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Drug overview for RIFABUTIN (rifabutin):
Generic name: RIFABUTIN (rye-fuh-BYOU-tin)
Drug class: Rifamycins
Therapeutic class: Anti-Infective Agents
Rifabutin, a semisynthetic spiropiperidyl derivative of rifamycin S, is an ansamycin antibiotic that is an antimycobacterial agent.
No enhanced Uses information available for this drug.
Generic name: RIFABUTIN (rye-fuh-BYOU-tin)
Drug class: Rifamycins
Therapeutic class: Anti-Infective Agents
Rifabutin, a semisynthetic spiropiperidyl derivative of rifamycin S, is an ansamycin antibiotic that is an antimycobacterial agent.
No enhanced Uses information available for this drug.
DRUG IMAGES
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The following indications for RIFABUTIN (rifabutin) have been approved by the FDA:
Indications:
Prevention of Mycobacterium avium complex disease
Professional Synonyms:
MAC complex prophylaxis
MAC infection prophylaxis
MAIC prophylaxis
MAIS complex prophylaxis
Mycobacterium avium complex prophylaxis
Mycobacterium avium-intracellulare complex prophylaxis
Mycobacterium avium-intracellulare prophylaxis
Mycobacterium, MAIS group prophylaxis
Indications:
Prevention of Mycobacterium avium complex disease
Professional Synonyms:
MAC complex prophylaxis
MAC infection prophylaxis
MAIC prophylaxis
MAIS complex prophylaxis
Mycobacterium avium complex prophylaxis
Mycobacterium avium-intracellulare complex prophylaxis
Mycobacterium avium-intracellulare prophylaxis
Mycobacterium, MAIS group prophylaxis
The following dosing information is available for RIFABUTIN (rifabutin):
When rifabutin is used in conjunction with other antituberculosis agents for the treatment of tuberculosis, the American Thoracic Society (ATS), US Centers for Disease Control and Prevention (CDC), Infectious Diseases Society of America (IDSA), and others recommend that adults and children 15 years of age or older receive a dosage of 5 mg/kg (up to 300 mg) given once daily or 5 mg/kg (up to 300 mg) given 2 or 3 times weekly.
The fact that rifabutin dosage may need to be altered if the drug is used for the treatment of tuberculosis in HIV-infected individuals receiving certain antiretroviral agents (e.g., HIV protease inhibitors, nonnucleoside reverse transcriptase inhibitors) should be considered. (See Drug Interactions: Antiretroviral Agents.) In addition, because of concerns that there may be an increased risk of acquired rifamycin resistance in HIV-infected individuals with CD4+ T-cell counts less than 100/mm3 who receive intermittent rifamycin regimens, the ATS, CDC, and IDSA recommend that rifabutin be administered once daily or 3-times weekly and that rifabutin regimens that involve once- or twice-weekly administration be avoided in these HIV-infected individuals pending further accumulation of data. The CDC also recommends directly observed therapy (DOT) for both the daily and 3-times weekly regimens.
(See Initial Treatment of Tuberculosis: Tuberculosis in HIV-Infected Patients, under General Principles in Antituberculosis Therapy in the Antituberculosis Agents General Statement 8:16.04.)
The ATS, CDC, and IDSA state that the appropriate dosage of rifabutin for use in conjunction with other antituberculosis agents for the treatment of tuberculosis in children has not been identified. However, the CDC has stated that a rifabutin dosage of 10-20 mg/kg (up to 300 mg) can be given daily or twice weekly in conjunction with other antituberculosis agents for the treatment of tuberculosis in children with HIV infection+.
Rifabutin concentrations reportedly are decreased in patients with impaired renal function as a result of decreased distribution and more rapid elimination of the drug. However, the clinical importance, if any, of this finding has not been determined, and the manufacturer currently makes no specific recommendations for modification of dosage in such patients.
The fact that rifabutin dosage may need to be altered if the drug is used for the treatment of tuberculosis in HIV-infected individuals receiving certain antiretroviral agents (e.g., HIV protease inhibitors, nonnucleoside reverse transcriptase inhibitors) should be considered. (See Drug Interactions: Antiretroviral Agents.) In addition, because of concerns that there may be an increased risk of acquired rifamycin resistance in HIV-infected individuals with CD4+ T-cell counts less than 100/mm3 who receive intermittent rifamycin regimens, the ATS, CDC, and IDSA recommend that rifabutin be administered once daily or 3-times weekly and that rifabutin regimens that involve once- or twice-weekly administration be avoided in these HIV-infected individuals pending further accumulation of data. The CDC also recommends directly observed therapy (DOT) for both the daily and 3-times weekly regimens.
(See Initial Treatment of Tuberculosis: Tuberculosis in HIV-Infected Patients, under General Principles in Antituberculosis Therapy in the Antituberculosis Agents General Statement 8:16.04.)
The ATS, CDC, and IDSA state that the appropriate dosage of rifabutin for use in conjunction with other antituberculosis agents for the treatment of tuberculosis in children has not been identified. However, the CDC has stated that a rifabutin dosage of 10-20 mg/kg (up to 300 mg) can be given daily or twice weekly in conjunction with other antituberculosis agents for the treatment of tuberculosis in children with HIV infection+.
Rifabutin concentrations reportedly are decreased in patients with impaired renal function as a result of decreased distribution and more rapid elimination of the drug. However, the clinical importance, if any, of this finding has not been determined, and the manufacturer currently makes no specific recommendations for modification of dosage in such patients.
Rifabutin is administered orally. Administration of rifabutin with a high-fat meal decreases the rate but not the extent of absorption. Therefore, the drug generally can be given orally without regard to meals.
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| RIFABUTIN 150 MG CAPSULE | Maintenance | Adults take 2 capsules (300 mg) by oral route once daily |
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| RIFABUTIN 150 MG CAPSULE | Maintenance | Adults take 2 capsules (300 mg) by oral route once daily |
The following drug interaction information is available for RIFABUTIN (rifabutin):
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 |
|---|---|
| Live Typhoid Vaccine/Antimicrobials 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 antimicrobial may be active against the organism in the live-vaccine. Antimicrobial therapy may prevent the vaccine organism from replicating enough to trigger an immune response.(1) CLINICAL EFFECTS: Vaccination may be ineffective. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Do not give oral typhoid vaccine until 72 hours after the last dose of antimicrobial. If possible, to optimize vaccine effectiveness, do not start antibacterial drugs for 72 hours after the last dose of oral typhoid vaccine. A longer interval should be considered for long-acting antimicrobials, such as azithromycin.(3) DISCUSSION: Because antimicrobial therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of live-attenuated typhoid vaccine and the Centers for Disease Control (CDC) state that the vaccine should not be administered to patients receiving antimicrobial therapy.(1-3) |
VIVOTIF |
| Isavuconazonium; Voriconazole/Selected 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: Strong inducers of CYP3A4 and rifabutin may increase the metabolism of isavuconazonium(1,2) and voriconazole.(3) CLINICAL EFFECTS: The concurrent use of strong inducers of CYP3A4 or rifabutin with isavuconazonium(1,2) or voriconazole(3) may result in severely reduced levels of the azole antifungal and therapeutic failure. PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The concurrent use of isavuconazonium(1,2) or voriconazole(3) with strong inducers of CYP3A4 is contraindicated. The concurrent use of voriconazole with rifabutin is also contraindicated.(3,4) The UK manufacturer of voriconazole states that concurrent use with rifabutin should be avoided. If concurrent use is necessary, the maintenance dose of voriconazole may be increased from 200 mg to 350 mg orally twice daily. If the patient weighs less than 40 kg, the maintenance dose of voriconazole may be increased from 100 mg to 200 mg orally twice daily. If concurrent use is necessary, the maintenance dose of intravenous voriconazole can be increased to 5 mg/kg intravenously twice daily.(9) The US manufacturer of isavuconazonium does not make any recommendations for concurrent use with rifabutin,(1) but the UK manufacturer states that concurrent use of rifabutin is contraindicated.(2) DISCUSSION: The concurrent use of rifampin (600 mg) with isavuconazonium (multiple doses) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of voriconazole by 75% and 97%, respectively.(1) The concurrent use of rifampin (600 mg once daily) with voriconazole (200 mg every 12 hours for 7 days) decreased the Cmax and AUC of voriconazole by 93% and 96%, respectively. Doubling the dose of voriconazole did not restore adequate exposure to voriconazole during rifampin.(3) The concurrent use of rifabutin (300 mg once daily) with voriconazole (200 mg twice daily) decreased the Cmax and AUC of voriconazole by 67% and 79%, respectively. The concurrent use of rifabutin (300 mg once daily) with voriconazole (400 mg twice daily) increased the Cmax and AUC of voriconazole to twice that seen with voriconazole alone at 200 mg twice daily. However, the Cmax and AUC of rifabutin were 3-fold and 4-fold higher, respectively, when given with voriconazole at 400 mg twice daily.(3) In a study in 16 subjects, subjects received single doses of voriconazole (400 mg) alone, after one dose of St. John's wort (300 mg), and after 15 days of St. John's wort (300 mg daily). After 10 hours of St. John's wort, voriconazole area-under-curve (AUC) increased 22%. After 15 days of St. John's wort, voriconazole AUC decreased 59%.(5) Therapeutic failures have been reported with voriconazole in patients treated concurrently with carbamazepine,(6) phenobarbital,(7) and rifampin.(8) In a study in 12 healthy male subjects, voriconazole (400 mg twice daily for 7 days) with rifabutin (300 mg daily for 7 days) increased rifabutin's AUC and Cmax by 331% and 195%, respectively. The AUC and Cmax of voriconazole were increased by approximately 100%.(4) Selected CYP3A4 inducers linked to this monograph include apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, ivosidenib, lumacaftor, mitotane, phenobarbital, primidone, rifabutin, rifampin, rifapentine, and St. John's wort. |
CRESEMBA, VFEND, VFEND IV, VORICONAZOLE |
| Ranolazine/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: Strong inducers of CYP3A4 may induce the metabolism of ranolazine.(1,2) CLINICAL EFFECTS: Concurrent use of a strong inducer of CYP3A4 may result in decreased levels and effectiveness of ranolazine.(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 ranolazine states that the concurrent use of CYP3A4 inducers is contraindicated.(1) The UK manufacturer of ranolazine states that ranolazine should not be used in patients receiving CYP3A4 inducers such as rifampin.(2) DISCUSSION: Concurrent rifampin (600 mg daily), strong inducer of CYP3A4, decreased ranolazine plasma concentrations by 95%.(1,2) 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.(1-4) |
ASPRUZYO SPRINKLE, RANOLAZINE ER |
| Nifedipine/Selected 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: CYP3A4 inducers may induce the hepatic metabolism of nifedipine.(1) CLINICAL EFFECTS: Concurrent use of an inducer of CYP3A4 may decrease levels and effectiveness of nifedipine.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The concurrent use of strong CYP3A4 inducers with nifedipine is contraindicated.(1) DISCUSSION: In a study in 12 healthy males, pretreatment with rifampin (600 mg daily for 14 days) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of nifedipine (20 mg) by 95% and 97%, respectively.(1) In a study of 6 healthy subjects, pretreatment with rifampin (600 mg daily for 7 days) increased the clearance of a single oral dose of nifedipine (20 mg) by 9.28-fold and decrease the nifedipine bioavailability by 87%. There were no significant effects on a single intravenous dose of nifedipine.(2) In a study in 6 healthy subjects, pretreatment with a single dose of rifampin (600 mg) 8 hours before a single oral dose of nifedipine decreased nifedipine bioavailability by 64.2%. Nifedipine half-life decreased by 60%. Nifedipine clearance increased by 1.89-fold.(3) There have been case reports of decreased effectiveness of nifedipine during concurrent rifampin therapy.(4-6) Enzalutamide is a strong inducer of CYP3A4.(7) Selected CYP3A4 inducers linked to this monograph include apalutamide, encorafenib, enzalutamide, ivosidenib, lumacaftor, mitotane, rifabutin, rifampin, and rifapentine. |
NIFEDIPINE, NIFEDIPINE ER, NIFEDIPINE MICRONIZED, PROCARDIA XL |
| Sofosbuvir-Containing Hepatitis C Products/Rifabutin 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: Rifabutin is an inducer of P-glycoprotein (P-gp) and may decrease the absorption of ledipasvir,(1-4) sofosbuvir,(1-12) velpatasvir,(5-12) and voxilaprevir.(9-12) CLINICAL EFFECTS: Concurrent or recent use of rifabutin may result in decreased levels and effectiveness of ledipasvir,(1-4) sofosbuvir,(1-12) velpatasvir,(5-12) and voxilaprevir.(9-12) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The Australian and US manufacturers of ledipasvir-sofosbuvir,(1,4) velpatasvir-sofosbuvir,(5,8) and sofosbuvir-velpatasvir-voxilaprevir,(9,12) and the Canadian manufacturer of velpatasvir-sofosbuvir (6) do not recommend coadministration with rifabutin. The UK manufacturer of ledipasvir-sofosbuvir,(3) velpatasvir-sofosbuvir,(7) and sofosbuvir-velpatasvir-voxilaprevir,(11) and the Canadian manufacturer of sofosbuvir-velpatasvir-voxilaprevir (10) state that concurrent use with rifabutin is contraindicated. DISCUSSION: In a phase I pharmacokinetic study with 20 healthy subjects, rifabutin (300 mg daily) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of sofosbuvir by 36% and 24%, respectively.(8) The impact of rifabutin on ledipasvir, velpatasvir, and voxilaprevir has not been studied, but rifabutin is expected to lower plasma concentrations of each of these substances. Although a reduction in dose of sofosbuvir of less than 50% is not expected to reduce its efficacy, the potential impact of rifabutin on ledipasvir, velpatasvir, and voxilaprevir warrants caution with concomitant use.(13) In a study in 31 subjects, rifampin (600 mg daily, a strong P-gp inducer) decreased the maximum concentration (Cmax) and AUC of ledipasvir by 35% and 59%, respectively.(4) In a study in 17 subjects, rifampin (600 mg daily) decreased the Cmax and AUC of sofosbuvir by 77% and 72%, respectively.(4) In a study in 12 subjects, rifampin (600 mg daily) decreased the Cmax and AUC of velpatasvir by 71% and 82%, respectively.(8) In a study in 24 subjects, rifampin (600 mg daily) decreased the Cmax and AUC of voxilaprevir by 9% and 73%, respectively.(12) |
EPCLUSA, HARVONI, LEDIPASVIR-SOFOSBUVIR, SOFOSBUVIR-VELPATASVIR, VOSEVI |
| Lonafarnib/Strong and Moderate 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: Strong and moderate CYP3A4 inducers may increase the metabolism of lonafarnib.(1) CLINICAL EFFECTS: Concurrent use of strong and moderate CYP3A4 inducers may decrease the serum levels and effectiveness of lonafarnib.(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 lonafarnib is contraindicated. 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) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2,3) |
ZOKINVY |
| 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 |
| Intramuscular Rilpivirine/Rifabutin 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: Rifabutin may induce the metabolism of rilpivirine by CYP3A4.(1) CLINICAL EFFECTS: Concurrent or recent use of rifabutin may result in decreased levels and effectiveness of 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 Swedish manufacturer of intramuscular rilpivirine states that concurrent use of rifabutin is contraindicated.(1) It may take several weeks after the discontinuation of an enzyme inducer for enzyme activity to return to normal.(1) DISCUSSION: Coadministration of rifabutin (300 mg once daily) with rilpivirine (25 mg once daily) decreased rilpivirine's area-under-the-curve (AUC), minimum concentration (Cmin), and maximum concentration (Cmax) by 42%, 48%, and 31%.(1) Coadministration of rifabutin (300 mg once daily) with rilpivirine (50 mg once daily) increased rilpivirine's AUC and Cmax by 16% and 43%.(1) |
RILPIVIRINE ER (CABENUVA) |
