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Drug overview for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
Generic name: FOSAMPRENAVIR CALCIUM (fos-am-PREN-uh-veer)
Drug class: Antiviral-HIV (Antiretroviral) Protease Inhibitors
Therapeutic class: Anti-Infective Agents
Fosamprenavir calcium, an antiretroviral agent, is a human immunodeficiency virus (HIV) protease inhibitor (PI).
No enhanced Uses information available for this drug.
Generic name: FOSAMPRENAVIR CALCIUM (fos-am-PREN-uh-veer)
Drug class: Antiviral-HIV (Antiretroviral) Protease Inhibitors
Therapeutic class: Anti-Infective Agents
Fosamprenavir calcium, an antiretroviral agent, is a human immunodeficiency virus (HIV) protease inhibitor (PI).
No enhanced Uses information available for this drug.
DRUG IMAGES
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The following indications for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium) have been approved by the FDA:
Indications:
HIV infection
Professional Synonyms:
Human immunodeficiency virus disease
Human immunodeficiency virus infection
Indications:
HIV infection
Professional Synonyms:
Human immunodeficiency virus disease
Human immunodeficiency virus infection
The following dosing information is available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
Dosage of fosamprenavir calcium is expressed in terms of fosamprenavir.
When fosamprenavir is used in combination with ritonavir, consult the full prescribing information for ritonavir.
Dosage of fosamprenavir in infants and children 4 weeks to 18 years of age is based on weight and should not exceed the recommended adult dosage. Only use fosamprenavir in infants born at 38 weeks' gestation or later who have attained a postnatal age of 28 days.
A once-daily regimen of fosamprenavir (with or without low-dose ritonavir) is not recommended in any pediatric patient.
Do not use fosamprenavir (with or without low-dose ritonavir) in PI-experienced pediatric patients younger than 6 months of age.
Do not use a twice-daily regimen of fosamprenavir (without low-dose ritonavir) in PI-naive or PI-experienced pediatric patients younger than 2 years of age.
When fosamprenavir is used in combination with ritonavir, consult the full prescribing information for ritonavir.
Dosage of fosamprenavir in infants and children 4 weeks to 18 years of age is based on weight and should not exceed the recommended adult dosage. Only use fosamprenavir in infants born at 38 weeks' gestation or later who have attained a postnatal age of 28 days.
A once-daily regimen of fosamprenavir (with or without low-dose ritonavir) is not recommended in any pediatric patient.
Do not use fosamprenavir (with or without low-dose ritonavir) in PI-experienced pediatric patients younger than 6 months of age.
Do not use a twice-daily regimen of fosamprenavir (without low-dose ritonavir) in PI-naive or PI-experienced pediatric patients younger than 2 years of age.
Fosamprenavir calcium is administered orally as oral suspension or tablets.
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| FOSAMPRENAVIR 700 MG TABLET | Maintenance | Adults take 1 tablet (700 mg) by oral route 2 times per day |
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| FOSAMPRENAVIR 700 MG TABLET | Maintenance | Adults take 1 tablet (700 mg) by oral route 2 times per day |
The following drug interaction information is available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
There are 25 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 |
|---|---|
| Protease Inhibitors/Oral Midazolam; Triazolam 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 protease inhibitors may inhibit the metabolism of the benzodiazepines midazolam and triazolam at CYP3A4.(1-30) CLINICAL EFFECTS: Concurrent administration may result in increased levels and clinical effects of the benzodiazepines, which may result in profound sedation, respiratory depression, coma, and/or death.(1-30) Higher triazolam levels may increase risk for anterograde amnesia, "sleep driving" and other complex behavior disorders.(30) PREDISPOSING FACTORS: The elderly are particularly sensitive to increased plasma concentrations of triazolam.(30) PATIENT MANAGEMENT: The manufacturers of the protease inhibitors and US guidelines on use of antiretroviral agents (31) state that concurrent administration of triazolam or oral midazolam with ritonavir-boosted(1-3) darunavir,(4-6) lopinavir,(7-9) nirmatrelvir,(10) paritaprevir,(11) saquinavir,(12-14) or tipranavir (15-17); ritonavir-boosted or unboosted amprenavir,(18-19) atazanavir,(20-21) fosamprenavir,(22-23) indinavir,(24-26); or nelfinavir,(27-29) is contraindicated. Midazolam may be administered by the intravenous route in patients with close clinical monitoring for respiratory depression and/or prolonged sedation. Caution should be exercised and dosage adjustments should be considered if these effects occur. DISCUSSION: In an open-label, randomized study in 14 subjects, lopinavir/ ritonavir (400/100 mg twice daily) decreased the metabolism of single doses of oral and intravenous midazolam (0.025 mg/kg and 5 mg, respectively) by 77% and 92%, respectively.(32) In a double-blind, randomized, cross-over study in 12 subjects, concurrent administration of saquinavir base with oral midazolam increased the bioavailability of oral midazolam from 41% to 90%. The midazolam maximum concentration (Cmax) and area-under-curve (AUC) increased two-fold and five-fold, respectively. The concurrent administration of saquinavir base with intravenous midazolam resulted in a decrease in midazolam clearance by 56% and increased the midazolam half-life from 4.1 hours to 9.5 hours.(33) In a study in 6 healthy subjects, saquinavir base (1200 mg twice daily) increased the AUC and Cmax of a single dose of midazolam (7.5 mg) by 514% and 235%, respectively.(12) In a study in 16 healthy subjects, saquinavir/ritonavir (1000/100 mg twice daily) increased the AUC and Cmax of a single dose of midazolam (7.5 mg) by 1144% and 327%, respectively.(14) In a double-blind study, ritonavir (four doses of 200 mg) decreased the clearance of a single dose of triazolam (0.125 mg) by 96%.(34) Amprenavir,(35), lopinavir,(36) and ritonavir(33,34) have been shown to inhibit triazolam metabolism in vitro in human liver microsomes. In a clinical trial of 13 healthy patients patients receiving concurrent midazolam (3mg) and ritonavir (100 mg three times daily), midazolam AUC increased by a factor of 28.4 +/- 4.2 and oral clearance was reduced to 4.2% of normal.(37) Protease inhibitors linked to this monograph include: amprenavir, atazanavir, fosamprenavir, darunavir, indinavir, lopinavir, nelfinavir, nirmatrelvir, paritaprevir, saquinavir, and tipranavir. Ritonavir, as a pharmacokinetic booster, will alert through the primary protease inhibitor. |
HALCION, MIDAZOLAM, MIDAZOLAM HCL, TRIAZOLAM |
| Selected Protease Inhibitors; Cobicistat/Pimozide 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: Protease inhibitors(1-13,15) and cobicistat(14) may inhibit the metabolism of pimozide at CYP3A4. CLINICAL EFFECTS: Concurrent administration may result in elevated levels of pimozide, which may result in prolongation of the QTc interval and potentially life-threatening ventricular arrhythmias.(1-15) 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.(17) 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).(17) The risk of anticholinergic toxicities including cognitive decline, delirium, falls and fractures is increased in geriatric patients using more than one medicine with anticholinergic properties.(18) PATIENT MANAGEMENT: The concurrent use of pimozide and the protease inhibitors amprenavir,(1) atazanavir,(2,3) darunavir,(4) fosamprenavir,(5) indinavir,(6,7) nelfinavir,(6,8) nirmatrelvir coadministered with ritonavir,(15) and tipranavir coadministered with ritonavir(13) and cobicistat(14) is contraindicated. If concurrent therapy is deemed medically necessary, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: An in vitro study indicates that pimozide is metabolized at CYP3A4.(15) Elevated levels of pimozide may prolong the QTc interval resulting in life-threatening ventricular arrhythmias.(6) Selected CYP3A inhibitors linked include: amprenavir, atazanavir, cobicistat, darunavir, fosamprenavir, indinavir, nelfinavir, nirmatrelvir, paritaprevir, and tipranavir. |
PIMOZIDE |
| Protease Inhibitors/Ergot Alkaloids 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 protease inhibitors may inhibit the metabolism of the ergot alkaloids by CYP3A4, including dihydroergotamine, ergotamine, ergonovine, and methylergonovine. (1-13) CLINICAL EFFECTS: The concurrent administration of a protease inhibitor with an ergot alkaloid may result in elevated levels, clinical effects, and adverse effects of the ergot alkaloids.(1-13) Signs of ergotism may include peripheral vasospasm and ischemia. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent administration of ergot alkaloids with amprenavir,(1) atazanavir,(2,3) darunavir,(4) fosamprenavir,(5) indinavir, (6) the combination of lopinavir and ritonavir,(7) nelfinavir,(8) nirmatrelvir coadministered with ritonavir,(25) ritonavir, (12) saquinavir,(9,10) and tipranavir coadministered with ritonavir(11) is contraindicated. The US manufacturer of methylergonovine states that methylergonovine should not be administered with potent CYP3A4 inhibitors such as protease inhibitors.(13) Protease inhibitors linked include: amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, nirmatrelvir, ritonavir, saquinavir, and tipranavir. DISCUSSION: There have been several case reports of ergotism developing in patients receiving concurrent ergotamine derivatives with indinavir,(14) nelfinavir,(15) or ritonavir.(16-23) 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. |
DIHYDROERGOTAMINE MESYLATE, ERGOLOID MESYLATES, ERGOMAR, ERGOTAMINE TARTRATE, ERGOTAMINE-CAFFEINE, METHYLERGONOVINE MALEATE, METHYSERGIDE MALEATE, MIGERGOT, MIGRANAL, TRUDHESA |
| Selected CYP3A4 Substrates/Rifampin 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: Rifampin may increase the metabolism of the protease inhibitors(1-12) and cobicistat(13) by inducing CYP3A4. CLINICAL EFFECTS: Concurrent use of rifampin with protease inhibitors may result in decreased levels and clinical effectiveness of the protease inhibitors(1-12,14) and cobicistat.(13) Concurrent use of rifampin with the combination of saquinavir/ritonavir may result in drug-induced hepatitis.(1,14-16) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturers of atazanavir,(3,4), cobicistat,(12) darunavir,(5) fosamprenavir,(6) the combination of lopinavir and ritonavir,(8) nelfinavir,(9) saquinavir,(1,11) and tipranavir(12) state that concurrent use of rifampin is contraindicated. The manufacturers of amprenavir,(2) indinavir,(7) and ritonavir(10) state that these agents should not be used with rifampin. The manufacturer of rifampin states that concurrent use of atazanavir, darunavir, fosamprenavir, saquinavir, and tipranavir is contraindicated.(14) The Department of Health and Human Services (DHHS) Guidelines for the Use of Antiretroviral Agents states that rifampin is contraindicated for patients on boosted or unboosted protease inhibitors. Additional ritonavir does not overcome the interaction and may increase hepatotoxicity, and additional cobicistat is not recommended. DHHS recommends use of rifabutin as an alternative.(17) The CDC/NIH guidelines on treatment of opportunistic infections (OI) in HIV(18) and the CDC's guidelines on managing drug interactions in HIV-related tuberculosis (TB)(19) provide guidance for the use of rifampin with the combination product of lopinavir/ritonavir when rifabutin is not available. The OI guidelines recommend increasing the dose of lopinavir/ritonavir by 50%, and subsequently, increasing to a full double dose, when used with rifampin. Transaminases should be monitored more frequently than usual. The guidelines on drug interactions in HIV-related TB state that higher doses of lopinavir/ritonavir should be used only when close monitoring for hepatotoxicity is possible, and when there is a pressing need to start antiretroviral therapy and other antiretrovirals are not an option. In adults, it is recommended to increase the dose of lopinavir/ritonavir by 50% (to 600/150 mg) for one week, then to double the dose (to 800/200 mg). In children, "super-boosted" lopinavir/ritonavir is recommended, achieved by using pediatric weight-based dosing for lopinavir/ritonavir, plus additional ritonavir to reach milligram to milligram parity of lopinavir and ritonavir doses. For both double dosing and super-boosting, the guidelines caution that unacceptable rates of hepatotoxicity was seen in healthy volunteers, though early clinical experience in HIV+ adults found that double dosing was reasonably well tolerated. DISCUSSION: The concurrent administration of amprenavir and rifampin decreased amprenavir maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) by 70%, 82%, and 92%, respectively. There was no change in rifampin Cmax or AUC.(2,6,20) In a study in 16 subjects, concurrent rifampin (600 mg daily) and atazanavir/ritonavir (300/100 mg daily) decreased atazanavir Cmax, AUC, and Cmin by 53%, 72%, and 98%, respectively.(3) In a study in 12 healthy, HIV-negative subjects, concurrent rifampin (600 mg daily) and indinavir (800 mg three times daily) decreased indinavir Cmax and AUC by 87% and 92%, respectively.(7) In a study in 6 HIV-positive subjects, concurrent indinavir/ritonavir (800/100 mg twice daily) and rifampin (300 mg daily) decreased the AUC of indinavir and ritonavir by 87% and 94%, respectively.(21) In a study in 11 HIV-positive subjects, concurrent indinavir (800 mg three times daily) increased the AUC of a dose of rifampin (600 mg) by 73%.(22) The concurrent administration of lopinavir/ritonavir (400/100 mg twice daily for 20 days) and rifampin (600 mg daily for 10 days) in 22 subjects decreased lopinavir Cmax, AUC, and Cmin by 55%, 75%, and 99%, respectively. Concurrent administration of lopinavir/ritonavir (800/200 mg twice daily for 9 days) and rifampin (600 mg daily for 14 days) in 10 subjects did not change lopinavir Cmax and decreased lopinavir AUC and Cmin by 16% and 57%, respectively. Concurrent lopinavir/ritonavir (400/400 mg twice daily for 9 days) and rifampin (600 mg daily for 14 days) in 9 subjects decreased lopinavir Cmax and AUC by 7% and 2%, respectively, and did not change lopinavir Cmin. In these studies, 28% of subjects experienced a grade 2 increase in ALT/AST, of which 7 (21%) prematurely discontinued the study per protocol.(8) In an open-label, randomized study in 32 healthy subjects, all subjects initially received lopinavir/ritonavir 400/100 mg twice daily. During concurrent rifampin (600 mg daily), subjects received either 800/200 mg or 400/400 mg of lopinavir/ritonavir twice daily. Concurrent 800/200 mg lopinavir/ritonavir and rifampin decreased lopinavir Cmin by 57% but did not affect lopinavir Cmax. During concurrent 400/400 mg lopinavir/ritonavir and rifampin, lopinavir Cmin and Cmax were similar to levels seen with 400/100 mg lopinavir/ritonavir. Twelve subjects dropped out of the study and 9 developed elevated liver enzymes during concurrent therapy with lopinavir/ritonavir and rifampin.(23) Three studies examining double dosing (800/200 mg) or super-boosting (400/400 mg) of lopinavir/ritonavir with concurrent rifampin in HIV+ patients have been conducted. A study of double dosing and super-boosting in 18 HIV-TB patients(24) and a study of double dosing in 21 HIV+ patients without TB(25) both found that adequate lopinavir/ritonavir levels were achieved with lopinavir/ritonavir dose adjustments. In the study of HIV-TB patients, there were 3 isolated subtherapeutic lopinavir levels which were attributed to poor adherence. Ten of the 11 patients who were followed to completion of TB therapy had undetectable viral loads. There were no grade 3/4 adverse events, and 10 patients had mild side effects. In the study of patients without TB, two patients experienced grade 3/4 transaminitis, and other adverse events were mild. The third study of 25 HIV-TB patients confirmed the frequent but mild GI toxicity and reported that 2 patients had grade 3 transaminitis.(26) Concurrent administration of nelfinavir (750 mg three times daily) and rifampin (600 mg daily) in 12 subjects decreased nelfinavir AUC, Cmax, and Cmin by 83%, 76%, and 92%, respectively.(9) The concurrent administration of ritonavir and rifampin decreased the area-under-curve (AUC), maximum concentration (Cmax), and minimum concentration (Cmin) of ritonavir by 35%, 25%, and 49%, respectively.(10) The concurrent administration of saquinavir and rifampin in 14 subjects reduced the AUC and Cmax of saquinavir by 70% and 65%, respectively.(1,11) In a study in 28 healthy subjects, concurrent administration of rifampin (600 mg daily) with saquinavir (1000 mg twice daily) and ritonavir (100 mg twice daily), 65% (11/17) of subjects developed significant hepatocellular toxicity during the 28 day study. Transaminase elevations of up to greater than 20 times the upper limit of normal values were noted. One subject was admitted to the hospital. All study medications were discontinued in all subjects and all liver function tests were returning to normal. No deaths had been reported.(1,15,16) In an open-label, prospective, single arm study, 32 HIV-positive subjects received concurrent daily didanosine, lamivudine, ritonavir (200 mg), saquinavir (1600 mg), rifampin (600 mg), and isoniazid (300 mg). After 48 weeks, 62.5% had an HIV RNA level less than 50 copies/ml. Two patients had hepatic toxicity. In 10 subjects, saquinavir Cmin was less than 0.05 mcg/ml and 5 of these had virologic failure. Saquinavir Cmin was 44% lower during concurrent rifampin.(27) In an open-label, randomized, cross-over study, rifampin decreased saquinavir AUC by 70% in healthy subjects and by 46% in HIV-positive subjects.(28) 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. |
RIFADIN, RIFAMPIN |
| Lovastatin; Simvastatin/Selected CYP3A4 Inhibitors 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 CYP3A4 inhibitors may inhibit the metabolism of HMG-CoA reductase inhibitors that are metabolized by CYP3A4. CLINICAL EFFECTS: Concurrent administration may result in elevated HMG levels, which may increase the risk of myopathy, including rhabdomyolysis.(1-18) PREDISPOSING FACTORS: The risk for myopathy or rhabdomyolysis may be greater in patients 65 years and older, inadequately treated hypothyroidism, renal impairment, carnitine deficiency, malignant hyperthermia, or in patients with a history of myopathy or rhabdomyolysis. Patients with a SLCO1B1 polymorphism that leads to decreased function of the hepatic uptake transporter OATP1B1 may have increased statin concentrations and be predisposed to myopathy or rhabdomyolysis. PATIENT MANAGEMENT: Do not use simvastatin with protease inhibitors,(1-3) with or without cobicistat(2,3) or ritonavir. The manufacturer of simvastatin states that the concurrent use of strong CYP3A4 inhibitors is contraindicated. The manufacturer of lovastatin states that the concurrent use of strong CYP3A4 inhibitors is contraindicated, including protease inhibitors, with or without cobicistat or ritonavir.(4, 25) The manufacturers of atazanavir,(5) cobicistat,(18) darunavir,(6) fosamprenavir,(7) indinavir,(8) the combination of lopinavir with ritonavir,(9) the combination of nirmatrelvir with ritonavir,(17) saquinavir,(11) and tipranavir(12) state that concurrent use of lovastatin or simvastatin is contraindicated. The manufacturer of nirmatrelvir/ritonavir recommends discontinuing use of lovastatin and simvastatin at least 12 hours prior to initiation of nirmatrelvir/ritonavir and holding statin therapy until 5 days after completing nirmatrelvir/ritonavir therapy.(17) The manufacturers of amprenavir(13) and nelfinavir(14) state that lovastatin and simvastatin should not be used with these agents. It would be prudent to utilize fluvastatin in patients treated with protease inhibitors who require HMG-CoA reductase therapy. DISCUSSION: A study in 15 subjects found that darunavir/ritonavir (300/100 mg twice daily) decreased the maximum concentration (Cmax) and area-under curve (AUC) of atorvastatin (10 mg daily) by 64% and 15%, when compared to atorvastatin (40 mg daily) administered alone. Atorvastatin minimum concentration (Cmin) increased by 81% during concurrent therapy.(6) A study in 16 subjects found that fosamprenavir increased atorvastatin Cmax and AUC by 304% and 130%, respectively. Atorvastatin Cmin decreased by 10%.(7) A study in 12 subjects found that lopinavir increased atorvastatin Cmax, AUC, and Cmin by 4.67-fold, 5.88-fold, and 2.28-fold, respectively. Atorvastatin had no clinically significant effect on lopinavir pharmacokinetics.(9) A study in 12 subjects found that lopinavir increased pravastatin Cmax and AUC by 1.26-fold and 1.33-fold, respectively. Pravastatin had no clinically significant effect on lopinavir pharmacokinetics.(9) A randomized, controlled trial in healthy subjects examined the effects of a combination of ritonavir and saquinavir on the pharmacokinetics of atorvastatin, pravastatin, and simvastatin and the effects of pravastatin on nelfinavir pharmacokinetics. The combination of ritonavir and saquinavir decreased pravastatin levels by 50% and increased atorvastatin and simvastatin levels by 79% and 3059%, respectively. Pravastatin had no statistically significant effect on nelfinavir pharmacokinetics.(14) An open-label study in healthy subjects examined the effects of nelfinavir on atorvastatin and simvastatin pharmacokinetics. Nelfinavir increased atorvastatin AUC, Cmax, and Cmin by 74%, 122%, and 39%, respectively. Nelfinavir increased simvastatin AUC and Cmax by 505% and 517%, respectively. There was no effect on nelfinavir pharmacokinetics when compared to historical controls.(14,16) A study in 14 healthy HIV-seronegative adults found that nelfinavir decreased median pravastatin AUC by 46.5%. Nelfinavir also decreased median pravastatin Cmax by 40.1%.(19) In a study of 25 HIV-positive patients, 13 patients were treated with pravastatin and 12 patients were treated with fluvastatin. Within the 25 patients, 8 patients were also on concomitant indinavir-containing highly active antiretroviral therapy (HAART). Indinavir plasma levels were not significantly influenced by pravastatin or fluvastatin therapy.(20) Rhabdomyolysis has been reported during concurrent use of simvastatin and nelfinavir(21) or ritonavir.(22) Lovastatin was tested in a single dose, open-labeled, randomized crossover study of ten healthy volunteers. Grapefruit juice increased Cmax of lovastatin 12-fold, and the area under the AUC 15-fold. Likewise, the active metabolite lovastatin acid demonstrated a 4-fold increase in Cmax and a 5-fold increase in AUC. Lovastatin and lovastatin acid concentrations and AUC increased in each subject.(23) A study found that itraconazole (200 mg for 4 days) increased lovastatin (40 mg on day 4)Cmax by greater than 25-fold and lovastatin acid AUC and Cmax by greater than 20-fold and 13-fold. A study found that itraconazole (100 mg for 4 days) increased lovastatin (40 mg on day 4) AUC and Cmax by greater than 14.8-fold and lovastatin acid AUC and Cmax by 15.4 and 11.5-fold.(25) 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. |
ALTOPREV, EZETIMIBE-SIMVASTATIN, FLOLIPID, LOVASTATIN, SIMVASTATIN, VYTORIN, ZOCOR |
| Eplerenone/Strong CYP3A4 Inhibitors; Protease Inhibitors 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 inhibitors of CYP3A4 and protease inhibitors may inhibit the metabolism of eplerenone.(1-3) CLINICAL EFFECTS: Concurrent use of eplerenone with a strong inhibitor of CYP3A4 or a protease inhibitor may result in 5-fold increases in eplerenone concentrations and toxicity (e.g. hyperkalemia, hypotension).(1-3) PREDISPOSING FACTORS: Severe renal disease increases the risk for hyperkalemia. PATIENT MANAGEMENT: The manufacturer of eplerenone states that the concurrent use of strong CYP3A4 inhibitors is contraindicated.(1) The US Department of Health and Human Services HIV guidelines state that protease inhibitors are contraindicated with eplerenone.(3) The US manufacturer of itraconazole states that concurrent use of eplerenone is contraindicated during and two weeks after itraconazole treatment.(4) The starting dose of eplerenone for hypertension should be reduced to 25 mg in patients receiving moderate CYP3A4 inhibitors.(1) In all patients taking eplerenone who start taking a moderate CYP3A4 inhibitor, check serum potassium and creatinine levels after 3-7 days of concurrent therapy.(1) DISCUSSION: Ketoconazole (200 mg BID) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of eplerenone (100 mg) by 1.7-fold and 5.4-fold, respectively.(1) The concurrent use of eplerenone with less potent CYP3A4 inhibitors (erythromycin 500 mg BID, fluconazole 200 mg daily, saquinavir 1200 mg TID, and verapamil 240 mg daily) increased the Cmax of eplerenone by 1.4-fold to 1.6-fold and the AUC of eplerenone by 2.0-fold and 2.9-fold.(1) Strong inhibitors of CYP3A4 and protease inhibitors linked to this monograph include: adagrasib, amprenavir, atazanavir, boceprevir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(1,2) |
EPLERENONE, INSPRA |
| Vardenafil (Greater Than 2.5 mg)/Selected Protease Inhibitors 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: Protease inhibitors may inhibit the metabolism of vardenafil by CYP3A4. CLINICAL EFFECTS: Concurrent use of vardenafil with protease inhibitors may result in increased levels of and adverse effects from vardenafil, including hypotension, visual changes, and sustained erections. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: US guidelines for the use of antiretroviral agents recommends patients receiving protease inhibitors should receive no more than 2.5 mg of vardenafil every 72 hours. US labeling recommendations for concurrent use of vardenafil with protease inhibitors state: -Patients receiving any ritonavir- or cobicistat-containing regimens, including atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nirmatrelvir, paritaprevir, saquinavir, and tipranavir should receive no more than 2.5 mg of vardenafil every 72 hours. -Patients receiving unboosted atazanavir, unboosted fosamprenavir, unboosted indinavir, or nelfinavir should take no more than 2.5 mg of vardenafil every 24 hours. Canadian labeling contraindicates concurrent use of atazanavir/ritonavir, lopinavir/ritonavir, and nirmatrelvir/ritonavir with vardenafil.(6,13,17) Patients should be counseled that they are at an increased risk of vardenafil adverse effects, including hypotension, visual changes, and priapism. DISCUSSION: Concurrent use of indinavir (800 mg three times daily) with vardenafil (10 mg) increased the vardenafil area-under-curve (AUC) and maximum concentration (Cmax) by 16-fold and 7-fold, respectively. Vardenafil half-life increased 2-fold. At 24-hours post-dose, vardenafil levels fell to approximately 4% of vardenafil Cmax. The AUC and Cmax of indinavir decreased by 30% and 40%, respectively. Concurrent use of ritonavir (600 mg twice daily)with vardenafil (5 mg) increased vardenafil AUC and Cmax by 49-fold and 13-fold, respectively. The half-life of vardenafil increased to 26 hours. The ritonavir AUC and Cmax decreased by 20%. |
VARDENAFIL HCL |
| Alfuzosin;Silodosin;Tamsulosin/Protease Inhibitors 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 protease inhibitors may inhibit the metabolism of alfuzosin,(1) silodosin,(2) and tamsulosin(3) by CYP3A4. CLINICAL EFFECTS: Co-administration of a protease inhibitor may result in increased alfuzosin,(1) silodosin,(2) and tamsulosin(3) levels and serious effects such as hypotension. PREDISPOSING FACTORS: In patients receiving tamsulosin, the interaction may be worse in patients who are CYP2D6 poor metabolizers because tamsulosin also undergoes metabolism by this pathway.(3) PATIENT MANAGEMENT: The US manufacturers of alfuzosin(1) and silodosin(2) state that concurrent use of strong CYP3A4 inhibitors is contraindicated. The US manufacturer of tamsulosin states that tamsulosin should not be used with strong CYP3A4 inhibitors.(3) The US manufacturers of atazanavir,(4) darunavir,(5) fosamprenavir,(6) indinavir,(7) lopinavir/ritonavir,(8) nelfinavir,(9), nirmatrelvir/ritonavir,(10 paritaprevir, (11) saquinavir,(12) and tipranavir(13) state that concurrent use of alfuzosin is contraindicated. DISCUSSION: Administration of ketoconazole (400 mg daily), another inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of alfuzosin (10 mg) by 2.3-fold and 3.2-fold, respectively.(1) Administration of ketoconazole (200 mg daily) increased the Cmax and AUC of a single dose of alfuzosin (10 mg) by 2.1-fold and 2.5-fold, respectively.(1) Administration of ketoconazole (200 mg daily for 4 days), increased the Cmax and AUC of a single dose of silodosin (4 mg) by 3.7-fold and 2.9-fold, respectively.(2) Administration of ketoconazole (400 mg daily for 4 days) increased the Cmax and AUC of a single dose of silodosin (8 mg) by 3.8-fold and 3.2-fold, respectively.(2) In a study in 24 healthy subjects, administration of ketoconazole (400 mg daily for 5 days) increased the Cmax and AUC of a single dose of tamsulosin (0.4 mg) by 2.2-fold and 2.8-fold, respectively.(3) |
ALFUZOSIN HCL ER, DUTASTERIDE-TAMSULOSIN, JALYN, RAPAFLO, SILODOSIN, TAMSULOSIN HCL, UROXATRAL |
| Rivaroxaban/HIV Protease Inhibitors; Cobicistat 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: Rivaroxaban is metabolized by CYP3A4 and is a substrate of the P-glycoprotein (P-gp) efflux transport protein.(1-3) HIV protease inhibitors are CYP3A4 and P-gp inhibitors and may increase the absorption and decrease the elimination of rivaroxaban.(1-4) CLINICAL EFFECTS: Concurrent use of protease inhibitors may result in elevated levels and clinical effects of rivaroxaban, including an increased risk of bleeding.(1-4) PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients 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). PATIENT MANAGEMENT: Recommendations for concurrent use of rivaroxaban and HIV protease inhibitors vary in different regions. The Australian(1) and Canadian(2) manufacturers of rivaroxaban state that the concurrent use of strong inhibitors of both P-gp and CYP3A4 with rivaroxaban is contraindicated. The UK manufacturer of rivaroxaban states that concurrent use of these agents is not recommended.(3) The US manufacturer of rivaroxaban states that concurrent use should be avoided.(4) The US manufacturer of atazanavir states that coadministration of atazanavir with ritonavir is not recommended. Coadministration of atazanavir alone should be monitored closely.(5) If concurrent therapy is warranted, 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. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation 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: Concurrent use of rivaroxaban with ritonavir (600 mg twice daily) increased rivaroxaban area-under-curve (AUC) and maximum concentration (Cmax) by 2.5-fold and 1.6-fold, respectively. There were also significant increases in pharmacodynamic effects.(1,2) HIV protease inhibitors linked to this monograph are: atazanavir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir. |
RIVAROXABAN, XARELTO |
| Sildenafil (for PAH)/HIV Protease Inhibitors; Cobicistat 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 metabolism of sildenafil by CYP3A4 may be inhibited by the protease inhibitors and cobicistat. CLINICAL EFFECTS: The concurrent administration of sildenafil with a protease inhibitor or cobicistat may result in elevated levels of sildenafil, which may result in increased adverse effects such as hypotension, syncope, visual changes, and priapism. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of atazanavir,(1) darunavir,(2) fosamprenavir,(3) indinavir,(4) lopinavir/ritonavir,(5) nelfinavir,(6) nirmatrelvir/ritonavir,(7) saquinavir,(9) tipranavir,(10) cobicistat(11), and ombitasvir-paritaprevir-ritonavir-dasabuvir(15) state that the concurrent use of sildenafil when used for the treatment of pulmonary arterial hypertension (PAH) is contraindicated. The US manufacturer of Revatio states that concurrent use is not recommended.(12) DISCUSSION: In a study in 16 subjects, administration of darunavir/ritonavir (400/100 mg twice daily) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of a single dose of sildenafil (25 mg) by 38% and 3%, respectively, when compared to the administration of a 100 mg single dose of sildenafil given without darunavir.(3) In a study in 6 HIV-infected males, indinavir (800 mg every 8 hours) increased the AUC and Cmax of indinavir by 11% and 48%, respectively. Sildenafil AUC increased by 340%.(4) The concurrent administration of ritonavir (400 mg twice daily) at steady state with sildenafil (100 mg single dose) resulted in increases in the sildenafil Cmax and AUC by 300% (4-fold) and 1000% (11-fold), respectively.(7,12-14) After 24 hours, plasma levels of sildenafil were still approximately 200 ng/ml (normally 5 ng/ml 24 hours post-dose).(14) In a study in 27 healthy volunteers, the concurrent use of saquinavir (1200 mg 3 times daily for 8 days) increased the AUC and Cmax of a single dose of sildenafil (100 mg) by 210% and 140%, respectively.(9) Because a safe and effective dosage regimen for the use of sildenafil for PAH with concurrent protease inhibitor therapy has not been determined, the US manufacturer of the protease inhibitors state that concurrent use is contraindicated.(1-10,15) |
REVATIO, SILDENAFIL CITRATE |
