: The concurrent use of amisulpride with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Use caution when using amisulpride concurrently with other agents that can prolong the QT interval. Amisulpride may cause a dose and concentration dependent increase in the QTc interval. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. ECG monitoring is recommended in patients with pre-existing arrhythmias or cardiac conduction disorders; electrolyte abnormalities; congestive heart failure; or in patients taking medications or with other medical conditions known to prolong the QT interval. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: QT prolongation and torsades de pointes have been reported with amisulpride. In a study in 40 patients with post operative nausea and vomiting, amisulpride increased baseline QTcF by 5 msec after a 2-minute intravenous infusion of 5 mg and by 23.4 msec after an 8-minute intravenous infusion of 40 mg. Based on an exposure-response relationship, it is expected that a 10 mg intravenous infusion over 1 minute may increase the QTcF by 13.4 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
BARHEMSYS |
| Osilodrostat/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Osilodrostat has been shown to prolong the QT interval. Concurrent use with QT prolonging agents may result in additive effects on the QT interval.(1) CLINICAL EFFECTS: The concurrent use of osilodrostat with agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Use caution when using osilodrostat concurrently with other agents that can prolong the QT interval and consider more frequent ECG monitoring. A dose-dependent QT interval prolongation was noted in clinical studies. Prior to initiating therapy with osilodrostat, obtain a baseline ECG and monitor for QTc interval changes thereafter. Consider temporary discontinuation of therapy if the QTc interval increases > 480 msec. When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2) DISCUSSION: QTc prolongation has been reported with osilodrostat. In a thorough QT study in 86 healthy patients, osilodrostat increased baseline QTcF by 1.73 msec at a 10 mg dose and 25.38 msec at a 150 mg dose (up to 2.5 times the maximum recommended dosage). The predicted mean placebo-corrected QTcF at the highest recommended dose in clinical practice (30 mg twice daily) was estimated as 5.3 msec.(1) In a clinical study, five patients (4%) were reported to have an event of QT prolongation, three patients (2%) had a QTcF increase of > 60 msec from baseline, and 18 patients (13%) had a new QTcF value of > 450 msec.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
ISTURISA |
| Artesunate/Strong UGT Inducers; Nevirapine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong inducers of UDP-glucuronosyltransferase (UGT) and nevirapine may increase the metabolism of dihydroartemisinin (DHA, the active metabolite of artesunate).(1) CLINICAL EFFECTS: Concurrent use of carbamazepine, efavirenz, etravirine, fosphenytoin, nevirapine, phenobarbital, phenytoin, primidone, rifampin, or ritonavir may result in decreased levels and effectiveness of DHA.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If coadministration of strong UGT inducers or nevirapine with artesunate is necessary, monitor for possible reduced antimalarial efficacy.(1) DISCUSSION: In a study, nevirapine decreased the maximum concentration (Cmax) and area-under-curve (AUC) of DHA by 59% and 68%, respectively.(1) In a study of healthy volunteers, ritonavir (100 mg twice daily for 7 days) decreased the Cmax and AUC of DHA by 27% and 38%, respectively.(1,2) A study of healthy subjects who were coadministered lopinavir-ritonavir 400 mg-100 mg twice daily for 14 days) and artesunate-mefloquine found that artesunate Cmax and AUC decreased by 37% and 45%, respectively, compared to artesunate-mefloquine alone.(3) Agents linked to this monograph include: carbamazepine, efavirenz, etravirine, fosphenytoin, nevirapine, phenobarbital, phenytoin, primidone, rifampin, and ritonavir. |
ARTESUNATE |
| Citalopram;Escitalopram/Slt 2C19&3A4 Inducer that Prolong QT SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Dual CYP2C19 and CYP3A4 inducers that prolong the QTc interval may induce the metabolism of citalopram and escitalopram and result in additive risk of QT prolongation.(1,2) CLINICAL EFFECTS: Concurrent use of dual CYP2C19 and CYP3A4 inducers that prolong QT may decrease systemic levels and effectiveness of citalopram and escitalopram and may cause additive effects on the QTc interval, which may result in life-threatening cardiac arrhythmias including torsades de pointes.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: When used concomitantly with CYP2C19 and CYP3A4 inducers, monitoring of concentrations or dosage adjustment of citalopram may be necessary.(1) Concurrent use of citalopram with agents known to prolong the QT interval should be avoided.(1) Due to the risk of QT prolongation, citalopram doses greater than 40 mg once daily are not recommended. Citalopram doses should be limited to 20 mg once daily in patients who are CYP2C19 poor metabolizers or patients receiving CYP2C19 inhibitors.(1) If patients have a persistent QTc measurement > 500 ms, discontinue citalopram. If a patient develops symptoms including dizziness, palpitations, or syncope, further evaluation is warranted included cardiac monitoring.(1) While the US FDA and manufacturer recommend no special precautions when escitalopram is used with QT prolonging agents,(3,4) Health Canada and the Canadian manufacturer of escitalopram discourage the concurrent use of agents known to prolong the QT interval(5,6) and the UK manufacturer states that concurrent use is contraindicated.(7) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Citalopram has been associated with dose-depended increases in the QTc interval. In healthy subjects, the maximum mean difference in QTc interval seen with 20 mg of citalopram and 60 mg of citalopram were 8.5 msec (90% CI = 6.2-10.8 msec) and 18.5 msec (90% CI = 16.0-21.0 msec), respectively. Based on extrapolation, a 40 mg dose of citalopram is expected to produce a mean increase in the QTc interval of 12.6 msec (90% CI = 10.9-14.3 msec).(1) In a clinical trial of use of citalopram for agitation in Alzheimer's disease, citalopram (30 mg daily) was associated with a mean increase in QTc of 18.1 msec.(8) Combined administration of racemic citalopram (40 mg/day for 14 days) and carbamazepine (a dual CYP3A4 and CYP2C19 inducer) titrated to 400 mg/day for 35 days did not affect citalopram plasma trough levels. Given the enzyme-inducing properties of carbamazepine, the possibility that carbamazepine might increase the clearance of escitalopram should be considered if the two drugs are coadministered.(1,3) A case report of a 55-year-old man receiving citalopram for panic disorder reported a decrease in the agent's therapeutic efficacy when rifampin was started. His condition improved when rifampin was stopped.(9) Dual CYP2C19 and CYP3A4 inducers that prolong QT linked to this monograph include: efavirenz and pacritinib.(10,11) |
CELEXA, CITALOPRAM HBR, ESCITALOPRAM OXALATE, LEXAPRO |