| Mavacamten/Moderate 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: Agents that induce the CYP3A4 isoenzyme may increase the metabolism of mavacamten.(1-3) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may decrease the levels and effectiveness of mavacamten.(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 US and Canadian manufacturers of mavacamten state concurrent use of mavacamten with moderate CYP3A4 inducers is contraindicated.(1,2) The UK manufacturer of mavacamten states that management of mavacamten during concomitant use with moderate CYP3A4 inducers is dependent on CYP2C19 phenotype. Labeling recommends: -When initiating or increasing the dose of a moderate inducer in patients who are CYP2C19 poor metabolizers, monitor patients closely and adjust mavacamten dose based on clinical response. -When discontinuing or decreasing the dose of a moderate inducer in patients who are CYP2C19 poor metabolizers, decrease the dose of mavacamten to 2.5 mg, or pause therapy if dose is 2.5 mg. -No dose adjustment is warranted with moderate inducers in patients who are CYP2C19 intermediate, normal, rapid, or ultrarapid metabolizers.(3) DISCUSSION: Concomitant use of mavacamten (a single 15 mg dose) with a strong CYP2C19 and CYP3A4 inducer (rifampin 600 mg daily dose) is predicted to decrease mavacamten area-under-curve (AUC) and maximum concentration (Cmax) by 87% and 22%, respectively, in CYP2C19 normal metabolizers, and by 69% and 4%, respectively, in CYP2C19 poor metabolizers.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, elagolix, lesinurad, modafinil, nafcillin, pexidartinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(4,5) |
CAMZYOS |
There are 110 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 Contraceptives/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifamycins (rifampin, rifabutin and rifapentine) induce the CYP3A4 mediated metabolism of both estrogen and progestin components of hormonal contraceptives. CLINICAL EFFECTS: Concurrent use of rifampin, rifabutin, or rifapentine may result in reduced levels and clinical effectiveness of hormone containing contraceptives. Breakthrough bleeding and contraceptive failure/pregnancy may result. Effects may be seen for several weeks after discontinuation of the rifamycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving rifamycins should be alerted to the risk for decreased effectiveness(e.g. contraceptive failure) of their hormonal contraceptive therapy. It is recommended that alternative or additional contraceptive methods be used during and for several weeks after rifamycin therapy. If a combined oral contraceptive is used, the preparation should contain at least 30 mcg of ethinyl estradiol should be used. The patient should be asked to report any spotting or bleeding. 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. 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 an open-label, randomized crossover study, 22 healthy females received oral contraceptives for 21 days, then were randomized to receive rifampin or rifabutin (300 mg/d for 10 days). Rifampin and rifabutin decreased the area-under-curve (AUC) of ethinyl estradiol by 64% and 35%, respectively, and maximum concentration (Cmax) by 42% and 20%, respectively. Rifampin and rifabutin decreased the AUC of norethindrone by 60% and 20%, respectively. Incidences of spotting were much greater in the rifampin co-administration group. In a study, a single dose of oral contraceptive (ethinyl estradiol 50 mcg and norethindrone acetate 1 mg) was administered to 7 female patients with tuberculosis, both during TB treatment and one month after stopping rifampin (450-600 mg/d). Upon cessation of rifampin therapy, the AUC for ethinyl estradiol significantly increased by 70%, and terminal plasma half-life more than doubled. A similar study design analyzed the pharmacokinetics of norethisterone (1 mg) in 8 women receiving rifampin (450-600 mg/d). Upon termination of TB treatment, it was found that rifampin reduced the AUC of a single dose of norethisterone (1 mg) by approximately 40%, with a half-life reduction of 50%. In a study, male volunteers received 50 mcg iv of ethinyl estradiol, followed by rifampin (600 mg for 6 days). Ethinyl estradiol half-life decreased by approximately 55%. The upward titration of ethinyl estradiol to 100 mcg resulted in a more than 2-fold increase in ethinyl estradiol metabolism caused by rifampicin treatment. An analytical trial evaluated liver biopsies from four patients treated with rifampin 600 mg for a period of 6-10 days. Hepatic microsomes from the biopsies were incubated with hormone substrates, including oestradiol and ethinyl estradiol. Rifampin resulted in a fourfold increase in hydroxylation. Not only did rifampin increase the rate of hydroxylation through enzyme induction, it also caused an increase in cytochrome P-450. There are reports of breakthrough bleeding and unintended pregnancy during concurrent use. 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.(25) |
AFIRMELLE, ALTAVERA, ALYACEN, AMETHIA, AMETHYST, ANNOVERA, APRI, ARANELLE, ASHLYNA, AUBRA, AUBRA EQ, AUROVELA, AUROVELA 24 FE, AUROVELA FE, AVERI, 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, DOLISHALE, DROSPIRENONE-ETH ESTRA-LEVOMEF, DROSPIRENONE-ETHINYL ESTRADIOL, ELINEST, ELURYNG, EMZAHH, ENILLORING, ENPRESSE, ENSKYCE, ERRIN, ESTARYLLA, ETHYNODIOL-ETHINYL ESTRADIOL, ETONOGESTREL-ETHINYL ESTRADIOL, FALMINA, FEIRZA, FEMLYV, FINZALA, GALBRIELA, 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, MELEYA, 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, ROSYRAH, 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, 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 |
| Rifamycins/Selected Anticoagulants (Vitamin K antagonists) SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifamycins may induce the hepatic metabolism of the anticoagulants. CLINICAL EFFECTS: Concurrent or recent use of a rifamycin may result in decreased levels of and clinical effects from anticoagulants. If the rifamycin is withdrawn, levels and effects of the anticoagulant may increase, increasing the risk of hemorrhage. This effect may be dose-related and continue beyond discontinuation of the rifamycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If concurrent use of rifamycins and warfarin is warranted, use caution during concurrent use and monitor patients closely. The dose of the anticoagulant will need to be adjusted when the rifamycin is initiated or discontinued. If concurrent use of rifampin and warfarin is warranted, monitor INR closely to maintain target INR. The dose of warfarin may need to be increased 3-5 times higher than a stable baseline dose. Goal INR may be delayed and labile for months after starting rifampin. After discontinuation of rifampin, INR requires close monitoring to de-escalate warfarin dose as induction effects fade. Evaluate patients closely for benefits of bridging with LMWH with risks of additional bleeding.(2) The time of highest risk for an anticoagulant drug interaction is when the precipitant drug is initiated or discontinued. Contact the prescriber before initiating, altering the dose, or discontinuing either drug. DISCUSSION: In a study in 4 healthy subjects, concurrent rifampin (300 mg twice daily) decreased warfarin (0.75 mg/kg) area-under-curve (AUC) by 70%.(1) In a study in 10 healthy males, concurrent rifampin (600 mg daily) decreased oral warfarin (1.5 mg/kg) AUC by 57%. Prothrombin time decreased by 52%. Intravenous warfarin AUC decreased by 58%. Prothrombin time decreased by 56%.(3) In a study in 8 healthy subjects, concurrent rifampin (600 mg daily) decreased warfarin (dosed to therapeutic effect) plasma levels by 85%. On warfarin alone, subjects averaged 25% of normal prothrombin activity. On concurrent rifampin, subjects averaged 85% of normal prothrombin activity.(4) There are several case reports of decreased warfarin(5-8) and phenprocoumon(9) effects during concurrent rifampin therapy. 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 warfarin and rifampin resulted in a ratio of rate ratios (RR) (95% CI) of 2.25 (1.1-4.61).(10) |
ANISINDIONE, DICUMAROL, JANTOVEN, PHENINDIONE, WARFARIN SODIUM |
| Selected Protease Inhibitors/Rifabutin; Rifapentine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Protease inhibitors may inhibit the metabolism of rifabutin by CYP3A4.(1-29) Rifabutin may induce the metabolism of some protease inhibitors.(1-14) Rifabutin may decrease the metabolism of darunavir by competitive inhibition at CYP3A4.(17-19) Rifapentine may induce the metabolism of the protease inhibitor by CYP3A4.(14) CLINICAL EFFECTS: The concurrent administration of amprenavir, atazanavir, boceprevir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, telaprevir or tipranavir with rifabutin may result in increased levels, clinical effects, and side effects (including neutropenia, lymphopenia, and influenza-like illness) of rifabutin.(1-29) Levels of amprenavir, indinavir, nelfinavir, and saquinavir may be decreased.(1-14) The increased levels of darunavir seen with concurrent rifabutin are not expected to be clinically significant.(17-19) Concurrent or recent use of rifapentine may result in decreased levels and effectiveness of the protease inhibitor.(14) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The Department of Health and Human Services (DHHS) Guidelines for the Use of Antiretroviral Agents,(27) the CDC/NIH guidelines on treatment of opportunistic infections (OI) in HIV(28), and the CDC's guidelines on managing drug interactions in HIV-related tuberculosis (TB)(29) all recommend that the dose of rifabutin be reduced to 150 mg once daily, or 300 mg three times weekly (a 50% reduction), when used with boosted or unboosted protease inhibitors. Previous iterations of the guidelines recommended a rifabutin dose of 150 mg three times weekly, but some studies have found subtherapeutic rifabutin levels as a result.(30-35) Given the risk of rifamycin resistance, the guidelines now recommend a higher dose of rifabutin than previously, but state that clinicians should recognize that there are limited safety data with this dose and patients need to be closely monitored for rifabutin-related toxicities. The Australian, UK, and US manufacturers of amprenavir,(1,2,3) fosamprenavir,(4,6) indinavir,(7,8,9) and nelfinavir(10,11,12) recommend reducing the dose of rifabutin by at least 50% when used concurrently. The Australian(7) and US(9) manufacturers of indinavir recommend that the dosage of indinavir be increased to 1,000 mg every eight hours. The UK manufacturer of indinavir recommends that the dosage of indinavir be increased to 1,000 mg or 1,200 mg every eight hours.(8) The US manufacturer of nelfinavir(12) and the US manufacturer of rifabutin(14) recommend a dosage of nelfinavir of 1,250 mg twice daily when used with rifabutin. Monitoring of patients should be increased. Monitor for neutropenia, liver enzyme levels, and consider monitoring rifabutin concentrations. The Australian, Canadian, UK, and US manufacturers of atazanavir,(15,16,17) darunavir,(18,19,20) fosamprenavir when used with ritonavir,(4,5,6) lopinavir-ritonavir,(21,22,23) saquinavir,(13) and tipranavir (24) recommend that the dosage of rifabutin be reduced by 75% (e.g. 150 mg every other day or 3 times per week) with careful monitoring. Additional dose adjustment may be warranted. In Australia, the combination of atazanavir with cobicistat is contraindicated with rifabutin.(15) Monitoring of patients should be increased. Monitor for neutropenia, liver enzyme levels, and consider monitoring rifabutin concentrations. When ritonavir is used as an antiretroviral agent at 500 mg bid or above, it is contraindicated with rifabutin.(25,26) When used as a boosting agent, refer to the dosing for the primary protease inhibitor. Consider alternatives to rifapentine in patients receiving protease inhibitors. DHHS guidelines state that rifapentine should not be coadministered with any protease inhibitors.(27) In Australia, the combination of atazanavir with cobicistat is contraindicated with rifapentine.(15) Selected protease inhibitors linked to this monograph include: amprenavir, atazanavir, boceprevir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, saquinavir, and telaprevir. DISCUSSION: Two open-label, randomized, cross-over studies, one in South Africa(30) and one in Vietnam(31), comparing rifabutin doses of 300 mg daily alone with 150 mg 3 times weekly or 150 mg daily given with lopinavir-ritonavir (LPVr) found that the 150 mg daily dose with LPVr attained higher rifabutin levels than 300 mg daily alone, and the 150 mg 3 times weekly dose with LPVr led to lower rifabutin levels than 300 mg daily alone. The levels of the rifabutin active metabolite 25-O-desacetylrifabutin was markedly elevated with both dosages in both studies. All 16 patients in the South Africa study and 22/24 patients in the Vietnam study had negative cultures at the end of TB therapy. Mild adverse events were common. Two cases of uveitis occurred in the South Africa study and none in the Vietnam study. Grade 3 neutropenia occurred in 5 patients and 1 patient in the South Africa and Vietnam study, respectively. A retrospective cohort study of HIV-TB co-infected patients on ritonavir-boosted atazanavir compared the use of rifabutin 150 mg 3 times weekly (n=118) with rifabutin 150 mg daily (n=174). Significantly more patients in the rifabutin daily group than the rifabutin three times weekly group achieved clinical cure (73% vs. 44.1%, p<0.001).(36) A number of other small studies in HIV-TB co-infected patients on ritonavir-based antiretroviral therapy have also found that a rifabutin dose of 150 mg 3 times weekly led to inadequate rifabutin levels but high 25-O-desacetylrifabutin levels. Many patients achieved clinical cure despite the low rifabutin levels, but studies did report patient deterioration, deaths, relapse, or resistance in patients with low rifabutin levels.(32-35) A case series of 3 patients with AIDS and TB reported that the patients developed acquired rifamycin resistance despite receiving directly observed therapy for TB. All the patients had been on ritonavir-boosted protease inhibitors and had a rifabutin dose of 150 mg every other day.(37) In a study in 7 subjects, atazanavir/ritonavir (300/100 mg daily) and rifabutin (150 mg twice weekly) increased the Cmax, AUC, and Cmin of rifabutin by 2.49-fold, 1.48-fold, and 1.40-fold, respectively, when compared to the administration of 150 mg daily of rifabutin. The Cmax, AUC, and Cmin of 25-O-desacetylrifabutin increased by 7.77-fold, 10.90-fold, and 11.45-fold, respectively.(15) Concurrent darunavir/ritonavir (600/100 mg twice daily) and rifabutin (150 mg every other day) decreased rifabutin Cmax and AUC by 28% and 7%, respectively, and increased rifabutin Cmin by 64% when compared to the administration of rifabutin (300 mg daily) alone. The Cmax, AUC, and Cmin of 25-O-desacetylrifabutin increased by 4.77-fold, 9.81-fold, and 27.1-fold, respectively. The Cmax, AUC, and Cmin of darunavir increased 42%, 57%, and 75%, respectively.(20) In a study using concurrent rifabutin (150 mg daily) with darunavir/ritonavir (400/100 mg twice daily), lymphopenia and influenza-like illnesses were reported at a higher frequency than in patients who received rifabutin alone. One patient experienced a grade 3 decrease in white blood cell count during concurrent therapy.(19) Concurrent fosamprenavir/ritonavir (700/100 mg twice daily) and rifabutin (150 mg every other day) increased amprenavir Cmax, AUC, and Cmin by 36%, 35%, and 17%, respectively. Rifabutin Cmax decreased by 14% and rifabutin Cmin increased by 28%. The Cmax, AUC, and Cmin of 25-O-desacetylrifabutin increased by 579%, 1120%, and 2510%, respectively. The AUC of rifabutin plus 25-O-desacetylrifabutin increased by 64%.(6) In a study in 14 healthy, HIV-negative subjects, concurrent rifabutin (150 mg once daily) and indinavir (800 mg every 8 hours) decreased indinavir Cmax, AUC, and Cmin by 20%, 32%, and 40%, respectively. Rifabutin Cmax, AUC, and Cmin increased by 1.29-fold, 1.54-fold, and 1.99-fold, respectively.(9,28) In a study in 18 healthy subjects, concurrent indinavir (1,000 mg three times daily) with rifabutin (150 mg daily) increased rifabutin and 25-O-desacetylrifabutin AUC by 70% and 120%, respectively, when compared to the administration of rifabutin (300 mg daily) alone. In a study in 10 HIV-positive subjects, concurrent administration of indinavir (1,000 mg three times daily) with rifabutin (150 mg daily) produced indinavir levels similar to indinavir (800 mg three time daily) administered alone.(39) Concurrent lopinavir/ritonavir (400/100 mg twice daily) with rifabutin (150 mg daily) increased lopinavir Cmax, AUC, and Cmin by 1.08-fold, 1.17-fold, and 1.20-fold, respectively. The Cmax, AUC, and Cmin of rifabutin increased by 2.12-fold, 3.03-fold, and by 4.90-fold, respectively. The Cmax, AUC, and Cmin of 25-O-desacetylrifabutin increased by 23.6-fold, 47.5-fold, and by 94.9-fold, respectively. The Cmax, AUC, and Cmin of rifabutin plus 25-O-desacetylrifabutin increased by 3.46-fold, 5.73-fold, and 9.53-fold, respectively.(23) Concurrent rifabutin (300 mg daily) and nelfinavir (750 mg every 8 hours) increased rifabutin AUC, Cmax, and Cmin by 207%, 146%, and 305%, respectively. Nelfinavir AUC, Cmax, and Cmin decreased by 32%, 24%, and 53%, respectively. Concurrent rifabutin (150 mg once daily) and nelfinavir (750 mg every 8 hours) increased rifabutin AUC, Cmax, and Cmin by 83%, 19%, and 177%, respectively. Nelfinavir AUC, Cmax, and Cmin decreased by 23%, 18%, and 25%, respectively. Concurrent rifabutin (150 mg once daily) and nelfinavir (1,250 mg every 12 hours) decreased nelfinavir Cmin by 15%. There was no effect on nelfinavir AUC or Cmax.(12) Rifapentine (600 mg twice weekly for 28 days) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of indinavir (800 mg 3 times daily on Days 15-28) by 70% and 55%, respectively. Indinavir clearance increased 3-fold. There was no affect on indinavir half-life. There were no effects on rifapentine pharmacokinetics.(14) 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. |