| Lurasidone/Protease Inhibitors; Cobicistat 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: Lurasidone is a sensitive substrate for CYP3A4.(1) Sensitive substrates will have at least a 5-fold increase in area-under-curve (AUC) when given with a strong inhibitor of the enzyme.(2) Protease inhibitors and cobicistat are strong and moderate inhibitors of CYP3A4 and may inhibit the metabolism of lurasidone.(1,3-5) CLINICAL EFFECTS: Concomitant use of lurasidone with inhibitors of CYP3A4 may lead to orthostatic hypotension, akathisia, acute dystonia, Parkinsonism, confusion, postural instability or other lurasidone toxicities.(1) PREDISPOSING FACTORS: Elderly patients, particularly those with a history of falls, swallowing disorders, Parkinson Disease, Lewy Body Disease, or other dementias are more sensitive to antipsychotics and have a greater risk for adverse effects.(1) PATIENT MANAGEMENT: The US manufacturer of lurasidone states that concurrent use of a strong CYP3A4 inhibitor is contraindicated.(1) The US Department of Health and Human Services HIV guidelines state that all protease inhibitors boosted with ritonavir or cobicistat are contraindicated.(5) If a patient maintained on lurasidone requires a protease inhibitor for treatment of HIV or hepatitis C, then the patient should be converted to another antipsychotic prior to initiation of protease inhibitor therapy. If a patient is currently on lurasidone and addition of unboosted atazanavir is necessary, the dose of lurasidone should be decreased by 50% of the original dose.(5) If a patient is currently on unboosted atazanavir and lurasidone is added to therapy, the recommended starting dose of lurasidone is 20 mg per day, and the maximum dose is 80 mg daily.(5) DISCUSSION: Pretreatment with ketoconazole (400 mg daily for 5 days), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of lurasidone (10 mg) by 6.9-fold, and 9.0-fold, respectively.(1) Pretreatment with diltiazem (240 mg daily for 5 days), a moderate inhibitor of CYP3A4, increased the Cmax and AUC of a single dose of lurasidone (20 mg) by 2.1-fold, and 2.2-fold, respectively.(1) Agents linked to this monograph are atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, nirmatrelvir, paritaprevir, saquinavir, telaprevir, and tipranavir. |
LATUDA, LURASIDONE HCL |
| Ticagrelor/Strong CYP3A4 Inhibitors; Protease Inhibitors 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 inhibitors of CYP3A4 may inhibit the metabolism of ticagrelor.(1,2) CLINICAL EFFECTS: Concurrent use of a strong inhibitor of CYP3A4 may result in a substantial increase in exposure to and effects from ticagrelor, including increased risk of bleeding.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The UK manufacturer of ticagrelor states that concurrent use of strong CYP3A4 inhibitors is contraindicated.(1) The US manufacturer of ticagrelor states that concurrent use of strong CYP3A4 inhibitors should be avoided.(2) The US manufacturer of itraconazole states that concurrent use of ticagrelor is contraindicated during and two weeks after itraconazole treatment.(3) DISCUSSION: Concurrent ketoconazole increased ticagrelor maximum concentration (Cmax) and area-under-curve (AUC) by 2.4-fold and 7.3-fold, respectively. The Cmax and AUC of the active ticagrelor metabolite decreased by 89% and 56%, respectively.(1) Strong CYP3A4 inhibitors linked include: adagrasib, atazanavir, boceprevir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir/ritonavir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tucatinib, and voriconazole.(4,5) |
BRILINTA, TICAGRELOR |
| Atorvastatin (>20 mg)/Selected Protease Inhibitors 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: Protease inhibitors may inhibit the metabolism of atorvastatin by CYP3A4.(1-5) CLINICAL EFFECTS: Concurrent use of protease inhibitors may result in elevated levels of atorvastatin, which could result in rhabdomyolysis.(1-5) PREDISPOSING FACTORS: The risk for myopathy or rhabdomyolysis may be greater in patients 65 years and older, inadequately treated hypothyroidism, renal impairment, carnitine deficiency, malignant hyperthermia, or in patients with a history of myopathy or rhabdomyolysis. Patients with a SLCO1B1 polymorphism that leads to decreased function of the hepatic uptake transporter OATP1B1 may have increased statin concentrations and be predisposed to myopathy or rhabdomyolysis. PATIENT MANAGEMENT: In patients receiving protease inhibitors, consider the use of fluvastatin. If atorvastatin is used with concurrent darunavir, fosamprenavir, lopinavir, or saquinavir, limit the dose of atorvastatin to 20 mg daily with careful monitoring.(1-5) DISCUSSION: A study in 15 subjects found that darunavir/ritonavir (300/100 mg twice daily) decreased the maximum concentration (Cmax) and area-under curve (AUC) of atorvastatin (10 mg daily) by 44% and 15%, when compared to atorvastatin (40 mg daily) administered alone. Atorvastatin minimum concentration (Cmin) increased by 81% during concurrent therapy.(2) In a study in 16 subjects, concurrent atorvastatin (10 mg daily for 4 days) and fosamprenavir (1400 mg twice daily for 2 weeks) increased atorvastatin Cmax and AUC by 304% and 130%, respectively. Atorvastatin Cmin decreased by 10%.(3) The Cmax, AUC, and Cmin of amprenavir decreased by by 18%, 27%, and 12%, respectively.(3) In a study in 16 subjects, the administration of atorvastatin (10 mg daily for 4 days) and fosamprenavir (700 mg twice daily for 2 weeks) with ritonavir (100 mg twice daily for 2 weeks) increased the atorvastatin Cmax, AUC, and Cmin by 184%, 153%, and 73%, respectively.(1,4) There were no changes in amprenavir Cmax, AUC, or Cmin.(3) A randomized, controlled trial in healthy subjects examined the effects of a combination of ritonavir and saquinavir on the pharmacokinetics of atorvastatin, pravastatin, and simvastatin and the effects of pravastatin on nelfinavir pharmacokinetics. The combination of ritonavir and saquinavir decreased pravastatin levels by 50% and increased atorvastatin and simvastatin levels by 79% and 3059%, respectively. Pravastatin had no statistically significant effect on nelfinavir pharmacokinetics.(6) Concurrent administration of atorvastatin (40 mg for 4 days) with ritonavir-saquinavir (400 mg twice daily) increased atorvastatin AUC and Cmax by 3.9-fold and 4.3-fold, respectively.(1) Concurrent administration of atorvastatin (20 mg) with lopinavir-ritonavir (400-100 mg twice daily) increased atorvastatin by 5.9-fold.(1) |
AMLODIPINE-ATORVASTATIN, ATORVALIQ, ATORVASTATIN CALCIUM, CADUET, LIPITOR |
| Flibanserin/Strong or Moderate CYP3A4 Inhibitors 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: Flibanserin is primarily metabolized by CYP3A4, though CYP2C19 also plays a role in metabolism.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in high to very high levels of and toxicity from flibanserin, including severe hypotension or syncope.(1) PREDISPOSING FACTORS: Patients with any degree of hepatic impairment, who are poor CYP2C19 metabolizers, or who also receive concomitant therapy with strong CYP2C19 inhibitors are expected to have increased systemic concentrations of flibanserin, adding to the risk for hypotension or syncopal episodes.(1) Hypotensive or syncopal episodes are more common when flibanserin is taken during waking hours.(1) PATIENT MANAGEMENT: The concomitant use of flibanserin with moderate or strong CYP3A4 inhibitors significantly increases flibanserin concentrations which may lead to hypotension and syncope. The manufacturer of flibanserin states moderate or strong CYP3A4 inhibitors are contraindicated.(1) If the benefit of initiating a CYP3A4 inhibitor within 2 days of stopping flibanserin clearly outweighs the risk flibanserin-associated hypotension or syncope, monitor and counsel the patient regarding symptoms of hypotension or syncope. Discontinue moderate or strong CYP3A4 inhibitors for 2 weeks before initiating or restarting flibanserin therapy.(1) DISCUSSION: In a drug interaction study with 15 healthy subjects, the combination of flibanserin (100 mg on day 6) and fluconazole (a moderate CYP3A4 and strong CYP2C19 inhibitor, 400 mg once then 200 mg daily for 5 days) resulted in an increased flibanserin exposure of 7-fold. Hypotension or syncope requiring supine placement with leg elevation occurred in 3 subjects (20%). One patient became unresponsive with a blood pressure of 64/41 mm Hg and required emergency room treatment where she required intravenous saline.(1) Though the combination has not been studied, a similar result is plausible with voriconazole, a strong CYP3A4 inhibitor and moderate CYP2C19 inhibitor.(1) In a drug interaction study with flibanserin 50 mg (one-half of the recommended dose) and ketoconazole 400 mg, flibanserin exposure increased 4.5-fold. One of 24 patients(4%) developed syncope.(1) A study of 12 healthy men and women on itraconazole (400 mg once then 200 mg daily for 4 days) with flibanserin 50 mg given 2 hours after itraconazole found that flibanserin exposure was increased 2.6-fold.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(1-3) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir/ritonavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole (also a CYP2C19 inhibitor), fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, ledipasvir, netupitant, schisandra, nilotinib, treosulfan and verapamil.(1-3) |
ADDYI, FLIBANSERIN |
| Avanafil (Greater Than 50 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of avanafil.(1) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inhibitor may result in elevated levels of avanafil, which may result in increased adverse effects such as hypotension, visual changes, and priapism. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of avanafil states that in patients receiving moderate inhibitors of CYP3A4, the dose of avanafil should be limited to 50 mg in 24 hours.(1) DISCUSSION: Ketoconazole (400 mg daily), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of avanafil (50 mg) by 3-fold and 13-fold, respectively. The half-life of avanafil increased from 5 hours to 9 hours.(1) Ritonavir (600 mg BID), a strong inhibitor of CYP3A4 and an inhibitor of 2C19, increased the Cmax and AUC of a single dose of avanafil (50 mg) by 2-fold and 13-fold, respectively. The half-life of avanafil increased from 5 hours to 9 hours.(1) Erythromycin (500 mg BID), a moderate inhibitor of CYP3A4, increased the Cmax and AUC of a single dose of avanafil (200 mg) by 2-fold and 3-fold, respectively. The half-life of avanafil increased from 5 hours to 8 hours.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, grapefruit juice, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan, and verapamil.(1-3) |
AVANAFIL, STENDRA |
| Ranolazine (Greater Than 500 mg BID)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of ranolazine. Verapamil may also increase the absorption of ranolazine by inhibiting P-glycoprotein.(1) CLINICAL EFFECTS: Concurrent use of moderate inhibitors of CYP3A4 may result in elevated levels of and clinical effects from ranolazine. Elevated ranolazine levels may result in QTc prolongation, which may result in life-threatening cardiac arrhythmia, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of ranolazine states that the dosage of ranolazine should be limited to 500 mg twice daily in patients receiving moderate inhibitors of CYP3A4.(1) If concurrent therapy is deemed medically necessary, obtain serum calcium, magnesium, and potassium levels and monitor ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Concurrent use of diltiazem, a moderate inhibitor of CYP3A4, at daily doses of 180 mg to 360 mg increased plasma levels of ranolazine (1000 mg twice daily) by 50% and 130%, respectively.(1,4) In healthy subjects, concurrent ranolazine (1000 mg twice daily) had no effects on the pharmacokinetics of diltiazem (60 mg three times daily).(1) Concurrent use of verapamil (120 mg three times daily) increased plasma levels of ranolazine (750 mg twice daily) by 100%.(1) In a study in 12 healthy males, ranolazine immediate release (IR, 240 mg three times daily) had no effect on diltiazem (60 mg three times daily) pharmacokinetics. However, at ranolazine IR steady state, diltiazem increased ranolazine IR area under the curve (AUC) by 85%, on average, and increased maximum concentration (Cmax) by 1.9-fold and minimum concentration (Cmin) by 2.1-fold.(4) In a study in 12 subjects, ranolazine sustained release (SR, 500 mg twice daily) had no effect on diltiazem (60 mg three times daily) pharmacokinetics. However, at ranolazine steady state, diltiazem increased ranolazine SR Cmax, concentration minimum (Cmin), AUC by 80%, 216%, and 90%, on average, respectively.(4) In a study in 8 healthy males, diltiazem modified release (MR, 180 mg, or 240 mg, or 360 mg, once daily) increased ranolazine sustained release (SR, 1000 mg twice daily) AUC by 52%, 93%, and 139%, respectively. Ranolazine half-lives did not show any consistent trend of changes with increasing doses of diltiazem.(4) In a study of patients with severe chronic angina, the addition of ranolazine 750 mg twice daily or 1,000 mg twice daily along with their standard dose of diltiazem (180 mg once daily) provided additional antianginal relief, without evident adverse, long-term survival consequences over 1 to 2 years of therapy.(5) Ranolazine-induced QTc prolongation is dose and concentration-related.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(1,3,6,7) |
ASPRUZYO SPRINKLE, RANOLAZINE ER |
| Naloxegol (Greater Than 12.5 mg)/Moderate CYP3A4 Inhibitors 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: Inhibitors of CYP3A4 may inhibit the metabolism of naloxegol.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 without a dosage adjustment of naloxegol may result in increased levels of naloxegol, which may precipitate opioid withdrawal symptoms.(1) PREDISPOSING FACTORS: Patients taking methadone may be more likely to experience gastrointestinal side effects such as abdominal pain and diarrhea as a result of opioid withdrawal.(1) PATIENT MANAGEMENT: The daily dose of naloxegol should be limited to 12.5 mg daily in patients taking moderate inhibitors of CYP3A4.(1) If concurrent use is deemed medically necessary, monitor patients for signs of opioid withdrawal such as sweating, chills, diarrhea, stomach pain, anxiety, irritability, yawning, restlessness, muscle/joint aches, increased lacrimation, running nose, and piloerection. Monitor patients taking methadone for abdominal pain and diarrhea as well.(1) DISCUSSION: Ketoconazole (400 mg daily for 5 days), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of naloxegol by 9.58-fold and 12.85-fold, respectively.(2) Diltiazem (240 mg XR daily), a moderate inhibitor of CYP3A4, increased the Cmax and AUC of a single dose of naloxegol by 2.85 and 3.41, respectively.(2) According to Physiologically-based-Pharmacokinetic (PBPK) models, erythromycin, a moderate inhibitor of CYP3A4, at a dose of 250 mg QID is expected to increase the Cmax and AUC of naloxegol by 2.77-fold and 3.47-fold, respectively.(2) According to PBPK models, erythromycin at a dose of 400 mg QID is expected to increase the Cmax and AUC of naloxegol by 3.42-fold and 4.63-fold, respectively.(2) According to PBPK models, fluconazole, a moderate inhibitor of CYP3A4, at a dose of 200 mg daily is expected to increase the Cmax and AUC of naloxegol by 2.4-fold and 2.81-fold, respectively.(2) According to PBPK models, verapamil moderate inhibitor of CYP3A4, at a dose of 120 mg daily is expected to increase the Cmax and AUC of naloxegol by 1.97-fold and 2.21-fold, respectively.(2) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(1,3,4) |
MOVANTIK |
| Lomitapide/Strong or Moderate CYP3A4 Inhibitors 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: Lomitapide is primarily metabolized via CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in high to very high levels of and toxicity from lomitapide.(1) PREDISPOSING FACTORS: The interaction may be more severe in patients with hepatic impairment or with end-stage renal disease.(1) PATIENT MANAGEMENT: Given the magnitude of this interaction and the potential toxicity of lomitapide, moderate and strong CYP3A4 inhibitors are contraindicated.(1) When possible use an alternative to the CYP3A4 inhibitor. If a moderate or strong CYP3A4 inhibitor is required, discontinue lomitapide. Due to its long half-life, it will take 1 to 2 weeks for remaining lomitapide to be eliminated; thus lomitapide adverse effects could occur after discontinuation. The US manufacturer of itraconazole states that concurrent use with lomitapide is contraindicated during and two weeks after itraconazole treatment.(4) DISCUSSION: Concurrent administration with ketoconazole (a strong inhibitor of CYP3A4) increased lomitapide area-under-curve (AUC) by 27-fold.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, tucatinib, and voriconazole.(1-3,5) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir/ritonavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole (also a CYP2C19 inhibitor), fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, lefamulin, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(1-3) |
JUXTAPID |
| Selected Antiarrhythmics/Amprenavir; Fosamprenavir 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: Fosamprenavir, a CYP3A4 inhibitor, may decrease the metabolism of some antiarrhythmics.(1-4) CLINICAL EFFECTS: Concurrent use of fosamprenavir(1-4) with bepridil, disopyramide, flecainide, or propafenone may result in elevated levels of and adverse events from (including life-threatening reactions) the antiarrhythmics. 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.(5) 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).(5) PATIENT MANAGEMENT: The Canadian(1,2) and UK(3) manufacturers of fosamprenavir state that the antiarrhythmics bepridil, flecainide, and propafenone are contraindicated in patients receiving fosamprenavir. The US manufacturer of fosamprenavir states that, when used with ritonavir, flecainide and propafenone are contraindicated. The US manufacturer also recommends caution and antiarrhythmic concentration monitoring with concurrent use of other antiarrhythmics.(4) If concurrent therapy is deemed medically necessary, obtain serum calcium, magnesium, and potassium levels and monitor ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Because of the risk of serious and potentially life-threatening reactions, the Canadian(1,2) and UK(3) manufacturers of fosamprenavir state that the antiarrhythmics bepridil, flecainide, and propafenone are contraindicated in patients receiving fosamprenavir. The US manufacturer of fosamprenavir states that, when used with ritonavir, flecainide and propafenone are contraindicated. The US manufacturer also recommends caution and antiarrhythmic concentration monitoring with concurrent use of these antiarrhythmics.(4) |
FLECAINIDE ACETATE, PROPAFENONE HCL, PROPAFENONE HCL ER |
| Cilostazol (Greater than 50 mg BID)/Selected Strong & Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of cilostazol.(1) CLINICAL EFFECTS: The concurrent use of cilostazol and strong and moderate inhibitors of CYP3A4 may result in elevated levels of cilostazol, which may produce increased effects of cilostazol and adverse effects.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of cilostazol should be limited to 50 mg twice daily in patients receiving concurrent therapy with strong and moderate inhibitors of CYP3A4.(1) DISCUSSION: In a study in 16 healthy males, the administration of a single dose of cilostazol (10 mg) with erythromycin (500 mg every eight hours) increased the maximum concentration (Cmax) and area-under-curve (AUC) of cilostazol by 47% and 73%, respectively. The Cmax and AUC of 4'-trans-hydroxy-cilostazol were increased by 29% and 141%, respectively.(2) Analysis of population pharmacokinetics indicated that the concurrent administration of diltiazem with cilostazol increased cilostazol concentrations by 53%. Concurrent administration of diltiazem and cilostazol decreased cilostazol clearance by 30%, increased the Cmax by 30%, and increased AUC by 40%.(1) In a study, the administration of a single dose of cilostazol (10 mg) with erythromycin (500 mg every eight hours) increased the Cmax and AUC of cilostazol by 47% and 73%, respectively. The AUC of 4'-trans-hydroxy-cilostazol was increased by 141%.(1) In an vitro study in human liver microsomes, ketoconazole inhibited the metabolism of cilostazol.(3) |
CILOSTAZOL |
| Lumateperone (>10.5 mg)/Strong CYP3A4 Inhib; Protease Inhib 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 inhibitors of CYP3A4 and protease inhibitors may inhibit the metabolism of lumateperone.(1,2) CLINICAL EFFECTS: Concurrent use of lumateperone with strong CYP3A4 inhibitors or protease inhibitors increases lumateperone exposure, which may increase the risk of adverse reactions.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lumateperone recommends decreasing the dosage of lumateperone to 10.5 mg once daily in patients receiving strong CYP3A4 inhibitors.(1) The US Department of Health and Human Services HIV guidelines state that protease inhibitors should not be coadministered with lumateperone.(2) DISCUSSION: Coadministration of lumateperone with itraconazole, a strong CYP3A4 inhibitor, resulted in a 4-fold and 3.5-fold increase in area-under-curve (AUC) and concentration maximum (Cmax), respectively.(1) Coadministration of lumateperone with diltiazem, a moderate CYP3A4 inhibitor, resulted in a 2.5-fold and 2-fold increase AUC and Cmax, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, amprenavir, atazanavir, boceprevir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, grapefruit, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2-4) |
CAPLYTA |
| Protease Inhibitors/Apalutamide 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 is a strong inducer of CYP3A4 and is expected to increase the metabolism of the HIV protease inhibitors.(1-5) HIV protease inhibitors are moderate to strong inhibitors of CYP3A4 and may decrease the metabolism of apalutamide.(1-5) CLINICAL EFFECTS: The net effect of the opposing effects of apalutamide and the protease inhibitors on CYP3A4 is unknown. Concurrent or recent use of apalutamide with a protease inhibitor may result in decreased levels and effectiveness of the protease inhibitor. Virologic failure and drug resistance may occur.(1-3) Alternatively, protease inhibitors may increase the plasma concentration and toxicities of apalutamide.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lopinavir-ritonavir and of ritonavir states that concurrent use with apalutamide is contraindicated due to the risk of virologic failure and development of drug resistance.(2,3) Since the other protease inhibitors are also CYP3A4 substrates and frequently used with ritonavir, they are included in this monograph. If alternatives are not available and concurrent use is deemed medically necessary, follow HIV viral loads closely. DISCUSSION: Co-administration of apalutamide with a single dose of midazolam (a CYP3A4 substrate) led to a 92 % decrease in the area-under-curve (AUC) of midazolam.(1) Ketoconazole, a strong CYP3A4 inhibitor, was predicted to increase the AUC of single-dose apalutamide by 24% and of steady-state apalutamide by 51%.(1) |
ERLEADA |
| Mitapivat (Greater Than 20 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of mitapivat.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels of and effects from mitapivat including decreased estrone and estradiol levels in males, increased urate, back pain, and arthralgias.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of moderate CYP3A4 inhibitors with mitapivat should be monitored closely for increased risk of adverse reactions. Mitapivat dose should not exceed 20 mg twice daily with concurrent moderate CYP3A4 inhibitors.(1) DISCUSSION: Mitapivat is a CYP3A4 substrate. In a pharmacokinetic study with mitapivat 5, 20, or 50 mg twice daily dosing, fluconazole increased mitapivat area-under-curve (AUC) and concentration maximum (Cmax) by 2.6-fold and 1.6-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, erythromycin, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(2)(2) |
PYRUKYND |
| Pimavanserin (Greater Than 10 mg)/Strong CYP3A4 Inhibitors; Protease Inhibitors 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 which inhibit the CYP3A4 enzyme may inhibit the metabolism of pimavanserin.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors or HIV protease inhibitors may increase systemic exposure and the risk for pimavanserin toxicities such as peripheral edema, confusion, or QT prolongation.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: When concomitant use of pimavanserin and a strong CYP3A4 inhibitor or HIV protease inhibitor is needed, the pimavanserin dose should be reduced to 10 mg once daily.(1,2) With unboosted atazanavir, consider using alternative antipsychotic agents.(2) During concomitant therapy with a strong CYP3A4 inhibitor or HIV protease inhibitor, monitor patients closely for prolongation of the QT interval. Obtain serum calcium, magnesium, and potassium levels and monitor ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a drug interaction study, ketoconazole increased pimavanserin maximum concentration (Cmax) 1.5-fold and area-under-curve(AUC) 3-fold. A thorough QTc study performed in 252 subjects found a mean maximum change from baseline of 13.5 msec (upper bound of the 90% confidence interval was 16.6 msec) at twice the therapeutic dose.(1) Thus, coadministration of pimavanserin and a QT prolonging agent, even at a reduced dose, may increase the risk for significant QT prolongation. CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, telaprevir, tipranavir, troleandomycin, and tucatinib.(4) |
NUPLAZID |
| Daridorexant (Greater Than 25 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of daridorexant.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels of and effects from daridorexant including somnolence, fatigue, CNS depressant effects, daytime impairment, or headache.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of daridorexant should be limited to 25 mg daily when used with a moderate CYP3A4 inhibitor.(1) DISCUSSION: Daridorexant is a CYP3A4 substrate. In a PKPB model, concurrent use of daridorexant with diltiazem, a moderate CYP3A4 inhibitor, increased daridorexant area-under-curve (AUC) and maximum concentration (Cmax) by 2.4-fold and 1.4-fold, respectively.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(2) |
QUVIVIQ |
There are 63 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 |
|---|---|
| Selected Protease Inhibitors/Alprazolam SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Protease inhibitors, including amprenavir, atazanavir, darunavir, fosamprenavir, lopinavir, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, saquinavir, and tipranavir, may inhibit the metabolism of alprazolam by CYP3A4.(1-3) CLINICAL EFFECTS: The concurrent administration of amprenavir, atazanavir, darunavir, fosamprenavir, lopinavir, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, saquinavir, and tipranavir may result in increased levels and clinical effects of alprazolam, which may result in extreme sedation and respiratory depression.(1-3) PREDISPOSING FACTORS: Inhibition of alprazolam may be greater in patients who have recently started therapy with a protease inhibitor.(1) PATIENT MANAGEMENT: Consider alternative benzodiazepines such as lorazepam, temazepam, or oxazepam. If concurrent use is necessary, patients receiving amprenavir, atazanavir, darunavir, fosamprenavir, lopinavir, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, saquinavir, or tipranavir should be observed for increased alprazolam effects. The dosage of alprazolam may need to adjusted, or alprazolam may need to be discontinued.(1-3) DISCUSSION: In a study in healthy subjects, the administration of a single dose of alprazolam (1.0 mg) following 12 days of ritonavir therapy (titrated up to 500 mg daily) resulted in a decrease in the alprazolam area-under-curve (AUC) by 12%.(1,3) The maximum concentration (Cmax) of alprazolam decreased by 16%.(1) In contrast to this, in a double-blind study in 10 healthy subjects, the administration of a single dose of alprazolam (1.0 mg) following four doses of ritonavir (200 mg) resulted in a decrease in alprazolam clearance by 59%. Ritonavir has been shown to inhibit and induce CYP3A4.(3) In a study in 17 subjects, telaprevir (750 mg every 8 hours for 10 days) increased the AUC of a single dose of alprazolam (0.5 mg) by 35%.(4) |
ALPRAZOLAM, ALPRAZOLAM ER, ALPRAZOLAM INTENSOL, ALPRAZOLAM ODT, ALPRAZOLAM XR, XANAX, XANAX XR |
| Selected Protease Inhibitors/Nevirapine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. CLINICAL EFFECTS: Concurrent administration of nevirapine with the protease inhibitors amprenavir, fosamprenavir, indinavir, nelfinavir, or saquinavir may decrease plasma concentrations of the protease inhibitor.(1-8) Decreased plasma concentrations of the protease inhibitor may result in decreased effectiveness and the development of resistance. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The exact clinical significance is unknown. Patients receiving concurrent therapy should be closely monitored. The US manufacturers of fosamprenavir(4) and nevirapine(2) state that concurrent use of nevirapine with fosamprenavir without ritonavir is not recommended. No dosage adjustment is required when nevirapine is given with fosamprenavir in combination with ritonavir twice daily.(2,4) The combination of nevirapine with fosamprenavir/ritonavir once daily has not been studied.(4) One set of investigators recommends that a dose of 1000 mg of indinavir every eight hours be considered in patients receiving concurrent therapy with nevirapine.(1) The manufacturers of indinavir(8) and nevirapine(2) state that the appropriate doses for this combination have not been established. Appropriate doses of the combinations of nevirapine with nelfinavir(2,5) or with saquinavir/ritonavir(6) have not been determined. DISCUSSION: In a study in 17 subjects, concurrent nevirapine (200 mg twice daily) and fosamprenavir (1400 mg twice daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of amprenavir by 25%, 33%, and 35%, respectively.(2,4) Nevirapine Cmax, AUC, and Cmin increased by 25%, 29%, and 34%, respectively.(4) In a study in 17 subjects, concurrent nevirapine (200 mg twice daily) with fosamprenavir (700 mg twice daily) and ritonavir (100 mg twice daily) decreased the AUC and Cmin of amprenavir by 11% and 19%, respectively.(2,4) Nevirapine Cmax, AUC, and Cmin increased by 13%, 14%, and 22%, respectively.(4) In a study in 19 HIV-infected patients, the concurrent administration of nevirapine with indinavir (800 mg every 8 hours) decreased indinavir AUC, Cmax, and Cmin, by 31%, 15%, and 44%, respectively.(2) There was a non-significant effect on nevirapine levels.(1) In a study in 23 HIV-infected patients, the concurrent administration of nevirapine (200 mg daily for 14 days, then 200 mg twice daily) with nelfinavir (750 mg 3 times daily) decreased the Cmin of nelfinavir by 32%. The AUC, Cmax, and Cmin of the M8-metabolite of nelfinavir decreased by 62%, 59%, and 66%, respectively.(2) In a study in 14 HIV-infected patients, the concurrent administration of nevirapine and ritonavir (600 mg twice daily) did not affect the AUC or Cmax of ritonavir.(2) There was no effect on nevirapine pharmacokinetics.(1) In a study in 23 HIV-infected patients, the concurrent administration of nevirapine with saquinavir (600 mg three times daily) decreased saquinavir AUC and Cmax by 38% and 32%, respectively.(2) There was no effect on the pharmacokinetics of nevirapine.(1) |
NEVIRAPINE, NEVIRAPINE ER |