| Galantamine/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Galantamine may reduce heart rate by increasing acetylcholine in the heart and increasing vagal tone. Bradycardia has been associated with increased risk of QTc interval prolongation.(1) Concurrent use of galantamine with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(2) CLINICAL EFFECTS: The use of galantamine in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, advanced age or when receiving concomitant treatment with an inhibitor of CYP3A4.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: The UK manufacturer of galantamine states that it should be used with caution in patients treated with drugs that affect the QTc interval.(2) If concurrent therapy is warranted, monitor ECG more frequently and consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Therapeutic doses of galantamine have been reported to cause QTc prolongation in patients.(2) An 85 year old male with dementia was restarted on galantamine 8 mg daily after a 2-week treatment interruption due to a syncopal episode that occurred 3 months previously. During his prior syncopal episode, he was hypotensive and bradycardic, but QTc interval was normal. After restarting galantamine, he was found to be hypotension and bradycardiac again, and QTc interval was significantly prolonged to 503 msec, over 60 msec longer than when he was off galantamine. Galantamine was discontinued and his QTc interval returned to baseline.(4) A 47 year old schizophrenic male experienced prolongation of the QTc interval to 518 msec after galantamine was increased from 8 mg daily to 12 mg daily. Although he was also on quetiapine and metoprolol, he had been stable on his other medications. His QTc interval normalized after galantamine was stopped.(5) The European pharmacovigilance (Eudravigilance) database contains 14 reports of torsades de pointe in patients on galantamine as of October 2019.(1) A pharmacovigilance study based on the FDA Adverse Event Reporting System (FAERS) database found that, of a total of 33,626 cases of TdP/QT prolongation reported between January 2004 and September 2022, 54 cases occurred in patients on galantamine. The disproportionality analysis found a ROR = 5.12, 95% CI (3.92,6.68) and a PRR = 5.11, chi-square = 175.44.(6) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(7) |
GALANTAMINE ER, GALANTAMINE HBR, GALANTAMINE HYDROBROMIDE, ZUNVEYL |
| Ponesimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ponesimod is a sphingosine 1-phosphate (S1P) receptor 1 modulator. Initiation of ponesimod has a negative chronotropic effect leading to a mean decrease in heart rate of 6 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1) CLINICAL EFFECTS: After a dose of ponesimod, a decrease in heart rate typically begins within an hour and reaches its nadir within 2-4 hours. The heart rate typically recovers to baseline levels 4-5 hours after administration. All patients recovered from bradycardia. The conduction abnormalities typically were transient, asymptomatic, and resolved within 24 hours. Second- and third-degree AV blocks were not reported. With up-titration after Day 1, the post-dose decrease in heart rate is less pronounced. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1,2) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to ponesimod initiation, factors associated with QTc prolongation, or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to ponesimod.(1) The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Prior to initiation of ponesimod, obtain an ECG to determine if preexisting conduction abnormalities are present. Ponesimod is generally not recommended in patients who are receiving concurrent treatment with a QT prolonging agent, anti-arrhythmic drugs, or drugs that may decrease heart rate. Consultation with a cardiologist is recommended.(1) In patients with heart rate (HR) less than 55 beats per minute (bpm), first- or second-degree AV block, or history of myocardial infarction or heart failure, monitor patients for 4 hours after the first dose for signs and symptoms of bradycardia with a minimum of hourly pulse and blood pressure measurements. Obtain an ECG in these patients prior to dosing and at the end of the 4-hour observation period.(1) Additional US monitoring recommendations include: If HR is less than 45 bpm, the heart rate 4 hours post-dose is at the lowest value post-dose or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. If patient requires treatment for symptomatic bradycardia, second-degree or higher AV block, or QTc interval greater than or equal to 500 msec, perform continuous overnight ECG monitoring and repeat the first dose monitoring strategy for the second dose of ponesimod. Consult the prescribing information for full monitoring recommendations. If fewer than 4 consecutive doses are missed during titration: resume treatment with the first missed titration dose and resume the titration schedule at that dose and titration day. If fewer than 4 consecutive doses are missed during maintenance: resume treatment with the maintenance dosage. If 4 or more consecutive daily doses are missed during treatment initiation or maintenance treatment, reinitiate Day 1 of the dose titration (new starter pack) and follow first-dose monitoring recommendations. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: After the first dose of ponesimod, heart rate decrease may begin within the first hour. Decline is usually maximal at approximately 4 hours. With continued, chronic dosing, post-dose decrease in heart rate is less pronounced. Heart rate gradually returns to baseline in about 4-5 hours.(1) |
PONVORY |
| Ozanimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Ozanimod is a sphingosine 1-phosphate (S1P) receptor modulator. Initiation of ozanimod has a negative chronotropic effect leading to a mean decrease in heart rate of 13 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block.(1,2) Ozanimod blocks the capacity of lymphocytes to egress from lymph nodes, reducing the number of lymphocytes in peripheral blood. The mechanism by which ozanimod exerts therapeutic effects in multiple sclerosis is unknown but may involve the reduction of lymphocyte migration into the central nervous system. CLINICAL EFFECTS: The initial heart rate lowering effect of ozanimod usually occurs within 5 hours. With continued up-titration, the maximal heart rate effect of ozanimod occurred on Day 8. Symptomatic bradycardia and heart block, including third degree block, have been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1,2) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to ozanimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to ozanimod.(1,2) The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Prior to initiation of ozanimod, obtain an ECG to determine if preexisting conduction abnormalities are present. Patients with preexisting cardiac conditions, significant QT prolongation (QTc >450 msec in males, >470 msec in females), concurrent Class Ia or Class III antiarrhythmics, or receiving concurrent treatment with a QT prolonging agent at the time ozanimod is initiated or resumed should be referred to a cardiologist.(1) The US recommendations state: Dose titration is recommended with initiation of ozanimod due to transient decrease in heart rate and AV conduction delays.(1) United Kingdom recommendations:(2) Due to the risk of transient decreases in HR with the initiation of ozanimod, first dose, 6-hour monitoring for signs and symptoms of symptomatic bradycardia is recommended in patients with resting HR <55 bpm, second-degree [Mobitz type I] AV block or a history of myocardial infarction or heart failure. Patients should be monitored with hourly pulse and blood pressure measurement during this 6-hour period. An ECG prior to and at the end of this 6-hour period is recommended. Additional monitoring after 6 hours is recommended in patients with: heart rate less than 45 bpm, heart rate at the lowest value post-dose (suggesting that the maximum decrease in HR may not have occurred yet), evidence of a new onset second-degree or higher AV block at the 6-hour post dose ECG, or QTc interval greater than 500 msec. In these cases, appropriate management should be initiated and observation continued until the symptoms/findings have resolved. Instruct patients to report any irregular heartbeat, dizziness, or fainting.(2,3) DISCUSSION: After the first dose of ozanimod heart rate decline is usually maximal at approximately 5 hours, returning to baseline at 6 hours. With continued, chronic dosing, maximum heart rate effect occurred on day 8.(1,2) |
ZEPOSIA |