APTIVUS, ATAZANAVIR SULFATE, DARUNAVIR, EVOTAZ, FOSAMPRENAVIR CALCIUM, KALETRA, LOPINAVIR-RITONAVIR, NORVIR, PREZCOBIX, PREZISTA, REYATAZ, RITONAVIR, SYMTUZA, TYBOST, VIRACEPT |
| Selected Calcium Channel Blockers/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Multiple mechanisms appear to be involved. Rifampin may increase the hepatic metabolism of the calcium channel blockers, increase first-pass hepatic metabolism of oral calcium channel blockers, and decrease the protein binding of calcium channel blockers.(1-8) CLINICAL EFFECTS: Concurrent use of rifampin may decrease levels and effectiveness of the calcium channel blocker.(1-8) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Observe the patient for a decrease in the therapeutic effects of the calcium channel blocker if rifampin is initiated. The dose of the calcium channel blocker may need to be adjusted if rifampin is initiated or discontinued.(1-7) The US manufacturer of diltiazem states that concurrent use should be avoided.(2) The manufacturer of lercanidipine states that concurrent use is not recommended.(10) DISCUSSION: In healthy subjects, pretreatment with rifampin (600 mg daily) reduced the concentration of a single dose of isradipine (5 mg) below a detectable level. The study concluded that the concentrations and effects of isradipine may be either reduced or absent as a result of increased isradipine metabolism.(1) Concurrent administration of rifampin has been shown to lower diltiazem levels below detectable limits.(2) In a study in 5 healthy subjects, pretreatment with rifampin (6 days) decreased the area-under-curve (AUC) of a single oral dose of nilvadipine (4 mg) by 96.5%. Pretreatment with rifampin abolished nilvadipine-induced hypotensive effects and tachycardia.(3) A study in six subjects examined the effects of pretreatment with rifampin (600 mg daily for 15 days) on single doses of verapamil (10 mg intravenously or 120 mg orally). Rifampin significantly decreased the maximum concentration (Cmax) and AUC of oral verapamil and resulted in no changes in the P-R interval. There were small decreases in the AUC of intravenous verapamil.(4) In a study in 8 male subjects, pretreatment with rifampin (600 mg daily for 15 days) increased the systemic clearance of S-verapamil by 1.3-fold and the apparent oral-clearance of S-verapamil by 32-fold. The bioavailability of S-verapamil decreased 25-fold. The effect of oral verapamil on AV conduction was almost abolished. No significant changes were noted for intravenous administration of verapamil.(5) In a study in 16 hypertensive chronic kidney disease patients, amlodipine levels decreased an average of 82% after initiation of rifampin. In eight of the 16 patients, the levels were undetectable.(9) There have been case reports of decreased effectiveness of barnidipine,(6) manidipine,(6) nisoldipine,(6) and verapamil(7,8) during concurrent rifampin therapy. |
AMLODIPINE BESILATE, AMLODIPINE BESYLATE, AMLODIPINE BESYLATE-BENAZEPRIL, AMLODIPINE-ATORVASTATIN, AMLODIPINE-OLMESARTAN, AMLODIPINE-VALSARTAN, AMLODIPINE-VALSARTAN-HCTZ, AZOR, CADUET, CARDIZEM, CARDIZEM CD, CARDIZEM LA, CARTIA XT, CONJUPRI, CONSENSI, DILT-XR, DILTIAZEM 12HR ER, DILTIAZEM 24HR ER, DILTIAZEM 24HR ER (CD), DILTIAZEM 24HR ER (LA), DILTIAZEM 24HR ER (XR), DILTIAZEM HCL, DILTIAZEM HCL-0.7% NACL, DILTIAZEM HCL-0.9% NACL, DILTIAZEM HCL-NACL, DILTIAZEM-D5W, EXFORGE, EXFORGE HCT, FELODIPINE ER, ISRADIPINE, KATERZIA, LEVAMLODIPINE MALEATE, LOTREL, MATZIM LA, NISOLDIPINE, NORLIQVA, NORVASC, OLMESARTAN-AMLODIPINE-HCTZ, PRESTALIA, SULAR, TELMISARTAN-AMLODIPINE, TIADYLT ER, TIAZAC, TRANDOLAPRIL-VERAPAMIL ER, TRIBENZOR, VERAPAMIL ER, VERAPAMIL ER PM, VERAPAMIL HCL, VERAPAMIL SR |
| Atovaquone/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown but likely involves rifabutin-induced increase in the metabolism of atovaquone.(1,2) CLINICAL EFFECTS: Concurrent administration of atovaquone with rifabutin may result in decreased levels and clinical effects of atovaquone(1,2). PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The administration of rifabutin during atovaquone therapy is not recommended.(1,2) Consider alternative agents to rifabutin during atovaquone therapy.(1) If coadministration is necessary, the National Institute of Health Opportunistic Infections guidelines recommend patients take atovaquone with a fatty meal and monitor for decreased atovaquone efficacy.(3) DISCUSSION: In a study of 13 HIV-positive patients, rifampin (600 mg every 24 hours) and atovaquone (750 mg every 12 hours) resulted in a decrease in average atovaquone steady-state plasma concentration by 52% and an increase in average rifampin steady-state plasma concentration by 37%.(1) In a trial of 24 healthy volunteers, rifabutin 300 mg once daily with atovaquone oral suspension 750 mg twice daily resulted in a 34% decrease in the mean steady-state plasma atovaquone concentration and a 19% decrease in the mean steady-state plasma rifabutin concentration.(1) |
ATOVAQUONE, ATOVAQUONE-PROGUANIL HCL, MALARONE, MEPRON |
| Posaconazole/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifamycins may induce the metabolism of posaconazole by CYP3A4.(1,2) Posaconazole may inhibit the metabolism of rifabutin.(2) CLINICAL EFFECTS: Concurrent use of rifamycins may result in decreased levels and clinical effectiveness of posaconazole.(1,2) Concurrent use of posaconazole may result in elevated levels of and toxicity from rifabutin, including uveitis and leukopenia.(2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The UK manufacturer of posaconazole states that concurrent use of rifamycins should be avoided unless the benefit to the patient outweighs the risk of concurrent therapy.(1) The US manufacturer of posaconazole states that concurrent use of rifabutin should be avoided unless benefit outweighs the risk. If concurrent use is warranted, frequent monitoring of full blood counts and for adverse effects such as uveitis and leucopenia should be performed.(2) DISCUSSION: Concurrent rifabutin (300 mg daily) decreased posaconazole area-under-curve (AUC) and maximum concentration (Cmax) by 51% and 57%, respectively.(1) Concurrent rifabutin (300 mg daily) with posaconazole (200 mg daily) decreased posaconazole AUC and Cmax by 43% and 49%, respectively. Rifabutin AUC and Cmax increased by 72% and by 31%, respectively.(2) |
NOXAFIL, POSACONAZOLE |
| Irinotecan/Selected 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 induce the metabolism of irinotecan by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inducers may result in decreased levels of irinotecan, as well as its active metabolites, and decreased clinical effectiveness. PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer states do not administer strong CYP3A4 inducers with irinotecan unless there are no therapeutic alternatives. Consideration should be given to substituting non-enzyme inducing therapies at least 2 weeks prior to irinotecan therapy.(1) Levels of irinotecan and the active metabolites should be monitored in patients receiving concurrent use of strong CYP3A4 inducers. If strong CYP3A4 inducers are added to or discontinued from concurrent irinotecan, the dosage of irinotecan may need to be adjusted to ensure therapeutic effects or prevent toxicity. DISCUSSION: The manufactures states that irinotecan may interact with strong CYP3A4 inducers which may result in increased irinotecan metabolism.(1) In a clinical trial, irinotecan clearance values were 65.4% higher in patients receiving phenytoin when compared to patients who were not taking enzyme-inducing anticonvulsants.(2) In another clinical trial, irinotecan clearance was 117% higher in patients receiving anticonvulsants that included phenytoin.(5) Data from another clinical trial also suggested that phenytoin increases irinotecan clearance.(6) Case reports have also noted increased irinotecan clearance by 4-fold(3) and by 62.7%(4) in patients receiving concurrent phenytoin. Levels of irinotecan and its active metabolite, SN-38 were both decreased. Selected strong CYP3A4 inducers linked include: apalutamide, encorafenib, enzalutamide, ivosidenib, lumacaftor, mitotane, rifabutin, rifampin, and rifapentine. |
CAMPTOSAR, IRINOTECAN HCL, ONIVYDE |
| Live BCG/Selected Antimycobacterials SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Bacillus Calmette-Guerin (BCG) is a live, attenuated strain of Mycobacterium bovis (M.bovis) used to induce a granulomatous response in the treatment of localized bladder cancer and as a vaccine to prevent tuberculosis.(1-2) Co-treatment with antibacterial agents active against M.bovis may lead to an attenuation of the immune response associated with BCG administration.(1-2) CLINICAL EFFECTS: The effectiveness of chemotherapy may be impaired, or the vaccine may be ineffective. Agents linked to this monograph may have activity against M.bovis: amikacin, capreomycin, ciprofloxacin, clofazimine, cycloserine, ethambutol, ethionamide, gatifloxacin, isoniazid, kanamycin, levofloxacin, moxifloxacin, ofloxacin, rifabutin, rifampin, rifapentine, and streptomycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Intravesical instillation of BCG should be postponed during treatment with antibacterials which may decrease effectiveness.(2) Administration of BCG vaccine to patients receiving antibiotic therapy should only be done under close medical supervision.(1) If a patient develops a systemic BCG infection due to intravesicular or vaccine administration, treatment with multiple antimycobacterial agents may be required. DISCUSSION: Because antibiotic therapy may prevent sufficient vaccine-organism replication to generate an immune response, the manufacturer of BCG vaccine states that administration of BCG vaccine to patients receiving antibiotic therapy should only be done under close medical supervision.(1) Pyrazinamide is not included in this interaction as BCG is not sensitive to pyrazinamide.(2) |
BCG (TICE STRAIN), BCG VACCINE (TICE STRAIN) |
| Rifabutin/Etravirine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Etravirine and rifabutin may induce the metabolism of each other.(1) CLINICAL EFFECTS: Concurrent use may result in decreased levels and effectiveness of both etravirine and rifabutin.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of etravirine recommends a rifabutin dose of 300 mg daily in patients not receiving concurrent therapy with a protease inhibitor.(1) The US manufacturer of etravirine recommends that rifabutin not be administered to patients receiving concurrent etravirine with darunavir/ritonavir, lopinavir/ritonavir, or saquinavir/ritonavir.(1) DISCUSSION: In a study in 12 subjects, concurrent rifabutin (300 mg daily) decreased etravirine maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) by 37%, 37%, and 35%. Rifabutin Cmax, AUC, and Cmin decreased by 10%, 17%, and 24%. The Cmax, AUC, and Cmin of 25-O-desacetylrifabutin decreased by 15%, 17%, and 22%, respectively.(1) |
ETRAVIRINE, INTELENCE |
| Selected Immunosuppressants/Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of CYP3A4 may increase the metabolism of cyclosporine, everolimus, sirolimus, tacrolimus, and temsirolimus.(1) CLINICAL EFFECTS: Concurrent use of strong inducers of CYP3A4 may result in decreased levels and effectiveness of cyclosporine, everolimus, sirolimus, tacrolimus, and temsirolimus.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The American Society of Transplantation guidelines state that cyclosporine and tacrolimus should be avoided in combination with rifabutin and rifampin. Everolimus should be avoided in combination with rifampin and is contraindicated with rifabutin. Sirolimus is contraindicated with rifabutin and rifampin. If concurrent therapy of cyclosporine, everolimus, sirolimus, or tacrolimus with rifampin is needed, increase the dose of the immunosuppressant by 2-fold when the combination is initiated and monitor immunosuppressant concentrations frequently with rapid subsequent dose increases as needed. The reverse is recommended when rifampin is discontinued.(62) The US manufacturer of everolimus states that concurrent use with strong CYP3A4 inducers should be avoided. If concurrent use is warranted, consider increasing the dose of everolimus. In patients with advanced hormone receptor-positive, HER2-negative breast cancer (HR+BC); advanced pancreatic neuroendocrine tumors (PNET); or advanced renal cell carcinoma; or renal angiomyolipoma with TSC, double the daily dose of everolimus using 5 mg increments or less. If the inducer is discontinued, return the dose to that used prior to inducer therapy once the inducer has been stopped for 5 days. In patients with subependymal giant cell astrocytoma with TSC, double the dose of everolimus using 5 mg increments or less. Subsequent dosing should be individualized based on therapeutic drug monitoring. If the inducer is discontinued, return the dose of everolimus to the dose used prior to the inducer once the inducer has been stopped for 5 days, and assess everolimus trough levels 2 weeks later.(1) St. John's wort may decrease everolimus levels unpredictably and should be avoided entirely.(1) The US manufacturer of temsirolimus states that concurrent use of strong inducers of CYP3A4, such as carbamazepine, phenobarbital, phenytoin, rifabutin, rifampicin, or rifampin should be avoided. If concurrent therapy is warranted, consider increasing the dosage of temsirolimus from 25 mg/week to 50 mg/week. If the inducer is discontinued, the dosage of temsirolimus should be returned to the previous dose.(2) If possible, consider alternatives to strong CYP3A4 inducers in patients maintained on cyclosporine, sirolimus, and tacrolimus. If concurrent therapy is warranted, monitor cyclosporine, sirolimus, and tacrolimus serum levels and observe the patient for graft rejection. The dosage of cyclosporine, sirolimus, and tacrolimus may need to be adjusted following the initiation or discontinuation of these agents. Strong CYP3A4 inducers linked to this monograph include: allobarbital, amobarbital, apalutamide, aprobarbital, barbexaclone, barbital, brallobarbital, butabarbital, butalbital, butethal, carbamazepine, cyclobarbital, difebarbamate, ethotoin, febarbamate, fosphenytoin, hexobarbital, lumacaftor, mephenytoin, mephobarbital, metharbital, mitotane, natisedine, pentobarbital, phenobarbital, phenytoin, primidone, probarbital, proxibarbal, rifabutin, rifampin, rifapentine, secobarbital, St. John's wort, talbutal, vinbarbital, and vinylbital. DISCUSSION: In a study in 10 lung transplant patients, significantly higher doses of cyclosporine were required during nafcillin therapy to maintain therapeutic trough levels. Patients also developed higher serum creatinine levels and more renal dysfunction than patients not receiving nafcillin. In a case report, a patient experienced 70% and 85% drops in cyclosporine levels during two separate courses of nafcillin therapy. Trough cyclosporine concentrations have been found to decrease within 48 hours after starting phenytoin even when the dose of cyclosporine is increased. Conversely, cyclosporine concentrations may increase when the hydantoin is discontinued. The effect of the hydantoin on cyclosporine may reverse over a period of one to three weeks after stopping the hydantoin. Concurrent administration of cyclosporine and rifampin has been associated with lowering of cyclosporine to undetectable serum levels. Decreases in cyclosporine levels have been observed within 2 days of concomitant therapy but will probably not be maximal for 1 week. The effects of the interaction may persist for up to 3 weeks after rifampin is stopped. In an open-label study in 11 renal transplant patients, subjects received St. John's wort (600 mg daily) for 14 days in addition to their normal cyclosporine regimen. After 14 days of St. John's wort, dose-corrected cyclosporine area-under-curve (AUC), maximum concentration (Cmax), and minimum concentration (Cmin) decreased by 46%, 42%, and 41%, respectively. Mean cyclosporine dose increased from 2.7 mg/kg/day at 4.2 mg/kg/day at the end of the study. Subjects required their first cyclosporine dosage adjustment at Day 3. There are several case reports of decreased cyclosporine with concurrent carbamazepine, phenobarbital, and St. John's wort. In healthy subjects, concurrent use of rifampin, a strong inducer of CYP3A4, decreased everolimus AUC and Cmax by 64% and 58%, respectively. Increasing the dosage of everolimus to 20 mg daily in patients taking a strong inducer of CYP3A4 is expected to increase the AUC of everolimus to levels seen without a concurrent inducer; however, there are no clinical data available with this dosage in patients receiving strong CYP3A4 inducers. In an open-label clinical trial, 10 male patients received ridaforolimus (40 mg daily, days 1 and 14) and rifampin (600 mg daily, days 1-21). Administration of rifampin resulted in a reduction in the mean whole-blood concentration of ridaforolimus (AUC-GMR 0.57, Cmax- GMR 0.66). The mean whole-blood concentration of ridaforolimus increased 1.5-fold following ketoconazole administration. In a study in 14 healthy subjects, pretreatment with rifampin (600 mg daily for 14 days) decreased the AUC and Cmax of a single dose of sirolimus (20 mg) by 82% and 71%, respectively. The oral clearance of sirolimus increased by 5.5-fold. There are case report of decreased sirolimus levels with concurrent phenytoin and rifampin. A study in six healthy subjects examined the effects of rifampin on single doses of oral (0.1 mg/kg) and intravenous (0.025 mg/kg/4 hours) tacrolimus. Rifampin increased tacrolimus clearance by 47% and decreased tacrolimus bioavailability by 51%. In a study in 10 healthy subjects, pretreatment with St. John's wort (300 mg 3 times daily for 18 days) decreased the AUC of a single dose of tacrolimus (0.1 mg/kg) by 35.3%. Tacrolimus apparent oral clearance and volume of distribution increased by 68% and 53%, respectively. In a study in 10 renal transplant patients, concurrent St. John's wort (600 mg daily) for 2 weeks increased tacrolimus dose requirements from a baseline of 4.5 mg/day to 8.0 mg/day. Dose-correct tacrolimus AUC decreased by 57.8%. There have been several case reports of decreased tacrolimus levels with concurrent carbamazepine, phenobarbital, phenytoin, rifampin, and St. John's wort. Phenobarbital and phenytoin have been used successfully to treat tacrolimus overdose. Concurrent rifampin had no significant effects on the AUC or Cmax of temsirolimus; however, sirolimus AUC and Cmax decreased by 56% and 65%, respectively. A dosage adjustment to 50 mg/week of temsirolimus in the presence of strong CYP3A4 inducers is predicted to adjust levels to those seen without inducers; however, there are no clinical data in patients using this dose. There is a case report of decreased temsirolimus effectiveness with concurrent rifampin. |