| Selected Protease Inhibitors/Contraceptives SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ritonavir-boosted protease inhibitors(1-10), fosamprenavir(1), and nelfinavir(2) may induce the metabolism of estrogens. Unboosted atazanavir may inhibit the metabolism of estrogens and progestins.(3) CLINICAL EFFECTS: Concurrent use of ritonavir-boosted protease inhibitors may result in decreased levels and effectiveness of estrogen and increased levels of progestins, which may increase the risk of insulin resistance, dyslipidemia, and acne.(1-10) Additionally, concurrent use of atazanavir-cobicistat with drospirenone-containing contraceptives may result in elevated levels of and effects from drospirenone, including hyperkalemia.(4) Atazanavir alone may result in elevated levels of estrogens.(3) Hormonal contraceptives may decrease the effectiveness of fosamprenavir.(1) Elevated liver enzymes may also occur.(1) Concurrent use with tipranavir may increase the risk of rash.(5) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US Department of Health and Human Services (DHHS) HIV guidelines recommend that concurrent use of oral contraceptives with atazanavir/ritonavir, darunavir/ritonavir, or lopinavir/ritonavir be done with a contraceptive product that contains at least 35 mcg ethinyl estradiol. If atazanavir is used without ritonavir, limit the dose of ethinyl estradiol to 30 mcg. Atazanavir/cobistat is contraindicated with drospirenone-containing products. No dose adjustment is needed when atazanavir/cobicistat is used with other oral contraceptives.(11) Most manufacturer recommendations differ from the DHHS guidelines. The manufacturer of atazanavir states that if an oral contraceptive agent containing either norgestimate or norethindrone is used with atazanavir without ritonavir, the contraceptive should contain no more than 30 mcg of ethinyl estradiol. These agents should be used with caution. Oral contraceptives containing progestins other than norethindrone or norgestimate and hormonal contraceptives other than oral (e.g. patches, rings, injections) have not been studied with atazanavir (boosted or unboosted), and alternative contraceptive methods are recommended.(3,4) The manufacturers of fosamprenavir,(1) darunavir,(5) and tipranavir(6) state that alternate methods of non-hormonal contraception are recommended. The manufacturers of the combination of lopinavir and ritonavir,(7) nelfinavir,(2) ritonavir,(8) and saquinavir(9) state that additional or alternate methods of contraception should be used in patients receiving these agents. The manufacturer of nirmatrelvir/ritonavir states that a non-hormonal method of contraception should be considered during nirmatrelvir/ritonavir therapy until one menstrual cycle after stopping therapy.(10) The CDC contraceptive guidelines state that intrauterine devices (copper or levonorgestrel) may be used with any antiretroviral agent.(12) DISCUSSION: Concurrent administration of unboosted amprenavir (1200 mg twice daily) with ethinyl estradiol/norethindrone (0.035 mg/1 mg daily) decreased the amprenavir area-under-curve (AUC) and minimum concentration (Cmin) by 22% and 20%, respectively. The Cmin of ethinyl estradiol was increased by 32%. The AUC and Cmin of norethindrone were increased by 18% and 45%, respectively. Fosamprenavir is a prodrug of amprenavir.(1) In contrast, a study of fosamprenavir/ritonavir (700/100 mg twice daily) with ethinyl estradiol/norethindrone (0.035/0.5 mg daily) in 25 subjects had no effect on amprenavir levels. In addition, this combination decreased the Cmax and AUC of ethinyl estradiol by 28% and 37%, respectively. The Cmax, AUC, and Cmin of norethindrone decreased by 38%, 34%, and 26%, respectively.(1) Concurrent administration of atazanavir (400 mg daily) with ethinyl estradiol-norethindrone (Ortho-Novum) increased the maximum concentration (Cmax), AUC, and Cmin of ethinyl estradiol by 15%, 48%, and 91%, respectively, and the Cmax, AUC, and Cmin of norethindrone by 67%, 210%, and 362%, respectively.(3) Concurrent administration of atazanavir/ritonavir (300/100 mg daily) with ethinyl estradiol-norgestimate (Ortho Tri-Cyclen) decreased the maximum concentration (Cmax), AUC, and Cmin of ethinyl estradiol by 16%, 19%, and 37%, respectively, and increased the Cmax, AUC, and Cmin of norgestimate by 68%, 85%, and 202%, respectively.(3) In a study in 11 subjects, concurrent administration of darunavir/ritonavir (600/100 mg twice daily) with ethinyl estradiol/norethindrone (0.035/1 mg daily) decreased ethinyl estradiol Cmax, AUC, and Cmin by 32%, 44%, and 62%, respectively. The Cmax, AUC, and Cmin, of norethindrone decreased by 10%, 14%, and 30%, respectively.(6) The concurrent administration of nelfinavir (2250 mg daily) and ethinyl estradiol (35 mcg daily) and norethindrone (0.4 mg daily) decreased the AUC, Cmax, and Cmin of ethinyl estradiol by 47%, 28%, and 62%, respectively, and decreased the AUC and Cmin of norethindrone by 18% and 46%, respectively. There was no effect on the Cmax of norethindrone.(2) Concurrent administration of lopinavir/ritonavir (400/100 mg twice daily) and Ortho Novum (once daily) decreased the Cmax, AUC, and Cmin of ethinyl estradiol by 41%, 42%, and 58%, respectively. The Cmax, AUC, and Cmin, of norethindrone decreased by 16%, 17%, and 32%, respectively.(7) Concurrent administration of ritonavir (500 mg twice daily) and ethinyl estradiol (50 mcg single dose) decreased ethinyl estradiol AUC and Cmax by 40% and 32%, respectively.(8,14) In a study in 8 healthy females, ethinyl estradiol/gestodene (0.03/0.075 mg) had no effect on the pharmacokinetics of a single dose of saquinavir (600 mg).(15) In a study in 21 subjects, concurrent ethinyl estradiol/norethindrone (0.035/1 mg) and tipranavir-ritonavir (500/100 mg twice daily) decreased tipranavir Cmin by 27%. Ethinyl estradiol AUC and Cmax decreased by 48% and 48%, respectively. There were no significant effects on norethindrone levels. In a study in 13 subjects, concurrent ethinyl estradiol/ norethindrone (0.035/1 mg) and tipranavir-ritonavir (750/200 mg twice daily) had no significant effects on tipranavir levels. Ethinyl estradiol AUC and Cmax decreased by 52% and 43%, respectively. There were no significant effects on norethindrone levels.(6) Selected protease inhibitors linked to this monograph include: amprenavir, atazanavir, darunavir, fosamprenavir, lopinavir, nelfinavir, nirmatrelvir, and ritonavir. Although not directly linked, protease inhibitor regimens containing saquinavir and tipranavir also alert. |
2-METHOXYESTRADIOL, AFIRMELLE, ALTAVERA, ALYACEN, AMETHIA, AMETHYST, ANNOVERA, APRI, ARANELLE, ASHLYNA, AUBRA, AUBRA EQ, AUROVELA, AUROVELA 24 FE, AUROVELA FE, AVIANE, AYUNA, AZURETTE, BALCOLTRA, BALZIVA, BEYAZ, BLISOVI 24 FE, BLISOVI FE, BRIELLYN, CAMRESE, CAMRESE LO, CAZIANT, CHARLOTTE 24 FE, CHATEAL EQ, CRYSELLE, CYRED, CYRED EQ, DASETTA, DAYSEE, DESOGESTR-ETH ESTRAD ETH ESTRA, DIETHYLSTILBESTROL, DOLISHALE, DROSPIRENONE-ETH ESTRA-LEVOMEF, DROSPIRENONE-ETHINYL ESTRADIOL, ELINEST, ENPRESSE, ENSKYCE, ESTARYLLA, ESTRADIOL, ESTRADIOL BENZOATE, ESTRADIOL CYPIONATE, ESTRADIOL HEMIHYDRATE, ESTRADIOL HEMIHYDRATE MICRO, ESTRADIOL MICRONIZED, ESTRADIOL VALERATE, ESTRIOL, ESTRIOL MICRONIZED, ESTRONE, ETHINYL ESTRADIOL, ETHYNODIOL-ETHINYL ESTRADIOL, FALMINA, FEIRZA, FEMLYV, FINZALA, GEMMILY, HAILEY, HAILEY 24 FE, HAILEY FE, ICLEVIA, ISIBLOOM, JAIMIESS, JASMIEL, 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, MARLISSA, MERZEE, MIBELAS 24 FE, MICROGESTIN, MICROGESTIN FE, MILI, MINZOYA, MONO-LINYAH, NATAZIA, NECON, NEXTSTELLIS, NIKKI, NORETHIN-ETH ESTRA-FERROUS FUM, NORETHINDRON-ETHINYL ESTRADIOL, NORETHINDRONE-E.ESTRADIOL-IRON, NORGESTIMATE-ETHINYL ESTRADIOL, NORTREL, NYLIA, OCELLA, ORTHO TRI-CYCLEN, ORTHO-NOVUM, PHILITH, PIMTREA, PORTIA, RECLIPSEN, RIVELSA, SAFYRAL, SETLAKIN, SIMLIYA, SIMPESSE, SLYND, SPRINTEC, SRONYX, SYEDA, TARINA 24 FE, TARINA FE, TARINA FE 1-20 EQ, TAYTULLA, TILIA FE, TRI-ESTARYLLA, TRI-LEGEST FE, TRI-LINYAH, TRI-LO-ESTARYLLA, TRI-LO-MARZIA, TRI-LO-MILI, TRI-LO-SPRINTEC, TRI-MILI, TRI-SPRINTEC, TRI-VYLIBRA, TRI-VYLIBRA LO, TRIVORA-28, TURQOZ, TWIRLA, TYBLUME, VALTYA, VELIVET, VESTURA, VIENVA, VIORELE, VOLNEA, VYFEMLA, VYLIBRA, WERA, WYMZYA FE, XARAH FE, XELRIA FE, YASMIN 28, YAZ, ZARAH, ZOVIA 1-35, ZUMANDIMINE |
| 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. |
PRIFTIN, RIFABUTIN, TALICIA |
| Protease Inhibitors/Carbamazepine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Carbamazepine may induce the metabolism of the protease inhibitors at CYP3A4.(1-7) Ritonavir may inhibit the metabolism of carbamazepine by CYP3A4.(8,9) CLINICAL EFFECTS: The concurrent use of indinavir and carbamazepine may result in higher than anticipated carbamazepine levels, decreased indinavir plasma levels, and antiretroviral therapy failure.(1,2) The concurrent use of amprenavir, fosamprenavir, lopinavir, nelfinavir, and saquinavir may result in decreased levels of these agents and antiretroviral therapy failure.(3-7) The concurrent use of darunavir/ritonavir(11) or ritonavir(7,9,11) and carbamazepine may result in elevated levels of carbamazepine and signs of carbamazepine toxicity. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Consider avoiding the concurrent use of carbamazepine and amprenavir, fosamprenavir, indinavir, lopinavir, nelfinavir, or saquinavir. If concurrent therapy is warranted, carbamazepine and protease inhibitor levels, as well as antiretroviral response, should be closely monitored. In patients receiving concurrent therapy with carbamazepine and darunavir/ritonavir(10) or ritonavir(8), carbamazepine levels should be closely monitored and the patient should be observed for signs of carbamazepine toxicity. The dosage of carbamazepine may need to be adjusted or carbamazepine may need to be discontinued. The manufacturer of lopinavir states that lopinavir/ritonavir should not be administered once daily to patients receiving carbamazepine.(5) DISCUSSION: In a study in 16 subjects, concurrent carbamazepine (200 mg twice daily) with darunavir/ritonavir (600/100 mg twice daily) had no significant effects on darunavir pharmacokinetics. The maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of carbamazepine increased by 43%, 45%, and 54%, respectively. The Cmax, AUC, and Cmin of carbamazepine epoxide decreased by 54%, 54%, and 52%, respectively.(10) In a case report, an HIV-positive male restarted antiretroviral therapy with indinavir (800 mg every 8 hours), lamivudine (150 mg twice daily), and zidovudine (200 mg three times daily) in November of 1997. In January of 1998, carbamazepine (200 mg daily) was started for post-herpetic neuralgia. Despite the low dose of carbamazepine, carbamazepine levels were 6.7 mg/L and 8.9 mg/L in February, 1998 and March, 1998, respectively. At the end of March, 1998, carbamazepine was discontinued. In January and February of 1998, the patient's viral load was undetectable and his CD4+ count was 340x106/L and 400x106/L, respectively. By April of 1998, his HIV-RNA level had risen to 6x103 copies/ml and his CD4+ count decreased to 200x106/L. His HIV-RNA level increased to 300x103 copies/ml three months later. Prior to carbamazepine therapy, the patient's indinavir levels had been 61% of the reference population. During carbamazepine therapy, his indinavir levels decreased to a value of 4% of the reference population. Two weeks after carbamazepine was discontinued, his indinavir levels increased to a value of 173% of the reference population.(2) In a case report, a 36 year-old male HIV-positive patient was treated with phenytoin (400 mg/day) and carbamazepine (600 mg/day) in addition to his antiretroviral regimen that included zidovudine and zalcitabine. His HIV regimen was changed to stavudine, lamivudine, and indinavir, which resulted in a partial viral-load response. This regimen was then replaced with lamivudine, didanosine, ritonavir, and saquinavir, which resulted in the patient's viral load becoming undetectable. Levels of carbamazepine at this time were normal (6.5 mcg/ml). Over the next two months, the patient developed a progressive gait disorder and dizziness. His carbamazepine level increased to 18 mcg/ml. Carbamazepine was replaced with primidone.(9) In a case report, a 20 year-old male had been HIV-positive since age 8 and been maintained on carbamazepine (350 mg twice daily) since age 12. The patient was admitted for changes to his antiretroviral regimen. On day 2, his carbamazepine level was 9.5 mcg/ml and his aminotransferase (ALT) value was normal. On day 8, a single dose of ritonavir (200 mg) was administered. Within 12 hours, his carbamazepine level increased to 17.8 mcg/ml. On day 9, ritonavir (200 mg three times daily), but ritonavir was discontinued on day 10 because of intractable nausea and vertigo. On day 12, the patient's ALT level was 141 International Units/L. On day 13, ritonavir (200 mg every 24 hours) was restarted. The patient's carbamazepine level increased to 16.3 mcg/ml and ritonavir was discontinued.(10) 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. |
CARBAMAZEPINE, CARBAMAZEPINE ER, CARBATROL, EPITOL, EQUETRO, TEGRETOL, TEGRETOL XR |
| Fosamprenavir; Saquinavir/Efavirenz SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Efavirenz may induce the metabolism of fosamprenavir,(1-3) and saquinavir (1,2,4) via CYP3A4. CLINICAL EFFECTS: Concurrent use of fosamprenavir and efavirenz without the correct amount of concurrent ritonavir may result in decreased levels of amprenavir.(1-3) Concurrent use of saquinavir as the sole protease inhibitor with efavirenz may result in decreased saquinavir levels and effectiveness.(1,2,4) Saquinavir may decrease efavirenz levels.(1,4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: An additional 100 mg/day (300 mg total) of ritonavir is recommended when efavirenz is administered with fosamprenavir/ritonavir once daily. No change in the ritonavir dose is required when efavirenz is administered with fosamprenavir/ritonavir twice daily. Appropriate doses of fosamprenavir and efavirenz administered without ritonavir have not been established.(1-3) Saquinavir should not be used as the sole protease inhibitor in patients receiving efavirenz.(1,2) Appropriate doses of the combination of efavirenz and saquinavir mesylate/ritonavir have not been determined.(4) DISCUSSION: In a study in 16 subjects, concurrent use of efavirenz (600 mg daily) with fosamprenavir (1400 mg daily) with ritonavir (200 mg daily) decreased the amprenavir AUC and minimum concentration (Cmin) by 13% and 36%, respectively. Administration of an additional 100 mg of ritonavir daily increased amprenavir Cmax and AUC by 18% and 11%, respectively.(3) In a study in 16 subjects, concurrent use of efavirenz (600 mg daily) with fosamprenavir (700 mg twice daily) with ritonavir (100 mg twice daily) decreased amprenavir Cmin by 17% but had no effect on amprenavir AUC or Cmax.(3) In a study in 12 subjects, concurrent use of efavirenz (600 mg daily) with saquinavir (1200 mg every 8 hours) decreased the saquinavir AUC, Cmax, and Cmin by 62%, 50%, and 56%, respectively. Efavirenz AUC, Cmax, and Cmin were decreased by 12%, 13%, and 14%, respectively.(1,4) |
EFAVIRENZ, EFAVIRENZ-EMTRIC-TENOFOV DISOP, EFAVIRENZ-LAMIVU-TENOFOV DISOP, SYMFI, SYMFI LO |
| Selected Steroids/Antiretroviral CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Antiretroviral CYP3A4 inhibitors may inhibit the metabolism of corticosteroids metabolized by CYP3A4. Dexamethasone may induce metabolism of agents that are substrates of CYP3A4.(1-13,50) CLINICAL EFFECTS: Concurrent use of antiretroviral CYP3A4 inhibitors may result in increased systemic exposure to and effects from corticosteroids metabolized by CYP3A4, including Cushing's syndrome and adrenal suppression. Concurrent dexamethasone may result in decreased levels and effectiveness of CYP3A4 substrates. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If possible, avoid concurrent therapy of betamethasone, budesonide, ciclesonide, fluticasone, dexamethasone, methylprednisolone, or triamcinolone with antiretroviral CYP3A4 inhibitors. Alternative corticosteroids that are less affected by CYP3A4 inhibitors should be considered, like beclomethasone, prednisone, and prednisolone. If concurrent therapy is warranted, patients should be closely monitored for systemic effects. The corticosteroid may need to be discontinued. Patients receiving concurrent therapy with dexamethasone and substrates of CYP3A4 should also be monitored for decreased effectiveness of the CYP3A4 substrate. The manufacturers of nasal fluticasone(14-16) and fluticasone for inhalation(17) state that concurrent use of fluticasone and atazanavir, indinavir, nelfinavir, ritonavir or saquinavir is not recommended. The US manufacturers of atazanavir,(1) fosamprenavir,(5) indinavir(6) and nelfinavir(8) recommend caution with concurrent use of inhaled or nasal fluticasone. Consider alternatives to fluticasone if long-term use is required. DISCUSSION: In a study, boceprevir (800 mg TID for 7 days) increased the area-under-curve (AUC) of a single dose of prednisone (40 mg) by 22%. The maximum concentration (Cmax) and AUC of prednisolone increased by 16% and 37%, respectively.(2) A study of 14 healthy adults found that concurrent use of ketoconazole with ciclesonide increased the AUC of ciclesonide's active metabolite, des-ciclesonide, by approximately 3.6-fold at steady state, while levels of ciclesonide remained unchanged. However, the study concluded that no dosage adjustments were required because ciclesonide has a very low potential to cause side effects.(18) A study in 18 healthy subjects examined the effects of ritonavir (100 mg twice daily) on fluticasone nasal spray (200 mcg daily). In most subjects, fluticasone was undetectable (<10 pg/ml) when administered alone. In subjects in whom fluticasone was detectable when given alone, Cmax and area-under-curve AUC averaged 11.9 pg/ml and 8.43 pg x hr/ml, respectively. With concurrent ritonavir, fluticasone Cmax and AUC increased to 318 pg/ml and 3102.6 pg x hr/ml, respectively.(7,11,14) This reflects increases in Cmax and AUC by 25-fold and 350-fold, respectively.(3) The cortisol AUC decreased by 86%.(6,14-16) In a study in 10 healthy subjects, ritonavir (200 mg twice daily for 4 and 14 days) increased the AUC of a single dose of prednisolone by 1.41-fold and 1.30-fold, respectively, after 4 days and 14 days of ritonavir.(19) There have been several case reports of Cushing's syndrome in patients treated concurrently with ritonavir and inhaled budesonide,(19-20) dexamethasone,(22) injectable triamcinolone,(23-26) nasal fluticasone.(28-46) Hepatitis has also been reported with concurrent budesonide and ritonavir.(47) In a study in 9 healthy subjects, mibefradil (50 mg once daily for 3 days) increased the AUC, Cmax, and elimination half-life of methylprednisolone by 3.8-fold, 1.8-fold, and 2.7-fold, respectively.(48) In a study in 8 healthy subjects, following nefazodone administration the following changes were seen with methylprednisolone: mean (+/-SD) area under the concentration-time curve was significantly higher (1393 +/- 343 vs. 2966 +/- 928 ug*h/L; P < 0.005), apparent clearance was lower (28.7 +/- 7.2 vs. 14.6 +/- 7.8 L/h; P < 0.02) and the terminal elimination half-life was longer (2.28 +/- 0.49 vs. 3.32 +/- 0.95 hours; P < 0.02).(49) Selected steroids linked to this monograph include: betamethasone, budesonide, ciclesonide, dexamethasone, fluticasone, methylprednisolone, and triamcinolone.(50) Selected CYP3A4 inhibitors and substrates linked to this monograph include: atazanavir, cobicistat, darunavir, fosamprenavir, indinavir, lenacapavir, lopinavir, nelfinavir, saquinavir, and tipranavir.(50) |
AIRSUPRA, ALVESCO, ARMONAIR DIGIHALER, ARNUITY ELLIPTA, AZELASTINE-FLUTICASONE, 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, BREO ELLIPTA, BREYNA, BREZTRI AEROSPHERE, BSP 0820, BUDESONIDE, BUDESONIDE DR, BUDESONIDE EC, BUDESONIDE ER, BUDESONIDE MICRONIZED, BUDESONIDE-FORMOTEROL FUMARATE, BUPIVACAINE-DEXAMETH-EPINEPHRN, CELESTONE, DEPO-MEDROL, DEXABLISS, DEXAMETHASONE, DEXAMETHASONE ACETATE, DEXAMETHASONE ACETATE MICRO, DEXAMETHASONE INTENSOL, DEXAMETHASONE ISONICOTINATE, DEXAMETHASONE MICRONIZED, DEXAMETHASONE SOD PHOS-WATER, DEXAMETHASONE SODIUM PHOSPHATE, DEXAMETHASONE-0.9% NACL, DEXONTO, DMT SUIK, DOUBLEDEX, DYMISTA, EOHILIA, FLUTICASONE PROPIONATE, FLUTICASONE PROPIONATE HFA, FLUTICASONE PROPIONATE MICRO, FLUTICASONE-VILANTEROL, HEMADY, HEXATRIONE, KENALOG-10, KENALOG-40, KENALOG-80, LIDOCIDEX-I, MAS CARE-PAK, MEDROL, MEDROLOAN II SUIK, MEDROLOAN SUIK, METHYLPREDNISOLONE, METHYLPREDNISOLONE AC MICRO, METHYLPREDNISOLONE ACETATE, METHYLPREDNISOLONE SODIUM SUCC, OMNARIS, ORTIKOS, PRO-C-DURE 5, PRO-C-DURE 6, PULMICORT, PULMICORT FLEXHALER, SOLU-MEDROL, SYMBICORT, TAPERDEX, TARPEYO, TICANASE, TRELEGY ELLIPTA, TRIAMCINOLONE, TRIAMCINOLONE ACETONIDE, TRIAMCINOLONE DIACETATE, TRIAMCINOLONE DIACETATE MICRO, TRILOAN II SUIK, TRILOAN SUIK, UCERIS, XHANCE, ZCORT, ZETONNA, ZILRETTA |
| Trazodone/Selected CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: CYP3A4 inhibitors may inhibit the metabolism of trazodone.(1) Trazodone has been shown to prolong the QT interval. Trazodone's active metabolite meta-chlorophenylpiperazine (m-CPP) is metabolized by CYP2D6. Cobicistat is also a weak CYP2D6 inhibitor.(1) CLINICAL EFFECTS: Concurrent use of CYP3A4 inhibitors may result in elevated levels of and adverse effects from trazodone, including nausea, dizziness, hypotension, syncope, serotonin syndrome,(9) and cardiac arrhthymias including QT prolongation or torsades de pointes, which may be life-threatening.(1) Symptoms of serotonin syndrome may include tremor, agitation, diaphoresis, hyperreflexia, clonus, tachycardia, hyperthermia, and muscle rigidity. PREDISPOSING FACTORS: This interaction may be more severe with larger and/or routine doses of trazodone. 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.(10) 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).(10) PATIENT MANAGEMENT: A lower dose of trazodone should be considered in patients receiving CYP3A4 inhibitors.(1-7) Instruct patients to report dizziness, any irregular heartbeat, fainting episodes or excessive daytime sedation. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. In addition to QT prolongation, patients should be monitored for signs and symptoms of serotonin syndrome. Instruct patients to report muscle twitching, tremors, shivering and stiffness, fever, heavy sweating, heart palpitations, restlessness, confusion, agitation, trouble with coordination, or severe diarrhea. DISCUSSION: In a cross-over study in 10 healthy subjects, pretreatment with clarithromycin (500 mg, 4 doses given over 32 hours) increased the maximum concentration, (Cmax) half-life, and area-under-curve (AUC) of a single dose of trazodone (50 mg) by 35% (p<0.005), 96% (p<0.02), and 99% (p<0.001), respectively. Trazodone oral clearance decreased by 46% (p<0.001). Pharmacodynamic effects of trazodone were also increased, as shown by changes in self-rated sedation, observer-rated sedation, digit-symbol substitution test (DSST) scores.(11) In a study in 10 healthy subjects, short-term ritonavir (four doses of 200 mg twice daily) increased the AUC and half-life of a single dose of trazodone (50 mg) by 2.4-fold and 2.2-fold, respectively. The Cmax of trazodone increased 34% and its clearance decreased 52%. Three subjects experienced nausea, dizziness, or hypotension and one of these subjects also experienced syncope during concurrent administration.(3) In a single case report, a female experienced serotonin syndrome characterized by high blood pressure (240/120 mmHg); intermittent numbness of the right side of her lips and nose and fingers of the right hand; nausea; loose stools; flushed, pruritic skin; confusion; and difficulty concentrating four days after the addition of trazodone (25-50 mg daily) to nefazodone.(9) An in vitro study in human liver microsomes showed that indinavir, ketoconazole, and ritonavir inhibited the metabolism of trazodone.(8) Amprenavir, atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, grapefruit, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, tipranavir, telaprevir, and tucatinib are considered to be potent inhibitors of the CYP3A4 isoenzyme.(12) |
RALDESY, TRAZODONE HCL |
| Amprenavir; Fosamprenavir/Tipranavir SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Tipranavir may induce the CYP3A4-mediated metabolism of amprenavir.(1) Fosamprenavir is a prodrug of amprenavir.(2) CLINICAL EFFECTS: Concurrent use of tipranavir coadministered with ritonavir may result in decreased levels of amprenavir.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of tipranavir states that concurrent administration of fosamprenavir is not recommended.(3) DISCUSSION: In a study in 16 subjects, concurrent amprenavir/ritonavir (600/100 mg twice daily) and tipranavir/ritonavir (500/200 mg twice daily) decreased the Cmax, AUC, and Cmin of amprenavir by 39%, 44%, and 55%, respectively.(3) |
APTIVUS |
| Ivabradine/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of ivabradine. Increased levels of ivabradine may cause ivabradine-induced reduction in heart rate which can contribute to increased QT prolongation risk.(1-3) CLINICAL EFFECTS: Concurrent use of moderate inhibitors may result in elevated levels of and toxicity from ivabradine including a reduction in heart rate which can contribute to QT prolongation or torsades de pointes.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of ivabradine states that concurrent use of moderate inhibitors of CYP3A4, including diltiazem and verapamil, should be avoided.(1) The Australian and UK manufacturers of ivabradine state that concurrent use of diltiazem or verapamil is contraindicated but that other moderate inhibitors of CYP3A4 may be considered with monitoring of heart rate and with a starting dose of 2.5 mg ivabradine twice daily if resting heart rate is above 70 bpm.(2-3) Monitor patients receiving concurrent therapy for bradycardia (heart rate less than 50 bpm), dizziness, fatigue, hypotension, and/or symptoms of atrial fibrillation (heart palpitations, chest pressure, shortness of breath). DISCUSSION: Concurrent use of potent CYP3A4 inhibitors ketoconazole (200 mg daily) and josamycin (1000 mg twice daily) increased mean ivabradine plasma exposure by 7- to 8-fold. Concurrent use of moderate CYP3A4 inhibitors diltiazem and verapamil increased ivabradine area-under-curve (AUC) by 2- to 3-fold and reduced heart rate by an additional 5 bpm.(2) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, diltiazem, duvelisib, fedratinib, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(5) |
CORLANOR, IVABRADINE HCL |
| Selected Immunosuppressants; Temsirolimus/Protease Inhibitors; Cobicistat SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: HIV and HCV protease inhibitors as well as cobicistat may inhibit the metabolism of cyclosporine, sirolimus, and temsirolimus by CYP3A4.(1-15) CLINICAL EFFECTS: Concurrent use of HIV or HCV protease inhibitors as well as cobicistat may result in increased levels of cyclosporine, sirolimus, or temsirolimus.(1-15) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: For patients concurrently taking cyclosporine, sirolimus, or temsirolimus and either a HIV or HCV protease inhibitor or cobicistat, therapeutic concentration monitoring of the immunosuppressant is recommended. Depending upon the agents involved, dose decreases of the immunosuppressant agent may be required.(1-15) Guidelines from the American Society of Transplantation recommend avoiding the use of ritonavir- or cobicistat-based HIV or HCV antiviral regimens with cyclosporine or sirolimus due to an increased risk of graft loss and death, as well as the availability of HIV integrase inhibitors that avoid interactions with immunosuppressants. If the combination must be used, lower the dose of cyclosporine to 25-50 mg daily or sirolimus to 1 mg once or twice weekly. Monitor drug concentrations closely.(1) The US manufacturer of sirolimus protein-bound injection (Fyarro) states a dose reduction to 56 mg/m2 is recommended when used concurrently with moderate or weak CYP3A4 inhibitors. Concurrent use with strong CYP3A4 inhibitors should be avoided.(16) The US manufacturer of temsirolimus recommends that concurrent therapy with strong CYP3A4 inhibitors such as protease inhibitors be avoided. If concurrent use is warranted, a dosage reduction to 12.5 mg/week of temsirolimus should be considered. If the protease inhibitor is discontinued, a washout period of 1 week should be allowed before adjusting the dosage of temsirolimus to previous levels.(2) The selected immunosuppressants linked to this monograph include: cyclosporine, sirolimus, and temsirolimus. The protease inhibitors linked to this monograph include: amprenavir, atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, ritonavir, telaprevir, and tipranavir. DISCUSSION: A retrospective study of 42 HIV+ kidney transplant recipients examined rejection rates in patients on ritonavir-boosted protease inhibitor (PI) antiretroviral regimens compared to patients on other antiretroviral regimens. Immunosuppression therapy consisted of cyclosporine in 7 patients (17%) and tacrolimus in 32 patients (76%). The remaining 3 patients were transitioning between drugs. Over 3 years, 65% of patients on PI-based antiretroviral therapy experienced rejection, compared with 36% of patients on other antiretroviral therapies (p<0.001). There was no difference in patient or graft survival at 3 years.(17) Cyclosporine: Boceprevir (800 mg TID for 7 days) increased the Cmax and AUC of cyclosporine (100 mg single dose) by 2-fold and 2.68-fold, respectively. Boceprevir AUC increased 16%.(4) In a case report, cyclosporine dosage requirements decreased 12-fold following the addition of amprenavir/ritonavir. In another patient, cyclosporine dosage requirements decreased 3.5-fold following the addition of fosamprenavir.(18) In a study in 3 HIV+ transplant patients who were receiving lopinavir/ ritonavir, cyclosporine doses were reduced to 5-20% of standard doses to prevent toxicity.(19) In a clinical study, 7 HIV+ patients concurrently taking cyclosporine and nelfinavir experienced a 19% increase in time to Cmax (Tmax) and a 2-fold increase in AUC of cyclosporine when nelfinavir was added.(20) In a case report, cyclosporine levels tripled and signs of toxicity developed 3 days after the addition of saquinavir (1200 mg 3 times daily) to cyclosporine (150 mg twice daily). Cyclosporine and saquinavir dosages were decreased to 75 mg twice daily and 600 mg 3 times daily, respectively. Cyclosporine Cmin levels were 90% of those seen with 150 mg twice daily. Saquinavir AUC was 4.3-fold higher than in patients taking saquinavir 600 mg twice daily without cyclosporine and 11.1-fold higher than literature values.(21) In a study in 9 subjects, the concurrent administration of telaprevir (750 mg TID) decreased the Cmax and AUC of a single dose of cyclosporine (10 mg) by 87% and 54%, respectively, when compared to levels achieved with a single 100 mg dose of cyclosporine. Extrapolated to level expected with the 100 mg dose, cyclosporine Cmax and AUC would have increased by 32% and 4.64-fold, respectively.(5) Sirolimus: Boceprevir (800 mg TID for 9 days) increased the Cmax and AUC of sirolimus (2 mg single dose) by 4.84-fold and 8.121-fold, respectively. Boceprevir Cmin increased 21%.(4) In a case report, the pharmacokinetics of a liver transplant patient concurrently taking nelfinavir (250 mg) and sirolimus (2 mg) were compared to the pharmacokinetics in 3 other liver transplant patients that were also taking sirolimus, but not nelfinavir. The maximum concentration (Cmax) was 3.2 times higher, the area-under-curve (AUC) was 1.6 times higher, the half life was prolonged by 60%, and the 0-hr and 24-hour trough levels (Cmin) of sirolimus were 9-fold and 5-fold higher, respectively, in patients concurrently taking nelfinavir and sirolimus.(22) Temsirolimus: Concurrent administration of ketoconazole, another inhibitor of CYP3A4, had no effects on temsirolimus AUC or Cmax; however, sirolimus AUC and Cmax increased 3.1-fold and 2.2-fold, respectively. Dosage adjustment of temsirolimus to 12.5 mg/week in the presence of strong CYP3A4 inhibitors is expected to adjust levels to the range observed without inhibitors; however, there are no data available with this dose adjustment.(3) |
CYCLOSPORINE, CYCLOSPORINE MODIFIED, FYARRO, GENGRAF, NEORAL, SANDIMMUNE, SIROLIMUS, TEMSIROLIMUS, TORISEL |
| Maraviroc/Selected Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Some protease inhibitors may inhibit the metabolism of maraviroc by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of protease inhibitors without a dosage adjustment of maraviroc may result in elevated levels of and toxicity from maraviroc.(1-3) PREDISPOSING FACTORS: This interaction may be more severe in patients with renal and/or hepatic impairment.(1) PATIENT MANAGEMENT: The US manufacturer of maraviroc states that adult patients receiving concurrent therapy with strong inhibitors of CYP3A4 such as protease inhibitors (except for tipranavir/ritonavir) should receive a dose of 150 mg maraviroc twice daily. This is the recommended dose in patients receiving strong CYP3A4 inhibitors regardless of whether or not the patient is also receiving a strong inducer of CYP3A4.(1) In adults, maraviroc should not be used with a potent CYP3A4 inhibitor in patients with a creatinine clearance less than 30 ml/min or end-stage renal disease. Patients with hepatic impairment should be closely monitored for maraviroc-related side effects.(1) In adults, patients receiving tipranavir/ritonavir should receive 300 mg maraviroc twice daily.(1) In pediatric patients aged 2 years and older weighing at least 10 kg, patients receiving concurrent therapy with strong inhibitors of CYP3A4 such as protease inhibitors (except for tipranavir/ritonavir) regardless of whether or not the patient is also receiving a strong inducer of CYP3A4 should receive the following maraviroc dose based on tablet or oral solution (20 mg/ml): - 10 - <20 kg: 50 mg twice daily or 50 mg (2.5ml) twice daily - 20 - <30 kg: 75 mg twice daily or 80 mg (4 ml) twice daily - 30 - <40 kg: 100 mg twice daily or 100 mg (5 ml) twice daily - >= 40 kg: 150 mg twice daily or 150 mg (7.5 ml) twice daily In pediatric patients aged 2 years and older weighing at least 10 kg, no dose recommendations are available with mild to moderate renal impairment. Maraviroc is contraindicated in pediatric patients with severe renal impairment or end-stage renal disease who are on concurrent therapy with strong CYP3A4 inhibitors.(1) DISCUSSION: In a study in 12 subjects, concurrent atazanavir (400 mg daily) increased the Cmin, AUC, and Cmax of maraviroc (300 mg twice daily) by 4.19-fold, 3.57-fold, and 2.09-fold, respectively.(1) In a study in 12 subjects, concurrent atazanavir/ritonavir (300/100 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (300 mg twice daily) by 6.67-fold, 4.88-fold, and 2.67-fold, respectively.(1) In a study in 12 subjects, concurrent darunavir/ritonavir (600/100 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (150 mg twice daily) by 8.00-fold, 4.05-fold, and 2.29-fold, respectively.(1) In a study in 10 subjects, concurrent darunavir/ritonavir (600/100 mg twice daily) and etravirine (200 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (150 mg twice daily) by 5.27-fold, 3.10-fold, 1.77-fold, respectively.(1) In a study in 12 subjects, concurrent ketoconazole (400 mg daily) increased the Cmin, AUC, and Cmax of maraviroc (100 mg twice daily) by 3.75-fold, 5.00-fold, and 3.38-fold, respectively.(1) In a study in 11 subjects, concurrent lopinavir/ritonavir (400/100 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (300 mg twice daily) by 9.24-fold, 3.95-fold, and 1.97-fold, respectively.(1) In a study in 11 subjects, concurrent lopinavir/ritonavir (400/100 mg twice daily) and efavirenz (600 mg daily) increased the Cmin, AUC, and Cmax of maraviroc (300 mg twice daily) by 6.29-fold, 2.53-fold, 1.25-fold, respectively.(1) In a study in 8 subjects, concurrent ritonavir (100 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (100 mg twice daily) by 4.55-fold, 2.61-fold, and 1.28-fold, respectively.(1) In a study in 11 subjects, concurrent saquinavir/ritonavir (1000/100 mg twice daily) increased the Cmin, AUC, and Cmax of maraviroc (100 mg twice daily) by 11.3-fold, 9.77-fold, 4.78-fold, respectively.(1) In a study in 11 subjects, concurrent saquinavir/ritonavir (1000/100 mg twice daily) and efavirenz (600 mg daily) increased the Cmin, AUC, and Cmax, of maraviroc (100 mg twice daily) by 8.42-fold, 5.00-fold, and 2.26-fold, respectively.(1) In a study in 12 subjects, concurrent tipranavir/ritonavir (500/200 mg twice daily) increased the Cmin and AUC of maraviroc (150 mg twice daily) by 80% and 2%, respectively. The Cmax of maraviroc decreased by 14%.(1) Selected protease inhibitors include: amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, nirmatrelvir/ritonavir, ritonavir, saquinavir, and tipranavir. |