| Sensitive CYP2B6 Substrates that Prolong QT/Midostaurin SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Midostaurin may induce the metabolism of CYP2B6 substrates.(1) Midostaurin may also prolong the QT interval. Concurrent use of midostaurin with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent midostaurin may result in decreased levels of sensitive CYP2B6 substrates, which may result in a decrease in or failure of clinical response.(1) The use of midostaurin in patients maintained on agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of midostaurin recommends caution in patients treated with CYP2B6 substrates that affect the QTc interval. If concurrent use is warranted, monitor patients for an adequate clinical response. The dosage of the CYP2B6 substrate may need to be adjusted, or alternative agents may need to be selected. Monitor ECG more frequently and consider obtaining serum calcium, magnesium, and potassium levels at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study, multiple doses of midostaurin (50 mg twice daily) decreased the area-under-curve (AUC) of a single dose of bupropion by 48% and of bupropion's metabolite, hydroxybupropion by 65%.(1) In a randomized study of midostaurin 75 mg twice daily for 3 days there was no clinically significant prolongation of QTc interval or relationship between changes in QTc and concentrations for midostaurin and its active metabolites (CGP62221 and CGP52421). However the study noted the duration was not long enough to estimate the effects of the metabolite CGP52421 on the QTc interval.(1) In a pooled analysis in patients with advanced systemic mastocytosis (SM), 4.7% of patients had a post-baseline QTcF > 480 ms, no patients had a QTcF > 500 ms, and 6.3% of patients had a QTcF > 60 ms compared to baseline.(1) In a randomized placebo-controlled study in patients with acute myeloid leukemia (AML), the proportion of patients with QTc prolongation was higher in the midostaurin group compared to placebo (QTcF > 480 ms: 10.1% vs 5.7%; QTcF > 500 ms: 6.2% vs 2.6%; QTcF > 60 ms change from baseline: 18.4% vs 10.7%).(1) Sensitive CYP2B6 substrates that prolong QT that are linked to this monograph include: efavirenz, levomethadone, and methadone.(3,4) |
RYDAPT |
| Panobinostat/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Panobinostat has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of panobinostat with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of panobinostat states concurrent use agents known to prolong the QT interval are not recommended. Panobinostat should not be started in patients with a QTcF > 450 msec or clinically significant baseline ST-segment or T-wave abnormalities. If during panobinostat therapy the QTcF increases to > 480 msec, interrupt treatment and correct any electrolyte abnormalities. If QT prolongation does not resolve, permanently discontinue treatment with panobinostat.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In the randomized multiple myeloma trial, QTc prolongation with values between 451 msec to 480 msec occurred in 10.8% of panobinostat treated patients and patients with values of 481 msec to 500 msec occurred in 1.3% of patients. A maximum QTcF increase from baseline of between 31 msec and 60 msec was reported in 14.5% of patients and a maximum QTcF increase from baseline of >60 msec was reported in 0.8% of patients.(1) Pooled clinical data from over 500 patients treated with single agent panobinostat in multiple indications and at different dose levels has shown that the incidence of CTC Grade 3 QTc prolongation (QTcF >500 msec) was approximately 1% overall and 5% or more at a dose of 60 mg or higher.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) |
FARYDAK |
| Triclabendazole/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Triclabendazole has been observed to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) Triclabendazole is partially metabolized by CYP1A2. Ciprofloxacin, propafenone, and vemurafenib are CYP1A2 inhibitors and may inhibit the CYP1A2 mediated metabolism of triclabendazole. CLINICAL EFFECTS: The concurrent use of triclabendazole with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) Hepatic impairment and concurrent use of CYP1A2 inhibitors may raise triclabendazole levels and increase the risk of QT prolongation.(1) PATIENT MANAGEMENT: The manufacturer of triclabendazole states concurrent use with agents known to prolong the QT interval should be used with caution. Monitor ECG in patients with a history of QTc prolongation, symptoms of long QT interval, electrolyte imbalances, concurrent CYP1A2 inhibitors, or hepatic impairment. If signs of a cardiac arrhythmia develop, stop treatment with triclabendazole and monitor ECG.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, a dose-dependent prolongation in the QTc interval was observed with triclabendazole. The largest placebo-corrected mean increase in QTc was 9.2 msec (upper limit of confidence interval (UCI): 12.2 msec) following oral administration of 10 mg/kg triclabendazole twice daily (at the recommended dose), and the largest placebo-corrected mean increase in QTc was 21.7 msec (UCI: 24.7 msec) following oral administration of 10 mg/kg triclabendazole twice daily for 3 days (3 times the approved recommended dosing duration).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(3) |
EGATEN |
| Tacrolimus/Moderate and Weak CYP3A4 Inducers that Prolong QT SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate or weak CYP3A4 inducers may accelerate the metabolism of tacrolimus.(1) In addition, concurrent use of tacrolimus and other agents that prolong the QT interval may result in additive or synergistic effects on the QTc interval.(1) CLINICAL EFFECTS: Concurrent use of a moderate or weak CYP3A4 inducer may result in decreased levels and effectiveness of tacrolimus.(1) In addition, concurrent administration of QT prolonging agents and tacrolimus may result in additive prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of tacrolimus recommends monitoring tacrolimus whole blood trough concentrations and adjusting tacrolimus dose if needed. Monitor clinical response closely.(1) Consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A 13-year-old cystic fibrosis patient with a history of liver transplant on stable doses of tacrolimus underwent 2 separate courses of nafcillin therapy (a moderate CYP3A4 inducer). During the 1st course of nafcillin, his tacrolimus levels started to fall 3 days after starting nafcillin, became undetectable at day 8, and recovered to therapeutic levels without a change in tacrolimus dose 5 days after discontinuation of nafcillin. During the 2nd course of nafcillin, tacrolimus level became undetectable 4 days after starting nafcillin and recovered 3 days after stopping nafcillin.(3) Tacrolimus has been associated with QT prolongation.(1) In a kidney transplant population, 98 patients received immunosuppressive management with tacrolimus, cyclosporine, everolimus, or azathioprine. All patients post-transplant had significantly prolonged QTc interval compared to pre-transplant in all groups.(4) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval but are generally accepted to have a risk of causing Torsades de Pointes. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or Torsades de Pointes in clinical trials and/or post-marketing reports.(5) Moderate inducers of CYP3A4 that prolong QT include: efavirenz, pacritinib, and thioridazine.(6,7) Weak inducers of CYP3A4 that prolong QT include: pitolisant and vemurafenib.(6,7) |
ASTAGRAF XL, ENVARSUS XR, PROGRAF, TACROLIMUS, TACROLIMUS XL |