AFINITOR, AFINITOR DISPERZ, ASTAGRAF XL, CYCLOSPORINE, CYCLOSPORINE MODIFIED, ENVARSUS XR, EVEROLIMUS, FYARRO, GENGRAF, NEORAL, PROGRAF, SANDIMMUNE, SIROLIMUS, TACROLIMUS, TACROLIMUS XL, TEMSIROLIMUS, TORISEL, TORPENZ, ZORTRESS |
| Tolvaptan/Strong 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 tolvaptan.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inducers may result in decreased levels and effectiveness of tolvaptan.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Concurrent administration with strong CYP3A4 inducers should be avoided. If concurrent use is required, the dosage of tolvaptan may need to be increased.(1) DISCUSSION: Concurrent administration of rifampin, a strong inducer of CYP3A4, decreased tolvaptan exposure by 85%.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(1,2) |
JYNARQUE, SAMSCA, TOLVAPTAN |
| Ulipristal/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifamycins (rifabutin, rifampin, rifapentine) may induce the metabolism of ulipristal by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use or use of rifamycins within the previous 2-3 weeks may result in decreased levels and effectiveness of ulipristal.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US and UK manufacturers of ulipristal state that concurrent use with CYP3A4 inducers such as rifampin is not recommended. Decreased effectiveness of ulipristal may occur even 2-3 weeks after discontinuation of rifamycins.(1,2) 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). Advise the patient to have a pregnancy test to exclude pregnancy after use and to seek medical advice if they do become pregnant. DISCUSSION: CYP3A4 inducers may decrease levels and effectiveness of ulipristal. Enzyme induction may take 2-3 weeks to wear off. Plasma levels of ulipristal may be reduced even if the CYP3A4 inducer was discontinued in the previous 2-3 weeks.(1) Concurrent administration of ulipristal 30 mg and rifampin 600 mg for 9 days decreased the maximum concentration (Cmax) and area-under-the-curve (AUC) by 90% and 93%, respectively. The Cmax and AUC of monodemethyl-ulipristal decreased by 84% and 90% respectively.(2) |
ELLA |
| Romidepsin/Strong CYP3A4 Inducers; Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of CYP3A4 and rifabutin may increase the metabolism of romidepsin.(1,2) CLINICAL EFFECTS: Concurrent use of a strong CYP3A4 inducer or rifabutin may result in decreased levels and effectiveness of romidepsin.(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 manufacturer of romidepsin recommends avoiding the use of strong inducers of CYP3A4 in patients receiving romidepsin.(1,2) The Canadian manufacturer includes rifabutin on its list of CYP3A4 inducers that should be avoided.(2) DISCUSSION: In a study in advanced cancer patients, rifampin, a strong inducer of CYP3A4 and an inhibitor and inducer of other CYP enzymes and transporters, unexpectedly increased the maximum concentration (Cmax) and area-under-curve (AUC) of romidepsin (14 mg/m2) by 60% and 80%, respectively. Romidepsin clearance and volume of distribution decreased by 44% and 52%, respectively. This is likely due to inhibition of an undetermined hepatic uptake process responsible for the disposition of romidepsin.(1) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, dexamethasone, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifapentine and St. John's wort.(1-3) |
ISTODAX, ROMIDEPSIN |
| Ixabepilone/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifamycins may induce the metabolism of ixabepilone by CYP3A4.(1) CLINICAL EFFECTS: Concurrent or recent use of rifamycins may result in decreased levels and effectiveness of ixabepilone.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of ixabepilone states that concurrent use of strong inducers of CYP3A4, such as rifampin, rifapentine, and rifabutin, should be avoided. If concurrent therapy is required, the dose of ixabepilone may be gradually increased from 40 mg/m2 to 60 mg/m2, depending on tolerance. If the dose is increased, ixabepilone should be given as a 4 hour infusion. Monitor patients closely for toxicity. If the inducer is discontinued, the dose of ixabepilone should be returned to the dose used prior to concurrent therapy.(1) DISCUSSION: Concurrent use of rifampin increased ixabepilone area-under-curve (AUC) by 43%, compared to treatment with ixabepilone alone.(1) Adjustment of the ixabepilone dose in the presence of a strong CYP3A4 inducer to 60 mg/m2 given over 4 hours is predicted to adjust the ixabepilone AUC to the range observed without inducers; however, there is no clinical data with this dose.(1) |
IXEMPRA |
| 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 |
| Toremifene/Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of CYP3A4 may induce the metabolism of toremifene.(1) Toremifene may inhibit the metabolism of phenytoin.(1) CLINICAL EFFECTS: Concurrent or recent use of apalutamide, barbiturates, carbamazepine, dexamethasone, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort may result in decreased levels and effectiveness of toremifene.(1) Concurrent use of toremifene may decrease phenytoin levels.(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 use of strong inducers of CYP3A4 in patients receiving toremifene. If concurrent toremifene and phenytoin are required, monitor phenytoin levels. The dosage of phenytoin may need to be adjusted.(1) DISCUSSION: In clinical trials, ten patients on anticonvulsants which included carbamazepine, phenobarbital, and phenytoin experienced a 2-fold increase in clearance and a decrease in the elimination half-life of toremifene.(1,2) The area-under-curve (AUC) and half-life of N-demethyltoremifene, an active metabolite of toremifene, decreased by 61% and 78%, respectively.(2) In a study in healthy males, rifampin (600 mg daily for 5 days) decreased maximum concentration (Cmax) and AUC of a single dose of toremifene (120 mg) by 55% and 87%, respectively. The Cmax of N-demethyltoremifene increased 48% and the AUC of N-demethyltoremifene decreased by 80%.(3) Strong inducers of CYP3A4 include apalutamide, barbiturates, carbamazepine, dexamethasone, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(4,5) |
FARESTON, TOREMIFENE CITRATE |
| 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 |
| Cobicistat-Elvitegravir/Selected CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Cobicistat may inhibit rifabutin and rifapentine metabolism by CYP3A4. Apalutamide, encorafenib, enzalutamide, lumacaftor, mitotane, oxcarbazepine, rifabutin, and rifapentine may induce the metabolism of cobicistat and elvitegravir.(1) CLINICAL EFFECTS: Concurrent use of cobicistat-elvitegravir with apalutamide, encorafenib, enzalutamide, lumacaftor, mitotane, oxcarbazepine, rifabutin, or rifapentine may result decreased levels of elvitegravir and development of resistance.(1) Concurrent use of cobicistat-elvitegravir may result in elevated levels of apalutamide, oxcarbazepine, rifabutin, or rifapentine, as well as ivacaftor (which is coformulated with lumacaftor).(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 combination product containing cobicistat-elvitegravir-emtricitabine-tenofovir and rifabutin or rifapentine is not recommended.(1) Consider the use of alternative anticonvulsants to oxcarbazepine.(1) Concurrent use with carbamazepine, phenobarbital, or phenytoin is contraindicated.(1) DISCUSSION: Concurrent cobicistat-elvitegravir (150 mg each daily) increased the maximum concentration (Cmax) of rifabutin (150 mg every other day) by 1.09-fold. The area-under-curve (AUC) and minimum concentration (Cmin) of rifabutin decreased by 8% and 6%, respectively, when compared to the administration of 300 mg daily of rifabutin. The Cmax, AUC, and Cmin of 25-O-desacetyl-rifabutin increased by 4.84-fold, 6.25-fold, and 4.94-fold, respectively, when compared to the administration of 300 mg daily of rifabutin. The Cmax, AUC, and Cmin of elvitegravir decreased by 9%, 21%, and 67%, respectively.(1) Concurrent cobicistat-elvitegravir (150 mg each daily) with carbamazepine (200 mg twice daily) decreased the Cmax, AUC, and Cmin of elvitegravir by 45%, 69%, and 97%, respectively. Concurrent cobicistat-elvitegravir (150 mg each daily) with carbamazepine (200 mg twice daily) increased the Cmax, AUC, and Cmin of carbamazepine by 40%, 43%, and 51%, respectively. The Cmax, AUC, and Cmin was decreased for carbamazepine-10,11-epoxide by 29%, 35%, and 41%, respectively. (2) |
GENVOYA, STRIBILD |
| Ponatinib/Strong CYP3A4 Inducers; Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of CYP3A4 and rifabutin may induce the metabolism of ponatinib via this pathway.(1-3) CLINICAL EFFECTS: Concurrent or recent use of strong CYP3A4 inducers or rifabutin may reduce the clinical effectiveness of ponatinib.(1-3) 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 ponatinib with strong CYP3A4 inducers.(1-3) The Canadian and UK manufacturers of ponatinib include rifabutin in their list of CYP3A4 inducers that should be avoided.(2-3) When possible, select alternative agents in place of the strong CYP3A4 inducer. Monitor patients receiving concurrent therapy for reduced efficacy. DISCUSSION: Coadministration of a single ponatinib 45 mg dose with rifampin 600 mg daily in 19 healthy volunteers resulted in a decrease in ponatinib area-under-the-curve (AUC) and maximum concentration (Cmax) by 62% and 42%, respectively. (1) Strong CYP3A4 inducers linked to this monograph are: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine and St John's Wort.(4,5) |
ICLUSIG |
| Bedaquiline/Strong & 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 bedaquiline.(1) CLINICAL EFFECTS: Concurrent or recent use of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of bedaquiline.(1) PREDISPOSING FACTORS: 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) 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) Strong inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(1-3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, sotorasib, telotristat and tovorafenib.(1-3) |
SIRTURO |
| 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 |
| Edoxaban/Selected P-glycoprotein (P-gp) Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Edoxaban is a P-glycoprotein (P-gp) substrate. P-gp induction may reduce systemic exposure to edoxaban.(1) CLINICAL EFFECTS: Concurrent or recent use of apalutamide, carbamazepine, efavirenz, fosphenytoin, lorlatinib, phenytoin, rifapentine, or St. John's wort may result in decreased effectiveness of edoxaban.(1-3) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of edoxaban states that concomitant use of rifampin should be avoided. Although there are no recommendations for other P-gp inducers, a similar precaution is reasonable.(4) The UK manufacturer of edoxaban recommends caution with co-administration of P-gp inducers such as carbamazepine, phenytoin, or St. John's wort.(1,3) Consider alternatives to the P-gp inducing agent. If therapy with an inducer of P-gp is required, alternatives to edoxaban may need to be considered. If a P-gp inducer is discontinued, edoxaban exposure will remain impaired for at least one week after the completion of therapy. DISCUSSION: Co-administration of another P-gp inducer, rifampin 600 mg QD for 7 days with a single dose of edoxaban 60 mg on Day 7, decreased total systemic exposure to edoxaban by 40% without having an apparent effect on peak exposure.(5) A 76-year-old male on apixaban for atrial fibrillation s/p pulmonary embolism 1 month prior was started on rifabutin 300 mg daily for tuberculosis. Apixaban was switched to edoxaban due to a drug interaction with rifabutin. At 1 month, rifabutin was increased to 450 mg daily. After another 8 weeks, the patient suffered a DVT that was thought to be a result of a drug-drug interaction with rifabutin.(6) Other inducers of P-glycoprotein linked to this monograph include apalutamide, carbamazepine, fosphenytoin, lorlatinib, phenytoin, rifabutin, rifapentine, and St. John's wort.(2,3) |
SAVAYSA |
| Flibanserin/Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Flibanserin is primarily metabolized by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inducers and flibanserin will result in decreased systemic concentrations of flibanserin and may lead to therapeutic failure.(1,6) 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 flibanserin states that concomitant use with CYP3A4 inducers is not recommended. In an interaction study, rifampin decreased flibanserin exposure(AUC) 95%.(1) The onset of induction is gradual but may begin within one week for potent agents (e.g. rifampin). The time to maximal induction may be 2 or more weeks depending upon the half-life and dose of the inducer. DISCUSSION: In an interaction study described in prescribing information, rifampin decreased flibanserin exposure (AUC) 95%.(1) FDA defines strong CYP inducers as agents which cause a > or = to 80% decrease in systemic exposure (area-under-curve or AUC) of a drug metabolized by a specific CYP enzyme.(2) Strong CYP3A4 inducers linked to this monograph are: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, natisedine, phenytoin, primidone, rifabutin, rifampin, rifapentine and St. John's Wort.(3) |
ADDYI, FLIBANSERIN |
| Ixazomib/Slt Moderate and Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ixazomib is primarily metabolized by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of strong or selected moderate CYP3A4 inducers will result in decreased systemic concentrations of ixazomib.(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 ixazomib states that concomitant use with CYP3A4 inducers should be avoided. In an interaction study, rifampin decreased ixazomib exposure(AUC) by 74%.(1) Use an alternative to the inducing agent when possible. The onset of induction is gradual but may begin within one week for potent agents (e.g. rifampin). The time to maximal induction may be 2 or more weeks depending upon the half-life and dose of the inducer. DISCUSSION: In an interaction study, coadministration with rifampin decreased ixazomib AUC 74% and maximum concentration (Cmax) by 54%(1) Selected moderate and strong CYP3A4 inducers linked to this monograph are: apalutamide, barbiturates, belzutifan, carbamazepine, cenobamate, dabrafenib, elagolix, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, pacritinib, pexidartinib, phenobarbital, phenytoin, primidone, repotrectinib, rifabutin, rifampin, rifapentine, St. John's Wort, sotorasib telotristat, and tovorafenib.(2) |
NINLARO |
| Elbasvir-Grazoprevir/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 elbasvir and grazoprevir.(1,2) CLINICAL EFFECTS: Concurrent use of a moderate 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 a moderate CYP3A4 inducers is not recommended.(1,2) If concurrent use is required, 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) Moderate inducers of CYP3A4 include belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine, and tovorafenib.(1-4) |
ZEPATIER |
| Vemurafenib/Strong CYP3A4 Inducers; Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Vemurafenib is a substrate of CYP3A4. Strong inducers of CYP3A4 and rifabutin may increase the metabolism of vemurafenib.(1-3) CLINICAL EFFECTS: Concurrent use of a strong inducer of CYP3A4 or rifabutin may result in decreased levels and effectiveness of vemurafenib.(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 vemurafenib states to avoid concurrent use with strong CYP3A4 inducers and replace these drugs with alternative drugs when possible.(1-3) The Canadian and UK manufacturers include rifabutin on their lists of CYP3A4 inducers that are to be avoided.(2,3) If concurrent administration with a strong CYP3A4 inducer is unavoidable, increase the dose of vemurafenib by 240 mg (one tablet) as tolerated.(1) If concurrent use of a strong CYP3A4 inducer is discontinued, allow a 2 week period to lapse and then resume the dose of vemurafenib that was taken prior to initiation of the strong CYP3A4 inducer.(1) DISCUSSION: In a study in healthy subjects, coadministration of single dose vemurafenib 960 mg with rifampin (600 mg daily, a strong CYP3A inducer) decreased vemurafenib area-under-curve (AUC) by 40% (90% CI: 24%, 53%) with no effect on maximum concentration (Cmax), when compared to vemurafenib alone.(1) Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(4-5) |