MARAVIROC, SELZENTRY |
| Fosamprenavir/Etravirine SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The mechanism of this interaction is unclear but may involve P-glycoprotein inhibition by etravirine. Fosamprenavir is a prodrug of amprenavir.(1-2) CLINICAL EFFECTS: Concurrent etravirine and fosamprenavir use with or without low-dose ritonavir may increase amprenavir levels and toxicity.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of etravirine states that coadministration with fosamprenavir (with or without ritonavir) is not recommended.(1) DISCUSSION: In a study in 8 subjects, etravirine increased amprenavir maximum concentration (Cmax), area-under-curve (AUC), and trough concentration (Cmin) by 62%, 69%, and 77%, respectively.(1) |
ETRAVIRINE, INTELENCE |
| Barbiturates; Phenobarbital; Phenytoin/Selected Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The anticonvulsants and protease inhibitors may induce the metabolism of each other.(1-3) Primidone is metabolized to phenobarbital. CLINICAL EFFECTS: Concurrent use of barbiturates, phenobarbital, phenytoin or primidone with fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir or tipranavir may result in decreased levels and effectiveness of both agents.(1-6) 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 concurrent therapy closely. The dosage of both agents may need to be adjusted.(1-6) US labeling states that use of fosamprenavir, indinavir, saquinavir or tipranavir in patients receiving concurrent phenobarbital or phenytoin should done used with caution.(1-2,4-5) The US manufacturer of lopinavir/ritonavir states that lopinavir/ritonavir should not be administered once daily in patients receiving concurrent phenobarbital or phenytoin.(3) DISCUSSION: In an open-label, randomized clinical trial in 24 subjects, the addition of phenytoin (300 mg daily) to lopinavir/ritonavir (400/100 mg twice daily) decreased lopinavir area-under-curve (AUC) by 30%. The addition of lopinavir/ritonavir (400/100 mg twice daily) to phenytoin (300 mg daily) decreased phenytoin AUC by 23%.(6) |
ASA-BUTALB-CAFFEINE-CODEINE, ASCOMP WITH CODEINE, BUTALB-ACETAMINOPH-CAFF-CODEIN, BUTALBITAL, BUTALBITAL-ACETAMINOPHEN, BUTALBITAL-ACETAMINOPHEN-CAFFE, BUTALBITAL-ASPIRIN-CAFFEINE, CEREBYX, DILANTIN, DILANTIN-125, DONNATAL, FIORICET, FIORICET WITH CODEINE, FOSPHENYTOIN SODIUM, MYSOLINE, PENTOBARBITAL SODIUM, PHENOBARBITAL, PHENOBARBITAL SODIUM, PHENOBARBITAL-BELLADONNA, PHENOBARBITAL-HYOSC-ATROP-SCOP, PHENOHYTRO, PHENYTEK, PHENYTOIN, PHENYTOIN SODIUM, PHENYTOIN SODIUM EXTENDED, PRIMIDONE, SEZABY, TENCON |
| Tolvaptan/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of tolvaptan.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in elevated levels of and toxicity from tolvaptan.(1) Elevated levels of tolvaptan may lead to increased clinical effects such as hypotension, hypovolemia, and thirst, as well as toxicity in the form of neurologic sequelae such as osmotic demyelination syndrome (ODS). ODS can lead to coma and death. Symptoms of ODS include dysarthria, mutism, dysphagia, lethargy, affective changes, spastic quadriparesis, seizures, and coma.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of Samsca for the treatment of clinically significant hypervolemic and euvolemic hyponatremia states that concurrent administration with moderate CYP3A4 inhibitors should be avoided.(1) The US manufacturer of Jynarque for the management to slow kidney function decline in adults at risk of rapidly progressing autosomal dominant polycystic kidney disease states concurrent administration with moderate CYP3A4 inhibitors warrants a dose reduction of Jynarque as follows: - Standard morning and evening dose: 90 mg and 30 mg should be dose adjusted to 45 mg and 15 mg, respectively - Standard morning and evening dose: 60 mg and 30 mg should be dose adjusted to 30 mg and 15 mg, respectively - Standard morning and evening dose: 45 mg and 15 mg should be dose adjusted to 15 mg and 15 mg, respectively Interrupt Jynarque temporarily for short term therapy with moderate CYP3A4 inhibitors if the recommended reduced doses are not available.(2) DISCUSSION: Fluconazole 400 mg (moderate inhibitor of CYP3A4) given one day prior and 200 mg given concomitantly produced an 80% and 200% increase in tolvaptan maximum concentration (Cmax) and area-under-curve (AUC), respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, crizotinib, darunavir, diltiazem, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(1-4) |
JYNARQUE, SAMSCA, TOLVAPTAN |
| Bosentan/Protease Inhibitors 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 bosentan by CYP3A4 and by inhibiting its uptake into hepatocytes by OATP.(1-11) Bosentan may induce the metabolism of atazanavir.(2) CLINICAL EFFECTS: Concurrent use of protease inhibitors without adjusting the dose of bosentan may result in elevated levels of and toxicity from bosentan.(1) Administration of bosentan and atazanavir without ritonavir may result in decreased levels of atazanavir.(2) PREDISPOSING FACTORS: Concurrent use of bosentan, a protease inhibitor that is a CYP3A4 inhibitor and a CYP2C9 inhibitor (e.g. amiodarone, fluconazole, oxandrolone, or sulfinpyrazone)(12) could lead to blockade of both major metabolic pathways for bosentan, resulting in large increases in bosentan plasma concentrations.(12) PATIENT MANAGEMENT: In patients who have been receiving a protease inhibitor for at least 10 days, initiate bosentan at a dosage of 62.5 mg once daily or every other day based on tolerability.(1-11) In patients who have been receiving bosentan, discontinue bosentan for at least 36 hours prior to initiating atazanavir, darunavir, fosamprenavir, lopinavir/ritonavir, nirmatrelvir/ritonavir, ritonavir, saquinavir, or tipranavir. After 10 days of protease inhibitor therapy, bosentan may be resumed at a dosage of 62.5 mg once daily or every other day based on tolerability.(1-8,11) In patients who have been receiving bosentan, adjust the dosage of bosentan to 62.5 mg once daily or every other day based on tolerability in patients who have been receiving indinavir or nelfinavir.(9-10) Review medication list to see if patient is also receiving a CYP2C9 inhibitor (e.g. amiodarone, fluconazole, miconazole, oxandrolone, sulfinpyrazone, or phenylbutazone). Concomitant use of both a CYP2C9 and CYP3A4 inhibitor is not recommended by the manufacturer as the combination may lead to large increases in bosentan plasma concentrations.(1) DISCUSSION: In a study in healthy subjects, concurrent lopinavir/ritonavir increased the initial and steady-state minimum concentrations (Cmin) of bosentan by 48-fold and 5-fold, respectively. There were no significant effects on lopinavir/ritonavir pharmacokinetics.(1) 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. |
BOSENTAN, TRACLEER |
| Colchicine (for Gout & FMF)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of colchicine(1-3) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in elevated levels of and toxicity from colchicine. Symptoms of colchicine toxicity include muscle weakness or pain; numbness or tingling in the fingers or toes; myelosuppression; abdominal pain; nausea; severe diarrhea or vomiting; feeling weak or tired; increased infections; and pale or gray color of the lips, tongue, or palms of hands.(1-3) PREDISPOSING FACTORS: This interaction is expected to be more severe in patients with renal and/or hepatic impairment.(1-3) PATIENT MANAGEMENT: Avoid use of colchicine concurrently with or within 14 days of taking moderate CYP3A4 inhibitors (without ritonavir). If concurrent use is unavoidable, the dosage of colchicine should be reduced.(1-3) For gout flares, the recommended dosage is 1.2 mg (2 tablets) for one dose. This dose should be repeated no earlier than in 3 days.(1-4) For gout prophylaxis, if the original dosage was 0.6 mg twice daily, use 0.3 mg twice daily or 0.6 mg daily. If the original dosage was 0.6 mg daily, use 0.3 mg daily.(1-4) For Familial Mediterranean fever (FMF), the recommended maximum daily dose is 1.2 mg (may be given as 0.6 mg twice a day).(1-4) Patients should be instructed to immediately report any signs of colchicine toxicity, such as muscle weakness/pain, numbness/tingling in fingers/toes, unusual bleeding or bruising, infections, weakness/tiredness, pale/gray color of the lips/tongue/palms of hands, and/or severe diarrhea/vomiting. DISCUSSION: Fluconazole (400 mg loading dose followed by 200 mg daily for 4 days) increased the area-under-curve (AUC) of colchicine by 40%.(2) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, clofazimine, conivaptan, crizotinib, duvelisib, fedratinib, fluconazole, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, and treosulfan.(1,5,6) |
COLCHICINE, COLCRYS, GLOPERBA, MITIGARE, PROBENECID-COLCHICINE |
| Salmeterol/Cobicistat; Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Some protease inhibitors may inhibit the metabolism of the portion of salmeterol that is swallowed, resulting in significant systemic absorption.(1-14) CLINICAL EFFECTS: Concurrent use of strong inhibitors of CYP3A4, such as atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, nirmatrelvir, saquinavir, telaprevir and tipranavir may result in systemic effects of salmeterol, including QTc prolongation, palpitations, and sinus tachycardia.(1-14) 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.(15) 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).(15) PATIENT MANAGEMENT: The US manufacturers of salmeterol and the protease inhibitors state that the concurrent use of salmeterol with HCV or HIV protease inhibitors is not recommended.(1-14) The National Institutes of Health COVID-19 treatment guidelines recommend holding salmeterol during and for at least 2-3 days after completion of nirmatrelvir/ritonavir therapy.(16) The Canadian manufacturer of salmeterol states that concurrent use of atazanavir, indinavir, nelfinavir, ritonavir, and saquinavir is not recommended.(17) Canadian labeling contraindicates concurrent use of atazanavir/ritonavir, darunavir/cobicistat, and lopinavir/ritonavir with salmeterol.(19-22) Consider the use of alternative agents. Advise patients receiving concurrent therapy to rinse their mouth thoroughly after administering salmeterol to limit the amount of salmeterol that is swallowed. If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. Protease inhibitors linked to this monograph include: amprenavir, atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, nirmatrelvir, saquinavir, telaprevir, and tipranavir. DISCUSSION: In a study in 20 healthy subjects, concurrent administration of salmeterol (50 mcg twice daily) and ketoconazole (400 mg once daily, a strong inhibitor of CYP3A4) for 7 days increased the plasma area-under-curve (AUC) and maximum concentration (Cmax) of salmeterol 16-fold and 1.4-fold, respectively. Concurrent use did not result in clinically significant changes in heart rate, mean blood potassium, mean blood glucose or mean QTc; however, concurrent use was associated with more frequent increases in QTc duration. Three subjects were withdrawn from the study because of systemic salmeterol effects (2 with QTc prolongation and 1 with palpitations and sinus tachycardia).(1) An in vitro study showed that ketoconazole completely inhibited the formation of alpha-hydroxysalmeterol by CYP3A4.(1,23) |
SEREVENT DISKUS |
| Quinine/Selected Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The mechanism of this interaction is not completely known and is likely multifactorial. Quinine is a substrate of CYP3A4, P-gp, and UGT.(1-3) Protease inhibitors primarily inhibit CYP3A4 but may also inhibit or induce other hepatic metabolic processes. In particular, ritonavir may induce P-glycoprotein (P-gp) and uridine-5'-diphospho-glucuronosyltransferase (UGT).(2-4) Nelfinavir and tipranavir are known to induce UGT while atazanavir and indinavir inhibit UGT. CLINICAL EFFECTS: Concurrent ritonavir has been reported to result in elevated levels of and toxicity from quinine. Quinine toxicity includes symptoms of cinchonism (headache, vasodilation/sweating, nausea/vomiting/diarrhea, tinnitus, hearing impairment, vertigo/dizziness, blurred vision/disturbance in color perception/blindness, abdominal pain, deafness) as well as QTc prolongation and life-threatening cardiac arrhythmias, including torsades de pointes.(1,5) On the other hand, concurrent lopinavir-ritonavir (fixed dose combination) has been reported to result in decreased levels of quinine. Whether this finding translates into reduced anti-malarial efficacy is unknown. One of the studies examining the use of lopinavir-ritonavir with quinine found that free, unbound levels of quinine was decreased, whereas the other found an increase in free quinine levels.(2,3) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(6) 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).(6) PATIENT MANAGEMENT: The US manufacturers of quinine and ritonavir recommend avoiding the use of quinine in patients maintained on ritonavir.(1,4) If concurrent therapy is required, consider reducing the dose of quinine.(1,4,5) There is no FDA or guideline recommendation for the concurrent use of other protease inhibitors with quinine. A physiologically based pharmacokinetic model suggests that quinine dosage may need to be increased when used with lopinavir-ritonavir, based on decreased quinine concentrations when used with lopinavir-ritonavir.(7) Patients receiving concurrent therapy should be monitored with electrocardiograms during treatment with quinine. Electrolytes (calcium, magnesium, and potassium) should also be monitored.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In 10 healthy subjects, ritonavir (200 mg every 12 hours for 9 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of quinine (600 mg) by 4-fold each. The clearance of quinine decreased 4.5-fold. There were no significant effects on the pharmacokinetics of ritonavir.(1,5) A pharmacokinetic study of 12 healthy volunteers who were coadministered quinine and lopinavir-ritonavir found that lopinavir-ritonavir led to a decrease in the Cmax and AUC of total quinine by 48% and 50%, respectively, and of free quinine by 33% and 36%, respectively. The AUC and Cmax of total 3-hydroxyquinine, the major active metabolite of quinine, both decreased by 69%, and of free 3-hydroxyquinine decreased by 65% and 39%, respectively. The mechanism of interaction was attributed to ritonavir induction of UGT enzymes and of the P-gp transporter.(2) The effects of other ritonavir-boosted protease inhibitor regimens on quinine has not been studied. Nelfinavir and tipranavir are known to induce UGT while atazanavir and indinavir inhibit UGT. In another pharmacokinetic study of 19 healthy subjects, quinine Cmax and AUC decreased by 49% and 58%, respectively, when administered concurrently with lopinavir-ritonavir, compared to when administered alone. The Cmax and AUC of 3-hydroxyquinine decreased by 85% and 98%, respectively, when given with lopinavir-ritonavir. A significant increase (236%) in free quinine Cmax was observed. The clinical significance of these changes is unclear.(3) A physiologically based pharmacokinetic model predicted that lopinavir-ritonavir decreases the AUC of unbound quinine by about 70%, compared to quinine alone. The authors suggested increasing the dose of quinine from 600 mg three times daily to 1,800 mg three times daily.(7) |
QUALAQUIN, QUININE HCL, QUININE SULFATE |
| Ivacaftor/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of ivacaftor.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in elevated levels of and toxicity from ivacaftor.(1) PREDISPOSING FACTORS: This interaction may be more severe in patients with hepatic impairment.(1) PATIENT MANAGEMENT: In patients receiving concurrent strong CYP3A4 inhibitors such as boceprevir, ceritinib, clarithromycin, cobicistat, conivaptan, idelalisib, indinavir, itraconazole, ketoconazole, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, troleandomycin, tucatinib, or voriconazole, the dose of ivacaftor should be reduced to one 150 mg tablet or one packet (25 mg if body weight 5 kg to < 7 kg, 50 mg if body weight < 14 kg, 75 mg if weight equal or > 14 kg) two times a week.(1) In patients receiving concurrent moderate CYP3A4 inhibitors such as amprenavir, aprepitant, atazanavir, berotralstat, crizotinib, cyclosporine, darunavir/ritonavir, diltiazem, dronedarone, erythromycin, fluconazole, fosamprenavir, fosaprepitant, imatinib, isavuconazonium, ledipasvir, netupitant, schisandra or verapamil, the dose of ivacaftor should be reduced to one 150 mg tablet or one packet (25 mg if body weight 5 kg to < 7 kg, 50 mg if body weight < 14 kg, 75 mg if weight equal or > 14 kg) daily.(1) In patients who are less than 6 months of age, concurrent use of ivacaftor with strong or moderate CYP3A4 inhibitors is not recommended.(1) DISCUSSION: Concurrent administration with ketoconazole (a strong inhibitor of CYP3A4) increased ivacaftor area-under-curve (AUC) by 8.5-fold.(1) Concurrent administration with fluconazole (a moderate inhibitor of CYP3A4) increased ivacaftor area-under-curve (AUC) by 3-fold.(1) A study in 12 subjects compared ivacaftor alone (study A), ivacaftor with ritonavir (a strong inhibitor of CYP3A4) 50 mg daily on days 1-4 (study B), and ivacaftor with ritonavir 50 mg daily for two weeks prior and on days 1-4 of ivacaftor administration (study C). In study A, B, and C, ivacaftor AUC increased from 10.94 mcg/hr to 215.6 mcg/hr and 216 mcg/hr, respectively, with the addition of ritonavir. Ivacaftor concentration maximum (Cmax) was 0.9944 mcg, 1.812 mcg, and 2.267 mcg in study A, B, and C, respectively.(2) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, posaconazole, ribociclib, ritonavir, saquinavir, telaprevir, telithromycin, troleandomycin, tucatinib, and voriconazole.(3-5) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir/ritonavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, ledipasvir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(3-5) |
KALYDECO |
| Mifepristone/Strong CYP3A4 Inhibitors; Amprenavir;Atazanavir SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong inhibitors of CYP3A4 may inhibit the metabolism of mifepristone. CLINICAL EFFECTS: Concurrent use of mifepristone with a strong inhibitor of CYP3A4 may result in a 5-fold increase in area-under-curve (AUC) or 80 per cent decrease in mifepristone clearance, leading to toxicity such as adrenal insufficiency and hypokalemia. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of mifepristone for use in patients with endogenous Cushing's syndrome states the benefit of the CYP3A4 inhibitor must be carefully weighed against the potential risks and concurrent use should only occur when necessary.(1) If starting mifepristone in a patient already taking a strong CYP3A4 inhibitor, initiate mifepristone at 300 mg and titrate if clinically indicated to a maximum dose of 900 mg.(1) If a strong CYP3A4 inhibitor is started in a patient already taking mifepristone, the following dose adjustments are recommended: - If current mifepristone dose is 300 mg, no dose change warranted; - If current mifepristone dose is 600 mg, reduce dose to 300 mg and titrate if clinically indicated to a maximum dose of 600 mg; - If current mifepristone dose is 900 mg, reduce dose to 600 mg and titrate if clinically indicated to a maximum dose of 900 mg; and - If current mifepristone dose if 1200 mg, reduce dose to 900 mg.(1) DISCUSSION: A drug interaction study examined mifepristone 600 mg daily with concurrent ketoconazole 200 mg twice daily on days 13-17. Concurrent administration increased mifepristone area-under-curve (AUC) and maximum concentration (Cmax) by 1.38-fold and 1.28-fold, respectively.(1) A drug interaction study of 33 healthy subjects on itraconazole 200 mg daily coadministered with mifepristone 900 mg daily for 14 days found that itraconazole increased the Cmax and AUC of mifepristone by 1.1-fold and 1.2-fold, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, amprenavir, atazanavir, boceprevir, clarithromycin, cobicistat, fosamprenavir, indinavir, itraconazole, josamycin, ketoconazole, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(1,2) |
KORLYM, MIFEPRISTONE |
| Bosutinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that inhibit CYP3A4 may inhibit the metabolism of bosutinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase levels of and effects from bosutinib.(1) Elevated levels of bosutinib may result in QTc prolongation, which may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes (TdP). Other toxicities include nausea, vomiting, diarrhea, abdominal pain, myelosuppression, transaminitis, renal toxicity, and cardiac failure.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the use of moderate CYP3A4 inhibitors in patients undergoing therapy with bosutinib.(1) DISCUSSION: In a study in 24 healthy subjects, ketoconazole (400 mg daily for 5 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of bosutinib (100 mg) by 5.2-fold and 8.6-fold, respectively.(1) In a cross-over study in 18 healthy subjects, aprepitant (125 mg) increased the Cmax and AUC of bosutinib (single dose 500 mg) by 1.5-fold and 2.0-fold, respectively.(1) A study using PKPB modeling found concurrent use of bosutinib and schisandra would result in an increase in bosutinib exposure with an increased AUC by 3.0-fold.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, boceprevir, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(3-4) |
BOSULIF |
| Dolutegravir/Selected UGT1A & CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Dolutegravir is metabolized by UGT1A1 and to a smaller extent by CYP3A4. Inducers of UGT1A1 and CYP3A4 may induce the metabolism of dolutegravir.(1-6) CLINICAL EFFECTS: Concurrent use of UGT1A1 and CYP3A4 inducers may result in decreased levels of and clinical effectiveness of dolutegravir.(1-6) PREDISPOSING FACTORS: Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: When used with carbamazepine, fosamprenavir/ritonavir, rifampin, or tipranavir/ritonavir, the dosage of dolutegravir should be 50 mg twice daily. When using the combination abacavir-dolutegravir-lamivudine or dolutegravir-lamivudine product, an additional 50 mg dolutegravir table should be taken 12 hours apart from the combination product. In pediatric patients, increase the weight-based dose to twice daily. Refer to the current labeling for the specific dosing recommendation. Alternative combinations that do not induce metabolic inducers should be considered when possible for INSTI-experience patients with certain INSTI-associated resistance substitutions or clinically suspected INSTI resistance.(1,4-6) Recommendations for other UGT1A1 and CYP3A4 inducers differ by region. The US manufacturer of dolutegravir states that concurrent use should be avoided due to insufficient data to make dosing recommendations for concomitant use.(1,4) The Canadian and UK manufacturers of dolutegravir state that the dosage of dolutegravir should be 50 mg twice daily when used concurrently with other UGT1A1 and CYP3A4 inducers. When using the combination abacavir-dolutegravir-lamivudine product, an additional 50 mg dolutegravir table should be taken 12 hours apart from the combination product. In pediatric patients, increase the weight-based dose to twice daily. Refer to the current labeling for the specific dosing recommendation. Alternative combinations that do not induce metabolic inducers should be considered when possible for patients with certain INSTI-associated resistance substitutions or clinically suspected INSTI resistance.(5,6) DISCUSSION: In a study in 12 subjects, the administration of fosamprenavir/ritonavir (700/100 mg BID) with dolutegravir (50 mg daily) decreased the maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) of dolutegravir by 24%, 35%, and 49%, respectively.(1) In a study in 11 subjects, the administration of rifampin (600 mg daily) with dolutegravir (50 mg BID) decreased the Cmax, AUC, and Cmin of dolutegravir by 43%, 54%, and 32%, respectively, when compared to the administration of dolutegravir (50 mg BID) alone.(1) In a study in 11 subjects, the administration of rifampin (600 mg daily) with dolutegravir (50 mg BID) increased the Cmax, AUC, and Cmin of dolutegravir by 18%, 33%, and 22%, respectively, when compared to the administration of dolutegravir (50 mg daily) alone.(1) In a study in 14 subjects, the administration of tipranavir/ritonavir (500/200 mg BID) with dolutegravir (50 mg daily) decreased the Cmax, AUC, and Cmin of dolutegravir by 46%, 59%, and 76%, respectively.(1) In a study in 16 subjects, the administration of carbamazepine (300 mg twice daily) with dolutegravir (50 mg daily) decreased the Cmax, AUC, and Cmin of dolutegravir by 33%, 49%, and 73%, respectively. (1) UGT1A1 and CYP3A4 inducers linked to this monograph include: apalutamide, barbiturates, carbamazepine, encorafenib, enzalutamide, fosamprenavir/ritonavir, fosphenytoin, ivosidenib, lorlatinib, lumacaftor, mitotane, oxcarbazepine, phenobarbital, phenytoin, primidone, rifampin, rifapentine, and tipranavir/ritonavir.(1,7) |
DOVATO, JULUCA, TIVICAY, TIVICAY PD, TRIUMEQ, TRIUMEQ PD |
| Vorapaxar/Strong CYP3A4 Inhibitors; Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of vorapaxar.(1-3) CLINICAL EFFECTS: Concurrent use of an agent that is a strong inhibitor of CYP3A4 or a protease inhibitor may result in elevated levels of and clinical effects of vorapaxar,(1) including an increased risk of bleeding. PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients 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). PATIENT MANAGEMENT: The US manufacturer of vorapaxar states that concurrent use with strong inhibitors of CYP3A4 should be avoided.(1) The US Department of Health and Human Services HIV guidelines state that protease inhibitors should not be coadministered with vorapaxar.(4) The US manufacturer of itraconazole states that concurrent use with vorapaxar is not recommended during and two weeks after itraconazole treatment.(5) If concurrent therapy is warranted, monitor patients receiving concurrent therapy for signs of blood loss, including decreased hemoglobin, hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation 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 in 12 healthy subjects, ketoconazole (400 mg daily for 28 days) increased exposure to vorapaxar (20 mg on Day 7, 2.5 mg on Days 8-28) by 2-fold.(1,2) Strong inhibitors of CYP3A4 and protease inhibitor linked to this monograph include: adagrasib, atazanavir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, tucatinib, and voriconazole.(6) |
ZONTIVITY |
| Suvorexant (Greater Than 10 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate and strong inhibitors of CYP3A4 may inhibit the metabolism of suvorexant.(1) CLINICAL EFFECTS: Concurrent use of an agent that is a moderate or strong inhibitor of CYP3A4 may result in elevated levels of and clinical effects of suvorexant.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of suvorexant recommends a starting dose of 5 mg daily and a maximum dose of 10 mg daily in patients receiving concomitant therapy with a moderate inhibitor of CYP3A4.(1) Concurrent use with strong inhibitors of CYP3A4 is not recommended.(1) DISCUSSION: Diltiazem, a moderate inhibitor of CYP3A4, increased suvorexant AUC and Cmax by approximately 2-fold and 1.25-fold, respectively.(1) Ketoconazole, a strong inhibitor of CYP3A4, increased suvorexant area-under-curve (AUC) and maximum concentration (Cmax) by approximately 2.75-fold and 1.25-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(1-3) |
BELSOMRA |
| Eliglustat/Strong & Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong or moderate inhibitors of CYP3A4 may inhibit the metabolism of eliglustat. If the patient is also taking an inhibitor of CYP2D6, eliglustat metabolism can be further inhibited.(1) CLINICAL EFFECTS: Concurrent use of an agent that is a strong or moderate inhibitor of CYP3A4 may result in elevated levels of and clinical effects of eliglustat, including prolongation of the PR, QTc, and/or QRS intervals, which may result in life-threatening cardiac arrhythmias.(1) PREDISPOSING FACTORS: If the patient has liver disease, is also taking an inhibitor of CYP2D6 and/or is an intermediate or poor metabolizer of CYP2D6, eliglustat metabolism can be further inhibited.(1) The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The concurrent use of eliglustat with strong or moderate inhibitors of CYP3A4 concomitantly with strong or moderate inhibitors of CYP2D6 in both extensive and intermediate metabolizers of CYP2D6 is contraindicated.(1) The concurrent use of eliglustat with strong inhibitors of CYP3A4 in intermediate and poor metabolizers of CYP2D6 is contraindicated.(1) The concurrent use of eliglustat with moderate inhibitors of CYP3A4 in intermediate and poor metabolizers of CYP2D6 should be avoided.(1) The dosage of eliglustat with strong or moderate inhibitors of CYP3A4 in extensive metabolizers of CYP2D6 should be limited to 84 mg daily.(1) The concurrent use of eliglustat with strong inhibitors of CYP3A4 concomitantly with strong or moderate inhibitors of CYP2D6 is contraindicated.(1) The concurrent use of eliglustat with moderate inhibitors of CYP3A4 concomitantly with strong or moderate inhibitors of CYP2D6 in poor metabolizers of CYP2D6 should be avoided and is contraindicated in extensive and intermediate metabolizers of CYP2D6.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Ketoconazole (400 mg daily), a strong inhibitor of CYP3A4, increased eliglustat (84 mg BID) maximum concentration (Cmax) and area-under-curve (AUC) by 4-fold and 4.4-fold, respectively, in extensive metabolizers. Physiologically-based pharmacokinetic (PKPB) models suggested ketoconazole would increase eliglustat Cmax and AUC by 4.4-fold and 5.4-fold, respectively, in intermediate metabolizers. PKPB models suggested ketoconazole may increase the Cmax and AUC of eliglustat (84 mg daily) by 4.3-fold and 6.2-fold, respectively, in poor metabolizers.(1) PKPB models suggested fluconazole, a moderate inhibitor of CYP3A4, would increase eliglustat Cmax and AUC by 2.8-fold and 3.2-fold, respectively, in extensive metabolizers and by 2.5-fold and 2.9-fold, respectively in intermediate metabolizers. PKPB models suggest that concurrent eliglustat (84 mg BID), paroxetine (a strong inhibitor of CYP2D6), and ketoconazole would increase eliglustat Cmax and AUC by 16.7-fold and 24.2-fold, respectively, in extensive metabolizers. In intermediate metabolizers, eliglustat Cmax and AUC would be expected to increase 7.5-fold and 9.8-fold, respectively.(1) PKPB models suggest that concurrent eliglustat (84 mg BID), terbinafine (a moderate inhibitor of CYP2D6), and ketoconazole would increase eliglustat Cmax and AUC by 10.2-fold and 13.6-fold, respectively, in extensive metabolizers. In intermediate metabolizers, eliglustat Cmax and AUC would be expected to increase 4.2-fold and 5-fold, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tucatinib, and voriconazole.(1,3,4) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, casopitant, clofazimine, conivaptan, crizotinib, darunavir, duvelisib, erythromycin, fluconazole, fosamprenavir, fosnetupitant, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam and treosulfan.(1,3,4) |
CERDELGA |
| Naloxegol (Less Than or Equal To 12.5 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of naloxegol.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 without a dosage adjustment of naloxegol may result in increased levels of naloxegol, which may precipitate opioid withdrawal symptoms.(1) PREDISPOSING FACTORS: Patients taking methadone may be more likely to experience gastrointestinal side effects such as abdominal pain and diarrhea as a result of opioid withdrawal.(1) PATIENT MANAGEMENT: Avoid the use of moderate inhibitors of CYP3A4 in patients who require therapy with naloxegol. If concurrent use cannot be avoided, the daily dose of naloxegol should be limited to 12.5 mg daily in patients taking moderate inhibitors of CYP3A4.(1) Monitor patients for signs of opioid withdrawal such as sweating, chills, diarrhea, stomach pain, anxiety, irritability, yawning, restlessness, muscle/joint aches, increased lacrimation, running nose, and piloerection. Monitor patients taking methadone for abdominal pain and diarrhea as well.(1) DISCUSSION: Ketoconazole (400 mg daily for 5 days), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of naloxegol by 9.58-fold and 12.85-fold, respectively.(2) Diltiazem (240 mg XR daily), a moderate inhibitor of CYP3A4, increased the Cmax and AUC of a single dose of naloxegol by 2.85 and 3.41, respectively.(2) According to Physiologically-based-Pharmacokinetic (PBPK) models, erythromycin, a moderate inhibitor of CYP3A4, at a dose of 250 mg QID is expected to increase the Cmax and AUC of naloxegol by 2.77-fold and 3.47-fold, respectively.(2) According to PBPK models, erythromycin at a dose of 400 mg QID is expected to increase the Cmax and AUC of naloxegol by 3.42-fold and 4.63-fold, respectively.(2) According to PBPK models, fluconazole, a moderate inhibitor of CYP3A4, at a dose of 200 mg daily is expected to increase the Cmax and AUC of naloxegol by 2.4-fold and 2.81-fold, respectively.(2) According to PBPK models, verapamil moderate inhibitor of CYP3A4, at a dose of 120 mg daily is expected to increase the Cmax and AUC of naloxegol by 1.97-fold and 2.21-fold, respectively.(2) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(1,3,4) |