| Bupropion Combinations/Moderate CYP2B6 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP2B6 inducers may induce the metabolism of bupropion.(1,2) For the dextromethorphan/bupropion combination, the metabolism of dextromethorphan may also be increased.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP2B6 inducers may decrease the effectiveness of bupropion.(1,2) For the dextromethorphan/bupropion combination, the levels and effectiveness of dextromethorphan may also be decreased.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Consider the use of alternative agents in patients maintained on bupropion for psychiatric indications and inform patients that bupropion may not be effective for smoking cessation during concurrent moderate CYP2B6 inducers. If concurrent use is warranted, monitor patients for decreased levels and effectiveness if moderate CYP2B6 inducers are initiated. The dosage of bupropion may need to be increased; however, the maximum recommended dose of bupropion should not be exceed.(2) DISCUSSION: In a clinical study, carbamazepine 200 mg decreased the maximum concentration (Cmax) and area-under-curve (AUC) of bupropion by 74% and 76%, respectively, and decreased the Cmax and AUC of dextromethorphan by 59% and 64%, respectively.(1) In a study with 34 subjects, the effects of 150 mg of bupropion alone and 150 mg of bupropion with carbamazepine (a strong CYP2B6 inducer) were compared. Carbamazepine decreased bupropion AUC by 90% and peak Cmax by 87%. In addition, carbamazepine increased hydroxybupropion Cmax by 71% and AUC by 50%.(3) In a study in 16 healthy subjects, rifampin (600 mg/day, a moderate CYP2B6 inducer) increased bupropion (150 mg single dose) apparent clearance 2-fold and decreased the bupropion half-life by 48%. In addition, concurrent rifampin increased the Cmax of hydroxybupropion by 43% and decreased the hydroxybupropion AUC by 38%.(4) Moderate CYP2B6 inducers linked include: dipyrone, efavirenz, rifampin, and ritonavir.(4,5) |
AUVELITY, CONTRAVE |
| Larotrectinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may increase the metabolism of larotrectinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of larotrectinib.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of larotrectinib states that the concurrent use of moderate CYP3A4 inducers requires a dose modification. Double the dose of larotrectinib when coadministered with moderate CYP3A4 inducers. After the moderate CYP3A4 inducer has been discontinued for 3 to 5 elimination half-lives, resume the larotrectinib dose at the dose taken prior to initiating the CYP3A4 inducer.(1) DISCUSSION: In a study, efavirenz (a moderate CYP3A4 inducer) was predicted to decrease area-under-curve (AUC) and maximum concentration (Cmax) by 72% and 60%, respectively, compared to larotrectinib administered alone.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(3-4) |
VITRAKVI |
| Adagrasib/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Adagrasib has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1-3) CLINICAL EFFECTS: The concurrent use of adagrasib with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of adagrasib states that the concurrent use of QT prolonging agents should be avoided.(1) When concurrent therapy cannot be avoided, obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) prior to the start of treatment, after initiation of any drug known to prolong the QT interval, and periodically monitor during therapy. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If patients develop QTc prolongation >500 msec or >60 msec from baseline, withhold adagrasib until QTc interval less than 481 msec or QTc interval returns to baseline. Resume adagrasib at the next lower dose level. If patients develop torsade de pointes, polymorphic ventricular tachycardia, or signs and symptoms of serious or life-threatening arrythmia, permanently discontinue adagrasib.(1) DISCUSSION: Adagrasib has been associated with QTc interval prolongation. Adagrasib increased QTc in a concentration-dependent manner. In patients administered adagrasib 600 mg twice daily, the mean QTcF change from baseline was 18 msec. In the pooled safety population, 6% of 366 patients with at least one post-baseline ECG had an average QTc greater than 501 msec and 11% of patients had a increase from baseline QTc greater than 60 msec.(1) Agents that are linked to this monograph may have been associated with Torsade de Pointes and/or QT prolongation but at this time lack substantial evidence for causing Torsade de Pointes.(3) |
KRAZATI |
| Sildenafil (PAH)/Strong and Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Sildenafil is metabolized by CYP3A4. Strong and moderate inducers of CYP3A4 may increase the metabolism of sildenafil.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in substantially decreased levels and effectiveness of sildenafil.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Concomitant use of sildenafil with strong or moderate CYP3A4 inducers should be monitored closely. An increased dosage of sildenafil may be needed. Reduce sildenafil dose to 20 mg three times daily when discontinuing treatment with strong and moderate CYP3A4 inducers.(1) DISCUSSION: Population pharmacokinetic analysis of data from patients in clinical trials found that sildenafil clearance increased about 3-fold when coadministered with mild CYP3A4 inducers.(1) A randomized, double-blind, placebo-controlled, parallel-group study of 55 healthy volunteers found that 10 days of bosentan (125 mg twice daily), a moderate CYP3A4 inducer, decreased the maximum concentration (Cmax) and area-under-curve (AUC) of sildenafil by 55.4% and 62.6%, respectively. Sildenafil increased bosentan Cmax and AUC by 42% and 49.8%, respectively. The combination was well tolerated without serious adverse events.(2) In a study of 15 HIV-negative subjects, etravirine (800 mg twice daily for 14 days), a moderate CYP3A4 inducer, decreased the Cmax and AUC of sildenafil by 45% and 57%, respectively.(3) The authors of a review article on drug interactions in pulmonary arterial hypertension therapy state that phenytoin and rifampin (strong CYP3A4 inducers) are not recommended with sildenafil due to an expected near-complete clearance of sildenafil.(4) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(5,6) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(5,6) |
REVATIO, SILDENAFIL CITRATE |
| Etrasimod/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Etrasimod is a sphingosine-1-phosphate (S1P) receptor modulator. Initiation of etrasimod has a negative chronotropic effect, which may increase the risk of developing QT prolongation. CLINICAL EFFECTS: Initiation of etrasimod may result in a transient decrease in heart rate. A mean decrease in heart rate of 7.2 (8.98) beats per minute was seen 2 to 3 hours after the first dose. The first dose has also been associated with heart block. Symptomatic bradycardia has been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsades de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to etrasimod initiation, factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia), or concomitant treatment with QT prolonging agents may increase risk for cardiovascular toxicity due to etrasimod. The risk of QT prolongation or torsades de pointes may also be increased in patients with a history of torsades de pointes, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of the QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Prior to initiation of etrasimod, obtain an ECG to determine if preexisting conduction abnormalities are present.(1) Advice from a cardiologist is recommended in patients with preexisting heart and cerebrovascular conditions, prolonged QTc interval, risk factors for QT prolongation, concurrent therapy with QT prolonging drugs or drugs that slow the heart rate or AV conduction.(1) Monitor blood pressure during treatment.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Initiation of etrasimod may result in a transient decrease in heart rate or transient AV conduction delays.(1) A transient decrease in heart rate was observed during the initial dosing phase of etrasimod and bradyarrhythmic events (AV blocks) were detected at a higher incidence under etrasimod treatment than placebo.(1) |
VELSIPITY |