ZELBORAF |
| Pimavanserin/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 inducers of CYP3A4 may induce the metabolism of pimavanserin.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inducer of CYP3A4 may result in decreased levels and effectiveness of pimavanserin.(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 pimavanserin recommends avoiding concomitant use of strong or moderate CYP3A4 inducers.(1) 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 inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(3-4) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, and tovorafenib.(3-4) |
NUPLAZID |
| Oral Rilpivirine/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifabutin may induce the metabolism of rilpivirine by CYP3A4.(1) CLINICAL EFFECTS: Concurrent or recent use of rifabutin may result in decreased levels and effectiveness of 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 oral rilpivirine states that concurrent use of CYP3A4 inducers such as rifabutin warrants dose adjustment. When administering rifabutin with oral rilpivirine, increase the dose of rilpivirine to 50 mg once daily. When rifabutin co-administration is stopped, the rilpivirine dose should be decreased to 25 mg once daily. 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 18 subjects, rifabutin (300 mg daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of rilpivirine (25 mg orally daily) by 31%, 42%, and 48%, respectively.(1) A study in 18 subjects compared rilpivirine administered alone (25 mg orally daily) to coadministration with rifabutin (300 mg daily) and rilpivirine (50 mg orally daily). A significant difference was not found with the Cmax (1.43), AUC (1.16), or Cmin (0.93) of rilpivirine. (1) |
COMPLERA, EDURANT, EDURANT PED, EMTRICITABINE-RILPIVIRNE-TENOF, JULUCA |
| 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 |
| Brigatinib/Strong CYP3A4 Inducers; Rifabutin 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. Strong inducers of CYP3A4 and rifabutin may induce the metabolism of brigatinib.(1,2) CLINICAL EFFECTS: Concurrent use of a strong inducer of CYP3A4 or rifabutin may result in decreased levels and effectiveness of brigatinib.(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 manufacturer of brigatinib states to avoid concurrent administration with strong CYP3A4 inducers.(1,2) The UK manufacturer of brigatinib includes rifabutin on its list of strong CYP3A4 inducers that should be avoided.(2) 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.(1) Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, and St. John's wort.(3-4) |
ALUNBRIG |
| 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 |
| 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/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 doravirine.(1-2) CLINICAL EFFECTS: Concurrent or recent use of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of doravirine.(1-2) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: If concurrent therapy is necessary, increase doravirine dosage to one tablet twice daily for the duration of coadministration with the CYP3A4 inducer.(1) Patients on the fixed-dose combination of doravirine-lamivudine-tenofovir should take 1 tablet (100 mg) of doravirine about 12 hours after their dose of doravirine-lamivudine-tenofovir.(2) DISCUSSION: Doravirine is metabolized by CYP3A4. Moderate inducers of CYP3A4 are expected to reduce doravirine levels, which may lead to loss of response.(1) In a study in 12 subjects, rifabutin (300 mg daily), a moderate inducer of CYP3A4, decreased the area-under-curve (AUC) and 24 hour concentration (C24) of a single dose of doravirine (100 mg) by 50% and 68%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dexamethasone, dipyrone, elagolix, eslicarbazepine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, thioridazine and tovorafenib.(3-4) |
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 |
| Larotrectinib/Strong CYP3A4 Inducers; Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inducers of CYP3A4 and rifabutin may increase the metabolism of larotrectinib.(1,2) CLINICAL EFFECTS: Concurrent use of a strong inducer of CYP3A4 or rifabutin may result in decreased levels and effectiveness of larotrectinib.(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 manufacturer of larotrectinib states that the concurrent use of strong CYP3A4 inducers should be avoided, and that alternative treatments with less CYP3A4 induction should be considered.(1,2) The Canadian manufacturer includes rifabutin on its list of CYP3A4 inducers that should be avoided.(2) If coadministration of a strong 3A4 inducer cannot be avoided, double the larotrectinib dose. After the strong 3A4 inducer has been discontinued for 3 to 5 elimination half-lives, resume the larotrectinib dose at the dose taken prior to initiating the 3A4 inducer.(1,2) DISCUSSION: In a study with healthy subjects, co-administration of rifampin (strong 3A4 inducer) with a single dose of larotrectinib (100 mg), decreased larotrectinib area-under-curve (AUC) by 81% and maximum concentration (Cmax) by 71%.(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.(3-4) |
VITRAKVI |
| Siponimod/Selected Moderate and Strong CYP3A4 Inducers 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. 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) 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. 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) DISCUSSION: In a study, efavirenz (a moderate CYP3A4 inducer) decreased the area-under-curve (AUC) of siponimod by up to 52% across CYP2C9 genotypes. Drugs that are moderate or strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, belzutifan, bosentan, cenobamate, dabrafenib, elagolix, etravirine, fosphenytoin, lesinurad, lorlatinib, lumacaftor, mavacamten, mitapivat, mitotane, modafinil, nafcillin, pexidartinib, phenobarbital, phenytoin, primidone, rifabutin, rifapentine, St John's Wort, sotorasib, telotristat ethyl, and tovorafenib.(2-3) |
MAYZENT |
| 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 |
| Entrectinib/Moderate CYP3A4 Inducers 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. Moderate inducers of CYP3A4 may induce the metabolism of entrectinib.(1) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of entrectinib.(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 entrectinib states that concurrent use with moderate CYP3A4 inducers should be avoided. (1) 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) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat, and tovorafenib.(2-3) |
ROZLYTREK |
| 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 |
| Intravenous and Oral Lefamulin/Moderate CYP3A4 Inducers 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 inducers of CYP3A4 may induce the metabolism of lefamulin.(1) Oral lefamulin tablets may inhibit the metabolism of agents that are also sensitive CYP3A4 substrates.(1-3) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of lefamulin.(1) Coadministration of oral lefamulin with agents that are also sensitive CYP3A4 substrates may result in elevated levels and toxicities of the sensitive CYP3A4 substrate. 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 lefamulin states that concurrent use with moderate CYP3A4 inducers should be avoided.(1) Concomitant use of lefamulin tablets with sensitive CYP3A4 substrates requires close monitoring for adverse effects of these drugs.(1) DISCUSSION: In a study, concurrent administration of rifampin (a 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 (a strong inducer) with oral lefamulin (tablets) decreased lefamulin AUC and Cmax by 72% and 57%.(1) In a study, oral lefamulin tablets administered concomitantly with and at 2 or 4 hours before oral midazolam (a CYP3A4 substrate) increased the area-under-curve (AUC) and maximum concentration (Cmax) of midazolam by 200% and 100%, respectively. No clinically significant effect on midazolam pharmacokinetics was observed when co-administered with lefamulin injection.(1) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mitapivat, modafinil, nafcillin, rifabutin, telotristat, and tovorafenib.(2-3) |
XENLETA |
| 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 |
| Selected Antineoplastic Systemic Enzyme Inhibitors/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifabutin is a moderate inducer of the CYP3A4 isoenzyme and may increase the metabolism of some antineoplastic systemic enzyme inhibitors, including cabozantinib,(1,2) ceritinib,(3) erlotinib,(4) imatinib,(5) lapatinib,(6) and sorafenib.(7) CLINICAL EFFECTS: Concurrent use of rifabutin may decrease the levels and effectiveness of some antineoplastic systemic enzyme inhibitors, including cabozantinib,(1,2) ceritinib,(3) erlotinib,(4) imatinib,(5) lapatinib,(6) and sorafenib.(7) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the concurrent use of rifabutin in patients receiving therapy with cabozantinib,(1,2) ceritinib,(3) erlotinib,(4) imatinib,(5) lapatinib,(6) and sorafenib.(7) Consider the use of alternative agents with less enzyme induction potential.(1-7) If concurrent use of rifabutin cannot be avoided: Increase the daily dose of cabozantinib TABlets by 20 mg (e.g. from 60 mg to 80 mg daily) as tolerated. The daily dose should not exceed 80 mg. Resume the dose that was used prior to initiating rifabutin 2 to 3 days after discontinuation of rifabutin.(1) Increase the daily dose of cabozantinib CAPsules by 40 mg (from 140 mg to 180 mg daily or from 100 mg to 140 mg daily) as tolerated. The daily dose of cabozantinib should not exceed 180 mg. If rifabutin is discontinued, reduce the dosage of cabozantinib to the dose used prior to initiation of rifabutin 2 to 3 days after discontinuation of rifabutin.(2) 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 rifabutin is discontinued.(4) The dose of imatinib should be increased by at least 50% and clinical response should be carefully monitored. Dosages up to 1,200 mg/day (600 mg twice daily) have been used in patients receiving concurrent therapy with strong CYP3A4 inducers.(5) The dose of lapatinib should be gradually titrated from 1,250 mg/day up to 4,500 mg/day (HER2 positive metastatic breast cancer indication) or from 1,500 mg/day up to 5,500 mg/day (hormone receptor positive, HER2 positive breast cancer indication) based on patient tolerability. If rifabutin is discontinued, the dose of lapatinib should be adjusted to the normal dose.(6) DISCUSSION: The US manufacturers of cabozantinib,(2) erlotinib,(4) imatinib,(5) lapatinib,(6) and sorafenib,(7) and the UK manufacturer of ceritinib(3) include rifabutin in their list of strong CYP3A4 inducers to be avoided. Although the combinations of these agents with rifabutin have not been studied, they have been studied with other strong CYP3A4 inducers. In a study in healthy subjects, rifampin (600 mg daily for 31 days) decreased the area-under-curve (AUC) of a single dose of cabozantinib by 77%.(1) In a study in 19 healthy subjects, rifampin (600 mg daily for 14 days) decreased the maximum concentration (Cmax) and AUC of a single dose of ceritinib by 44% and 70%, respectively.(3) Pretreatment and concurrent therapy with rifampin increased erlotinib clearance by 3-fold and decreased the erlotinib AUC by 66% to 80%. This is equivalent to a dose of about 30 mg to 50 mg in NSCLC.(4) 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.(4) 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).(8) Pretreatment of 14 healthy subjects with rifampin (600 mg daily for 10 days) increased the clearance of a single dose of imatinib (400 mg) by 3.8-fold. The AUC and Cmax decreased by 74% and 54%, respectively.(5,9) The Cmax of the CGP74588 metabolite increased by 88.6%, but the AUC of CGP74588 decreased by 11%.(9) In healthy subjects, carbamazepine (100 mg twice daily for 3 days and 200 mg twice daily for 17 days), another CYP3A4 inducer, decreased the AUC of lapatinib by 72%. The dose adjustment recommendations are based on pharmacokinetic studies and are predicted to adjust lapatinib AUC to the range observed without concurrent CYP3A4 inducers; however, there are no clinical data with these doses in patients receiving strong CYP3A4 inducers.(6) Concurrent rifampin (600 mg daily for 5 days) decreased the AUC of a single dose of sorafenib (400 mg) by 37%.(7) |
CABOMETYX, COMETRIQ, ERLOTINIB HCL, GLEEVEC, IMATINIB MESYLATE, IMKELDI, LAPATINIB, NEXAVAR, SORAFENIB, TYKERB, ZYKADIA |
| 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 |
| Abiraterone; Cabazitaxel; Vincristine/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifabutin is an inducer of CYP3A4 and may increase the metabolism of abiraterone,(1) cabazitaxel,(2,3) and vincristine.(4) CLINICAL EFFECTS: Concurrent or recent use of rifabutin may result in decreased levels and effectiveness of abiraterone,(1) cabazitaxel,(3) and vincristine.(4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concurrent use of rifabutin with abiraterone,(1) cabazitaxel,(3) and vincristine.(4) Consider the use of agents with no or minimal induction potential if possible. Monitor patients for decreased response to therapy. If concurrent administration of abiraterone and rifabutin is required, increase the dosing frequency of abiraterone from once daily to twice daily during the co-administration period. If rifabutin is discontinued, reduce the dose of abiraterone back to the previous dose and frequency.(1) DISCUSSION: Abiraterone,(1) cabazitaxel,(2,3) and vincristine (3) are metabolized by CYP3A4. Strong inducers of this isoenzyme are expected to decrease levels of these agents. The US manufacturers of abiraterone(1) and vincristine(4) and the UK manufacturer of cabazitaxel(3) include rifabutin on the list of strong CYP3A4 inducers that should be avoided. In a drug interaction trial, concurrent administration of rifampin, a strong CYP3A4 inducer, decreased abiraterone levels by 55%.(1) In a study in 21 advanced cancer patients, rifampin (600mg) decreased the exposure to cabazitaxel (15mg/m2) by 17%.(2) |
ABIRATERONE ACETATE, ABIRTEGA, AKEEGA, JEVTANA, VINCASAR PFS, VINCRISTINE SULFATE, YONSA, ZYTIGA |
| 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 |
| Glasdegib/Moderate CYP3A4 Inducers 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. Moderate inducers of CYP3A4 may induce the metabolism of glasdegib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inducer of CYP3A4 may result in decreased levels and effectiveness of glasdegib.(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 glasdegib states to avoid concurrent administration with moderate CYP3A4 inducers. If concurrent use 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) 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) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2-3) |
DAURISMO |
| 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 |
| 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 |
| Selpercatinib/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 selpercatinib.(1) CLINICAL EFFECTS: Coadministration of selpercatinib with a strong or moderate CYP3A4 inducer decreases selpercatinib plasma concentrations, which may decrease the efficacy of selpercatinib.(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 selpercatinib states that concurrent use with strong and moderate CYP3A4 inducers should be avoided.(1) 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 inducers of CYP3A4 include: apalutamide, barbiturates, carbamazepine, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and St. John's wort.(2,3) Moderate inducers of CYP3A4 include: belzutifan, bosentan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, and telotristat ethyl.(2,3) |
RETEVMO |
| Clopidogrel/Selected Strong CYP2C19 Inducers 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.(1-3) As CYP2C19 contributes to both steps, it is thought to be the more important enzyme involved in formation of the pharmacologically active metabolite. Strong inducers of CYP2C19 may increase the conversion of clopidogrel to its active metabolite.(1,2) CLINICAL EFFECTS: Concurrent use of strong CYP2C19 inducers with clopidogrel may increase the effects and toxicity of clopidogrel, including bleeding.(1,2) PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patient with disease-associated factors (e.g. thrombocytopenia). Drug associated risk factors include concurrent use of multiple drugs which inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (e.g. NSAIDs). Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of clopidogrel states that concomitant use of strong CYP2C19 inducers should be avoided.(1,2) If concurrent therapy cannot be avoided, monitor patients for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Discontinue clopidogrel in patients with active pathologic bleeding. Instruct patients to report any signs and symptoms of bleeding, such as unusual bleeding from the gums or nose; unusual bruising; red or black, tarry stools; red, pink or dark brown urine; acute abdominal or joint pain and/or swelling. DISCUSSION: In a study of 12 healthy volunteers, rifampin (300 mg twice daily for 7 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of the active metabolite of clopidogrel by approximately 4-fold. In conjunction with this, there was a higher level of P2Y12 receptor blockade by clopidogrel after rifampin pre-treatment. Clopidogrel 600 mg alone decreased the number of unblocked receptors at 4 hours from 248 +/- 40 to 48 +/- 24 per platelet. After rifampin pre-treatment, clopidogrel decreased the number of unblocked receptors from 266 +/- 63 to 4 +/- 2 (p < 0.0001).(4) A study of 10 healthy volunteers found that rifampin 300 mg twice daily for 4 days then combined with clopidogrel 75 mg daily for 6 days led to a significantly greater inhibition of platelet aggregation compared to clopidogrel alone (56% versus 33%, respectively). Three subjects who were initially clopidogrel nonresponders and 1 subject who was a low responder all became responders after treatment with rifampin.(5) Strong CYP2C19 inducers linked to this monograph include: apalutamide, rifabutin and rifampin.(6,7) |