MOVANTIK |
| Venetoclax/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors inhibit the metabolism of venetoclax.(1) CLINICAL EFFECTS: Concurrent use of moderate inhibitors of CYP3A4 may result in elevated levels of venetoclax, increasing the risk for tumor lysis syndrome and other toxicities.(1) PREDISPOSING FACTORS: Risk factors for tumor lysis syndrome include (1): - the ramp-up phase of venetoclax therapy when tumor burden is highest - initial magnitude of tumor burden - renal impairment The risk of venetoclax toxicities may be increased in patients with severe hepatic impairment.(1) PATIENT MANAGEMENT: Avoid moderate CYP3A4 inhibitors and consider alternative treatments when possible. If a moderate CYP3A4 inhibitor must be used, reduce venetoclax dose by at least 50%. Monitor more closely for signs of toxicity such as tumor lysis syndrome, hematologic and non-hematologic toxicities.(1) Canadian labeling for atazanavir contraindicates concurrent use of atazanavir/ritonavir with venetoclax at venetoclax dose initiation and during the ramp-up phase.(2) If the moderate CYP3A4 inhibitor is discontinued, the manufacturer of venetoclax recommends resuming the prior (i.e. pre-inhibitor) dose of venetoclax 2 to 3 days after discontinuation of the moderate CYP3A4 inhibitor. DISCUSSION: In 11 previously treated NHL subjects, ketoconazole (a strong CYP3A4 inhibitor which also inhibits P-gp and BCRP) 400 mg daily for 7 days increased the maximum concentration (Cmax) and area-under-curve (AUC) of venetoclax 2.3-fold and 6.4-fold respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(3-4) |
VENCLEXTA, VENCLEXTA STARTING PACK |
| Deflazacort/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Deflazacort is a prodrug and is rapidly metabolized to the active metabolite, 21-desDFZ, by esterases. The metabolite 21-desDFZ is metabolized by CYP3A4 to inactive metabolites.(1) Inhibitors of CYP3A4 may inhibit the metabolism of the active metabolite of deflazacort metabolized by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of strong or moderate CYP3A4 inhibitors may result in increased systemic exposure to and effects from deflazacort.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer recommends decreasing the dose to one-third of the recommended dose of deflazacort when used concurrently with strong or moderate CYP3A4 inhibitors. For example, if the recommended dose of deflazacort is 36 mg per day, the reduced dose would be 12 mg per day when administered with strong or moderate CYP3A4 inhibitors.(1) DISCUSSION: Deflazacort is a prodrug and is rapidly metabolized to the active metabolite, 21-desDFZ. The metabolite 21-desDFZ is metabolized by CYP3A4.(1) Coadministration of deflazacort with clarithromycin, a strong CYP3A4 inhibitor, increased total geometric mean exposure (maximum concentration (Cmax) and area-under-curve (AUC)) to the active metabolite 21-desDFZ by 2.3- to 3.4-fold.(1) |
DEFLAZACORT, EMFLAZA |
| Disopyramide/Selected Strong CYP3A4 Inhibitors; Protease Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong CYP3A4 inhibitors and protease inhibitors may inhibit the metabolism of disopyramide by inhibition of CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors and protease inhibitors with disopyramide may result in elevated levels of disopyramide and serious and/or life-threatening effects, including QT prolongation.(1,2) PREDISPOSING FACTORS: Renal and hepatic impairment may increase risk for excessive QTc prolongation as disopyramide is eliminated renally and hepatically. To prevent increased serum levels and risk for ventricular arrhythmias, disopyramide must be dose adjusted in renal and hepatic insufficiency. The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: Coadministration of strong CYP3A4 inhibitors and protease inhibitors with disopyramide should be avoided. If use of the combination is warranted, clinical monitoring is recommended.(1,2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Strong CYP3A4 inhibitors and protease inhibitors may inhibit the metabolism and increase levels of disopyramide by inhibition of CYP3A4.(1,2) Selected CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, darunavir, fosamprenavir, idelalisib, indinavir, josamycin, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, telaprevir, tipranavir, and tucatinib.(4,5) |
DISOPYRAMIDE PHOSPHATE, NORPACE, NORPACE CR |
| Tezacaftor-Ivacaftor/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of tezacaftor-ivacaftor.(1,2) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in elevated levels of and toxicity from tezacaftor-ivacaftor.(1,2) PREDISPOSING FACTORS: This interaction may be more severe in patients with hepatic impairment.(1,2) PATIENT MANAGEMENT: Refer to current prescribing information for tezacaftor-ivacaftor for dose adjustment recommendations with strong and moderate CYP3A4 inhibitors.(2) Dose modifications for concurrent use of strong CYP3A4 inhibitors: - In adults, patients 12 years and older, and patients 6 to 12 years old weighing at least 30 kg who are receiving concurrent strong CYP3A4 inhibitors, the morning dose of tezacaftor 100 mg/ivacaftor 150 mg should be given twice a week, approximately 3 to 4 days apart. The evening dose of ivacaftor 150 mg should not be taken. - In patients 6 to 12 years old weighing less than 30 kg who are receiving concurrent strong CYP3A4 inhibitors, the morning dose of tezacaftor 50 mg/ivacaftor 75 mg should be given twice a week, approximately 3 to 4 days apart. The evening dose of ivacaftor 75 mg should not be taken.(2) Dose modifications for concurrent use of moderate CYP3A4 inhibitors: - In adults, patients 12 years and older, and patients 6 to 12 years old weighing at least 30 kg who are receiving concurrent moderate CYP3A4 inhibitors, the morning dose of tezacaftor 100 mg/ivacaftor 150 mg should be given every other day alternating with ivacaftor 150 mg. The evening dose of ivacaftor 150 mg should not be taken. - In patients 6 to 12 years old weighing less than 30 kg who are receiving concurrent moderate CYP3A4 inhibitors, the morning dose of tezacaftor 50 mg/ivacaftor 75 mg should be given every other day alternating with ivacaftor 75 mg. The evening dose of ivacaftor 75 mg should not be taken.(2) DISCUSSION: Concurrent administration with ketoconazole (a strong inhibitor of CYP3A4) increased ivacaftor area-under-curve (AUC) by 8.5-fold.(1) Concurrent administration with fluconazole (a moderate inhibitor of CYP3A4) increased ivacaftor AUC by 3-fold.(1) Concurrent administration with itraconazole (a strong inhibitor of CYP3A4) increased tezacaftor AUC by 4-fold and ivacaftor by 15.6-fold.(2) Concurrent administration with fluconazole (a moderate inhibitor of CYP3A4) increased tezacaftor AUC by 2-fold.(2) A study in 12 subjects compared ivacaftor alone (study A), ivacaftor with ritonavir (a strong inhibitor of CYP3A4) 50 mg daily on days 1-4 (study B), and ivacaftor with ritonavir 50 mg daily for two weeks prior and on days 1-4 of ivacaftor administration (study C). In study A, B, and C, ivacaftor AUC increased from 10.94 mcg/hr to 215.6 mcg/hr and 216 mcg/hr, respectively, with the addition of ritonavir. Ivacaftor concentration maximum (Cmax) was 0.9944 mcg, 1.812 mcg, and 2.267 mcg in study A, B, and C, respectively.(3) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, posaconazole, ribociclib, ritonavir, saquinavir, telaprevir, telithromycin, troleandomycin, tucatinib, and voriconazole.(4-6) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir/ritonavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(4-6) |
SYMDEKO |
| Encorafenib/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of encorafenib.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in elevated levels of and toxicity from encorafenib, including QT prolongation.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: Concurrent use of strong or moderate CYP3A4 inhibitors with encorafenib should be avoided. If concurrent use of strong or moderate CYP3A4 inhibitors with encorafenib is unavoidable, reduce the encorafenib dose as follows: - If the current daily dose of encorafenib is 450 mg, reduce encorafenib to 150 mg with strong CYP3A4 inhibitors, and 225 mg with moderate CYP3A4 inhibitors. - If the current daily dose of encorafenib is 300 mg, reduce encorafenib to 75 mg with strong CYP3A4 inhibitors, and 150 mg with moderate CYP3A4 inhibitors. - If the current daily dose of encorafenib is 225 mg or 150 mg, reduce encorafenib to 75 mg with both strong and moderate CYP3A4 inhibitors. - After the inhibitor has been discontinued for 3 to 5 half-lives, resume encorafenib dose that was taken prior to initiating the CYP3A4 inhibitor.(1) When concurrent therapy cannot be avoided, monitor patients closely for prolongation of the QT interval. Obtain ECGs and electrolyte values (serum calcium, magnesium, and potassium) at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. Recommended dosage modifications for encorafenib and QTc prolongation adverse reactions include: - QTcF greater than 500 ms and less than or equal to 60 ms increase from baseline: Withhold encorafenib until QTcF less than or equal to 500 ms. Resume at reduced dose. If more than one recurrence, permanently discontinue encorafenib. - QTcF greater than 500 ms and greater than 60 ms increase from baseline: Permanently discontinue encorafenib.(1) See prescribing information for additional information regarding dose reductions.(1) DISCUSSION: Coadministration of posaconazole (strong CYP3A4 inhibitor) or diltiazem (moderate CYP3A4 inhibitor) increased the area-under-curve (AUC) of encorafenib by 3-fold and 2-fold, respectively, and increased the maximum concentration (Cmax) by 68% and 45%, respectively, after a single dose of encorafenib 50 mg (0.1 times the recommended dose).(1) Encorafenib has been associated with a dose-dependent QTc interval prolongation. Following administration of encorafenib in combination with binimetinib, the largest mean (90% CI) QTcF change from baseline was 18 ms (14-22 ms), based on central tendency analysis.(1) Strong inhibitors of CYP3A4 include: indinavir, josamycin, ketoconazole, mibefradil, nefazodone, nelfinavir, tipranavir, and troleandomycin.(4-6) Moderate inhibitors of CYP3A4 include: amprenavir, berotralstat, clofazimine, conivaptan, fluvoxamine, fosamprenavir, letermovir, schisandra, and treosulfan.(4-6) |
BRAFTOVI |
| Brigatinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Brigatinib is a substrate of CYP3A4. Moderate inhibitors of CYP3A4 may inhibit the metabolism of brigatinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels and toxicity from brigatinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of brigatinib states to avoid concurrent administration with moderate CYP3A4 inhibitors. If concurrent therapy cannot be avoided, reduce the once daily dose of brigatinib by approximately 40% (i.e. from 180 mg to 120 mg, 120 mg to 90 mg). Upon discontinuation of a moderate CYP3A4 inhibitor, resume the brigatinib dose that was tolerated prior to initiating the moderate CYP3A4 inhibitor.(1) Monitor patient for signs of brigatinib toxicity with concurrent use. DISCUSSION: Brigatinib is a substrate of CYP3A4.(1) Concurrent administration of itraconazole (200 mg twice daily, a strong CYP3A4 inhibitor) with a single 90 mg dose of brigatinib increased the brigatinib maximum concentration (Cmax) by 21% and area-under-curve (AUC) by 101% compared to brigatinib alone. Moderate CYP3A4 inhibitors are expected to increase the AUC of brigatinib by approximately 40%.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(2,3) |
ALUNBRIG |
| Quetiapine/Protease Inhibitors 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 quetiapine. Quetiapine is a sensitive substrate for CYP3A4 and so an approximately 5-fold or higher increase in exposure (AUC, area-under-curve) can be anticipated when it is given with a protease inhibitor.(1) CLINICAL EFFECTS: Concurrent use of a protease inhibitor may result in elevated levels of and toxicity from quetiapine, including life-threatening arrhythmias such as torsades de pointes.(2-4) 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.(5) 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).(5) PATIENT MANAGEMENT: If possible, avoid the use of protease inhibitors with quetiapine. If addition of concomitant therapy with a protease inhibitor is required, US manufacturers state the quetiapine dose should be reduced to 1/6th of the original dose.(2,3) The UK manufacturer states the concurrent use of quetiapine with strong CYP3A4 inhibitors is contraindicated.(4) When the inhibitor is discontinued, return to the original quetiapine dose.(2) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, fainting, excessive drowsiness, rapid pulse/hypotension, weakness, fatigue, dizziness, or muscle stiffness/tremors (EPS). DISCUSSION: In a study, concurrent use of ketoconazole (200 mg daily for 4 days, a strong inhibitor of CYP3A4) and quetiapine resulted in an increase in quetiapine Cmax and AUC by 3.35-fold and 6.2-fold, respectively. Ketoconazole also decreased the mean apparent oral clearance of quetiapine by 84%, and increased quetiapine mean elimination half-life by 2.6-fold.(2,6) Protease inhibitors would be expected to cause similar changes to quetiapine levels and elimination. |
QUETIAPINE FUMARATE, QUETIAPINE FUMARATE ER, SEROQUEL, SEROQUEL XR |
| Protease Inhibitors/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 are expected to increase the metabolism of protease inhibitors.(1-2) CLINICAL EFFECTS: Concurrent or recent use of strong CYP3A4 inducers may result in decreased levels and effectiveness of protease inhibitors.(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 manufacturers of darunavir and lopinavir/ritonavir advise caution with concurrent use of drugs that induce CYP3A4 as they would be expected to decrease the plasma concentrations of the protease inhibitor.(1,2) The manufacturers of enzalutamide and mitotane (strong CYP3A4 inducers) advise avoiding concomitant use with narrow therapeutic drugs that are metabolized by CYP3A4.(3-5) If enzalutamide is discontinued, the effects of enzyme induction may persist for one month or longer.(4) DISCUSSION: In a study using rifampin 600 mg once daily with lopinavir/ritonavir 400 mg/100 mg twice daily, lopinavir area-under-curve (AUC) and maximum concentration (Cmax) were decreased by 75% and 55%, respectively, compared to lopinavir/ritonavir given alone.(2) Protease inhibitors linked to this monograph include: amprenavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir.(3,4) Strong CYP3A4 inducers linked to this monograph include: enzalutamide and mitotane.(6,7) |
LYSODREN, MITOTANE, XTANDI |
| Clopidogrel/Selected Protease Inhibitors; Cobicistat SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Clopidogrel is a prodrug and is converted to its active metabolite via a 2 step process. The first conversion step is mediated by CYP2C19, CYP1A2 and CYP2B6, while the second step is mediated by CYP3A4, CYP2B6 and CYP2C19.(1,2) CYP2C19 contributes to both steps and is thought to be the more important enzyme involved in formation of the pharmacologically active metabolite.(1) CYP3A4 is responsible for 39.8% of the second step of metabolism. Protease inhibitors that are strong CYP3A4 inhibitors may inhibit the metabolism of clopidogrel to its active form by CYP3A4.(1,3) CLINICAL EFFECTS: Concurrent use of protease inhibitors that are strong CYP3A4 inhibitors may result in decreased clopidogrel effectiveness, resulting in increased risk of adverse cardiac events.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of clopidogrel does not make specific recommendations for concurrent use with strong CYP3A4 inhibitors. Patient monitoring for adequate inhibition of platelet reactivity with clopidogrel is warranted. HIV treatment guidelines from the US Department of Health and Human Services and the European AIDS Clinical Society, and the University of Liverpool HIV Drug Interactions database all recommend not to coadminister clopidogrel with any protease inhibitor or cobicistat.(4-6) Consider alternatives to protease inhibitors that are strong CYP3A4 inhibitors in patients stabilized on clopidogrel and alternatives to clopidogrel in patients stabilized on protease inhibitors that are strong CYP3A4 inhibitors. If concurrent therapy is warranted, consider appropriate testing to assure adequate inhibition of platelet reactivity. DISCUSSION: In a randomized, cross-over study in healthy subjects, ketoconazole (400 mg daily) decreased the maximum concentration (Cmax) of the active metabolite of clopidogrel (300 mg loading dose, followed by 75 mg daily) by 61%. The area-under-curve (AUC) of the active metabolite of clopidogrel was decreased by 22% following the loading dose and by 29% during maintenance dosing. Clopidogrel-induced inhibition of platelet aggregation was decreased by 28% following the loading dose and by 33% during the maintenance dose.(7) A randomized cross over study in 12 healthy volunteers and 9 HIV-infected patients evaluated the impact of boosted antiretroviral therapy (ARV) on the pharmacokinetics and efficacy of clopidogrel. Healthy patients had 3.2-fold lower AUC (p=0.02) and Cmax of clopidogrel active metabolite (p=0.03) than HIV patients. Platelet reactivity was also 35% lower in health patients compared to HIV patients (p=0.04). All healthy patients had a platelet reactivity below the cut-off value at 4 hours after clopidogrel dose, while 44% of HIV patients were above the cut-off value of 206.(8) A cross-sectional study in 240 post acute coronary syndrome (ACS) patients compared platelet reactivity under aspirin and P2Y12 inhibitor therapy between HIV and non-HIV patients with first episode ACS on dual antiplatelet therapy. Study evaluated residual platelet aggregation (RPA), P2Y12 assay (PRU), and VASP platelet reactivity index (VASP-PRI). HIV patients were all on ARV therapy, most commonly with protease inhibitors (darunavir, lopinavir, atazanavir, and indinavir in combination with ritonavir in all but two patients). Patients on ARV containing protease inhibitors compared to other combinations had increased platelet reactivity to P2Y12 inhibitors and higher prevalence of high residual platelet reactivity (HPR) (OR 4.4 (95%CI 1.1-18.1) with RPA, P = 0.04; OR 3.1 (95%CI = 0.84-11.5) with VASP-PRI; P = 0.09, and OR 4.3 (95%CI 1.02-18.1) with PRU, P = 0.047). Patients with CD4 T cell count lower than 350/mm3 also had consistently increased platelet reactivity to P2Y12 inhibitors and higher prevalence of HPR (OR 3.41 (95%CI 0.60-19.4) with RPA, P = 0.17; OR 7.1 (95%CI 0.94-54.2) with VASP-PRI, P = 0.06; and OR 7.9 (95%CI 1.42-44.8) with PRU, P = 0.002), although this association was not significant for all three tests.(9) Selected protease inhibitors that are strong CYP3A4 inhibitors linked to this monograph include: atazanavir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, paritaprevir, saquinavir, and tipranavir.(10) |
CLOPIDOGREL, CLOPIDOGREL BISULFATE, PLAVIX |
| Entrectinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of entrectinib.(1,2) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in elevated levels and increased effects of entrectinib, such as QT prolongation, hepatotoxicity, CNS effects, hyperuricemia, anemia, or neutropenia.(1,2) Symptoms of hepatotoxicity can include nausea, vomiting, jaundice, dark urine, abdominal pain, and unexplained fatigue. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of entrectinib states that entrectinib coadministration with moderate inhibitors of CYP3A4 should be avoided.(1) If concurrent therapy cannot be avoided, reduce the entrectinib dose as follows for adult and pediatric patients 2 years and older: -If the starting dose is 600 mg, reduce the entrectinib dose to 200 mg daily. -If the starting dose is 400 mg, reduce the entrectinib dose to 200 mg daily. -If the starting dose is 300 mg, reduce the entrectinib dose to 100 mg daily. -If the starting dose is 200 mg, reduce the entrectinib dose to 50 mg daily.(1) For pediatric patients less than 2 years old, avoid coadministration with moderate CYP3A4 inhibitors.(1) If concomitant use of a moderate CYP3A4 inhibitor is discontinued, increase the entrectinib dose to the dose that was used before starting the inhibitor after three to five plasma half-lives of the moderate CYP3A4 inhibitor. Monitor liver tests, including AST and ALT. Advise patients to immediately report any symptoms of hepatotoxicity. During concomitant therapy with a moderate CYP3A4 inhibitor, monitor patients closely for prolongation of the QT interval. Obtain serum calcium, magnesium, and potassium levels and monitor ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Coadministration of itraconazole (strong CYP3A4 inhibitor) with a single 100 mg entrectinib dose increased entrectinib maximum concentration (Cmax) and area-under-the-curve (AUC) by 1.7-fold and 6-fold.(1) Coadministration of a moderate CYP3A4 inhibitor with entrectinib is predicted to increase entrectinib Cmax and AUC by 2.9-fold and 3-fold.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, ciprofloxacin, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(1,3) |
ROZLYTREK |
| Elexacaftor-Tezacaftor-Ivacaftor/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the CYP3A4-mediated metabolism of elexacaftor, tezacaftor, and ivacaftor.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in elevated levels of and toxicity from elexacaftor, tezacaftor, and ivacaftor.(1) PREDISPOSING FACTORS: This interaction may be more severe in patients with hepatic impairment.(1) PATIENT MANAGEMENT: The dosage of elexacaftor-tezacaftor-ivacaftor should be reduced when co-administered with moderate CYP3A4 inhibitors as follows: - In patients 12 years and older and patients 6 to 12 years old weighing at least 30 kg who are receiving concurrent moderate CYP3A4 inhibitors, the evening dose of ivacaftor should not be taken. The morning dose of therapy should be modified to the following alternate daily dosing schedule: Day 1 - two tablets of elexacaftor 100 mg-tezacaftor 50 mg-ivacaftor 75 mg (total dose of elexacaftor 200 mg-tezacaftor 100 mg-ivacaftor 150 mg); Day 2 - one tablet of ivacaftor 150 mg. - In patients 6 to 12 years old weighing less than 30 kg who are receiving concurrent moderate CYP3A4 inhibitors, the evening dose of ivacaftor should not be taken. The morning dose of therapy should be modified to the following alternate daily dosing schedule: Day 1 - two tablets of elexacaftor 50 mg-tezacaftor 25 mg-ivacaftor 37.5 mg (total daily dose of elexacaftor 100 mg-tezacaftor 50 mg-ivacaftor 75 mg); Day 2 - one tablet of ivacaftor 75 mg. - In patients 2 to less than 6 years old weighing at least 14 kg who are receiving concurrent moderate CYP3A4 inhibitors, the evening dose of ivacaftor should not be taken. The morning dose of therapy should be modified to the following alternate daily dosing schedule: Day 1 - one packet of oral granules containing elexacaftor 100 mg-tezacaftor 50 mg-ivacaftor 75 mg; Day 2 - one packet of oral granules containing ivacaftor 75 mg.(1) - In patients 2 to less than 6 years old weighing less than 14 kg who are receiving concurrent moderate CYP3A4 inhibitors, the evening dose of ivacaftor should not be taken. The morning dose of therapy should be modified to the following alternate daily dosing schedule: Day 1 - one packet of oral granules containing elexacaftor 80 mg-tezacaftor 40 mg-ivacaftor 60 mg; Day 2 - one packet of oral granules containing ivacaftor 59.5 mg.(1) DISCUSSION: In a study, fluconazole (400 mg on day 1 then 200 mg daily) increased the area-under-curve (AUC) and maximum concentration (Cmax) of ivacaftor (150 mg every 12 hours) by 2.95-fold and 2.45-fold, respectively.(1) Simulations suggest that moderate CYP3A inhibitors may increase the AUC of elexacaftor and tezacaftor by approximately 1.9 to 2.3-fold and 2.1-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(2-4) |
TRIKAFTA |
| Lemborexant/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of lemborexant.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in increased levels of and effects from lemborexant, including somnolence, fatigue, CNS depressant effects, daytime impairment, headache, and nightmare or abnormal dreams.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of strong or moderate CYP3A4 inhibitors with lemborexant should be avoided.(1) DISCUSSION: Lemborexant is a CYP3A4 substrate. In a PKPB model, concurrent use of lemborexant with itraconazole increased area-under-curve (AUC) and concentration maximum (Cmax) by 3.75-fold and 1.5-fold, respectively. Concurrent use of lemborexant with fluconazole increased AUC and Cmax by 4.25-fold and 1.75-fold, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, troleandomycin, tucatinib, and voriconazole.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(2) |
DAYVIGO |
| Tazemetostat/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of tazemetostat.(1) CLINICAL EFFECTS: Coadministration of tazemetostat with a moderate CYP3A4 inhibitor may increase tazemetostat plasma concentrations and increase the frequency or severity of adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of tazemetostat states to avoid coadministration of moderate CYP3A4 inhibitors with tazemetostat.(1) If coadministration of moderate CYP3A4 inhibitors cannot be avoided, reduce the tazemetostat dose as follows: If the current tazemetostat dose is 800 mg twice daily, reduce the dose to 400 mg twice daily. If the current tazemetostat dose is 600 mg twice daily, reduce the dose to 400 mg for the first dose and 200 mg for the second dose. If the current tazemetostat dose is 400 mg twice daily, reduce the dose to 200 mg twice daily.(1) After discontinuation of the moderate CYP3A4 inhibitor for 3 elimination half-lives, resume the prior tazemetostat dose.(1) DISCUSSION: Coadministration of fluconazole, a moderate CYP3A4 inhibitor, with tazemetostat 400 mg twice daily in patients increased tazemetostat area-under-curve (AUC) by 3.1-fold and maximum concentration (Cmax) by 2.3-fold.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(2-4) |
TAZVERIK |
| Selumetinib/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of selumetinib.(1) CLINICAL EFFECTS: Concurrent use of a strong or moderate inhibitor of CYP3A4 may result in increased levels of and effects from selumetinib, including vomiting, diarrhea, skin rashes, ocular toxicity (e.g., blurred vision, visual loss), cardiomyopathy, and rhabdomyolysis.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of selumetinib states that the coadministration of selumetinib with strong or moderate CYP3A4 inhibitors should be avoided. If coadministration cannot be avoided, the dosage of selumetinib should be reduced as follows: -If the current dose is 25 mg/m2 twice daily, reduce to 20 mg/m2 twice daily. -If the current dosage is 20 mg/m2 twice daily, reduce to 15 mg/m2 twice daily. If the strong or moderate CYP3A4 inhibitor is discontinued, resume the selumetinib dose that was taken prior to the initiation of the inhibitor after 3 half-lives of the CYP3A4 inhibitor have elapsed.(1) DISCUSSION: In a study of 26 healthy subjects, itraconazole 200 mg twice daily (a strong CYP3A4 inhibitor) increased the area-under-curve (AUC) and maximum concentration (Cmax) of selumetinib 25 mg by 49% and 19%, respectively. Fluconazole 400 mg loading dose then 200 mg daily (a moderate CYP3A4 inhibitor and strong CYP2C19 inhibitor) increased AUC and Cmax of selumetinib (25 mg) by 53% and 26%.(1,2) In a pharmacokinetic model, erythromycin (a moderate CYP3A4 inhibitor) was predicted to increase selumetinib AUC and Cmax by 41% and 23%, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib and voriconazole.(3) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(3) |
KOSELUGO |
| Pemigatinib/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of pemigatinib.(1) CLINICAL EFFECTS: Concomitant use of a strong or moderate CYP3A4 inhibitor increases pemigatinib plasma concentrations, which may increase the incidence and severity of adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of pemigatinib states that coadministration with strong or moderate CYP3A4 inhibitors should be avoided. If coadministration cannot be avoided, the dosage of pemigatinib should be reduced as follows: -Reduce dose from 13.5 mg to 9 mg. -Reduce dose from 9 mg to 4.5 mg. If the strong or moderate CYP3A4 inhibitor is discontinued, resume the pemigatinib dose that was taken prior to the initiation of the inhibitor after 3 half-lives of the CYP3A4 inhibitor have elapsed.(1) DISCUSSION: Itraconazole, a strong CYP3A4 inhibitor, increased the maximum concentration (Cmax) by 17% and area-under-curve (AUC) by 88% following a single oral pemigatinib dose of 4.5 mg. Concomitant use of moderate CYP3A4 inhibitors is predicted to increase pemigatinib exposure by approximately 50-80%.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, grapefruit, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(2) |
PEMAZYRE |
| Selpercatinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of selpercatinib.(1) Cimetidine increases gastric pH and may decrease pH-dependent solubility and absorption of selpercatinib.(1) CLINICAL EFFECTS: Concurrent administration of a moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from selpercatinib.(1) Elevated levels of selpercatinib may increase the risk of QTc prolongation and potentially life-threatening arrhythmias, including torsades de pointes, hepatotoxicity, hypertension, and severe or life-threatening hemorrhagic events.(1) Conversely, concurrent use of cimetidine may result in decreased levels and effectiveness of selpercatinib. The overall effect of cimetidine on selpercatinib pharmacokinetics is unknown.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of selpercatinib recommends avoiding concomitant use of moderate CYP3A4 inhibitors with selpercatinib. If concomitant use cannot be avoided, reduce the dose of selpercatinib as follows: - If the current dose of selpercatinib is 160 mg twice daily, decrease the dose to 120 mg twice daily. - If the current dose of selpercatinib is 120 mg twice daily, decrease the dose to 80 mg twice daily. - If the current dose of selpercatinib is 80 mg twice daily, decrease the dose to 40 mg twice daily. - If the current dose of selpercatinib is 40 mg three times daily, decrease the dose to 40 mg once daily. If concomitant use of cimetidine is unavoidable, take selpercatinib at least 2 hours before or 10 hours after cimetidine. When concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If grade 3 QT interval prolongation occurs, withhold selpercatinib until recovery to baseline or Grades 0 or 1, then resume selpercatinib at a reduced dose. If grade 4 QT interval prolongation occurs, discontinue selpercatinib.(1) After the inhibitor has been discontinued for 3 to 5 elimination half-lives, resume selpercatinib at the dose taken prior to initiating the CYP3A inhibitor.(1) DISCUSSION: Coadministration of diltiazem, fluconazole, or verapamil (moderate CYP3A inhibitors) is predicted to increase the area-under-curve (AUC) and maximum concentration (Cmax) of selpercatinib by 60-99% and 46-76%, respectively.(1) In a thorough QT study, selpercatinib 160 mg twice daily increased QTc by a mean of 10.6 msec (upper 90% confidence interval: 12.1 msec). An increase in QTcF interval to greater than 500 msec was measured in 6% of patients and an increase in the QTcF interval of at least 60 msec over baseline was measured in 15% of patients.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, conivaptan, darunavir, diltiazem, fedratinib, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(3) |
RETEVMO |