| Dexmedetomidine Sublingual/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Dexmedetomidine sublingual has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of dexmedetomidine sublingual with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of dexmedetomidine sublingual states that concurrent use should be avoided with other agents known to prolong the QTc interval.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a QT study, dexmedetomidine sublingual had a concentration dependent effect on the QT interval. The mean QTc (95% confidence interval) increased from baseline by 6 (7) msec with a 120 mcg single dose, 8 (9) msec with 120 mcg followed by 2 additional doses of 60 mcg (total 3 doses), 8 (11) msec with a single 180 mcg dose, and 11 (14) msec with 180 mcg followed by 2 additional doses of 90 mcg (total 3 doses), respectively.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
IGALMI |
| Mavorixafor/QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Mavorixafor has been shown to prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of mavorixafor with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of mavorixafor states that concurrent use of mavorixafor with other agents known to prolong the QTc interval should be approached with caution. ECG monitoring is recommended prior to initiation, during concurrent therapy, and as clinically indicated with other agents known to prolong the QTc interval.(1) If QT prolongation occurs, a dose reduction or discontinuation of mavorixafor may be required.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a thorough QT study, a dose of mavorixafor 800 mg increased the mean QTc 15.6 msec (upper 90% CI = 19.9 msec). The dose of mavorixafor was 2 times the recommended maximum daily dose.(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
XOLREMDI |
| Givinostat/Possible QT Prolonging Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Givinostat may prolong the QTc interval. Concurrent use with other agents that prolong the QTc interval may result in additive effects on the QTc interval.(1) CLINICAL EFFECTS: The concurrent use of givinostat with other agents that prolong the QTc interval may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of givinostat states that the concurrent use of QT prolonging agents should be avoided. If concurrent use cannot be avoided, obtain ECGs prior to initiating givinostat, during concomitant use, and as clinically indicated.(1) If the QTc interval is greater than 500 ms or the change from baseline is greater than 60 ms, withhold givinostat therapy.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a QT study, the largest mean increase in QTc interval of 13.6 ms (upper confidence interval of 17.1 ms) occurred 5 hours after administration of givinostat 265.8 mg (approximately 5 times the recommended 53.2 mg dose in patients weighing 60 kg or more).(1) Agents that are linked to this monograph may have varying degrees of potential to prolong the QTc interval. Agents linked to this monograph have been shown to prolong the QTc interval either through their mechanism of action, through studies on their effects on the QTc interval, or through reports of QTc prolongation and/or torsades de pointes in clinical trials and/or postmarketing reports.(3) |
DUVYZAT |
| Crinecerfont/Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inducers of CYP3A4 may induce the metabolism of crinecerfont.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may reduce the clinical effectiveness of crinecerfont.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The US manufacturer of crinecerfont states that concurrent use of moderate CYP3A4 inducers requires a dose adjustment of crinecerfont. Increase the evening dose of crinecerfont by 2-fold. Do not increase the morning dose. In adults, increase the dosage of crinecerfont to 100 mg in the morning and 200 mg in the evening. In pediatric patients 4 years and older weighing: - 10 kg to <20 kg: increase the crinecerfont dosage to 25 mg in the morning and 50 mg in the evening, - 20 kg to <55 kg: increase the crinecerfont dosage to 50 mg in the morning and 100 mg in the evening, - >=55 kg: increase the crinecerfont dosage to 100 mg in the morning and 200 mg in the evening.(1) DISCUSSION: In a study, concomitant use of rifampin (strong CYP3A4 inducer) decreased crinecerfont maximum concentration (Cmax) by 23% and area-under-curve (AUC) by 62%.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
CRENESSITY |
The following contraindication information is available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
Drug contraindication overview.
*Clinically important hypersensitivity reaction (e.g., Stevens-Johnson syndrome, erythema multiforme, toxic skin eruption) to efavirenz or any other ingredient in the formulation. *Concomitant use with elbasvir and grazoprevir. *None. *Previous hypersensitivity to lamivudine.
*Clinically important hypersensitivity reaction (e.g., Stevens-Johnson syndrome, erythema multiforme, toxic skin eruption) to efavirenz or any other ingredient in the formulation. *Concomitant use with elbasvir and grazoprevir. *None. *Previous hypersensitivity to lamivudine.
There are 4 contraindications.
Absolute contraindication.
| Contraindication List |
|---|
| Acute pancreatitis |
| Chronic pancreatitis |
| Lactation |
| Lactic acidosis |
There are 14 severe contraindications.
Adequate patient monitoring is recommended for safer drug use.
| Severe List |
|---|
| Acute renal failure |
| Chronic kidney disease stage 3A (moderate) GFR 45-59 ml/min |
| Chronic kidney disease stage 3B (moderate) GFR 30-44 ml/min |
| Chronic kidney disease stage 4 (severe) GFR 15-29 ml/min |
| Chronic kidney disease stage 5 (failure) GFr<15 ml/min |
| Depression |
| Disease of liver |
| Fanconi syndrome |
| Hypophosphatemia |
| Manic disorder |
| Osteomalacia |
| Paranoid disorder |
| Pathological fracture |
| Suicidal ideation |
There are 9 moderate contraindications.
Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.
| Moderate List |
|---|
| Aggressive behavior |
| Chronic kidney disease stage 3A (moderate) GFR 45-59 ml/min |
| CYp2b6*6/*6 genotype |
| Hypercholesterolemia |
| Hypertriglyceridemia |
| Insomnia |
| Kidney disease with likely reduction in glomerular filtration rate (GFr) |
| Osteopenia |
| Seizure disorder |
The following adverse reaction information is available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
Adverse reaction overview.
Moderate to severe adverse effects occurring in >5% of patients receiving efavirenz include impaired concentration, abnormal dreams, rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting. The most common adverse effects (incidence >=10%; grades 2-4) in HIV-infected patients receiving tenofovir DF are rash, diarrhea, headache, pain, depression, asthenia, and nausea. The most common adverse effect (all grades) in HBV-infected patients with compensated liver disease was nausea (9%).
The most common adverse effects (incidence >=10%; all grades) in HBV-infected patients with decompensated liver disease were abdominal pain, nausea, vomiting, pruritus, insomnia, dizziness, and pyrexia. Adverse reactions in pediatric patients were consistent with those observed in adults. In the treatment of HIV infection in adults, the most common reported adverse reactions (incidence >=15%) were headache, nausea, malaise and fatigue, nasal signs and symptoms, diarrhea, and cough.
In the treatment of HIV infection in pediatric patients, the most common reported adverse reactions (incidence >=15%) were fever and cough. In the treatment of HBV infection, the most common reported adverse reactions (incidence >=10% and reported at a rate greater than placebo) were ear, nose, and throat infections; sore throat; and diarrhea.
Moderate to severe adverse effects occurring in >5% of patients receiving efavirenz include impaired concentration, abnormal dreams, rash, dizziness, nausea, headache, fatigue, insomnia, and vomiting. The most common adverse effects (incidence >=10%; grades 2-4) in HIV-infected patients receiving tenofovir DF are rash, diarrhea, headache, pain, depression, asthenia, and nausea. The most common adverse effect (all grades) in HBV-infected patients with compensated liver disease was nausea (9%).