CLOPIDOGREL, CLOPIDOGREL BISULFATE, PLAVIX |
| 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 |
| Azole Antifungal Agents/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Multiple mechanisms may be involved: 1) Rifabutin may induce the CYP3A4 metabolism of the azole antifungal agents. 2) The azole antifungals may inhibit the CYP3A4 metabolism of rifabutin.(1) CLINICAL EFFECTS: The levels and effectiveness of the azole antifungals may decrease. The levels and toxicities of rifabutin may increase, including uveitis.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Rifabutin is not recommended two weeks before, during, and two weeks after treatment with itraconazole or ketoconazole.(2,3) If co-administration cannot be avoided, observe the patient for a decrease in the therapeutic effect of the antifungal agent. It may be necessary to increase the dose of the antifungal agent. Monitor for rifabutin-associated adverse events. Reduce the rifabutin dose or suspend rifabutin use if toxicity is suspected.(1) If uveitis occurs, temporary discontinuance of rifabutin and ophthalmologic evaluation are recommended. In most mild cases, rifabutin may be restarted; however, if signs or symptoms recur, use of rifabutin should be discontinued.(1) DISCUSSION: Concurrent fluconazole (200 mg daily for 2 weeks) with rifabutin (300 mg daily for 2 weeks) in 12 HIV-infected patients resulted in an increase in rifabutin's area-under-the-curve (AUC) and maximum concentration (Cmax) by 82% and 88%, respectively. No change was seen in fluconazole's AUC or Cmax.(1,4) Concurrent itraconazole (200 mg daily) with rifabutin (300 mg daily) in six HIV-infected patients resulted in an increased effect on rifabutin and a decrease in itraconazole's AUC and Cmax by 70% and 75%, respectively.(2) |
CLOTRIMAZOLE, DIFLUCAN, ECONAZOLE NITRATE, FLUCONAZOLE, FLUCONAZOLE-NACL, ITRACONAZOLE, ITRACONAZOLE MICRONIZED, KETOCONAZOLE, MICONAZOLE, MICONAZOLE NITRATE, ORAVIG, SPORANOX, TOLSURA |
| 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/Selected 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 crizotinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inducers may decrease the levels and effectiveness of crizotinib.(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 crizotinib.(1) Consider the use of alternative agents with less enzyme induction potential.(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) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, modafinil, nafcillin, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2) |
XALKORI |
| Letermovir/Rifabutin 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) Rifabutin is an inducer of P-gp and UGT.(2,3) Rifabutin is a CYP3A4 substrate.(2) Letermovir may inhibit the CYP3A4 metabolism of rifabutin.(1,3) CLINICAL EFFECTS: Concurrent or recent use of P-glycoprotein or UGT1A1/3 inducers may result in decreased levels and loss of effectiveness of letermovir.(1) The levels and toxicities of rifabutin may increase, including uveitis.(2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of letermovir states that coadministration of P-gp inducers or UGT1A1/3 inducers is not recommended.(1) Monitor for rifabutin-associated adverse events. Reduce the rifabutin dose or suspend rifabutin use if toxicity is suspected.(1) If uveitis occurs, temporary discontinuance of rifabutin and ophthalmologic evaluation are recommended. In most mild cases, rifabutin may be restarted; however, if signs or symptoms recur, use of rifabutin should be discontinued.(2) DISCUSSION: In a study, at 24 hours after the last dose of rifampin (600 mg daily), a P-gp and UGT inducer, the area-under-curve (AUC) of letermovir was decreased by 85 %, compared to letermovir when taken alone.(1) In a study of five healthy subjects, concurrent use of rifabutin (150 mg daily for 16 days) and ritonavir (500 mg BID for 10 days), a CYP3A4 inhibitor, increased the AUC and concentration maximum (Cmax) by 300% and 150%, respectively.(2) |
PREVYMIS |
| Dapsone/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown but likely involves induction of hepatic enzymes resulting in increased clearance of dapsone.(1-3) CLINICAL EFFECTS: Concurrent use may lead to decreased levels and clinical effects of dapsone when it is used for treatment or prophylaxis of Pneumocystis jiroveci pneumonia (PCP).(1-5) Since dapsone is extremely potent for treatment of leprosy, this interaction is not clinically relevant in the setting of leprosy.(5) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US Department of Health and Human Service guidelines for prevention and treatment of opportunistic infections in patients with HIV recommend avoiding concomitant administration of dapsone with rifamycins if possible and considering use of alternatives to dapsone.(4) Since dapsone is extremely potent for treatment of leprosy, this interaction is not clinically relevant in the setting of leprosy.(5) DISCUSSION: When given with rifampin, dapsone levels have been found to decrease by 7- to 10-fold.(3,4) In a trial of 16 HIV-positive patients, rifabutin (300 mg daily) lowered the area-under-curve (AUC) of dapsone (50 mg daily) by 27% to 40%.(2,4) Although dapsone dose adjustment is not necessary when it is used for leprosy, the implications of this interaction when dapsone is used for PCP is unknown. Mycobacterium leprae is very sensitive to dapsone, with a minimum inhibitory concentration (MIC) of 2.5 to 10 mcg/L. In contrast, the MIC of dapsone against P. jiroveci is 100 to 10,000 mcg/L. Dapsone concentrations reached with typical PCP therapy is in the range of 100 to 7,000 mcg/L. Thus, a 10-fold reduction in dapsone levels could result in dapsone levels below the MIC for PCP.(5) |
DAPSONE |
| 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 |
| Glecaprevir-Pibrentasvir/Moderate CYP3A4 and P-gp Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Glecaprevir and pibrentasvir are substrates of the P-glycoprotein (P-gp) transporter. Glecaprevir is also a minor substrate of CYP3A4. Agents that are inducers of P-gp and CYP3A4 may induce efflux and decrease the absorption as well as induce the metabolism of glecaprevir-pibrentasvir.(1) CLINICAL EFFECTS: The combination of glecaprevir-pibrentasvir may not be effective for the treatment of hepatitis C.(1) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Because of the risk of treatment failure, the UK manufacturer of glecaprevir-pibrentasvir states that concomitant use with moderate CYP3A4 and P-gp inducers is not recommended.(1) DISCUSSION: While not designed to evaluate effects on glecaprevir-pibrentasvir, a study of the effects of glecaprevir-pibrentasvir on efavirenz-emtricitabine-tenofovir observed that geometric mean exposures of glecaprevir and pibrentasvir were 47% lower than historical controls.(2) In a single dose study in 12 subjects, a single dose of rifampin (600 mg, a strong CYP3A4 and P-gp inducer) with glecaprevir/pibrentasvir (300mg/120 mg single dose) increased glecaprevir's maximum concentration (Cmax) and area-under-the-curve (AUC) by 6.52-fold and 8.55-fold, respectively. In another single dose study in 12 subjects, rifampin (600 mg daily) with glecaprevir/pibrentasvir (300 mg/120 mg single dose) decreased glecaprevir's Cmax and AUC by 86% and 88% and pibrentasvir's Cmax and AUC by 83% and 87%, respectively.(1) In a study in 10 subjects, carbamazepine (200 mg twice daily, a strong CYP3A4 and P-gp inducer) administered concomitantly with glecaprevir/pibrentasvir (300/120 mg daily) decreased the Cmax and AUC of glecaprevir by 67% and 66%, and the Cmax and AUC of pibrentasvir by 50% and 51%, respectively.(1) Moderate CYP3A4 and P-gp inducers linked to this monograph include: lorlatinib and rifabutin.(3) |
MAVYRET |
| 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 |
| 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 |
| Intramuscular Cabotegravir/Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Rifabutin may induce the metabolism of cabotegravir by CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent or recent use of rifabutin may result in decreased levels and effectiveness of cabotegravir.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The implications of this interaction differs depending on the indication for cabotegravir. If cabotegravir is used with rilpivirine for treatment of HIV infection: - Rifabutin should be avoided.(1) If cabotegravir is used alone for pre-exposure prophylaxis: - In a patient already on or just starting rifabutin, increase the frequency of cabotegravir doses to 600 mg every 2 weeks for the first 2 doses, then 600 mg monthly thereafter while on rifabutin. - In a patient starting rifabutin after the second injection or later of cabotegravir, increase cabotegravir injections to 600 mg monthly while on rifabutin. After stopping rifabutin, the recommended dosing schedule of cabotegravir is 600 mg every 2 months.(2) DISCUSSION: Coadministration of rifabutin (300 mg once daily) with cabotegravir (30 mg once daily) decreased cabotegravir's area-under-the-curve (AUC), minimum concentration (Cmin), and maximum concentration (Cmax) by 23%, 26%, and 17%.(1,2) |
APRETUDE, CABOTEGRAVIR ER (CABENUVA) |
| Rifabutin/Nirmatrelvir-Ritonavir SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Nirmatrelvir-ritonavir may inhibit the metabolism of rifabutin by CYP3A4.(1,2) CLINICAL EFFECTS: The concurrent use of nirmatrelvir-ritonavir with rifabutin may result in increased levels, clinical effects, and side effects (including neutropenia, lymphopenia, and influenza-like illness) of rifabutin.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of nirmatrelvir with rifabutin may require a dose adjustment of rifabutin. The US manufacturer of rifabutin recommends a rifabutin dose reduction of 75% (to a maximum of 150 mg every other day or 3 times weekly) with concomitant ritonavir-boosted protease inhibitors.(1,2) In the HIV setting, subtherapeutic rifabutin levels have been observed with a 75% dose reduction.(3-8) Given the risk of rifamycin resistance, the Department of Health and Human Services (DHHS) Guidelines for the Use of Antiretroviral Agents(9) and the CDC's guidelines on managing drug interactions in HIV-related tuberculosis (TB)(10) both recommend that the dose of rifabutin be reduced to 150 mg once daily, or 300 mg three times weekly (a 50% reduction), when used with protease inhibitors. Clinicians should recognize that there are limited safety data with this dose and patients need to be closely monitored for rifabutin-related toxicities. Consider increased monitoring for increased side effects of rifabutin including uveitis, thrombocytopenia, and neutropenia, and consider monitoring rifabutin concentrations.(2) DISCUSSION: Nirmatrelvir-ritonavir is a strong CYP3A4 inhibitor.(1) |
PAXLOVID |
| 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 Inducer & Substrate SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Bosentan, carbamazepine, dabrafenib, elagolix, ivosidenib, lorlatinib, lumacaftor, and mitapivat are both moderate to strong inducers and substrates of CYP3A4.(1,2) Moderate and strong inducers of CYP3A4 may increase the CYP3A4-mediated metabolism of vonoprazan and clarithromycin.(3) Clarithromycin is a strong inhibitor of CYP3A4 and may decrease the metabolism of CYP3A4 substrates.(3) CLINICAL EFFECTS: Concurrent use of moderate to strong CYP3A4 inducers may result in decreased levels and effectiveness of vonoprazan and clarithromycin.(3) Concurrent use of CYP3A4 substrates with clarithromycin may result in elevated levels of and toxicity from the substrate.(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 vonoprazan states that concurrent use with strong or moderate CYP3A4 inducers should be avoided.(3) 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) Strong inducers of CYP3A4 that are CYP3A4 substrates include: carbamazepine, ivosidenib, and lumacaftor. Moderate inducers of CYP3A4 that are CYP3A4 substrates include: bosentan, dabrafenib, elagolix, lorlatinib, mitapivat, and rifabutin.(2-3) |
VOQUEZNA TRIPLE PAK |
| 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, YEZTUGO |
| 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, 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 |
| Fecal Microbiota Spores/Antibiotics SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Fecal microbiota spores is a suspension of live bacterial spores, which may be compromised by concurrent use of antibiotics.(1) CLINICAL EFFECTS: Antibiotics may decrease the effectiveness of fecal microbiota spores.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Antibiotics should not be used concurrently with fecal microbiota spores. Antibacterial treatment should be completed for 2 to 4 days before initiating treatment with fecal microbiota spores.(1) DISCUSSION: Antibiotics may compromise the effectiveness of fecal microbiota spores. |
VOWST |
| 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 |
| 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 |
| Quizartinib/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 quizartinib.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inducers may decrease the levels and effectiveness of quizartinib.(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 quizartinib.(1) 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. 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: bosentan, cenobamate, dabrafenib, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2-3) |
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 |
| Lemborexant/Strong and Moderate CYP3A4 Inducers 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. Strong or moderate inducers of CYP3A4 may induce the metabolism of lemborexant.(1) CLINICAL EFFECTS: The concurrent administration of strong or moderate CYP3A4 inducers may result in decreased levels and effectiveness of lemborexant.(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 lemborexant states that concurrent use with strong or 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) 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, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(2,3) |
DAYVIGO |
| 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 |
| 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 |
| Bictegravir-Emtricitabine-Tenofovir Alafenamide/Strong CYP3A4 and P-gp Inducers; Rifabutin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Bictegravir is a CYP3A4 substrate and tenofovir alafenamide (TAF) is a substrate of the intestinal efflux transporter P-glycoprotein (P-gp). Concurrent use of agents that are both CYP3A4 and P-gp inducers may induce the metabolism of bictegravir and decrease systemic absorption of TAF.(1) Phenobarbital may also induce the metabolism of TAF.(1) Primidone is metabolized to phenobarbital. CLINICAL EFFECTS: Concurrent or recent use of strong CYP3A4 and P-gp inducers, phenobarbital, primidone, or rifabutin may result in decreased systemic levels of bictegravir and tenofovir alafenamide, virologic failure, and 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 manufacturer of bictegravir recommends considering alternatives to carbamazepine, phenobarbital, and phenytoin for patients on bictegravir.(1) The National Institute of Health HIV guidelines do not recommend coadministration of carbamazepine, phenobarbital or phenytoin with bictegravir.(2) Fosphenytoin and primidone are metabolized to phenytoin and phenobarbital, respectively. Other CYP3A4 inducers are not recommended to be coadministered with bictegravir.(1,2) DISCUSSION: Coadministration of rifampin (600 mg daily, a strong CYP3A4 inducer) decreased bictegravir area-under-curve (AUC) by 75% and maximum concentration (Cmax) by 28%.(1) Although the other strong CYP3A4 inducers linked to this monograph have not been studied with bictegravir, a similar effect is expected. Coadministration of rifabutin (300 mg daily) with bictegravir decreased bictegravir AUC and Cmax by 38% and 20%, respectively.(1) When tenofovir alafenamide (TAF) was coadministered with carbamazepine, the maximum concentration (Cmax) and area-under-curve (AUC) were decreased 57% and 55%, respectively.(1-4) A subsequent study suggests that this interaction may not have clinically significant effects on intracellular levels of tenofovir diphosphate, the active metabolite of tenofovir alafenamide. In a study of 23 healthy volunteers, the intracellular Cmax and AUC of tenofovir diphosphate were 38% and 36% lower, respectively, when tenofovir alafenamide was coadministered with rifampin than without rifampin. However, these levels of tenofovir diphosphate were 4.4- and 4.21-fold higher, respectively, than levels obtained from tenofovir disoproxil 300 mg daily without rifampin.(3) CYP3A4 and P-gp inducers linked to this monograph include: apalutamide, carbamazepine, fosphenytoin, phenytoin, rifabutin, rifapentine, and St. John's wort.(1,4) Phenobarbital and primidone are known strong CYP3A4 inducers (4) and the manufacturer of bictegravir also classifies phenobarbital as a P-gp inducer.(1) |