| Pralsetinib/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong and moderate CYP3A4 inhibitors (including combined moderate CYP3A4 and P-glycoprotein (P-gp) inhibitors) may inhibit the metabolism of pralsetinib.(1) CLINICAL EFFECTS: Concurrent administration of a strong or moderate CYP3A4 inhibitor (including combined moderate CYP3A4 and P-gp inhibitors) may result in elevated levels of and toxicity from pralsetinib, including QTc prolongation which may lead to potentially life-threatening cardiac arrhythmias like torsades de pointes (TdP). Other toxicities include hemorrhagic events, pneumonitis, hepatotoxicity, and hypertension.(1-3) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(4) 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).(4) PATIENT MANAGEMENT: Coadministration of pralsetinib with strong or moderate CYP3A4 inhibitors (including combined moderate CYP3A4 and P-gp inhibitors) should be avoided.(1) If coadministration with a strong or moderate CYP3A4 inhibitor cannot be avoided, use with caution and reduce the dose of pralsetinib as follows: -If the current dose is 400 mg once daily, decrease the dose to 300 mg daily. -If the current dose is 300 mg once daily, decrease the dose to 200 mg daily. -If the current dose is 200 mg once daily, decrease the dose to 100 mg daily. After the inhibitor is discontinued for three to five half-lives, resume the dose of pralsetinib at the dose taken prior to initiation of the inhibitor.(1) When concurrent therapy is warranted: consider obtaining serum calcium, magnesium, and potassium levels and monitoring EKG at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If the QTc interval exceeds 500 ms, interrupt pralsetinib therapy until QTc is <470 ms. Resume pralsetinib at the same dose if risk factors that cause QT prolongation an are identified and corrected. If risk factors that cause QT prolongation are not identified, resume pralsetinib at a reduced dose. Permanently discontinue pralsetinib if the patient develops life-threatening arrhythmia.(3) DISCUSSION: Coadministration of voriconazole 400 mg twice daily for 1 day then 200 mg twice daily (a strong CYP3A inhibitor) resulted in 122% and 20% increase in pralsetinib area-under-curve (AUC) and maximum concentration (Cmax), respectively.(1) Fluconazole 400 mg daily (a moderate CYP3A4 inhibitor) increased pralsetinib AUC and Cmax by 71% and 15%, respectively.(1) Verapamil 80 mg three times daily (a moderate CYP3A4 and P-glycoprotein inhibitor) increased pralsetinib AUC and Cmax by 108% and 60%, respectively.(1) Strong CYP3A4 inhibitors linked to this monograph include: boceprevir, idelalisib, nelfinavir, and troleandomycin.(5,6) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, clofazimine, conivaptan, darunavir, duvelisib, fedratinib, fosamprenavir, fosnetupitant, imatinib, letermovir, netupitant, nilotinib, tofisopam, treosulfan, and voxelotor.(5,6) Dual moderate CYP3A4 and P-gp inhibitors include: berotralstat, diltiazem, fluvoxamine, isavuconazonium, lenacapavir, schisandra, and verapamil.(5,6) |
GAVRETO |
| Voclosporin/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that inhibit the CYP3A4 isoenzyme may inhibit the metabolism of voclosporin.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase levels of and effects from voclosporin, including infection, neurotoxicity, nephrotoxicity, hypertension, or hyperkalemia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The prescribing information for voclosporin states the use of moderate CYP3A4 inhibitors in patients undergoing therapy with voclosporin requires a dose adjustment. Voclosporin dose should be reduced to 15.8 mg in the morning and 7.9 mg in the evening.(1) Consider alternatives with no or minimal enzyme inhibition. DISCUSSION: Concurrent use of voclosporin and ketoconazole 400 mg daily (strong CYP3A4 inhibitor) for 9 days increased the concentration maximum (Cmax) and area-under-curve (AUC) by 6.45-fold and 18.55-fold, respectively.(1) Concurrent use of voclosporin and verapamil 80 mg three times a day for 10 days (moderate CYP3A4 inhibitor and P-gp inhibitor) increased Cmax and AUC by 2.08-fold and 2.71-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2,3) |
LUPKYNIS |
| Dronedarone/Atazanavir; Fosamprenavir SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Atazanavir and fosamprenavir, moderate inhibitors of CYP3A4, may decrease the metabolism of dronedarone.(1-4) CLINICAL EFFECTS: Concurrent use of atazanavir or fosamprenavir may result in prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes.(1-4) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(5) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, and/or renal/hepatic dysfunction).(5) PATIENT MANAGEMENT: The US manufacturer of dronedarone states that concurrent administration of strong CYP3A4 inhibitors is contraindicated. There are no recommendations for use of dronedarone with moderate CYP3A4 inhibitors.(1) The US Department of Health and Human Services guidelines for use of antiretroviral agents state that ritonavir-boosted atazanavir (a moderate CYP3A4 inhibitor) is contraindicated with dronedarone, and that unboosted atazanavir should not be coadministered. Since fosamprenavir is also a moderate CYP3A4 inhibitor, it may be prudent to apply the same guidance to ritonavir-boosted and unboosted fosamprenavir.(4) If alternatives are not available and concurrent therapy is deemed medically necessary, obtain serum calcium, magnesium, and potassium levels and monitor ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Concurrent use of ketoconazole (a strong CYP3A4 inhibitor) and dronedarone (dosages not stated) increased the area-under-curve (AUC) and maximum concentration (Cmax) of dronedarone by 17-fold and 9-fold, respectively.(1) |
MULTAQ |
| Mavacamten/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may decrease the metabolism of mavacamten.(1-3) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase the plasma levels and the incidence and severity of adverse reactions of mavacamten.(1-3) PREDISPOSING FACTORS: CYP2C19 poor metabolizers may experience an increased incidence or severity of adverse effects.(1-3) PATIENT MANAGEMENT: The US manufacturer of mavacamten recommend initiating mavacamten at the recommended starting dosage of 5 mg orally once daily in patients who are on stable therapy with a moderate CYP3A4 inhibitor. Reduce dose by one level (i.e., 15 to 10 mg, 10 to 5 mg, or 5 to 2.5 mg) in patients who are on mavacamten treatment and intend to initiate a moderate CYP3A4 inhibitor. Schedule clinical and echocardiographic assessment 4 weeks after inhibitor initiation, and do not up-titrate mavacamten until 12 weeks after inhibitor initiation.(1) Avoid initiation of concomitant moderate CYP3A4 inhibitors in patients who are on stable treatment with 2.5 mg of mavacamten because a lower dose is not available.(1) For short-term use (e.g. 1 week), interrupt mavacamten therapy for the duration of the strong CYP3A4 inhibitor. After therapy with the strong CYP3A4 inhibitor is discontinued, mavacamten may be reinitiated at the previous dose immediately upon discontinuation.(1) The Canadian manufacturer of mavacamten recommends additional monitoring when concurrent use of moderate CYP3A4 inhibitors is warranted. Adjust the dose of mavacamten based on clinical assessment.(2) The UK manufacturer of mavacamten states no dose adjustment is necessary when starting mavacamten in patients on moderate CYP3A4 inhibitors or in intermediate, normal, rapid, or ultra-rapid CYP2C19 metabolizers already on mavacamten and starting a moderate CYP3A4 inhibitor. If starting a moderate CYP3A4 inhibitor in a patient who is a poor CYP2C19 metabolizer, reduce mavacamten 5 mg to 2.5 mg or if on 2.5 mg pause treatment for 4 weeks. Monitor left ventricular ejection fraction (LVEF) in 4 weeks then resume usual monitoring schedule.(3) DISCUSSION: Concomitant use of mavacamten (25 mg) with verapamil sustained release (240 mg), a moderate CYP3A4 inhibitor, increased mavacamten area-under-curve (AUC) by 15% and maximum concentration (Cmax) by 52% in intermediate metabolizers and normal metabolizers of CYP2C19.(1) Concomitant use of mavacamten with diltiazem, a moderate CYP3A4 inhibitor, in CYP2C19 poor metabolizers is predicted to increase mavacamten AUC and Cmax up to 55% and 42%, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, clofazimine, conivaptan, darunavir, dronedarone, erythromycin, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, and treosulfan.(4,5) |
CAMZYOS |
| Tacrolimus/Protease Inhibitors; Cobicistat SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Strong CYP3A4 inhibitors may inhibit the metabolism of tacrolimus CYP3A4.(1,2) HIV and HCV protease inhibitors as well as cobicistat are CYP3A4 inhibitors.(1-17) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors may result in increased levels of tacrolimus, including QT prolongation, nephrotoxicity, neurotoxicity, cardiovascular toxicity, hypertension, anemia, and increased risk of serious infections.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of tacrolimus states that concurrent use with strong CYP3A4 inhibitors may result in a rapid and sharp rise in tacrolimus concentration despite immediate tacrolimus dose reduction. Frequent monitoring of tacrolimus levels should start within 1-3 days of initiation of concurrent therapy and continue as necessary.(2) For patients concurrently taking tacrolimus and either a HIV or HCV protease inhibitor or cobicistat, therapeutic concentration monitoring of the immunosuppressant is recommended. Depending upon the agents involved, dose decreases of the immunosuppressant agent may be required.(1-17) Guidelines from the American Society of Transplantation recommend avoiding the use of ritonavir- or cobicistat-based HIV or HCV antiviral regimens with tacrolimus due to an increased risk of graft loss and death, as well as the availability of HIV integrase inhibitors that avoid interactions with immunosuppressants. If the combination must be used, lower the dose of tacrolimus to 1 mg once or twice a week. Monitor drug concentrations closely.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. The protease inhibitors linked to this monograph include: amprenavir, atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, telaprevir, and tipranavir. DISCUSSION: A retrospective study of 42 HIV+ kidney transplant recipients examined rejection rates in patients on ritonavir-boosted protease inhibitor (PI) antiretroviral regimens compared to patients on other antiretroviral regimens. Immunosuppression therapy consisted of cyclosporine in 7 patients (17%) and tacrolimus in 32 patients (76%). The remaining 3 patients were transitioning between drugs. Over 3 years, 65% of patients on PI-based antiretroviral therapy experienced rejection, compared with 36% of patients on other antiretroviral therapies (p<0.001). There was no difference in patient or graft survival at 3 years.(18) Boceprevir (800 mg TID for 11 days) increased the Cmax and AUC of tacrolimus (0.5 mg single dose) by 9.90-fold and 17.1-fold, respectively. There were no significant effects on boceprevir pharmacokinetics.(4) In a case report, tacrolimus levels in a 50 year-old male kidney transplant recipient increased from 7.5 ng/ml to 111.2 ng/ml one week after initiation of an HIV regimen including elvitegravir 150 mg, cobicistat 150 mg, emtricitabine 200 mg, and tenofovir disoproxil fumarate 300 mg once daily. The patient experienced headache, insomnia, stomachache, hyperkalemia, and increased SCr at which time the HIV regimen was stopped. On day 15 the patient's tacrolimus level returned to 4.0 ng/ml at which time the patient resumed tacrolimus at previous stable dose and the HIV regimen was changed to abacavir 600 mg, dolutegravir 50 mg, and lamivudine 300 mg daily without any further increase in tacrolimus levels.(19) In a case report, tacrolimus levels in a 41 year-old male kidney transplant recipient increased from 8.7 ng/ml to 106 ng/ml within 3 days of the addition of tenofovir and darunavir/ritonavir therapy, despite the patient's tacrolimus dosage being decreased 12%. Concurrent therapy was eventually titrated to 0.5 mg of tacrolimus given once weekly.(20) There are several case reports of decreased tacrolimus requirements and/or toxicity during concurrent indinavir,(21) lopinavir/ritonavir,(22-24) and nelfinavir.(25) In a study in 5 HIV+ liver transplant patients, tacrolimus needs were 38 times lower with concurrent nelfinavir.(23) A case report describes a 52 year-old male with HIV and hepatitis C who experienced severe tacrolimus toxicity after the addition of an HIV regimen including nelfinavir (750 mg three times daily) following his liver transplantation. The HIV regimen was temporarily stopped until the tacrolimus levels normalized at which time the medications were restarted having replaced nelfinavir with saquinavir (400 mg twice/day) and ritonavir (400 mg twice/day). The patient again experienced neurological symptoms associated with tacrolimus toxicity and was found to have a tacrolimus level over 120 ng/ml. The medications were held allowing for a long recovery. The HIV regimen was rechallenged a third time using the original combination which included nelfinavir. The dose of tacrolimus was dramatically decreased and the schedule changed until the tacrolimus levels finally stabilized.(26) In a study in 9 subjects, the concurrent administration of telaprevir (750 mg TID) decreased the Cmax and AUC of a single dose of tacrolimus (0.5 mg) by 2.34-fold and 17.6-fold, respectively, when compared to levels achieved with a single 2 mg dose of tacrolimus. Extrapolated to level expected with the 2 mg dose, tacrolimus Cmax and AUC would have increased by 9.35-fold% and 70.3-fold, respectively.(5) The protease inhibitors linked to this monograph include: amprenavir, atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, telaprevir, and tipranavir. |
ASTAGRAF XL, ENVARSUS XR, PROGRAF, TACROLIMUS, TACROLIMUS XL |
| Betibeglogene Autotemcel/Anti-Retrovirals; Hydroxyurea SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Betibeglogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. Hydroxyurea may interfere with hematopoietic stem cell (HSC) mobilization of CD34+ cells.(1) CLINICAL EFFECTS: Use of hydroxyurea before mobilization may result in unsuccessful stem cell mobilization. Use of antiretrovirals before mobilization and apheresis may interfere with the production of betibeglogene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals and hydroxyurea for at least one month prior to mobilization and until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications and hydroxyurea may interfere with the manufacturing of betibeglogene autotemcel therapy.(1) |
ZYNTEGLO |
| Elivaldogene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Elivaldogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of elivaldogene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization and until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications may interfere with the manufacturing of elivaldogene autotemcel therapy.(1) |
SKYSONA |
| Pexidartinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of pexidartinib.(1,2) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in elevated levels and increased effects of pexidartinib, such as hepatotoxicity.(1,2) Symptoms can include nausea, vomiting, jaundice, dark urine, abdominal pain, and unexplained fatigue. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of pexidartinib states that pexidartinib coadministration with moderate inhibitors of CYP3A4 should be avoided.(1) If coadministration with a moderate CYP3A4 inhibitor cannot be avoided, reduce the pexidartinib dose according to the following recommendations. If the planned total daily dose is currently 500 mg, modify the total daily dose to 250 mg by administering 125 mg twice daily. If the planned total daily dose is currently 375 mg, modify the total daily dose to 250 mg by administering 125 mg twice daily. If the planned total daily dose is currently 250 mg, modify the total daily dose to 125 mg by administering 125 mg once daily. If concomitant use of a moderate CYP3A4 inhibitor is discontinued, increase the pexidartinib dose to the dose that was used before starting the inhibitor after three plasma half-lives of the moderate CYP3A4 inhibitor. Monitor liver tests, including AST, ALT, total bilirubin, direct bilirubin, ALP and gamma-glutamyltransferase (GGT) according to the recommendations in the Turalio package insert. Advise patients to immediately report any symptoms of hepatotoxicity. DISCUSSION: Coadministration of fluconazole (a moderate CYP3A4 inhibitor) increased pexidartinib maximum concentration (Cmax) and area-under-the-curve (AUC) by 41% and 67%.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, erythromycin, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, and verapamil.(1,3) |
TURALIO |
| Tadalafil (BPH)/Select Protease Inhibitors; Cobicistat SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The protease inhibitors may inhibit the metabolism of tadalafil.(1-11) CLINICAL EFFECTS: The concurrent administration of a protease inhibitor may result in elevated levels of tadalafil, which may result in increased adverse effects such as hypotension, visual changes, and priapism.(1-11) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of tadalafil states that tadalafil for benign prostatic hyperplasia (BPH) is not recommended with strong CYP3A4 inhibitors.(1) The HIV guidelines state that the recommended daily dose of tadalafil for BPH should be 2.5 mg daily in patients receiving concurrent therapy.(12) The US manufacturers of tadalafil(2) and the protease inhibitors(3-11) state that the recommended dose of as needed tadalafil for the treatment of erectile dysfunction is 10 mg of tadalafil every 72 hours in patients receiving concurrent therapy. The US manufacturer of tadalafil states that the recommended dose of daily tadalafil for the treatment of erectile dysfunction in patients taking potent inhibitors of CYP3A4 is 2.5 mg.(2) The US manufacturers of the protease inhibitors state that in patients who have received a protease inhibitor for at least one week, the initial dosage of tadalafil for the treatment of primary pulmonary hypertension should be 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(3-11) The US manufacturers of the protease inhibitors state that in patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be discontinued for 24 hours before beginning protease inhibitor therapy other than nelfinavir without concurrent ritonavir. After one week, tadalafil may be resumed at a dosage of 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(3-11) In patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be adjusted to 20 mg daily prior to beginning therapy with nelfinavir without concurrent ritonavir. The dosage may be increased to 40 mg daily based upon tolerability.(8) Patients should be counseled that they are at an increased risk of tadalafil adverse effects, including hypotension, syncope, visual changes, and priapism. Patients experiencing these effects should report them promptly to their physician. DISCUSSION: Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (500 mg or 600 mg twice daily) increased tadalafil area-under-curve (AUC) by 32% and decreased tadalafil concentration maximum (Cmax) by 30%. Concurrent administration of tipranavir/ritonavir (500/200 mg twice daily for 17 doses) had no significant effects on the AUC of a single dose of tadalafil (10 mg). Tadalafil Cmax decreased 30%. Tipranavir Cmax, AUC, and concentration minimum (Cmin) decreased by 10%, 15%, and 19%, respectively. Administration of a single dose of tipranavir/ritonavir (500/200 mg) increased the AUC of a single dose of tadalafil (10 mg) by 2.33-fold. Tadalafil Cmax decreased 22%. Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (200 mg twice daily) increased tadalafil AUC by 124%. |
ENTADFI, TADALAFIL |
| Elacestrant/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of elacestrant.(1) CLINICAL EFFECTS: Concomitant use of a strong or moderate CYP3A4 inhibitor increases elacestrant plasma concentrations, which may increase the incidence and severity of adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant use of strong or moderate CYP3A4 inhibitors with elacestrant.(1) DISCUSSION: Coadministration of itraconazole (a strong CYP3A4 inhibitor) increased elacestrant area-under-curve (AUC) and maximum concentration (Cmax) by 5.3-fold and 4.4-fold, respectively.(1) Coadministration of fluconazole (a moderate CYP3A4 inhibitor) is predicted to increase elacestrant AUC and Cmax by 2.3-fold and 1.6-fold, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2) |
ORSERDU |
| Apixaban/HIV Protease Inhibitors; Cobicistat SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Apixaban is metabolized by CYP3A4 and is a substrate of the P-glycoprotein (P-gp) efflux transport protein.(1-4) HIV protease inhibitors are CYP3A4 and P-gp inhibitors and may increase the absorption and decrease the elimination of apixaban.(1-5) CLINICAL EFFECTS: Concurrent use of protease inhibitors may result in elevated levels and clinical effects of apixaban, including an increased risk of bleeding.(1-5) PREDISPOSING FACTORS: The risk for bleeding episodes may be greater in patients 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). PATIENT MANAGEMENT: Recommendations for concurrent use of apixaban and HIV protease inhibitors vary in different regions. The Australian(1) and Canadian(2) manufacturers of apixaban state that the concurrent use of agents that are strong inhibitors of both P-gp and CYP3A4 with apixaban is contraindicated. The UK manufacturer of apixaban states that concurrent use of these agents is not recommended.(3) The US manufacturer of apixaban states that if concurrent use cannot be avoided, the dosage of apixaban should be reduced by 50% except in patients already receiving apixaban 2.5 mg twice daily, for whom concurrent use should be avoided.(4) The US manufacturer of atazanavir states that coadministration of unboosted atazanavir should be closely monitored.(5) If concurrent therapy is warranted, 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. When applicable, perform agent-specific laboratory test (e.g. INR, aPTT) to monitor efficacy and safety of anticoagulation. Discontinue anticoagulation 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: Concurrent ketoconazole (400 mg daily), a strong CYP3A4 and P-gp inhibitor, increased the area-under-curve (AUC) and maximum concentration (Cmax) of apixaban by 2-fold and 1.6-fold, respectively.(1) HIV protease inhibitors linked to this monograph are: atazanavir, cobicistat, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir. |
ELIQUIS |
| Omaveloxolone/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents which inhibit the CYP3A4 enzyme may inhibit the metabolism of omaveloxolone.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels of and effects from omaveloxolone including hepatotoxicity and hyperlipidemia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of moderate CYP3A4 inhibitors with omaveloxolone should be avoided. If concurrent use cannot be avoided, reduce the omaveloxolone dosage to 100 mg daily and monitor closely. If adverse reactions emerge, reduce the dose to 50 mg once daily.(1) DISCUSSION: Coadministration of omaveloxolone with verapamil (a moderate CYP3A4 inhibitor) increased both the concentration maximum (Cmax) and area-under-curve (AUC) of omaveloxolone by 1.25-fold.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2,3) |
SKYCLARYS |
| Colchicine (for Cardioprotection)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of colchicine.(1,2) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in elevated levels of and toxicity from colchicine. Symptoms of colchicine toxicity include muscle weakness or pain; numbness or tingling in the fingers or toes; myelosuppression; abdominal pain; nausea; severe diarrhea or vomiting; feeling weak or tired; increased infections; and pale or gray color of the lips, tongue, or palms of hands.(1,2) PREDISPOSING FACTORS: This interaction is expected to be more severe in patients with renal and/or hepatic impairment.(1,2) PATIENT MANAGEMENT: Monitor patients receiving moderate CYP3A4 inhibitors for signs of colchicine toxicity. Avoid concurrent use in patients with existing renal or hepatic impairment.(1) Patients should be instructed to immediately report any signs of colchicine toxicity, such as muscle weakness/pain, numbness/tingling in fingers/toes, unusual bleeding or bruising, infections, weakness/tiredness, pale/gray color of the lips/tongue/palms of hands, and/or severe diarrhea/vomiting. DISCUSSION: There is one case report of colchicine toxicity with concurrent erythromycin.(4) In a study in 20 subjects, pretreatment with diltiazem (240 mg daily for 7 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of colchicine (0.6 mg) by 44.2% (range -46.6% to 318.3%) and by 93.4% (range -30.2% to 338.6%), respectively.(1) In a study in 18 subjects, pretreatment with ritonavir (100 mg twice daily for 5 days) increased the Cmax and AUC of a single dose of colchicine (0.6 mg) by 184.4% (range 79.2% to 447.4%) and by 296% (range 53.8% to 924.4%), respectively.(1) In a study in 24 subjects, pretreatment with verapamil (240 mg twice daily for 7 days) increased the Cmax and AUC of a single dose of colchicine (0.6 mg) by 40.1% (range -47.1% to 149.5%) and by 103.3% (range -9.8% to 217.2%), respectively.(1) Colchicine toxicity has been reported with concurrent use of CYP3A4 inhibitors such as clarithromycin, cyclosporine, diltiazem, erythromycin, and verapamil.(1,2) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, clofazimine, conivaptan, crizotinib, duvelisib, fedratinib, fluconazole, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, and treosulfan.(1,5,6) |
LODOCO |
| Lurbinectedin/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of lurbinectedin.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors with lurbinectedin may increase systemic exposure and the risk for toxicities such as myelosuppression, hepatotoxicity, neuropathy, fatigue, nausea, and musculoskeletal pain.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of lurbinectedin states that the concurrent use of lurbinectedin with moderate CYP3A4 inhibitors should be avoided. If the use of a moderate CYP3A4 inhibitor cannot be avoided, consider a dose reduction of lurbinectedin if clinically indicated based on adverse events as recommended in the lurbinectedin prescribing information.(1) DISCUSSION: Itraconazole (a strong CYP3A4 inhibitor) increased the area-under-curve (AUC) of total lurbinectedin by 2.7-fold and unbound lurbinectedin by 2.4-fold.(1) In a study including data from 443 patients with solid and hematologic malignancies treated in six phase I and three phase II trials with lurbinectedin as a single agent or combined with other agents, lurbinectedin clearance decreased by 30%, area-under-curve (AUC) increased by 42%, and concentration maximum (Cmax) increased by 7% when coadministered with a CYP3A inhibitor.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(3,4) |
ZEPZELCA |
| Repotrectinib/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of repotrectinib.(1) CLINICAL EFFECTS: Concomitant use of a strong or moderate CYP3A4 inhibitor increases repotrectinib plasma concentrations, which may increase the incidence and severity of adverse reactions, including CNS effects (dizziness, ataxia, cognitive disorders), interstitial lung disease/pneumonitis, hepatotoxicity, and myalgia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant use of strong or moderate CYP3A4 inhibitors with repotrectinib. Discontinue CYP3A4 inhibitors for 3 to 5 half lives of the inhibitor prior to initiating repotrectinib.(1) DISCUSSION: In a study, itraconazole (a strong CYP3A4 and P-gp inhibitor) increased the area-under-curve (AUC) and maximum concentration (Cmax) of repotrectinib by 5.9-fold and 1.7-fold, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, grapefruit, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, erythromycin, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, and verapamil.(2) |
AUGTYRO |
| Nirogacestat/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of nirogacestat.(1) CLINICAL EFFECTS: Concomitant use of a strong or moderate CYP3A4 inhibitor increases nirogacestat plasma concentrations, which may increase the incidence and severity of adverse reactions, including hepatotoxicity, diarrhea, hypokalemia, and hypophosphatemia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant use of strong or moderate CYP3A4 inhibitors with nirogacestat.(1) DISCUSSION: In a study, itraconazole (a strong CYP3A4 inhibitor) increased the area-under-curve (AUC) and maximum concentration (Cmax) of nirogacestat by 8.2-fold and 2.5-fold, respectively, following a single 100 mg dose of nirogacestat. In a PKPB model, nirogacestat AUC was predicted to increase by 6.33-, 5.19-, and 3.46-fold following coadministration of multiple doses of nirogacestat (150 mg BID) with itraconazole, ketoconazole and clarithromycin (strong CYP3A inhibitors), respectively.(1) In a PKPB model, nirogacestat AUC was predicted to increase 2.73-and 3.18-fold following coadministration of multiple doses of nirogacestat (150 mg BID) with erythromycin (moderate CYP3A inhibitor) and fluconazole (moderate CYP3A inhibitor), respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, boceprevir, ceritinib, clarithromycin, cobicistat, grapefruit, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2) |
OGSIVEO |
| Lovotibeglogene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lovotibeglogene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of lovotibeglogene autotemcel.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization and until all cycles of apheresis are completed.(1) There are some long-acting antiretroviral medications that may require a longer duration of discontinuation for elimination of the medication. If a patient is taking anti-retrovirals for HIV prophylaxis, confirm a negative test for HIV before beginning mobilization and apheresis of CD34+ cells.(1) DISCUSSION: Antiretroviral medications may interfere with the manufacturing of lovotibeglogene autotemcel therapy.(1) |
LYFGENIA |
| Atidarsagene Autotemcel/Anti-Retrovirals SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Atidarsagene autotemcel is prepared from apheresed cells that are transduced with a replication defective, self-inactivating lentiviral vector. Antiretrovirals may interfere with the manufacturing of apheresed cells. CLINICAL EFFECTS: Use of antiretrovirals before mobilization and apheresis may interfere with the production of atidarsagene autotemcel. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Discontinue antiretrovirals for at least one month prior to mobilization (or the expected duration of time needed for elimination of the medication) until all cycles of apheresis are completed. If a patient requires antiretrovirals for HIV prophylaxis, then confirm a negative HIV test before beginning mobilization and apheresis of CD34+ cells. DISCUSSION: Antiretroviral medications may interfere with the manufacturing of atidarsagene autotemcel therapy.(1) |
LENMELDY |
| Darunavir; Fosamprenavir/Lumacaftor SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lumacaftor, a strong inducer of CYP3A4, may induce the metabolism of darunavir and fosamprenavir.(1-3) Darunavir and fosamprenavir are designated as sensitive CYP3A4 substrates; strong inducers may decrease exposure by 80% or more.(4) CLINICAL EFFECTS: Concurrent use of lumacaftor may decrease the levels and effectiveness of darunavir and fosamprenavir.(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 lumacaftor states concurrent use with sensitive CYP3A4 substrates is not recommended.(1) DISCUSSION: In an interaction study lumacaftor reduced exposure to ivacaftor, another CYP3A4 sensitive substrate, by 80%.(1) |
ORKAMBI |
| Cariprazine/Moderate CYP3A4 Inhibitors 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.(1-4) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from cariprazine.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: When possible, avoid the use of moderate CYP3A4 inhibitors with cariprazine. The US manufacturer of cariprazine states that concurrent use of moderate CYP3A4 inhibitors requires a dose adjustment. If a moderate CYP3A4 inhibitor is initiated in a patient on a stable dose of cariprazine, the following dose adjustments are recommended: -If current cariprazine dose is 1.5 or 3 mg daily - Decrease cariprazine dose to 1.5 mg every other day. -If current cariprazine dose is 4.5 or 6 mg daily - Decrease cariprazine dose to 1.5 mg daily. Cariprazine has two active metabolites, DCAR and DDCAR which have similar in vitro activity and potency. However, DDCAR has a longer half-life (1-3 weeks) than cariprazine (2-4 days), resulting in systemic DDCAR concentrations that are about 4-fold higher than cariprazine. Thus although interaction onset may begin within a few days, the full effect of inhibition may not be seen for 4 or more weeks. If a patient is already on a moderate CYP3A4 inhibitor when cariprazine is started, the following dose adjustments are recommended: -For schizophrenia or bipolar mania - Start cariprazine dose at 1.5 mg every other day; Increase to 1.5 mg daily, if needed. -For bipolar depression or adjunctive therapy for treatment of Major Depressive Disorder (MDD) - Start cariprazine dose at 1.5 mg every other day.(1) When the inhibitor is discontinued, cariprazine, DCAR and DDCAR will begin to fall and the dosage may need be increased. Monitor for decreased effectiveness for 4 or more weeks. The Australian, Canadian, and UK manufacturers of cariprazine state that concurrent use of moderate CYP3A4 inhibitors is contraindicated.(2-4) The Canadian manufacturer of cariprazine states that concurrent use of moderate CYP3A4 inhibitors is also contraindicated for at least 2 weeks after cariprazine discontinuation.(3) DISCUSSION: In an interaction study, coadministration of ketoconazole 400 mg/day with cariprazine 0.5 mg/day increased cariprazine exposure (AUC, area-under-curve) 4-fold and increased DDCAR AUC about 1.5-fold.(1) In a PKPB model, coadministration of ketoconazole 400 mg/day with cariprazine 0.5 mg/day is predicted to increase cariprazine concentration maximum (Cmax) and AUC by 5.5-fold and 6-fold, respectively. Coadministration of fluconazole 200 mg/day with cariprazine 0.5 mg/day is predicted to increased cariprazine Cmax and AUC by up to 3-fold.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazole, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(5,6) |
VRAYLAR |
There are 50 moderate interactions.