The most common adverse effects (incidence >=10%; all grades) in HBV-infected patients with decompensated liver disease were abdominal pain, nausea, vomiting, pruritus, insomnia, dizziness, and pyrexia. Adverse reactions in pediatric patients were consistent with those observed in adults. In the treatment of HIV infection in adults, the most common reported adverse reactions (incidence >=15%) were headache, nausea, malaise and fatigue, nasal signs and symptoms, diarrhea, and cough.
In the treatment of HIV infection in pediatric patients, the most common reported adverse reactions (incidence >=15%) were fever and cough. In the treatment of HBV infection, the most common reported adverse reactions (incidence >=10% and reported at a rate greater than placebo) were ear, nose, and throat infections; sore throat; and diarrhea.
There are 71 severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Depression Elevated serum lipase Paresthesia Pruritus of skin Skin rash |
Hallucinations Hypercholesterolemia Increased alanine transaminase Increased aspartate transaminase Neutropenic disorder Osteopenia Pneumonia Prolonged QT interval Thrombocytopenic disorder |
| Rare/Very Rare |
|---|
|
Abnormal desquamation Abnormal hepatic function tests Acute cognitive impairment Acute hepatic failure Acute pancreatitis Acute renal failure Anaphylaxis Anemia Angioedema Ataxia Behavioral disorders Blistering skin Catatonia Delusional disorder Dermal necrosis Drug-induced psychosis Dysphasia Dyspnea Encephalopathy Erythema multiforme Exfoliative dermatitis Fanconi syndrome Fever Graves' disease Guillain-barre syndrome Hepatitis Hypokalemia Hypophosphatemia Interstitial nephritis Kidney disease with reduction in glomerular filtration rate (GFr) Lactic acidosis Lymphadenopathy Manic disorder Nephrogenic diabetes insipidus Osteomalacia Pancreatitis Paranoid disorder Paresthesia Peripheral neuropathy Phototoxicity Polymyositis Pure red cell aplasia Renal tubular necrosis Rhabdomyolysis Seizure disorder Skin ulcer Splenomegaly Steatosis of liver Stevens-johnson syndrome Suicidal Suicidal ideation Syncope Toxic epidermal necrolysis Tremor Urticaria Visual changes Wheezing |
There are 82 less severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Acute abdominal pain Back pain Concentration difficulty Cough Diarrhea Dizziness Dream disorder Drowsy Dyspepsia Fatigue Fever General weakness Headache disorder Infection of ear Insomnia Lipodystrophy associated with human immunodeficiency virus infection Malaise Nausea Pain Peripheral neuropathy Pruritus of skin Sore throat Vomiting |
Abdominal pain with cramps Acute abdominal pain Anorexia Arthralgia Chest pain Chills Depression Dizziness Dyspepsia Elevated serum amylase Elevated serum lipase Flatulence Hypercholesterolemia Hyperlipidemia Hypertriglyceridemia Insomnia Myalgia Nervousness Pharyngitis Polyuria Proteinuria Rhinitis Sinusitis Skin rash Symptoms of anxiety Vomiting Weight loss |
| Rare/Very Rare |
|---|
|
Aggressive behavior Agitation Alopecia Anorexia Arthralgia Constipation Cough Cramps Depersonalization Euphoria Flushing Folliculitis General weakness Gynecomastia Hyperglycemia Hyperhidrosis Hypertriglyceridemia Hypoesthesia Malabsorption states Memory impairment Mood changes Muscle weakness Myalgia Myopathy Palpitations Pruritus of skin Skin rash Stomatitis Tinnitus Urticaria Vertigo Wheezing |
The following precautions are available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
Safety and efficacy of single-entity efavirenz have not been established in neonates and infants <3 months of age or in those weighing <3.5 kg, and the drug should not be used in these pediatric patients. Adverse effects reported in pediatric patients 3 months to 21 years of age receiving efavirenz are similar to those reported in adults receiving the drug.
Rash has been reported more frequently in children than adults, and the incidence of grade 3 or 4 rash has been greater in children than adults. Because of the high incidence of dermatologic reactions in children, antihistamines should be considered for the prevention of rash when initiating efavirenz in children. Safety and efficacy of tenofovir DF for treatment of HIV-1 infection in pediatric patients 2 to <18 years of age are supported by data from 2 randomized controlled trials.
Peak plasma concentrations and AUC of tenofovir in HIV-1-infected pediatric patients 2 to <18 years of age receiving 8 mg/kg of tenofovir DF (up to 300 mg) once daily as oral powder or receiving 300 mg once daily as tablets were similar to peak plasma concentrations and AUC reported in adults receiving 300 mg once daily. Safety and efficacy of tenofovir DF for treatment of HIV-1 infection have not been established in children <2 years of age weighing <10 kg. In HBV-infected pediatric patients 12 to <18 years of age receiving tenofovir DF 300 mg once daily as tablets, and pediatric patients 2 to <12 years of age receiving 8 mg/kg of tenofovir DF (up to 300 mg) once daily as tablets or oral powder, tenofovir exposures were similar to those reported in HIV-1-infected adults receiving identical doses.
Safety and efficacy of tenofovir DF for treatment of chronic HBV infection have not been established in children <2 years of age weighing <10 kg. The safety and efficacy of lamivudine for the treatment of HIV-1 (Epivir(R)) have been established in pediatric patients 3 months of age and older. The scored tablet is the preferred formulation for HIV-1-infected pediatric patients weighing at least 14 kg for whom a solid dosage form is appropriate; in the ARROW trial, pediatric patients who received the oral solution had lower rates of virologic suppression, lower plasma lamivudine exposure, and developed viral resistance more frequently. The safety and efficacy of lamivudine for the treatment of chronic HBV (Epivir-HBV(R)) in pediatric patients younger than 2 years of age have not been established.
Contraindicated
Severe Precaution
Management or Monitoring Precaution
Rash has been reported more frequently in children than adults, and the incidence of grade 3 or 4 rash has been greater in children than adults. Because of the high incidence of dermatologic reactions in children, antihistamines should be considered for the prevention of rash when initiating efavirenz in children. Safety and efficacy of tenofovir DF for treatment of HIV-1 infection in pediatric patients 2 to <18 years of age are supported by data from 2 randomized controlled trials.
Peak plasma concentrations and AUC of tenofovir in HIV-1-infected pediatric patients 2 to <18 years of age receiving 8 mg/kg of tenofovir DF (up to 300 mg) once daily as oral powder or receiving 300 mg once daily as tablets were similar to peak plasma concentrations and AUC reported in adults receiving 300 mg once daily. Safety and efficacy of tenofovir DF for treatment of HIV-1 infection have not been established in children <2 years of age weighing <10 kg. In HBV-infected pediatric patients 12 to <18 years of age receiving tenofovir DF 300 mg once daily as tablets, and pediatric patients 2 to <12 years of age receiving 8 mg/kg of tenofovir DF (up to 300 mg) once daily as tablets or oral powder, tenofovir exposures were similar to those reported in HIV-1-infected adults receiving identical doses.