BIKTARVY |
| Revumenib/Moderate CYP3A4 Inducers 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) 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 moderate CYP3A4 inducers should be avoided.(1) 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) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(3) |
REVUFORJ |
| Ensartinib/Selected 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 ensartinib.(1) CLINICAL EFFECTS: Concurrent or recent use of moderate CYP3A4 inducers may reduce the clinical effectiveness of ensartinib.(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 ensartinib states that concurrent use of moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Ensartinib is predominately metabolized by CYP3A4.(1) Moderate CYP3A4 inducers linked to this monograph are: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, efavirenz, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, pacritinib, repotrectinib, rifabutin, telotristat, thioridazine, and tovorafenib.(2,3) |
ENSACOVE |
| 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 |
| 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 |
| 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 |
| Defactinib/Moderate CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inducers may accelerate the metabolism of defactinib by CYP3A4.(1) CLINICAL EFFECTS: The concurrent use of defactinib and a moderate CYP3A4 inducer may result in decreased levels and effectiveness of defactinib.(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 defactinib states that the concurrent use of moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: The impact of moderate CYP3A4 inhibitors on the pharmacokinetics of defactinib has not been investigated in clinical studies. In a study, defactinib maximum concentration (Cmax) decreased by 83% and area-under-curve (AUC) by 87% following coadministration with phenytoin (strong CYP3A4 inducer) three times daily for 23 days and a single dose of defactinib 200 mg (1.0 times the approved recommended dose) on Day 14. The AUC and Cmax of N-desmethyl amide (M4), a major active metabolite of defactinib, decreased by 79% and 70%, 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, thioridazine, and tovorafenib.(2) |
AVMAPKI-FAKZYNJA, FAKZYNJA |
| Emtricitabine-Rilpivirine-TAF/P-gp & Moderate CYP3A4 Inducer 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 rilpivirine. P-glycoprotein (P-gp) inducers may decrease the absorption of tenofovir alafenamide (TAF).(1) CLINICAL EFFECTS: Concurrent or recent use of dual P-gp and moderate CYP3A4 inducers may result in decreased levels and effectiveness of rilpivirine and TAF, 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 emtricitabine-rilpivirine-TAF states that concurrent use of P-gp and moderate CYP3A4 inducers is not recommended.(1) DISCUSSION: In a study in 18 subjects, rifabutin (300 mg daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of rilpivirine (25 mg orally daily) by 31%, 42%, and 48%, respectively.(1) P-gp and moderate CYP3A4 inducers linked to this monograph include: efavirenz, lorlatinib, and rifabutin.(2) |
ODEFSEY |
| Taletrectinib/Moderate CYP3A4 Inducers 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 taletrectinib.(1) CLINICAL EFFECTS: Concurrent or recent use of a moderate CYP3A4 inducer may result in decreased levels and effectiveness of taletrectinib.(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 taletrectinib states that concomitant use of moderate CYP3A4 inducers should be avoided.(1) DISCUSSION: Taletrectinib is primarily metabolized by CYP3A4.(1) Concomitant administration of taletrectinib with a moderate inducer (efavirenz) is predicted to decrease taletrectinib area under the curve (AUC) and maximum concentration (Cmax) by 66% and 40%, respectively.(1) Concomitant administration of taletrectinib with a strong inducer (rifampin; 600 mg once daily) resulted in a decrease in taletrectinib area under the curve (AUC) and maximum concentration (Cmax) by 86% and 42%, respectively.(1) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, and tovorafenib.(2) |
IBTROZI |
There are 17 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 |
|---|---|
| Corticosteroids/Selected Strong CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong CYP3A4 inducers may induce the metabolism of corticosteroids. Corticosteroids may affect the metabolism of phenytoin. CLINICAL EFFECTS: Concurrent or recent use of strong CYP3A4 inducers may result in decreased levels and effectiveness of corticosteroids. Dexamethasone has been shown to increase and decrease phenytoin levels. 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 a strong CYP3A4 inducer should be monitored for decreased effectiveness of their corticosteroid. Increased dosage of corticosteroid may be required during concurrent therapy and for several weeks after completing concurrent therapy. If concurrent therapy is discontinued, the dosage of the corticosteroid may need to be adjusted. Phenytoin levels should be closely monitored in patients receiving corticosteroids. The dosage of phenytoin may need to be adjusted if corticosteroids are initiated or discontinued. DISCUSSION: Carbamazepine has been shown to increase the metabolism of methylprednisolone, prednisolone, and prednisone, resulting in decreased levels and effectiveness of these agents. Phenobarbital has been shown to increase the metabolism of dexamethasone, methylprednisolone, and prednisolone. Primidone is metabolized to phenobarbital. Phenytoin has been shown to increase the metabolism of dexamethasone, hydrocortisone, methylprednisolone, prednisolone, and prednisone, resulting in decreased levels and effectiveness of these agents Rifampin has been shown to increase the metabolism of cortisol, dexamethasone, methylprednisolone, prednisolone, and prednisone. Strong CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenobarbital, phenytoin, primidone, rifabutin, rifapentine, rifampin, and St. John's wort. |
ALDOSTERONE, ALKINDI SPRINKLE, ANUCORT-HC, ANUSOL-HC, BECLOMETHASONE DIPROPIONATE, BETA 1, BETALOAN SUIK, BETAMETHASONE ACETATE MICRO, BETAMETHASONE ACETATE-SOD PHOS, BETAMETHASONE DIPROPIONATE, BETAMETHASONE SOD PHOS-ACETATE, BETAMETHASONE SOD PHOS-WATER, BETAMETHASONE SODIUM PHOSPHATE, BETAMETHASONE VALERATE, BSP 0820, BUDESONIDE, BUDESONIDE DR, BUDESONIDE EC, BUDESONIDE ER, BUDESONIDE MICRONIZED, BUPIVACAINE-DEXAMETH-EPINEPHRN, CELESTONE, CLOBETASOL PROPIONATE MICRO, CORTEF, CORTENEMA, CORTIFOAM, CORTISONE ACETATE, DEFLAZACORT, DEPO-MEDROL, DESONIDE MICRONIZED, DESOXIMETASONE, DESOXYCORTICOSTERONE ACETATE, DEXABLISS, DEXAMETHASONE, DEXAMETHASONE ACETATE, DEXAMETHASONE ACETATE MICRO, DEXAMETHASONE INTENSOL, DEXAMETHASONE ISONICOTINATE, DEXAMETHASONE MICRONIZED, DEXAMETHASONE SOD PHOS-WATER, DEXAMETHASONE SODIUM PHOSPHATE, DEXAMETHASONE-0.9% NACL, DMT SUIK, DOUBLEDEX, EMFLAZA, EOHILIA, FLUDROCORTISONE ACETATE, FLUNISOLIDE, FLUOCINOLONE ACETONIDE, FLUOCINOLONE ACETONIDE MICRO, FLUOCINONIDE MICRONIZED, FLUTICASONE PROPIONATE, FLUTICASONE PROPIONATE MICRO, HEMADY, HEMMOREX-HC, HEXATRIONE, HYDROCORTISONE, HYDROCORTISONE ACETATE, HYDROCORTISONE SOD SUCCINATE, HYDROCORTISONE-PRAMOXINE, KENALOG-10, KENALOG-40, KENALOG-80, KHINDIVI, LIDOCIDEX-I, MAS CARE-PAK, MEDROL, MEDROLOAN II SUIK, MEDROLOAN SUIK, METHYLPREDNISOLONE, METHYLPREDNISOLONE AC MICRO, METHYLPREDNISOLONE ACETATE, METHYLPREDNISOLONE SODIUM SUCC, MILLIPRED, MILLIPRED DP, MOMETASONE FUROATE, ORAPRED ODT, ORTIKOS, PEDIAPRED, PREDNISOLONE, PREDNISOLONE ACETATE MICRONIZE, PREDNISOLONE MICRONIZED, PREDNISOLONE SODIUM PHOS ODT, PREDNISOLONE SODIUM PHOSPHATE, PREDNISONE, PREDNISONE INTENSOL, PREDNISONE MICRONIZED, PRO-C-DURE 5, PRO-C-DURE 6, PROCTOCORT, RAYOS, SOLU-CORTEF, SOLU-MEDROL, TAPERDEX, TARPEYO, TRIAMCINOLONE, TRIAMCINOLONE ACETONIDE, TRIAMCINOLONE DIACETATE, TRIAMCINOLONE DIACETATE MICRO, TRILOAN II SUIK, TRILOAN SUIK, UCERIS, VERIPRED 20, ZCORT, ZILRETTA |
| Disopyramide; Mexiletine; Propafenone/Rifamycins SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rifampin and other rifamycins may increase the hepatic metabolism of disopyramide,(1-2) mexiletine(3) and propafenone(4-6). CLINICAL EFFECTS: Concurrent use of rifampin may result in decreased levels and effectiveness of disopyramide,(2) mexiletine(3) and propafenone(4-6). PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Monitor patient's cardiac function and serum disopyramide, mexiletine or propafenone levels. Adjust the dosage accordingly. DISCUSSION: Coadministration of mexiletine and rifampin have been reported to decrease the elimination half-life and increase the nonrenal clearance of mexiletine.(3) In a study in six elderly subjects, pretreatment with rifampin (600 mg daily for 9 days) decreased the bioavailability of a single dose of oral propafenone (300 mg) by 86%. Maximum QRS prolongation after oral propafenone was decreased by 50%. There were no significant effects on intravenous propafenone.(5) In a study in six extensive CYP2D6 metabolizers and six poor CYP2D6 metabolizers, pretreatment with rifampin (600 mg daily for 9 days) decreased the bioavailability of a single dose of oral propafenone by 67% and by 41% in extensive and poor metabolizers, respectively. Maximum QRS prolongation after oral propafenone decreased by 38% and by 40% in extensive and poor metabolizers, respectively. There were no effects on intravenous propafenone.(6) During concomitant administration of disopyramide and rifampin to patients with tuberculosis, serum disopyramide concentrations decreased by approximately 50% while the concentration of an active metabolite of disopyramide increased.(1) Concurrent administration of disopyramide and rifampin to a 62-year-old patient produced subtherapeutic disopyramide levels and a failure in correcting the patient's arrhythmia. Five days after stopping rifampin, disopyramide levels increased and the arrhythmia was abolished.(2) Rifamycins linked to this monograph are rifabutin, rifampin and rifapentine. |
DISOPYRAMIDE PHOSPHATE, MEXILETINE HCL, NORPACE, NORPACE CR, PROPAFENONE HCL, PROPAFENONE HCL ER |
| Digitalis Glycosides/Rifamycins SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rifamycins may inhibit the absorption of digitalis glycosides by inducing P-glycoprotein.(1-2) CLINICAL EFFECTS: Concurrent or recent use of rifamycins may result in decreased levels and effectiveness of digitalis glycosides. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Monitor digoxin levels if a rifamycin is initiated or discontinued. The dosage of digoxin may need to be increased by 20% to 40%.(2) DISCUSSION: In a study in 18 healthy volunteers, rifampin (300 mg BID for 7 days) decreased the maximum concentration (Cmax), 3-hour area-under-curve (AUC), and 24-hour AUC by 38.5%, 30.4%, and 24.6%, respectively.(1) Case reports also document decreased digoxin(3-5) and digitoxin(6-7) levels with rifampin. |
DIGITEK, DIGOXIN, DIGOXIN MICRONIZED, LANOXIN, LANOXIN PEDIATRIC |
| Beta-Blockers, Oral/Rifamycins SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rifampin is a well recognized enzyme inducer that increases the clearance of many drugs that are metabolized.(1) Beta-blockers that are extensively metabolized may be affected by rifampin. CLINICAL EFFECTS: Decreased pharmacologic effects of certain beta-blockers. PREDISPOSING FACTORS: Dose ranging of rifampin did not suggest a dose proportional interaction.(2) PATIENT MANAGEMENT: Monitor the patient's response to beta-blocker therapy when starting or stopping treatment with rifampin and adjust the dose accordingly. DISCUSSION: Controlled studies involving healthy volunteers have demonstrated rifampin to increase the clearance of metoprolol and propranolol by more than two fold.(2),(3),(4) Steady state plasma concentrations of propranolol were also reduced. The elimination half-life and protein binding of propranolol were not altered by rifampin. In a study in eight subjects, the concurrent administration of rifampin and carvedilol decreased carvedilol concentrations by 70%.(5) |
BYSTOLIC, CARVEDILOL, CARVEDILOL ER, COREG, COREG CR, HEMANGEOL, INDERAL LA, INDERAL XL, INNOPRAN XL, KAPSPARGO SPRINKLE, LOPRESSOR, METOPROLOL SUCCINATE, METOPROLOL TARTRATE, METOPROLOL-HYDROCHLOROTHIAZIDE, NEBIVOLOL HCL, PROPRANOLOL HCL, PROPRANOLOL HCL ER, PROPRANOLOL-HYDROCHLOROTHIAZID, TOPROL XL |
| 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) |
EFAVIRENZ, EFAVIRENZ-EMTRIC-TENOFOV DISOP, EFAVIRENZ-LAMIVU-TENOFOV DISOP, SYMFI |
| Clarithromycin; Erythromycin/Rifabutin SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Clarithromycin and erythromycin inhibit CYP3A4 isoenzymes and may inhibit the CYP3A4 mediated metabolism of rifabutin.(1-5) Rifabutin has been shown to induce CYP3A4 isoenzymes and therefore may accelerate the metabolism of clarithromycin and erythromycin and may decrease the plasma concentrations of both agents.(2,3) CLINICAL EFFECTS: The clinical effects of clarithromycin or erythromycin may be decreased. Rifabutin plasma levels may be increased possibly leading to toxicity. PREDISPOSING FACTORS: In patients with hepatic impairment or severe renal impairment, increased rifabutin levels from this interaction may have an even greater impact. PATIENT MANAGEMENT: The US manufacturer of rifabutin recommends using caution and monitoring for adverse events when rifabutin is given with CYP3A4 inhibitors. Reduce the dose or suspend use of rifabutin if toxicity is suspected.(1) The Australian manufacturer of rifabutin recommends reducing the dose of rifabutin to 300 mg daily when given concomitantly with clarithromycin.(2) The US manufacturer of clarithromycin states the concomitant use of clarithromycin and rifabutin should be approached with caution.(5) DISCUSSION: Concurrent use of clarithromycin and rifabutin in 12 HIV-infected patients resulted in the rifabutin area-under-curve (AUC) increasing by 75% and the clarithromycin AUC decreasing by 50%.(1) In a study in 34 subjects, rifabutin (300 mg daily) decreased clarithromycin area-under-curve (AUC) by 44%. The AUC of 14-hydroxyclarithromycin was 57% higher.(6) The Australian and U.K. manufacturers of rifabutin have stated that rifabutin has been shown to induce CYP3A4 isoenzymes and may decrease the plasma concentrations of erythromycin.(2,3) The Australian manufacturer of erythromycin has stated that erythromycin is an inhibitor of CYP3A4 isoenzymes and there have been published reports and spontaneous reports of CYP3A4 based interactions with erythromycin and rifabutin.(2) |
CLARITHROMYCIN, CLARITHROMYCIN ER, E.E.S. 200, E.E.S. 400, ERY-TAB, ERYPED 200, ERYPED 400, ERYTHROCIN LACTOBIONATE, ERYTHROCIN STEARATE, ERYTHROMYCIN, ERYTHROMYCIN ESTOLATE, ERYTHROMYCIN ETHYLSUCCINATE, ERYTHROMYCIN LACTOBIONATE, LANSOPRAZOL-AMOXICIL-CLARITHRO, OMECLAMOX-PAK, VOQUEZNA TRIPLE PAK |