The clinician should assess the patient’s characteristics and take action as needed. Actions required for moderate interactions include, but are not limited to, discontinuing one or both agents, adjusting dosage, altering administration.
| Drug Interaction | Drug Names |
|---|---|
| Cilostazol (Less Than or Equal To 50 mg BID)/Selected Strong & Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of cilostazol.(1) CLINICAL EFFECTS: The concurrent use of cilostazol and strong and moderate inhibitors of CYP3A4 may result in elevated levels of cilostazol, which may produce increased effects of cilostazol and adverse effects.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of cilostazol should be limited to 50 mg twice daily in patients receiving concurrent therapy with strong and moderate inhibitors of CYP3A4.(1) DISCUSSION: In a study in 16 healthy males, the administration of a single dose of cilostazol (10 mg) with erythromycin (500 mg every eight hours) increased the maximum concentration (Cmax) and area-under-curve (AUC) of cilostazol by 47% and 73%, respectively. The Cmax and AUC of 4'-trans-hydroxy-cilostazol were increased by 29% and 141%, respectively.(2) Analysis of population pharmacokinetics indicated that the concurrent administration of diltiazem with cilostazol increased cilostazol concentrations by 53%. Concurrent administration of diltiazem and cilostazol decreased cilostazol clearance by 30%, increased the Cmax by 30%, and increased AUC by 40%.(1) In a study, the administration of a single dose of cilostazol (10 mg) with erythromycin (500 mg every eight hours) increased the Cmax and AUC of cilostazol by 47% and 73%, respectively. The AUC of 4'-trans-hydroxy-cilostazol was increased by 141%.(1) In an vitro study in human liver microsomes, ketoconazole inhibited the metabolism of cilostazol.(3) |
CILOSTAZOL |
| Artemether;Lumefantrine/Strong CYP3A4 Inhib; Protease Inhib SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Potent inhibitors of CYP3A4 may inhibit the metabolism of artemether and lumefantrine.(1) CLINICAL EFFECTS: Concurrent use of potent CYP3A4 inhibitors with artemether-lumefantrine may result in elevated levels of the antimalarial agents and toxicity, including prolongation of the QT interval which may result in life threatening arrhythmia and death.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of artemether-lumefantrine states that concurrent use with potent CYP3A4 inhibitors should be approached with caution.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a study in 13 healthy subjects, administration of ketoconazole (400 mg Day 1, 200 mg Days 2-5, a potent inhibitor of CYP3A4) with a single dose of artemether-lumefantrine (20 mg/120 mg) increased the area-under-curve (AUC) of artemether and lumefantrine by 2.3-fold and 1.6-fold, respectively.(1) CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, telaprevir, tipranavir, and tucatinib.(3,4) |
COARTEM |
| Slt Calcium Channel Blockers/Atazanavir;Darunavir;Fosamprenavir SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Atazanavir, darunavir, and fosamprenavir may inhibit the CYP3A4-mediated metabolism of calcium channel blockers.(1-5) CLINICAL EFFECTS: Concurrent use of atazanavir, darunavir, or fosamprenavir may result in increased levels of calcium channel blockers. The combination of atazanavir with non-dihydropyridines may result in an additive effect on the PR interval.(1-2,6-7) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US Department of Health and Human Services HIV guidelines recommend that concurrent use of calcium channel blockers with protease inhibitors be monitored closely. The dose of the calcium channel blocker should be titrated to clinical response and adverse events.(5) Additional recommendations apply to patients on atazanavir. EKG monitoring is recommended for patients on concurrent therapy with calcium channel blockers. A dose reduction of diltiazem by 50% should be considered for patients starting atazanavir.(1,2,5) DISCUSSION: In a study in 28 subjects, concurrent atazanavir (400 mg daily) with diltiazem (180 mg daily) increased the diltiazem area-under-curve (AUC) and maximum concentration (Cmax) by 225% and 98%, respectively.(1,2) Diltiazem minimum concentration (Cmin) increased by 242%. The Cmax, AUC, and Cmin of desacetyl-diltiazem increased by 272%, 265%, and 221%, respectively. There were no significant effects on atazanavir levels.(1) |
AMLODIPINE BESILATE, AMLODIPINE BESYLATE, AMLODIPINE BESYLATE-BENAZEPRIL, AMLODIPINE-ATORVASTATIN, AMLODIPINE-OLMESARTAN, AMLODIPINE-VALSARTAN, AMLODIPINE-VALSARTAN-HCTZ, AZOR, CADUET, CARDENE I.V., 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, KATERZIA, LEVAMLODIPINE MALEATE, LOTREL, MATZIM LA, NICARDIPINE HCL, NICARDIPINE HCL-0.9% NACL, NIFEDIPINE, NIFEDIPINE ER, NIFEDIPINE MICRONIZED, NORLIQVA, NORVASC, OLMESARTAN-AMLODIPINE-HCTZ, PRESTALIA, PROCARDIA XL, TELMISARTAN-AMLODIPINE, TIADYLT ER, TIAZAC, TRANDOLAPRIL-VERAPAMIL ER, TRIBENZOR, VERAPAMIL ER, VERAPAMIL ER PM, VERAPAMIL HCL, VERAPAMIL SR |
| Vardenafil (Less Than or Equal To 2.5 mg)/Selected Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Protease inhibitors may inhibit the metabolism of vardenafil by CYP3A4. CLINICAL EFFECTS: Concurrent use of vardenafil with protease inhibitors may result in increased levels of and adverse effects from vardenafil, including hypotension, visual changes, and sustained erections. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: US guidelines for the use of antiretroviral agents recommends patients receiving protease inhibitors should receive no more than 2.5 mg of vardenafil every 72 hours. US labeling recommendations for concurrent use of vardenafil with protease inhibitors state: -Patients receiving any ritonavir- or cobicistat-containing regimens, including atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nirmatrelvir, paritaprevir, saquinavir, and tipranavir should receive no more than 2.5 mg of vardenafil every 72 hours. -Patients receiving unboosted atazanavir, unboosted fosamprenavir, unboosted indinavir, or nelfinavir should take no more than 2.5 mg of vardenafil every 24 hours. Canadian labeling contraindicates concurrent use of atazanavir/ritonavir, lopinavir/ritonavir, and nirmatrelvir/ritonavir with vardenafil.(3,12,14) Patients should be counseled that they are at an increased risk of vardenafil adverse effects, including hypotension, visual changes, and priapism. DISCUSSION: Concurrent use of indinavir (800 mg three times daily) with vardenafil (10 mg) increased the vardenafil area-under-curve (AUC) and maximum concentration (Cmax) by 16-fold and 7-fold, respectively. Vardenafil half-life increased 2-fold. At 24-hours post-dose, vardenafil levels fell to approximately 4% of vardenafil Cmax. The AUC and Cmax of indinavir decreased by 30% and 40%, respectively. Concurrent use of ritonavir (600 mg twice daily)with vardenafil (5 mg) increased vardenafil AUC and Cmax by 49-fold and 13-fold, respectively. The half-life of vardenafil increased to 26 hours. The ritonavir AUC and Cmax decreased by 20%. |
VARDENAFIL HCL |
| Selected Antiarrhythmics/Selected Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Darunavir (coadministered with cobicistat or ritonavir)(1), fosamprenavir (with or without ritonavir),(2) lopinavir-ritonavir(3), and ombitasvir-paritaprevir-ritonavir(4) are CYP3A4 inhibitors and may decrease the metabolism of ajmaline, amiodarone, and quinidine. CLINICAL EFFECTS: Concurrent use of darunavir (coadministered with cobicistat or ritonavir)(1), fosamprenavir (with or without ritonavir),(2) lopinavir-ritonavir(3), or ombitasvir-paritaprevir-ritonavir(4) with ajmaline, amiodarone, or quinidine may result in elevated levels of these antiarrhythmics and serious and/or life-threatening arrhythmias, including torsades de pointes. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(5) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(5) PATIENT MANAGEMENT: Darunavir (coadministered with cobicistat or ritonavir),(1) fosamprenavir (with or without ritonavir),(2) lopinavir-ritonavir,(3) and ombitasvir-paritaprevir-ritonavir(4) should be used with caution with ajmaline, amiodarone, and quinidine, along with concentration monitoring of these agents. The US Department of Health and Human Services HIV guidelines state that amiodarone should not be coadministered with darunavir or lopinavir unless benefits outweigh risks, and that quinidine should not be coadministered with protease inhibitors.(12) The Canadian and UK manufacturers of darunavir,(6,7) fosamprenavir,(8,9) and lopinavir-ritonavir(10,11) state that concurrent use of amiodarone is contraindicated. The UK manufacturers of darunavir(7) and fosamprenavir(9) state that concurrent use of quinidine is contraindicated. If used concurrently, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Darunavir and fosamprenavir are moderate inhibitors of CYP3A4. Lopinavir-ritonavir is a strong inhibitor of CYP3A4.(13) |
AMIODARONE HCL, AMIODARONE HCL-D5W, NEXTERONE, NUEDEXTA, PACERONE, QUINIDINE GLUCONATE, QUINIDINE SULFATE |
| Tricyclic Compounds/Fosamprenavir; Tipranavir SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Fosamprenavir and tipranavir may inhibit the metabolism of tricyclic compounds.(1,2) CLINICAL EFFECTS: Concurrent use of fosamprenavir(1) or tipranavir(2) with tricyclic compounds may result in elevated levels of the tricyclic agents and serious and/or life-threatening effects. PREDISPOSING FACTORS: The risk of seizures may be increased in patients with a history of head trauma or prior seizure; CNS tumor; severe hepatic cirrhosis; excessive use of alcohol or sedatives; addiction to opiates, cocaine, or stimulants; use of over-the-counter stimulants and anorectics; diabetics treated with oral hypoglycemics or insulin; or with concomitant medications known to lower seizure threshold (antipsychotics, theophylline, systemic steroids). The risk of anticholinergic toxicities including cognitive decline, delirium, falls and fractures is increased in geriatric patients using more than one medicine with anticholinergic properties.(4) PATIENT MANAGEMENT: The manufacturer of fosamprenavir(1) recommends caution with concurrent use of these agents with tricyclic compounds, along with concentration monitoring of the tricyclics. The manufacturer of tipranavir recommends dosage reduction and concentration monitoring of desipramine when coadministered with tipranavir/ritonavir.(2) DISCUSSION: Amprenavir has been shown to be a potent inhibitor of CYP3A4.(1,3) Fosamprenavir is a prodrug of amprenavir.(1) Therefore, the manufacturer of amprenavir(3) and fosamprenavir(1) recommends caution with concurrent use of these agents with tricyclic compounds, along with concentration monitoring of the tricyclic compounds. No interaction studies have been performed on the combination of tipranavir-ritonavir and desipramine. Desipramine is a sensitive substrate of CYP2D6 while tipranavir-ritonavir is a moderate CYP2D6 inhibitor.(5,6) In one clinical study, six subjects were given 50 mg desipramine on three occasions: alone, after a 60 mg dose of fluoxetine (strong CYP2D6 inhibitor), and after eight daily 60 mg doses of fluoxetine. Fluoxetine significantly reduced oral clearance of desipramine by up to 10-fold and prolonged the half-life of desipramine by up to 4-fold.(7) |
AMITRIPTYLINE HCL, AMOXAPINE, AMRIX, ANAFRANIL, CHLORDIAZEPOXIDE-AMITRIPTYLINE, CLOMIPRAMINE HCL, CYCLOBENZAPRINE HCL, CYCLOBENZAPRINE HCL ER, CYCLOPAK, CYCLOTENS, DESIPRAMINE HCL, DOXEPIN HCL, FEXMID, IMIPRAMINE HCL, IMIPRAMINE PAMOATE, NORPRAMIN, NORTRIPTYLINE HCL, PAMELOR, PERPHENAZINE-AMITRIPTYLINE, PROTRIPTYLINE HCL, SILENOR, TRIMIPRAMINE MALEATE |
| Itraconazole; Ketoconazole/Selected CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Atazanavir,(1) cobicistat,(2) darunavir with cobicistat or ritonavir,(3) fosamprenavir,(4) lopinavir/ritonavir,(5) nirmatrelvir/ritonavir,(6) saquinavir,(7) and tipranavir/ritonavir(8) may inhibit the metabolism of itraconazole and ketoconazole. Itraconazole and ketoconazole may inhibit the metabolism of the protease inhibitors and elvitegravir/cobicistat.(2,9-11) CLINICAL EFFECTS: Concurrent use may result in increased levels of and toxicity from itraconazole, ketoconazole, the protease inhibitors, or elvitegravir/cobicistat.(1-11) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of boosted protease inhibitors or elvitegravir/cobicistat with high doses of ketoconazole or itraconazole greater than 200 mg daily is not recommended.(1-11) Use of high doses of itraconazole should be guided by itraconazole concentrations.(11) The US Department of Health and Human Service HIV guidelines state that dosing of itraconazole when used concurrently with unboosted atazanavir should be guided by itraconazole concentrations.(11) The manufacturer of fosamprenavir states that a dose reduction of itraconazole or ketoconazole may be needed for patients receiving more than 400 mg of these agents a day with unboosted fosamprenavir.(4) The manufacturer of saquinavir states that concurrent use with itraconazole should be monitored for saquinavir toxicity due to the risk of cardiac arrhythmias.(7) Monitor for adverse effects from either the antifungal or the protease inhibitor. DISCUSSION: A study of 14 subjects found that ketoconazole (200 mg daily) used concurrently with atazanavir (400 mg daily) had negligible effects on atazanavir area-under-curve (AUC) and maximum concentration (Cmax).(1) In a study of 18 subjects, ketoconazole (200 mg twice daily) increased the Cmax and AUC of elvitegravir by 1.17-fold and 1.48-fold.(2) In a study in 14 subjects, concurrent ketoconazole (200 mg twice daily) and darunavir/ritonavir (400/100 mg twice daily) increased darunavir Cmax, AUC, and minimum concentration (Cmin) by 1.21-fold, 1.42-fold, and 1.73-fold, respectively. Ketoconazole Cmax, AUC, and Cmin increased by 2.11-fold, 3.12-fold, and 9.68-fold, respectively.(3) In a study in 12 subjects, administration of a single dose of ketoconazole (400 mg) with a single dose of amprenavir (1200 mg) decreased the amprenavir Cmax by 16%. Amprenavir AUC was increased by 31%. Ketoconazole Cmax and AUC were increased by 19% and 44%, respectively.(4) In a study in 15 subjects, concurrent ketoconazole (200 mg daily) with fosamprenavir/ritonavir (700/100 mg twice daily) resulted in no changes in amprenavir levels. Ketoconazole Cmax and AUC increased by 25% and 169%, respectively.(4) In a study in 12 subjects, administration of a single dose of ketoconazole (200 mg) after 16 days of lopinavir with ritonavir (400 mg with 100 mg twice daily) decreased lopinavir Cmax, AUC, Cmin levels 11%, 13%, and 25%, respectively. Ketoconazole Cmax and AUC were increased 1.13-fold and 3.04-fold, respectively.(5) A study of 11 subjects found that itraconazole (200 mg daily) increased the Cmax and AUC of nirmatrelvir by 119% and 139%, respectively.(6) In a study in 12 subjects, administration of ketoconazole (200 mg daily) and saquinavir (1000 mg twice daily) with ritonavir (100 mg twice daily) resulted in no changes in saquinavir levels. Ketoconazole AUC and Cmax increased by 168% and 45%, respectively.(7) Ketoconazole has been shown to increase the Cmax and AUC of telithromycin by 51% and 95%, respectively.(9) Selected CYP3A4 inhibitors linked to this monograph include: atazanavir, cobicistat, darunavir, fosamprenavir, lopinavir, nirmatrelvir/ritonavir, saquinavir, and tipranavir. |
ITRACONAZOLE, ITRACONAZOLE MICRONIZED, KETOCONAZOLE, SPORANOX, TOLSURA |
| Selected Protease Inhibitors/Lopinavir SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Lopinavir may inhibit the metabolism of amprenavir, fosamprenavir, indinavir, nelfinavir, and saquinavir. Amprenavir and fosamprenavir may inhibit the metabolism of lopinavir. Nelfinavir may induce the metabolism of lopinavir.(1-4) CLINICAL EFFECTS: Concurrent administration of lopinavir with indinavir, nelfinavir, or saquinavir may result in elevated levels of indinavir, nelfinavir, and saquinavir. Concurrent administration of lopinavir with amprenavir or fosamprenavir may result in decreased levels of amprenavir or fosamprenavir. Concurrent amprenavir, fosamprenavir may result in may result in increased levels of lopinavir. Concurrent nelfinavir may result in decreased levels of lopinavir.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Appropriate doses of fosamprenavir with lopinavir/ritonavir have not been established.(1,4) When used concurrently, the dosage of indinavir should be 600 mg twice daily and the dosage of lopinavir/ritonavir should be 400/100 mg twice daily.(1,2) Lopinavir/ritonavir should not be administered once daily in combination with nelfinavir. Administration of lopinavir/ritonavir with nelfinavir in patients less than 6 months of age is not recommended.(1) The dose of lopinavir/ritonavir tablets should be 500/125 mg (two 200/50 mg tablets and one 100/25 mg tablet) in adults receiving concurrent nelfinavir.(1) The dose of lopinavir/ritonavir oral solution should be 520/130 mg (6.5 ml) twice daily in adults receiving concurrent nelfinavir.(1,2) The US manufacturer of lopinavir/ritonavir states that pediatric patients aged 6 months to 18 years receiving nelfinavir require a dosage increase to 300/75 mg/m2 of oral solution (not to exceed the recommended adult dose).(1) If weight-based dosing is preferred, patients weighing less than 15 kg should receive 13/3.25 mg/kg of lopinavir/ritonavir oral solution twice daily with food and patients weighing 15 kg to 45 kg should receive 11/2.75 mg/kg of lopinavir/ritonavir oral solution twice daily with food.(1) Refer to the current Kaletra tablet labeling for information on dosing Kaletra tablets in pediatric patients taking nelfinavir who can swallow tablets.(1) Concurrent use of saquinavir and lopinavir/ritonavir does not require dose adjustment, but should be approached with caution due to additive effects on the QT interval.(1-3) DISCUSSION: In a study in 12 subjects, the concurrent administration of amprenavir (750 mg twice daily) with lopinavir/ritonavir (400/100 mg twice daily) decreased the lopinavir maximum concentration (Cmax), area-under-curve (AUC), and minimum concentration (Cmin) by 28%, 38%, and 57%, respectively. The Cmax, AUC, and Cmin of amprenavir increased by 12%, 72%, and 457%, respectively.(1) In a study in 18 subjects, the concurrent administration of fosamprenavir (700 mg twice daily with 100 mg ritonavir twice daily) and lopinavir/ ritonavir (400/100 mg twice daily) increased the lopinavir Cmax, AUC, and Cmin by 30%, 37%, and 52%, respectively. The Cmax, AUC, and Cmin of amprenavir decreased by 58%, 63%, and 65%, respectively.(1,4) A 3-arm, randomized cross-over study in healthy subjects examined the pharmacokinetics of lopinavir and amprenavir during concurrent therapy. Amprenavir Cmax, AUC, and Cmin were 13%, 26%, and 42% lower when administered with lopinavir/ritonavir than with ritonavir.(4) In a study in 13 subjects, concurrent indinavir (600 mg twice daily) and lopinavir/ritonavir (400/100 mg twice daily) decreased indinavir maximum concentration (Cmax) and area-under-curve (AUC) by 29% and 9%, respectively. The minimum concentration (Cmin) of indinavir increased by 3.47-fold.(1,2) In a study in 13 subjects, concurrent nelfinavir (1000 mg twice daily) and lopinavir/ritonavir (400/100 mg twice daily) decreased lopinavir Cmax, AUC, and Cmin by 21%, 27%, and 38%, respectively. The AUC and Cmin of nelfinavir increased by 7% and by 86%, respectively. The Cmax of nelfinavir decreased 7%. The Cmax, AUC, and Cmin of the M8 metabolite of nelfinavir increased by 2.36-fold, 3.46-fold, and 7.49-fold, respectively.(1,2) In a study in 14 subjects, concurrent saquinavir (800 mg twice daily) with lopinavir/ritonavir (400/100 mg twice daily) increased the Cmax, AUC, and Cmin of saquinavir by 634%, 962%, and 1674%, respectively. In a study in 10 subjects, concurrent saquinavir (1200 mg twice daily) with lopinavir/ ritonavir (400/100 mg twice daily) increased the Cmax, AUC, and Cmin of saquinavir by 644%, 991%, and by 1654%, respectively.(1,2) Data from trials indicates that saquinavir concentrations achieved with concurrent saquinavir (1000 mg) with lopinavir/ritonavir (400/100 mg) twice daily are similar to those seen with saquinavir/ritonavir (1000/100 mg) twice daily.(5) |
KALETRA, LOPINAVIR-RITONAVIR |
| Ranolazine (Less than or Equal To 500 mg BID)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of ranolazine. Verapamil may also increase the absorption of ranolazine by inhibiting P-glycoprotein.(1) CLINICAL EFFECTS: Concurrent use of moderate inhibitors of CYP3A4 may result in elevated levels of and clinical effects from ranolazine. Elevated ranolazine levels may result in QTc prolongation, which may result in life-threatening cardiac arrhythmia, including torsades de pointes.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(5) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of ranolazine states that the dosage of ranolazine should be limited to 500 mg twice daily in patients receiving moderate inhibitors of CYP3A4.(1) Consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Concurrent use of diltiazem, a moderate inhibitor of CYP3A4, at daily doses of 180 mg to 360 mg increased plasma levels of ranolazine (1000 mg twice daily) by 50% and 130%, respectively.(1,3) In healthy subjects, concurrent ranolazine (1000 mg twice daily) had no effects on the pharmacokinetics of diltiazem (60 mg three times daily).(1) Concurrent use of verapamil (120 mg three times daily) increased plasma levels of ranolazine (750 mg twice daily) by 100%.(1) In a study in 12 healthy males, ranolazine immediate release (IR, 240 mg three times daily) had no effect on diltiazem (60 mg three times daily) pharmacokinetics. However, at ranolazine IR steady state, diltiazem increased ranolazine IR area under the curve (AUC) by 85%, on average, and increased maximum concentration (Cmax) by 1.9-fold and minimum concentration (Cmin) by 2.1-fold.(4) In a study in 12 subjects, ranolazine sustained release (SR, 500 mg twice daily) had no effect on diltiazem (60 mg three times daily) pharmacokinetics. However, at ranolazine steady state, diltiazem increased ranolazine SR Cmax, concentration minimum (Cmin), AUC by 80%, 216%, and 90%, on average, respectively.(4) In a study in 8 healthy males, diltiazem modified release (MR, 180 mg, or 240 mg, or 360 mg, once daily) increased ranolazine sustained release (SR, 1000 mg twice daily) AUC by 52%, 93%, and 139%, respectively. Ranolazine half-lives did not show any consistent trend of changes with increasing doses of diltiazem.(4) In a study of patients with severe chronic angina, the addition of ranolazine 750 mg twice daily or 1,000 mg twice daily along with their standard dose of diltiazem (180 mg once daily) provided additional antianginal relief, without evident adverse, long-term survival consequences over 1 to 2 years of therapy.(5) Ranolazine-induced QTc prolongation is dose and concentration-related.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, erythromycin, dronedarone, duvelisib, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(1,3,6,7) |
ASPRUZYO SPRINKLE, RANOLAZINE ER |
| Posaconazole/Fosamprenavir SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The exact mechanism responsible for decreased posaconazole levels is unknown, but may involve P-glycoprotein (P-gp) or UGT1A4 induction.(1) CLINICAL EFFECTS: Concurrent use of fosamprenavir may result in decreased levels and effectiveness of posaconazole.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving concurrent therapy with fosamprenavir should be monitored for decreased levels and effectiveness of posaconazole.(1,2) DISCUSSION: In a study in 20 subjects, concurrent fosamprenavir (700 mg BID for 10 days) decreased the maximum concentration (Cmax) and area-under-curve (AUC) of posaconazole (200 mg Day 1, 200 mg BID Day 2, then 400 mg BID for 8 days) by 21% and 23%, respectively.(1,2) During posaconazole administration, amprenavir Cmax and AUC were 36% and 65% lower than during the administration of fosamprenavir/ritonavir (700/100 mg BID), suggesting that posaconazole cannot replace ritonavir as a booster for fosamprenavir. However, amprenavir levels were comparable to historical levels of unboosted fosamprenavir.(1) |
NOXAFIL, POSACONAZOLE |
| Everolimus/Moderate CYP3A4; P-gp Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 and/or p-glycoprotein (P-gp) may inhibit the metabolism of everolimus.(1) CLINICAL EFFECTS: Concurrent use of moderate inhibitors of CYP3A4 and/or P-gp may result in elevated levels of and toxicity from everolimus.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If concurrent therapy with everolimus and moderate inhibitors of CYP3A4 and/or P-gp is warranted, reduce the dosage of everolimus.(1) 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, decrease the dose of everolimus to 2.5 mg daily. An increase to 5 mg daily may be considered based on patient tolerance. If the inhibitor is discontinued, allow an elimination period of 2-3 days before increasing the dose to that used prior to the inhibitor.(1) In patients with subependymal giant cell astrocytoma with TSC, reduce the dosage of everolimus by 50% to maintain trough concentrations of 5 ng/ml to 15 ng/ml. If the patient is already receiving 2.5 mg daily, consider a dose of 2.5 mg every other day. Assess everolimus levels 2 weeks after the addition of the inhibitor. Resume the everolimus dose used prior to initiation of the inhibitor after the inhibitor has been discontinued for 3 days, and assess everolimus trough levels 2 weeks later.(1) Guidelines from the American Society of Transplantation state that protease inhibitors are contraindicated, and recommend avoiding the use of erythromycin with everolimus. If the combination must be used, lower the dose of everolimus by up to 50% upon initiation of the antibiotic and monitor levels daily.(3) DISCUSSION: In a study in healthy subjects, concurrent use of erythromycin, a moderate CYP3A4 inhibitor and a P-gp inhibitor, increased everolimus AUC and Cmax by 2.0-fold and 4.4-fold, respectively.(1) In a study in healthy subjects, concurrent use of ketoconazole, a strong CYP3A4 inhibitor and a P-gp inhibitor, increased everolimus area-under-curve (AUC) and maximum concentration (Cmax) by 3.9-fold and 15.0-fold, respectively.(1) In a study in healthy subjects, concurrent use of verapamil, a moderate CYP3A4 inhibitor and a P-gp inhibitor, increased everolimus AUC and Cmax by 2.3-fold and 3.5-fold, respectively.(1) In a study in 16 healthy subjects, concurrent use of verapamil increased everolimus Cmax and AUC by 130% and 250%, respectively.(4) Moderate CYP3A4 and/or P-gp inhibitors include: abrocitinib, amiodarone, amprenavir, aprepitant, asciminib, asunaprevir, atazanavir, avacopan, azithromycin, belumosudil, cimetidine, clofazimine, conivaptan, crizotinib, danicopan, daridorexant, delavirdine, diltiazem, diosmin, dronedarone, duvelisib, erythromycin, fedratinib, flibanserin, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, fostamatinib, imatinib, isavuconazonium, ivacaftor, ledipasvir, lenacapavir, letermovir, mavorixafor, netupitant, nilotinib, nirogacestat, pirtobrutinib, propafenone, schisandra, tepotinib, tezacaftor, tofisopam, treosulfan, vemurafenib, verapamil, vimseltinib, and voclosporin.(5-7) |
AFINITOR, AFINITOR DISPERZ, EVEROLIMUS, TORPENZ, ZORTRESS |