Safety and efficacy of tenofovir DF for treatment of chronic HBV infection have not been established in children <2 years of age weighing <10 kg. The safety and efficacy of lamivudine for the treatment of HIV-1 (Epivir(R)) have been established in pediatric patients 3 months of age and older. The scored tablet is the preferred formulation for HIV-1-infected pediatric patients weighing at least 14 kg for whom a solid dosage form is appropriate; in the ARROW trial, pediatric patients who received the oral solution had lower rates of virologic suppression, lower plasma lamivudine exposure, and developed viral resistance more frequently. The safety and efficacy of lamivudine for the treatment of chronic HBV (Epivir-HBV(R)) in pediatric patients younger than 2 years of age have not been established.
Contraindicated
| None |
Severe Precaution
| None |
Management or Monitoring Precaution
| None |
Efavirenz may cause fetal harm if administered during the first trimester of pregnancy. There are retrospective case reports of neural tube defects in infants born to mothers who were exposed to efavirenz during the first trimester of pregnancy. Although prospective data in humans are inadequate to assess risks and a causal relationship between efavirenz exposure in the first trimester and neural tube defects has not been established, similar malformations have been observed in animal studies.
The manufacturer states that efavirenz should not be used during the first trimester of pregnancy. The Antiretroviral Pregnancy Registry (APR) monitors pregnancy outcomes in women exposed to antiretroviral agents, including efavirenz, during pregnancy. Clinicians are encouraged to contact the registry at 800-258-4263 or https://www.apregistry.com
to report cases of prenatal exposure to antiretroviral agents. Based on prospective reports from the APR of approximately 1000 live births following exposure to efavirenz (including more than 800 live births following first-trimester exposures), there was no difference between overall birth defects with efavirenz compared with the background birth defect rate (2.7% in the US reference population of the Metropolitan Atlanta Congenital Defects Program). An interim report issued in December 2014 that used data from the registry indicated that the prevalence of birth defects was 2.3%
following first-trimester exposures to efavirenz. Defects reported prospectively in first-trimester exposures included 1 case of neural tube defect and 1 case of anophthalmia with severe oblique facial clefts and amniotic banding. Females of reproductive potential should be advised about the teratogenic potential of efavirenz.
Such patients should undergo pregnancy testing before initiation of therapy. If efavirenz is used during the first trimester, or if pregnancy occurs during therapy, the patient should be apprised of the potential risk to the fetus. The Antiretroviral Pregnancy Registry (APR) monitors pregnancy outcomes in women exposed to tenofovir DF during pregnancy.
Clinicians are encouraged to register patients in the APR by calling 1-800-258-4263 or visiting https://www.apregistry.com/.
Based on prospective data from the APR, the prevalence of birth defects in live births was 2.3% and 2.1% following first and second/third trimester exposure, respectively, to tenofovir DF-containing regimens.
The overall risk of birth defects with first-trimester exposure for tenofovir DF was not markedly different compared to the background rate for major birth defects of 2.7% in the United States reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). Limitations of using an external comparator (the MACDP) include differences in populations and methodology, and confounding due to the underlying disease.
The rate of miscarriage is not reported in the APR. Tenofovir crosses the human placenta. In published studies that included HBV-infected pregnant women treated with tenofovir DF, an increased risk of adverse pregnancy-related outcomes was not observed with use of tenofovir DF during the third trimester.
Two stillbirths were identified, and there was 1 major birth defect (talipes) and 1 occurrence of multiple congenital abnormalities (not further specified) in infants exposed to tenofovir DF. No clinically relevant drug-related safety findings were found in infants exposed to tenofovir DF during late gestation. Animal reproduction studies did not find any adverse developmental effects when tenofovir DF was administered at doses >=14 (tenofovir DF) and exposures 2.7
(tenofovir) times the recommended daily dose of tenofovir DF in humans. Lamivudine crosses the placenta and is distributed into cord blood in concentrations similar to maternal serum concentrations. To monitor maternal-fetal outcomes of pregnant women exposed to antiretroviral agents, including lamivudine, the Antiretroviral Pregnancy Registry was established.
Clinicians are encouraged to contact the registry at 800-258-4263 or https://www.apregistry.com/ to report cases of prenatal exposure to antiretroviral agents.
Data from the Antiretroviral Pregnancy Registry show no difference in the risk of overall major birth defects for lamivudine compared with the background rate for major birth defects in the US reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). Reproduction studies in rats or rabbits using oral lamivudine dosages that resulted in plasma concentrations up to approximately 35 times higher than plasma concentrations attained with the recommended human dosage used for the treatment of HIV infection in adults have not revealed evidence of teratogenicity. Although there was evidence of early embryolethality in rabbits at exposure levels similar to those observed in humans, this effect was not seen in rats at exposure levels up to 35 times higher than those in humans.
The manufacturer states that efavirenz should not be used during the first trimester of pregnancy. The Antiretroviral Pregnancy Registry (APR) monitors pregnancy outcomes in women exposed to antiretroviral agents, including efavirenz, during pregnancy. Clinicians are encouraged to contact the registry at 800-258-4263 or https://www.apregistry.com
to report cases of prenatal exposure to antiretroviral agents. Based on prospective reports from the APR of approximately 1000 live births following exposure to efavirenz (including more than 800 live births following first-trimester exposures), there was no difference between overall birth defects with efavirenz compared with the background birth defect rate (2.7% in the US reference population of the Metropolitan Atlanta Congenital Defects Program). An interim report issued in December 2014 that used data from the registry indicated that the prevalence of birth defects was 2.3%
following first-trimester exposures to efavirenz. Defects reported prospectively in first-trimester exposures included 1 case of neural tube defect and 1 case of anophthalmia with severe oblique facial clefts and amniotic banding. Females of reproductive potential should be advised about the teratogenic potential of efavirenz.
Such patients should undergo pregnancy testing before initiation of therapy. If efavirenz is used during the first trimester, or if pregnancy occurs during therapy, the patient should be apprised of the potential risk to the fetus. The Antiretroviral Pregnancy Registry (APR) monitors pregnancy outcomes in women exposed to tenofovir DF during pregnancy.
Clinicians are encouraged to register patients in the APR by calling 1-800-258-4263 or visiting https://www.apregistry.com/.
Based on prospective data from the APR, the prevalence of birth defects in live births was 2.3% and 2.1% following first and second/third trimester exposure, respectively, to tenofovir DF-containing regimens.
The overall risk of birth defects with first-trimester exposure for tenofovir DF was not markedly different compared to the background rate for major birth defects of 2.7% in the United States reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). Limitations of using an external comparator (the MACDP) include differences in populations and methodology, and confounding due to the underlying disease.