| Selected Benzodiazepines/Selected 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 some benzodiazepines. CLINICAL EFFECTS: Concurrent or recent use of CYP3A4 inducers may result in decreased levels and loss of effectiveness of some benzodiazepines. PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Monitor patients receiving CYP3A4 inducers or who have received these agents in the previous 2 weeks for decreased benzodiazepine effectiveness. The dose of the benzodiazepine may need to be adjusted or an alternative agent used. If the CYP3A4 inducer is discontinued, benzodiazepine levels will gradually rise as induction effects diminish. Monitor for increased benzodiazepine effects and adjust the dose accordingly. DISCUSSION: In a study in 95 healthy subjects, rifampin (450 mg daily for 5 days) decreased the plasma concentrations of a single oral dose of alprazolam (1 mg) by 79%.(1) In another study in 4 healthy subjects, rifampin (given for 4 days) decreased the area-under-curve (AUC) of a single oral dose of alprazolam (1 mg) by 88%.(2) In a double-blind, randomized, cross-over trial in 13 healthy subjects, rifampin (450 mg daily for 7 days) decreased the maximum concentration (Cmax), AUC, and half-life of a single oral dose of brotizolam (0.5 mg) by 69%, 90%, and 69%, respectively. Concurrent rifampin increased scores on the Digit Symbol Substitution Test (DSST) and decreased scores on the Stanford Sleepiness Scale.(3) In a study in 21 healthy subjects, rifampin (600 mg or 1200 mg daily for 7 days) increased total body clearance of diazepam by 300%.(4) An in vitro study in human hepatocytes found that rifampin increased the biotransformation of diazepam and midazolam by 1.9-fold.(5) In a study in 24 healthy subjects, rifampin (600 mg daily for 10 days) increased the clearance of a single intravenous dose of lorazepam by 140%.(6) In an open-label cross-over study in 19 healthy subjects, rifampin (600 mg daily for 9 days) increased the clearance of a single oral dose of midazolam (0.075 mg/kg) by 7-fold.(7) In a study in 57 healthy subjects, rifampin increased the systemic and oral clearance of midazolam by 2-fold and 16-fold, respectively.(8) In a study in 8 healthy subjects, rifampin (given for 6 days) significantly increased the clearance of midazolam.(9) In a study in 9 healthy subjects, received a single oral dose of midazolam (15 mg) before, one day after the administration of rifampin (600 mg daily for 5 days), and 4 days after the last dose of rifampin. One day after rifampin, the AUC of midazolam was decreased by 97.7% when compared to the administration of midazolam prior to rifampin. Four days after the completion of rifampin, the AUC of midazolam was decreased by 87% when compared to the administration of midazolam prior to rifampin.(10) In a double-blind, randomized, cross-over study in 10 healthy subjects, rifampin (600 mg daily for 5 days) decreased the Cmax, AUC, and half-life of a single oral dose of midazolam (15 mg) by 94%, 96%, and 58%, respectively. The pharmacodynamic effects of midazolam were also significantly decreased during rifampin therapy.(11) In a study in 16 healthy subjects, rifampin (600 mg daily for 7 days) increased the clearance of nitrazepam by 83%. There were no significant effects on the pharmacokinetics of temazepam.(12) In a randomized, double-blind, cross-over study in 10 healthy subjects, rifampin (600 mg daily for 5 days) decreased the Cmax, AUC, and half-life of a single dose of triazolam (0.5 mg) by 87.6%, 94.9%, and 54%, respectively. The pharmacodynamic effects of triazolam were also significantly decreased during rifampin therapy.(13) In an open-label, randomized, cross-over study in 27 healthy subjects, rifaximin (200 mg three times daily for 7 days) had no effect on the pharmacokinetics of single doses of oral or intravenous midazolam.(14) In a study in 98 patients with schizophrenia or bipolar disorder, the expression of CYP3A4 was found to be the major determinant of clonazepam plasma concentrations normalized by the dose and bodyweight (1263 +/- 482.9 and 558.5 +/- 202.4 ng/mL per mg/kg bodyweight in low and normal expressers, respectively, p<0.0001).(18) Selected CYP3A4 inducers linked to this monograph include: apalutamide, carbamazepine, encorafenib, enzalutamide, fosphenytoin, ivosidenib, lumacaftor, mitotane, phenytoin, rifabutin, rifampin, rifapentine, and St. John's wort. |
ALPRAZOLAM, ALPRAZOLAM ER, ALPRAZOLAM INTENSOL, ALPRAZOLAM ODT, ALPRAZOLAM XR, ATIVAN, CLONAZEPAM, DIAZEPAM, HALCION, KLONOPIN, LORAZEPAM, LORAZEPAM INTENSOL, LOREEV XR, MIDAZOLAM, MIDAZOLAM HCL, MIDAZOLAM HCL-0.8% NACL, MIDAZOLAM HCL-0.9% NACL, MIDAZOLAM HCL-D5W, MIDAZOLAM HCL-NACL, MIDAZOLAM-0.9% NACL, MIDAZOLAM-NACL, MKO (MIDAZOLAM-KETAMINE-ONDAN), NAYZILAM, TRIAZOLAM, VALIUM, VALTOCO, XANAX, XANAX XR |
| 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 |
| Tenofovir alafenamide/Selected P-gp Inducers; Phenobarbital SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tenofovir alafenamide (TAF) is a substrate of the intestinal efflux transporter P-glycoprotein (P-gp). Inducers of P-gp may decrease systemic absorption of TAF.(1-4) Phenobarbital may also induce the metabolism of tenofovir alafenamide.(1-4) Primidone is metabolized to phenobarbital. CLINICAL EFFECTS: Concurrent or recent use of P-gp inducers, phenobarbital, or primidone may result in decreased systemic levels and effectiveness of tenofovir alafenamide.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Recommendations regarding concurrent use of tenofovir alafenamide and P-gp inducers vary depending on the region and drug formulation. The European manufacturer of tenofovir alafenamide (DESCOVY for HIV infection and VEMLIDY for hepatitis B) states that concurrent use is not recommended with carbamazepine, phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, or St. John's wort.(1,2) The US manufacturer of DESCOVY states that rifabutin, rifampin, rifapentine, and St. John's wort are not recommended. Alternatives should be considered for carbamazepine, phenobarbital, phenytoin, and primidone.(3) The Australian and US manufacturers of tenofovir alafenamide (VEMLIDY for hepatitis B) states that concurrent use with phenobarbital, phenytoin, primidone, rifabutin, rifampin, rifapentine, or St. John's wort is not recommended. If concurrent therapy with carbamazepine is indicated during treatment for Hepatitis B, the manufacturer recommends increasing the dose of tenofovir alafenamide to two tablets (50 mg) once daily.(4-5) DISCUSSION: When tenofovir alafenamide (TAF) was coadministered with carbamazepine, the maximum concentration (Cmax) and area-under-curve (AUC) were decreased 57% and 55%, respectively.(1-4) A subsequent study suggests that this interaction may not have clinically significant effects on intracellular levels of tenofovir diphosphate, the active metabolite of tenofovir alafenamide. In a study of 23 healthy volunteers, the intracellular Cmax and AUC of tenofovir diphosphate were 38% and 36% lower, respectively, when tenofovir alafenamide was coadministered with rifampin than without rifampin. However, these levels of tenofovir diphosphate were 4.4- and 4.21-fold higher, respectively, than levels obtained from tenofovir disoproxil 300 mg daily without rifampin.(6) Selected P-gp inducers linked to this monograph include: apalutamide, carbamazepine, fosphenytoin, lorlatinib, phenytoin, rifabutin, rifampin, rifapentine, or St. John's wort.(1-7) The manufacturer of tenofovir alafenamide also classifies phenobarbital as a P-gp inducer.(1-4) |
DESCOVY, VEMLIDY |
| Estrogen Replacement Therapy/Rifamycins SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rifamycins (rifampin, rifabutin and rifapentine) induce the the CYP3A4 mediated metabolism of estrogens and progestins. CLINICAL EFFECTS: Concurrent use of rifampin, rifabutin, or rifapentine may result in reduced levels and clinical effectiveness of hormone replacement therapy. Effects may be seen for several weeks after discontinuation of the rifamycin. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving rifamycins should be alerted to the risk for decreased effectiveness of their hormone replacement therapy. The patient should be asked to report any spotting or bleeding. DISCUSSION: In an open-label, randomized crossover study, 22 healthy females received oral contraceptives for 21 days, then were randomized to receive rifampin or rifabutin (300 mg/d for 10 days). Rifampin and rifabutin decreased the area-under-curve (AUC) of ethinyl estradiol by 64% and 35%, respectively, and maximum concentration (Cmax) by 42% and 20%, respectively. Rifampin and rifabutin decreased the AUC of norethindrone by 60% and 20%, respectively. Incidences of spotting were much greater in the rifampin co-administration group. In a study, a single dose of oral contraceptive (ethinyl estradiol 50 mcg and norethindrone acetate 1 mg) was administered to 7 female patients with tuberculosis, both during TB treatment and one month after stopping rifampin (450-600 mg/d). Upon cessation of rifampin therapy, the AUC for ethinyl estradiol significantly increased by 70%, and terminal plasma half-life more than doubled. A similar study design analyzed the pharmacokinetics of norethisterone (1 mg) in 8 women receiving rifampin (450-600 mg/d). Upon termination of TB treatment, it was found that rifampin reduced the AUC of a single dose of norethisterone (1 mg) by approximately 40%, with a half-life reduction of 50%. In a study, male volunteers received 50 mcg iv of ethinyl estradiol, followed by rifampin (600 mg for 6 days). Ethinyl estradiol half-life decreased by approximately 55%. The upward titration of ethinyl estradiol to 100 mcg resulted in a more than 2-fold increase in ethinyl estradiol metabolism caused by rifampicin treatment. An analytical trial evaluated liver biopsies from four patients treated with rifampin 600 mg for a period of 6-10 days. Hepatic microsomes from the biopsies were incubated with hormone substrates, including oestradiol and ethinyloestradiol. Rifampin resulted in a fourfold increase in hydroxylation. Not only did rifampin increase the rate of hydroxylation through enzyme induction, it also caused an increase in cytochrome P-450. There are reports of breakthrough bleeding and unintended pregnancy during concurrent use. |
2-METHOXYESTRADIOL, ABIGALE LO, ACTIVELLA, ANGELIQ, BIJUVA, CLIMARA, CLIMARA PRO, COMBIPATCH, COVARYX, COVARYX H.S., DELESTROGEN, DEPO-ESTRADIOL, DIETHYLSTILBESTROL, DIVIGEL, DOTTI, DUAVEE, EEMT, EEMT H.S., ELESTRIN, ESTRACE, ESTRADIOL, ESTRADIOL (ONCE WEEKLY), ESTRADIOL (TWICE WEEKLY), ESTRADIOL BENZOATE, ESTRADIOL CYPIONATE, ESTRADIOL HEMIHYDRATE, ESTRADIOL HEMIHYDRATE MICRO, ESTRADIOL MICRONIZED, ESTRADIOL VALERATE, ESTRADIOL-NORETHINDRONE ACETAT, ESTRATEST F.S., ESTRATEST H.S., ESTRING, ESTRIOL, ESTRIOL MICRONIZED, ESTROGEL, ESTROGEN-METHYLTESTOSTERONE, ESTRONE, ETHINYL ESTRADIOL, EVAMIST, FEMRING, FYAVOLV, JINTELI, LYLLANA, MENEST, MENOSTAR, MIMVEY, MINIVELLE, NORETHINDRON-ETHINYL ESTRADIOL, PREMARIN, PREMPHASE, PREMPRO, VAGIFEM, VIVELLE-DOT, YUVAFEM |
| 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, PERAMPANEL |
| 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 |
| 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 |
| 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 |
| Apixaban; Rivaroxaban/Strong & Moderate CYP3A4 Inducers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Apixaban and rivaroxaban are both substrates of CYP3A4 and P-glycoprotein (P-gp). Apixaban is about 20% metabolized and rivaroxaban is about 18% metabolized, mainly by CYP3A4.(1-8) Strong and moderate CYP3A4 inducers may induce the metabolism of apixaban and rivaroxaban by CYP3A4. CLINICAL EFFECTS: Concurrent or recent use of a CYP3A4 inducer may result in decreased levels and effectiveness of apixaban(1-4) or rivaroxaban,(5-8) especially in the setting of concurrent therapy with an agent that induces P-gp. PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. Drug-associated risk factors include concurrent use of P-gp inducers. PATIENT MANAGEMENT: The US, Australian, Canadian, and UK manufacturers of apixaban provide recommendations regarding concurrent use with strong inducers of both CYP3A4 and P-gp, but do not provide guidance for concurrent use with agents that induce CYP3A4 alone.(1) The US manufacturer of rivaroxaban provides recommendations regarding concurrent use with strong inducers of both CYP3A4 and P-gp, but does not provide guidance for concurrent use with agents that induce CYP3A4 alone.(5) The Australian manufacturer of rivaroxaban states that concurrent use of strong CYP3A4 inducers should be approached with caution.(6) The Canadian and UK labels for rivaroxaban state that concurrent use of strong CYP3A4 inducers should be avoided.(7-8) When considering concurrent therapy with a strong or moderate CYP3A4 inducer with either apixaban or rivaroxaban, evaluate the patient's other concurrent therapy for CYP3A4 and P-gp effects. In patients who are taking strong CYP3A4 inducers and are also on concurrent P-gp inducers, consider the manufacturer recommendations for use with dual CYP3A4 and P-gp inducers. The US manufacturers of apixaban and rivaroxaban both state to avoid the concurrent use of agents that are combined P-gp and strong CYP3A4 inducers in patients receiving apixaban or rivaroxaban.(1-8) In patients who are taking moderate CYP3A4 inducers and are also on concurrent P-gp inducers, It may be prudent to consider alternative therapy or monitor the patient closely. DISCUSSION: The concurrent use of apixaban or rivaroxaban with strong CYP3A4 inducers that are not also P-gp inducers has not been studied. Apixaban and rivaroxaban are metabolized primarily by CYP3A4. Strong CYP3A4 inducers may decrease the levels and effectiveness of apixaban and rivaroxaban. The US manufacturer of apixaban states that apixaban dose reduction is recommended when apixaban exposure increases by more than 50%, while efficacy is maintained when exposure is 25% lower. Therefore, no dose adjustment of apixaban is recommended for drug interactions that affect apixaban exposure by 75% to 150%.(9) An article evaluating the clinical significance of efflux transporters like P-gp and BCRP in apixaban exposure analyzed pharmacokinetic data from drug-drug interaction studies and concluded that all apixaban interactions can be explained by inhibition of intestinal CYP3A4. The authors explain that apixaban is a highly permeable and soluble compound, so its ability to undergo passive diffusion renders the role of membrane transporters irrelevant, as evidenced by a lack of change in apixaban absorption rate in the presence of drugs known to inhibit P-gp and BCRP.(10) Strong CYP3A4 inducers linked to this monograph include: barbiturates, encorafenib, ivosidenib, lumacaftor, and mitotane.(11,12) Moderate CYP3A4 inducers linked to this monograph include: belzutifan, bosentan, cenobamate, dabrafenib, dipyrone, elagolix, etravirine, lesinurad, lorlatinib, mavacamten, mitapivat, modafinil, nafcillin, pacritinib, pexidartinib, repotrectinib, rifabutin, sotorasib, telotristat ethyl, thioridazine, and tovorafenib.(11,12) |
ELIQUIS, RIVAROXABAN, XARELTO |
The following contraindication information is available for RIFABUTIN (rifabutin):
Drug contraindication overview.
No enhanced Contraindications information available for this drug.
No enhanced Contraindications information available for this drug.
There are 0 contraindications.
There are 3 severe contraindications.
Adequate patient monitoring is recommended for safer drug use.
| Severe List |
|---|
| Chronic kidney disease stage 4 (severe) GFR 15-29 ml/min |
| Chronic kidney disease stage 5 (failure) GFr<15 ml/min |
| Clostridioides difficile infection |
There are 3 moderate contraindications.
Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.
| Moderate List |
|---|
| Kidney disease with likely reduction in glomerular filtration rate (GFr) |
| Neutropenic disorder |
| Thrombocytopenic disorder |
The following adverse reaction information is available for RIFABUTIN (rifabutin):
Adverse reaction overview.
No enhanced Common Adverse Effects information available for this drug.
No enhanced Common Adverse Effects information available for this drug.
There are 28 severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Skin rash |
Leukopenia |
| Rare/Very Rare |
|---|
|
Acute generalized exanthematous pustulosis Agranulocytosis Anaphylaxis Angioedema Arthralgia Bronchospastic pulmonary disease Clostridioides difficile infection Conjunctivitis DRESS syndrome Dysgeusia Hemolysis Hepatitis Hypersensitivity drug reaction Hypotension Jaundice Lymphopenia Myalgia Myositis Neutropenic disorder Pancytopenia Seizure disorder Stevens-johnson syndrome Thrombocytopenic disorder Toxic epidermal necrolysis Urticaria Uveitis |
There are 20 less severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Discoloration of sweat Discolored feces Dyschromia Nausea Saliva discoloration Sputum discoloration Tear discoloration Urine discoloration Vomiting |
Dyspepsia Dyspnea Flatulence Insomnia |
| Rare/Very Rare |
|---|
|
Acute abdominal pain Chest pain Diarrhea Eosinophilia Eructation Fever Flu-like symptoms |
The following precautions are available for RIFABUTIN (rifabutin):
No enhanced Pediatric Use information available for this drug.
Contraindicated
Severe Precaution
Management or Monitoring Precaution
Contraindicated
| None |
Severe Precaution
| None |
Management or Monitoring Precaution
| None |
Reproduction studies in rats and rabbits using rifabutin dosages up to 200 mg/kg daily (40 times the recommended human daily dosage) did not reveal evidence of teratogenicity. In rats receiving 200 mg/kg daily, decreased fetal viability occurred. An increase in fetal skeletal variants was observed in rats receiving rifabutin dosages of 40 mg/kg daily (8 times the recommended human daily dosage).
In rabbits receiving rifabutin dosages of 80 mg/kg daily (16 times the recommended human daily dosage), maternotoxicity and an increase in fetal skeletal anomalies occurred. There are no adequate and controlled studies to date using rifabutin in pregnant women, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus. The American Thoracic Society (ATS), US Centers for Disease Control and Prevention (CDC), and Infectious Diseases Society of America (IDSA) state that data are insufficient to date to recommend use of rifabutin in pregnant women.
In rabbits receiving rifabutin dosages of 80 mg/kg daily (16 times the recommended human daily dosage), maternotoxicity and an increase in fetal skeletal anomalies occurred. There are no adequate and controlled studies to date using rifabutin in pregnant women, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus. The American Thoracic Society (ATS), US Centers for Disease Control and Prevention (CDC), and Infectious Diseases Society of America (IDSA) state that data are insufficient to date to recommend use of rifabutin in pregnant women.
It is not known whether rifabutin is distributed into human milk. Because of the potential for serious adverse reactions to rifabutin in nursing infants, a decision should be made whether to discontinue nursing or the drug, taking into account the importance of the drug to the woman.
No enhanced Geriatric Use information available for this drug.
The following prioritized warning is available for RIFABUTIN (rifabutin):
No warning message for this drug.
No warning message for this drug.
The following icd codes are available for RIFABUTIN (rifabutin)'s list of indications:
No ICD codes found for this drug.
No ICD codes found for this drug.
Formulary Reference Tool