The rate of miscarriage is not reported in the APR. Tenofovir crosses the human placenta. In published studies that included HBV-infected pregnant women treated with tenofovir DF, an increased risk of adverse pregnancy-related outcomes was not observed with use of tenofovir DF during the third trimester.
Two stillbirths were identified, and there was 1 major birth defect (talipes) and 1 occurrence of multiple congenital abnormalities (not further specified) in infants exposed to tenofovir DF. No clinically relevant drug-related safety findings were found in infants exposed to tenofovir DF during late gestation. Animal reproduction studies did not find any adverse developmental effects when tenofovir DF was administered at doses >=14 (tenofovir DF) and exposures 2.7
(tenofovir) times the recommended daily dose of tenofovir DF in humans. Lamivudine crosses the placenta and is distributed into cord blood in concentrations similar to maternal serum concentrations. To monitor maternal-fetal outcomes of pregnant women exposed to antiretroviral agents, including lamivudine, the Antiretroviral Pregnancy Registry was established.
Clinicians are encouraged to contact the registry at 800-258-4263 or https://www.apregistry.com/ to report cases of prenatal exposure to antiretroviral agents.
Data from the Antiretroviral Pregnancy Registry show no difference in the risk of overall major birth defects for lamivudine compared with the background rate for major birth defects in the US reference population of the Metropolitan Atlanta Congenital Defects Program (MACDP). Reproduction studies in rats or rabbits using oral lamivudine dosages that resulted in plasma concentrations up to approximately 35 times higher than plasma concentrations attained with the recommended human dosage used for the treatment of HIV infection in adults have not revealed evidence of teratogenicity. Although there was evidence of early embryolethality in rabbits at exposure levels similar to those observed in humans, this effect was not seen in rats at exposure levels up to 35 times higher than those in humans.
The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding. The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant.
Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. Tenofovir is distributed into human milk in low concentrations.
In a study of breast-feeding women (not infected with HIV) who were on a tenofovir-containing regimen started between 1-24 weeks postpartum, tenofovir was undetectable in the plasma of most infants after 7 days of treatment in mothers. No serious adverse events were reported in mothers or infants. It is not known whether tenofovir DF affects human milk production or has effects on the breast-fed infant.
The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding. The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant.
Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. If using tenofovir DF for the treatment of HBV infection, consider the developmental and health benefits of breast-feeding and the importance of tenofovir DF to the mother along with the potential adverse effects on the breast-fed infant from the drug or from the underlying maternal condition.
Lamivudine is distributed into milk in humans. It is not known whether the drug affects human milk production or affects the breast-fed infant. The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding.
The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant. Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk.
Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. If lamivudine is being used for treatment of chronic HBV infection, the benefits of breast-feeding and the importance of lamivudine to the woman should be considered along with the potential adverse effects on the breast-fed infant from the drug or from the underlying maternal condition.
Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. Tenofovir is distributed into human milk in low concentrations.
In a study of breast-feeding women (not infected with HIV) who were on a tenofovir-containing regimen started between 1-24 weeks postpartum, tenofovir was undetectable in the plasma of most infants after 7 days of treatment in mothers. No serious adverse events were reported in mothers or infants. It is not known whether tenofovir DF affects human milk production or has effects on the breast-fed infant.
The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding. The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant.
Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. If using tenofovir DF for the treatment of HBV infection, consider the developmental and health benefits of breast-feeding and the importance of tenofovir DF to the mother along with the potential adverse effects on the breast-fed infant from the drug or from the underlying maternal condition.
Lamivudine is distributed into milk in humans. It is not known whether the drug affects human milk production or affects the breast-fed infant. The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding.
The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant. Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk.
Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery. If lamivudine is being used for treatment of chronic HBV infection, the benefits of breast-feeding and the importance of lamivudine to the woman should be considered along with the potential adverse effects on the breast-fed infant from the drug or from the underlying maternal condition.
Clinical studies of efavirenz have not included sufficient numbers of adults 65 years of age or older to determine whether geriatric individuals respond differently to the drug than younger adults. Dosage selection in elderly patients should be cautious, reflecting the greater frequency of decreased hepatic, renal, and/or cardiac function and the potential for concomitant disease and drug therapy. Clinical studies did not include sufficient numbers of patients >=65 years of age to determine whether they respond differently to tenofovir DF than younger adults.
Select dosage in geriatric patients with caution because of the greater frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease or drug therapy. Pharmacokinetic studies have not been conducted in patients >=65 years of age. Clinical trials of lamivudine (Epivir(R) and Epivir-HBV(R)) did not include sufficient numbers of patients 65 years of age or older to determine whether they respond differently from younger subjects. Use caution when administering lamivudine to geriatric patients, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
Select dosage in geriatric patients with caution because of the greater frequency of decreased hepatic, renal, and/or cardiac function and of concomitant disease or drug therapy. Pharmacokinetic studies have not been conducted in patients >=65 years of age. Clinical trials of lamivudine (Epivir(R) and Epivir-HBV(R)) did not include sufficient numbers of patients 65 years of age or older to determine whether they respond differently from younger subjects. Use caution when administering lamivudine to geriatric patients, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
The following prioritized warning is available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate):
WARNING: If you have hepatitis B infection as well as HIV, your hepatitis symptoms may get worse or become very serious if you stop taking this medication. Talk with your doctor before stopping this medication. Your doctor will check your liver function tests for several months after you stop. Tell your doctor right away if you develop symptoms of worsening liver problems.
WARNING: If you have hepatitis B infection as well as HIV, your hepatitis symptoms may get worse or become very serious if you stop taking this medication. Talk with your doctor before stopping this medication. Your doctor will check your liver function tests for several months after you stop. Tell your doctor right away if you develop symptoms of worsening liver problems.
The following icd codes are available for SYMFI LO (efavirenz/lamivudine/tenofovir disoproxil fumarate)'s list of indications:
| HIV infection | |
| B20 | Human immunodeficiency virus [HIv] disease |
| B97.35 | Human immunodeficiency virus, type 2 [HIV 2] as the cause of diseases classified elsewhere |
| O98.7 | Human immunodeficiency virus [HIv] disease complicating pregnancy, childbirth and the puerperium |
| O98.71 | Human immunodeficiency virus [HIv] disease complicating pregnancy |
| O98.711 | Human immunodeficiency virus [HIv] disease complicating pregnancy, first trimester |
| O98.712 | Human immunodeficiency virus [HIv] disease complicating pregnancy, second trimester |
| O98.713 | Human immunodeficiency virus [HIv] disease complicating pregnancy, third trimester |
| O98.719 | Human immunodeficiency virus [HIv] disease complicating pregnancy, unspecified trimester |
| O98.72 | Human immunodeficiency virus [HIv] disease complicating childbirth |
| O98.73 | Human immunodeficiency virus [HIv] disease complicating the puerperium |
| Z21 | Asymptomatic human immunodeficiency virus [HIv] infection status |
Formulary Reference Tool