| Sildenafil (ED);Tadalafil (ED)/Slt Protease Inhib;Cobicistat SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The protease inhibitors may inhibit the metabolism of sildenafil and tadalafil.(1-13) CLINICAL EFFECTS: The concurrent administration of a protease inhibitor may result in elevated levels of sildenafil or tadalafil, which may result in increased adverse effects such as hypotension, visual changes, and priapism. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of Viagra (sildenafil, 1) and the protease inhibitors (2-11) state that the recommended dose of sildenafil, when used for erectile dysfunction, is 25 mg of sildenafil in a 48 hour period for patients receiving concurrent therapy. Patients should be counseled that they are at an increased risk of sildenafil adverse effects, including hypotension, syncope, visual changes, and priapism. Patients experiencing these effects should report them promptly to their physician. The US manufacturers of the protease inhibitors state that concurrent use of sildenafil when used for the treatment of pulmonary arterial hypertension (PAH) is contraindicated.(2-11) The US manufacturer of Revatio (sildenafil) states that concurrent use with ritonavir is not recommended.(12) The US manufacturers of tadalafil(12) and the protease inhibitors(2-10) state that the recommended dose of as needed tadalafil for the treatment of erectile dysfunction is 10 mg of tadalafil every 72 hours in patients receiving concurrent therapy. The US manufacturer of tadalafil states that the recommended dose of daily tadalafil for the treatment of erectile dysfunction in patients taking potent inhibitors of CYP3A4 is 2.5 mg.(13) The US manufacturer of tadalafil chewable tablets (Chewtadzy) states the maximum recommended dose of as needed tadalafil for erectile dysfunction in patients taking strong CYP3A4 inhibitors is 10 mg every 72 hours. The use of tadalafil chewable tablets (Chewtazdy) for once daily use for erectile dysfunction or benign prostatic hyperplasia (BPH) is not recommended in patients taking strong CYP3A4 inhibitors due to the lack of a 2.5 mg tablet strength.(14) The US manufacturers of the protease inhibitors state that in patients who have received a protease inhibitor for at least one week, the initial dosage of tadalafil for the treatment of primary pulmonary hypertension should be 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(2-11) The US manufacturers of the protease inhibitors state that in patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be discontinued for 24 hours before beginning protease inhibitor therapy other than nelfinavir without concurrent ritonavir. After one week, tadalafil may be resumed at a dosage of 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(2-9) In patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be adjusted to 20 mg daily prior to beginning therapy with nelfinavir without concurrent ritonavir. The dosage may be increased to 40 mg daily based upon tolerability.(10) Patients should be counseled that they are at an increased risk of tadalafil adverse effects, including hypotension, syncope, visual changes, and priapism. Patients experiencing these effects should report them promptly to their physician. DISCUSSION: In a study in 16 subjects, administration of darunavir/ritonavir (400/100 mg twice daily) decreased the area-under-curve (AUC) and maximum concentration (Cmax) of a single dose of sildenafil (25 mg) by 38% and 3%, respectively, when compared to the administration of a 100 mg single dose of sildenafil given alone.(3) In a study in 6 HIV-infected males, indinavir (800 mg every 8 hours) increased the AUC and Cmax of indinavir by 11% and 48%, respectively. Sildenafil AUC increased by 340%.(5) The concurrent administration of ritonavir (400 mg twice daily) at steady state with sildenafil (100 mg single dose) resulted in increases in the sildenafil Cmax and AUC by 300% (4-fold) and 1000% (11-fold), respectively.(1,8) After 24 hours, plasma levels of sildenafil were still approximately 200 ng/ml (normally 5 ng/ml 24 hours post-dose).(1) In a study in 27 healthy volunteers, the concurrent use of saquinavir (1200 mg 3 times daily for 8 days) increased the AUC and Cmax of a single dose of sildenafil (100 mg) by 210% and 140%, respectively.(9) In a study of 28 healthy male volunteers, the effects of sildenafil when coadministered with ritonavir were determined in 14 of these volunteers. Ritonavir showed increases in sildenafil AUC and Cmax of 11-fold and 3.9-fold respectively.(15) Concurrent administration of tipranavir/ritonavir (500/200 mg twice daily for 17 doses) had no significant effects on the AUC of a single dose of tadalafil (10 mg). Tadalafil Cmax decreased 30%. Tipranavir Cmax, AUC, and Cmin decreased by 10%, 15%, and 19%, respectively. Administration of a single dose of tipranavir/ritonavir (500/200 mg) increased the AUC of a single dose of tadalafil (10 mg) by 2.33-fold. Tadalafil Cmax decreased 22%.(9) Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (200 mg twice daily) increased tadalafil AUC by 124%.(2,7) Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (500 mg or 600 mg twice daily) increased tadalafil AUC by 32% and decreased tadalafil Cmax by 30%.(13) |
CIALIS, SILDENAFIL CITRATE, TADALAFIL, VIAGRA |
| Selected Opioids/Selected Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of alfentanil, benzhydrocodone, fentanyl,(1) hydrocodone, meperidine,(2) oxycodone,(3) and sufentanil.(4) CLINICAL EFFECTS: The concurrent administration of a CYP3A4 inhibitor may result in elevated levels of and toxicity from alfentanil, benzhydrocodone, fentanyl,(1,5) hydrocodone, meperidine,(2) oxycodone(3) and sufentanil(4), including somnolence and potentially fatal respiratory depression. PREDISPOSING FACTORS: Heat. PATIENT MANAGEMENT: Monitor patients receiving moderate CYP3A4 inhibitors for an extended period of time. Dosage adjustments should be made if warranted. The manufacturer of sufentanil sublingual tablets states that if concomitant use with CYP3A4 inhibitors is necessary, consider use of an alternate agent that allows dose adjustment.(4) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with agents that may increase opioid drug levels.(6) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(7) Avoid exposing the fentanyl patch application site and surrounding area to direct external heat sources as there have been reports of overdose and death as a result of exposure to heat.(1) DISCUSSION: Fentanyl(1) and oxycodone(3) are metabolized by the CYP3A4 isoenzyme. Moderate and strong inhibitors of this isoenzyme are expected to increase fentanyl(1) and oxycodone(3) levels. In a single dose study of sufentanil sublingual tablet 15 mcg with a strong CYP3A4 inhibitor, ketoconazole, resulted in 77% and 19% greater AUC and Cmax values of sufentanil, respectively, compared to its administration alone.(4) In a randomized study in 30 patients, continuous diltiazem (1 mcg/kg/min) infusion had no effect on epidural fentanyl consumption when compared to placebo. There were no significant differences in Visual Analogue Scores (VAS), Verbal Rating Scores (VRS), or incidence of side effects, although there was a trend towards increased nausea with concurrent diltiazem.(5) In a randomized study of coronary artery bypass patients, concurrent diltiazem (60 mg orally 2 hours before induction of anesthesia then 0.1 mg/kg/hr infusion) increased the area-under-curve (AUC) and half-life of alfentanil by 40% and 50%, respectively, when compared to placebo. Patients who received diltiazem were extubated an average of 2.5 hours later than in patients who received placebo.(8) In a study in 13 patients, administration of a single dose of verapamil (75mcg/kg to 150mcg/kg) had no significant effects on the pharmacodynamic effects of a single dose of fentanyl; however, individual patients had modest decreases in blood pressure.(9) In a case report, concurrent diltiazem and fentanyl produced delirium.(10) A study in healthy subjects shown that the application of heat over the fentanyl patch system increased mean overall fentanyl exposure by 120% and average maximum fentanyl level by 61%.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, duvelisib, fedratinib, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(11,12) |
APADAZ, BENZHYDROCODONE-ACETAMINOPHEN, DEMEROL, DSUVIA, ENDOCET, FENTANYL, FENTANYL CITRATE, FENTANYL CITRATE-0.9% NACL, FENTANYL CITRATE-D5W, FENTANYL CITRATE-STERILE WATER, FENTANYL CITRATE-WATER, FENTANYL-BUPIVACAINE-0.9% NACL, FENTANYL-BUPIVACAINE-NACL, FENTANYL-ROPIVACAINE-0.9% NACL, FENTANYL-ROPIVACAINE-NACL, HYCODAN, HYDROCODONE BITARTRATE, HYDROCODONE BITARTRATE ER, HYDROCODONE-ACETAMINOPHEN, HYDROCODONE-CHLORPHENIRAMNE ER, HYDROCODONE-HOMATROPINE MBR, HYDROCODONE-IBUPROFEN, HYDROMET, HYSINGLA ER, MEPERIDINE HCL, MEPERIDINE HCL-0.9% NACL, NALOCET, OXYCODONE HCL, OXYCODONE HCL ER, OXYCODONE HYDROCHLORIDE, OXYCODONE-ACETAMINOPHEN, OXYCONTIN, PERCOCET, PRIMLEV, PROLATE, ROXICODONE, ROXYBOND, SUFENTANIL CITRATE, XTAMPZA ER |
| Atorvastatin (<= 20 mg)/Selected Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Protease inhibitors may inhibit the metabolism of atorvastatin by CYP3A4.(1-5) CLINICAL EFFECTS: Concurrent use of protease inhibitors may result in elevated levels of atorvastatin, which could result in rhabdomyolysis.(1-5) PREDISPOSING FACTORS: The risk for myopathy or rhabdomyolysis may be greater in patients 65 years and older, inadequately treated hypothyroidism, renal impairment, carnitine deficiency, malignant hyperthermia, or in patients with a history of myopathy or rhabdomyolysis. Patients with a SLCO1B1 polymorphism that leads to decreased function of the hepatic uptake transporter OATP1B1 may have increased statin concentrations and be predisposed to myopathy or rhabdomyolysis. PATIENT MANAGEMENT: In patients receiving protease inhibitors, consider the use of fluvastatin. If atorvastatin is used with concurrent darunavir, fosamprenavir, lopinavir, or saquinavir, limit the dose of atorvastatin to 20 mg daily with careful monitoring.(1-5) Monitor for signs and symptoms of myopathy (e.g. muscle weakness, muscle pain, rising creatine kinase). DISCUSSION: A study in 15 subjects found that darunavir/ritonavir (300/100 mg twice daily) decreased the maximum concentration (Cmax) and area-under curve (AUC) of atorvastatin (10 mg daily) by 64% and 15%, when compared to atorvastatin (40 mg daily) administered alone. Atorvastatin minimum concentration (Cmin) increased by 81% during concurrent therapy.(2) In a study in 16 subjects, concurrent atorvastatin (10 mg daily for 4 days) and fosamprenavir (1400 mg twice daily for 2 weeks) increased atorvastatin Cmax and AUC by 304% and 130%, respectively. Atorvastatin Cmin decreased by 10%.(3) The Cmax, AUC, and Cmin of amprenavir decreased by by 18%, 27%, and 12%, respectively.(3) In a study in 16 subjects, the administration of atorvastatin (10 mg daily for 4 days) and fosamprenavir (700 mg twice daily for 2 weeks) with ritonavir (100 mg twice daily for 2 weeks) increased the atorvastatin Cmax, AUC, and Cmin by 184%, 153%, and 73%, respectively.(1,4) There were no changes in amprenavir Cmax, AUC, or Cmin.(3) A randomized, controlled trial in healthy subjects examined the effects of a combination of ritonavir and saquinavir on the pharmacokinetics of atorvastatin, pravastatin, and simvastatin and the effects of pravastatin on nelfinavir pharmacokinetics. The combination of ritonavir and saquinavir decreased pravastatin levels by 50% and increased atorvastatin and simvastatin levels by 79% and 3059%, respectively. Pravastatin had no statistically significant effect on nelfinavir pharmacokinetics.(6) Concurrent administration of atorvastatin (40 mg) with ritonavir-saquinavir (400 mg twice daily) increased atorvastatin AUC and Cmax by 3.9-fold and 4.3-fold, respectively.(1) Concurrent administration of atorvastatin (20 mg) with lopinavir-ritonavir (400-100 mg twice daily) increased atorvastatin by 5.9-fold.(1) |
AMLODIPINE-ATORVASTATIN, ATORVASTATIN CALCIUM, CADUET, LIPITOR |
| Ibrutinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents that inhibit the CYP3A4 isoenzyme may inhibit the metabolism of ibrutinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase levels of and effects from ibrutinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of moderate CYP3A4 inhibitors in patients undergoing therapy with ibrutinib requires a dose adjustment.(1) If a moderate CYP3A4 inhibitor is required for B-cell malignancies treatment, reduce the dose of ibrutinib to 280 mg daily.(1) If a moderate CYP3A4 inhibitor is required for chronic graft versus host disease treatment, reduce the dose of ibrutinib in patients 12 years and older to 420 mg once daily, and in patients 1 year to 12 years old to 240 mg/m2 once daily.(1) After discontinuation of a CYP3A4 inhibitor, resume previous dose of ibrutinib.(1) DISCUSSION: The coadministration of multiple doses of erythromycin (moderate CYP3A inhibitor) increased ibrutinib's concentration maximum (Cmax) and area-under-curve (AUC) by 3.4-fold and 3-fold.(1) In a case report, concomitant administration of ibrutinib and verapamil/trandolapril resulted in ibrutinib toxicity consisting of nausea, dizziness, malaise, and severe diarrhea.(2) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, casopitant, clofazimine, clotrimazole, conivaptan, crizotinib, darunavir, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, grapefruit juice, imatinib, isavuconazonium, ledipasvir, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(1,3,4) |
IMBRUVICA |
| Avanafil (Less Than or Equal To 50 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of avanafil.(1) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inhibitor may result in elevated levels of avanafil, which may result in increased adverse effects such as hypotension, visual changes, and priapism. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of avanafil states that in patients receiving moderate inhibitors of CYP3A4, the dose of avanafil should be limited to 50 mg in 24 hours.(1) DISCUSSION: Ketoconazole (400 mg daily), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of avanafil (50 mg) by 3-fold and 13-fold, respectively. The half-life of avanafil increased from 5 hours to 9 hours.(1) Ritonavir (600 mg BID), a strong inhibitor of CYP3A4 and an inhibitor of 2C19, increased the Cmax and AUC of a single dose of avanafil (50 mg) by 2-fold and 13-fold, respectively. The half-life of avanafil increased from 5 hours to 9 hours.(1) Erythromycin (500 mg BID), a moderate inhibitor of CYP3A4, increased the Cmax and AUC of a single dose of avanafil (200 mg) by 2-fold and 3-fold, respectively. The half-life of avanafil increased from 5 hours to 8 hours.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, grapefruit juice, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(1-3) |
AVANAFIL, STENDRA |
| Suvorexant (Less Than or Equal To 10 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of suvorexant.(1) CLINICAL EFFECTS: Concurrent use of an agent that is a moderate inhibitor of CYP3A4 may result in elevated levels of and clinical effects of suvorexant.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of suvorexant recommends a starting dose of 5 mg daily and a maximum dose of 10 mg daily in patients receiving concurrent therapy with a moderate CYP3A4 inhibitor.(1) DISCUSSION: Diltiazem, a moderate inhibitor of CYP3A4, increased suvorexant AUC and Cmax by approximately 2-fold and 1.25-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, erythromycin, duvelisib, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(1-3) |
BELSOMRA |
| Bromocriptine; Cabergoline/Selected CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Certain azole antifungals (itraconazole(1,6), ketoconazole(2), posaconazole(3,4), and voriconazole(5)), protease inhibitors (amprenavir(7), atazanavir(8), boceprevir(9), darunavir(10), fosamprenavir(11), indinavir(12), lopinavir(13), nelfinavir(14), nirmatrelvir/ritonavir,(15) ritonavir(16), saquinavir(17), telaprevir(18), and tipranavir(19)), and other strong CYP3A4 inhibitors (cobicistat, idelalisib, levoketoconazole, mibefradil, nefazodone, and ribociclib(20)) may inhibit the metabolism of bromocriptine and cabergoline by CYP3A4. CLINICAL EFFECTS: Concurrent use of bromocriptine or cabergoline with azole antifungals, protease inhibitors, or other strong CYP3A4 inhibitors may result in increased levels of bromocriptine and cabergoline, which may result in increased side effects of these agents. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Use caution with concurrent therapy with bromocriptine and cabergoline with azole antifungals, protease inhibitors, or other strong CYP3A4 inhibitors. DISCUSSION: Itraconazole has been shown to increase cabergoline concentrations with concurrent use. A case report including 2 patients with concurrent therapy of cabergoline and itraconazole noted plasma levels of cabergoline to be increased by 300% in one of the patients. This increase in cabergoline concentrations was noted to increase clinical improvement.(6) Posaconazole has been shown to inhibit the CYP3A4 mediated metabolism of midazolam by 83%.(3) Voriconazole (400 mg every 12 hours for one day, then 200 mg every 12 hours for 8 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of sirolimus (2 mg) by 7-fold and 11-fold, respectively. Ergot alkaloids are metabolized by the same isoenzyme system.(5) |
BROMOCRIPTINE MESYLATE, CABERGOLINE, CYCLOSET |
| Pimavanserin (Less Than or Equal To 10 mg)/Strong CYP3A4 Inhibitors; Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents which inhibit the CYP3A4 enzyme may inhibit the metabolism of pimavanserin.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors or HIV protease inhibitors may increase systemic exposure and the risk for pimavanserin toxicities such as peripheral edema, confusion, or QT prolongation.(1,2) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: When concomitant use of pimavanserin and a strong CYP3A4 inhibitor or HIV protease inhibitor is needed, the pimavanserin dose should be reduced to 10 mg once daily.(1,2) With unboosted atazanavir, consider using alternative antipsychotic agents.(2) During concomitant therapy with a strong CYP3A4 inhibitor or HIV protease inhibitor, monitor patients closely for prolongation of the QT interval. Obtain serum calcium, magnesium, and potassium levels and monitor ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a drug interaction study, ketoconazole increased pimavanserin maximum concentration (Cmax) 1.5-fold and area-under-curve(AUC) 3-fold. A thorough QTc study performed in 252 subjects found a mean maximum change from baseline of 13.5 msec (upper bound of the 90% confidence interval was 16.6 msec) at twice the therapeutic dose.(1) Thus, coadministration of pimavanserin and a QT prolonging agent, even at a reduced dose, may increase the risk for significant QT prolongation. CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, telaprevir, tipranavir, troleandomycin, and tucatinib.(4) |
NUPLAZID |
| Acalabrutinib/Selected Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents that inhibit the CYP3A4 isoenzyme may inhibit the metabolism of acalabrutinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase levels of and effects from acalabrutinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Recommendations for management of this interaction vary in different regions. The US and Australian manufacturers of acalabrutinib state that the concurrent chronic use of strong CYP3A4 inhibitors with acalabrutinib is not recommended. For short-term use of strong CYP3A4 inhibitors, such as 7 days or less of antibiotics/antifungals, consider interruption of acalabrutinib therapy. If a moderate CYP3A4 inhibitor is required, reduce the dose of acalabrutinib to 100 mg once daily.(1,2) The UK manufacturer of acalabrutinib makes the same recommendation regarding strong CYP3A4 inhibitors, but states that no dose adjustment is needed for concurrent use of acalabrutinib with moderate CYP3A4 inhibitors. Patients should be monitored closely for adverse effects.(3) DISCUSSION: In a study with healthy volunteers, single-dose fluconazole 400 mg and isavuconazole 200 mg daily for 5 days (both moderate CYP3A4 inhibitors) increased the maximum concentration (Cmax) and area-under-curve (AUC) of acalabrutinib by 1.4- to 2-fold. The Cmax and AUC of the active metabolite ACP-5862 was decreased by 0.65- to 0.88-fold.(2) A physiologically based pharmacokinetic simulation with acalabrutinib and moderate CYP3A inhibitors (erythromycin, fluconazole, diltiazem) predicted that coadministration increases acalabrutinib Cmax and AUC by 2- to almost 3-fold.(1) In a study in healthy subjects, itraconazole (200mg once daily for 5 days, a strong inhibitor) increased the Cmax and AUC of acalabrutinib by 3.9-fold and 5.1-fold, respectively.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, grapefruit juice, imatinib, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(4,5) |
CALQUENCE |
| Ivosidenib/Selected Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents which inhibit the CYP3A4 enzyme may inhibit the metabolism of ivosidenib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase systemic exposure and the risk for ivosidenib toxicities such as QT prolongation.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of ivosidenib recommends considering an alternative concomitant medication with less potential for CYP3A4 inhibition.(1) During concomitant therapy with a moderate CYP3A4 inhibitor, monitor patients closely for prolongation of the QT interval. Obtain serum calcium, magnesium, and potassium levels and monitor ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: In a drug interaction study in healthy subjects, coadministration of itraconazole (200 mg once daily for 18 days) with a single dose of ivosidenib (250 mg) increased ivosidenib area-under-the-curve (AUC) by 269%. No change was seen in ivosidenib's maximum concentration (Cmax).(1) Data from a pharmacokinetic simulation suggests that fluconazole, a moderate CYP3A4 inhibitor, may increase ivosidenib (500 mg) single-dose AUC by 173%. In regards to multiple-dosing, coadministration of ivosidenib with fluconazole is predicted to increase ivosidenib Cmax and AUC by 152% and 190%, respectively.(1) Moderate CYP3A4 inhibitors linked to this monograph include amprenavir, berotralstat, clofazimine, conivaptan, fluvoxamine, fosamprenavir, letermovir, schisandra, tofisopam, and treosulfan.(3) |
TIBSOVO |
| Brexpiprazole/Strong CYP3A4 Inhibitors; Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong CYP3A4 inhibitors may inhibit the metabolism of brexpiprazole.(1) CLINICAL EFFECTS: Concurrent administration of a strong CYP3A4 inhibitor may result in elevated levels of and toxicity from brexpiprazole.(1) PREDISPOSING FACTORS: With brexpiprazole(1) this interaction is expected to be more severe in patients who are CYP2D6 poor metabolizers, or who receive concomitant treatment with a strong CYP2D6 inhibitor (e.g. bupropion, fluoxetine, paroxetine, quinidine) in addition to treatment with a strong CYP3A4 inhibitor. Strong CYP3A4 inhibitors are expected to increase brexpiprazole levels 4.8-fold in poor CYP2D6 metabolizers. Concurrent use of strong CYP2D6 and CYP3A4 inhibitors is expected to increase brexpiprazole levels 5.1-fold in extensive metabolizers of CYP2D6. With brexpiprazole, the interaction may also be more severe in patients taking moderate CYP2D6 inhibitors.(1) PATIENT MANAGEMENT: The US manufacturer of brexpiprazole recommends the following dose adjustments for patients who are receiving a strong CYP3A4 inhibitor: - in patients taking a strong CYP3A4 inhibitor without a strong or moderate CYP2D6 inhibitor, administer half the usual dosage of brexpiprazole. - in patients taking a strong CYP3A4 inhibitor who are poor CYP2D6 metabolizers or are receiving a strong or moderate inhibitor of CYP2D6, decrease the dose to one-fourth the usual dose.(1) The dose of brexpiprazole should be adjusted to its original level if the CYP3A4 inhibitor is discontinued.(1) The US Department of Health and Human Services HIV guidelines recommend that patients taking any ritonavir- or cobicistat-boosted protease inhibitor have their dose of brexpiprazole decreased to 25% of the usual dose. Patients on unboosted atazanavir should have their dose of brexpiprazole decreased to 50% of the usual dose.(2) DISCUSSION: Coadministration of ketoconazole increased the AUC of brexpiprazole approximately 2-fold.(1) CYP3A4 inhibitors linked to this monograph include: adagrasib, amprenavir, atazanavir, boceprevir, clarithromycin, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, tucatinib, and voriconazole.(3) |
REXULTI |
| Lidocaine/Selected Protease Inhibitors; Cobicistat SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Protease inhibitors(1-15) may inhibit the metabolism of lidocaine via CYP3A4. CLINICAL EFFECTS: Concurrent use of protease inhibitors(1-15) with antiarrhythmic doses of lidocaine may result in elevated levels and toxicity from lidocaine. PREDISPOSING FACTORS: Lidocaine clearance is significantly impaired in patients with moderate or severe hepatic impairment. PATIENT MANAGEMENT: The US manufacturers of atazanavir,(1) atazanavir-cobicistat,(2) darunavir,(4) darunavir-cobicistat,(5) fosamprenavir,(8) indinavir,(10) lopinavir-ritonavir,(11) nelfinavir,(12) nirmatrelvir/ritonavir,(13) ombitasvir-paritaprevir-ritonavir,(14) and tipranavir(15) recommend caution and therapeutic concentration monitoring when lidocaine is administered concurrently as an antiarrhythmic. Recommendations differ in other regions. The UK manufacturer of atazanavir-cobicistat(3) and the Canadian manufacturer of darunavir,(6) darunavir-cobicistat,(7) and fosamprenavir(9) state that concurrent use of lidocaine is contraindicated. DISCUSSION: The protease inhibitors are moderate to strong inhibitors of CYP3A4, one of the metabolic pathways for lidocaine elimination.(16-17) |
LIDOCAINE, LIDOCAINE HCL, LIDOCAINE HCL IN 5% DEXTROSE |
| Iloperidone/Selected Strong CYP3A4 Inhibitors;Protease Inhib SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong CYP3A4 inhibitors and protease inhibitors may inhibit the metabolism of iloperidone.(1,2) CLINICAL EFFECTS: Concurrent administration of a strong CYP3A4 inhibitor or protease inhibitor may result in elevated levels of and toxicity from iloperidone.(1,2) Elevated levels of iloperidone may increase the risk of QTc prolongation.(1) PREDISPOSING FACTORS: With iloperidone, 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. 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).(1,3) PATIENT MANAGEMENT: The dose of iloperidone should be reduced to one-half of its normal dose when strong CYP3A inhibitors or protease inhibitors are coadministered.(1,2) If the patient is also receiving a CYP2D6 inhibitor, iloperidone should be reduced to one-half of its normal dose but no additional dose reduction is required with both a CYP2D6 inhibitor and CYP3A4 inhibitor. When the inhibitor is discontinued, the dose of iloperidone should be increased.(1) When concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Coadministration of ketoconazole (200 mg twice daily for 4 days) increased the AUC of iloperidone (3 mg single dose) and its P88 and P95 metabolites by 57%, 55%, and 35%, respectively.(1) Coadministration of ketoconazole (200 mg twice daily) and iloperidone (12 mg twice daily) was associated with a mean QTcF increase of 19 msec from baseline, compared with an increase of 9 msec with iloperidone alone.(1) Coadministration of ketoconazole and paroxetine (a CYP2D6 inhibitor) did not increase the effects on iloperidone compared with either agent alone.(1) CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, telaprevir, tipranavir, and tucatinib.(2,4) |
FANAPT |
| Oral Lefamulin/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of oral lefamulin.(1,2) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in elevated levels and increased effects of lefamulin, such as QT prolongation. PREDISPOSING FACTORS: The risk of QT prolongation or torsade de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsade de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsade de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(4) PATIENT MANAGEMENT: The US manufacturer of lefamulin states that oral lefamulin coadministration with moderate inhibitors of CYP3A4 should be monitored for adverse effects.(1) During concomitant therapy with a moderate CYP3A4 inhibitor, monitor patients closely for prolongation of the QT interval. Obtain serum calcium, magnesium, and potassium levels and monitor ECG at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: Coadministration of ketoconazole (strong CYP3A4 inhibitor) with lefamulin tablets increased lefamulin area-under-the-curve (AUC) and maximum concentration (Cmax) by 165% and 58%.(1) Moderate inhibitors of CYP3A4 include: amprenavir, avacopan, clofazimine, conivaptan, duvelisib, fedratinib, fosamprenavir, fosnetupitant, imatinib, lenacapavir, letermovir, netupitant, schisandra, tofisopam and treosulfan.(1,3) |
XENLETA |
| Zanubrutinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of zanubrutinib.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from zanubrutinib.(1) PREDISPOSING FACTORS: Patients with severe hepatic impairment (Child-Pugh class C) have elevated zanubrutinib plasma concentrations and may be more susceptible to the effects of this interaction.(1) PATIENT MANAGEMENT: The dosage of zanubrutinib should be reduced to 80 mg twice daily when co-administered with moderate CYP3A4 inhibitors. Modify the dose as recommended by prescribing information for adverse reactions.(1) DISCUSSION: Co-administration with itraconazole 200 mg once daily, a strong CYP3A4 inhibitor, increased zanubrutinib concentration maximum (Cmax) and area-under-curve (AUC) by 157% and 278%, respectively. It is predicted co-administration with fluconazole 200 mg daily, a moderate CYP3A4 inhibitor, would increase zanubrutinib Cmax and AUC by 179% and 177%, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(2-4) |
BRUKINSA |
| Mefloquine/Selected Strong CYP3A4 Inhibitors;Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Inhibitors of CYP3A4 may inhibit the metabolism of mefloquine.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors or protease inhibitors with mefloquine may result in elevated levels of mefloquine and toxicity.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of mefloquine states that concurrent use with strong CYP3A4 inhibitors should be approached with caution.(1) The US Department of Health and Human Services HIV guidelines recommend considering alternative therapies to protease inhibitors or monitoring for adverse events and virologic response.(2) DISCUSSION: In a study in 8 healthy subjects, administration of ketoconazole (400 mg daily) for 10 days followed by a single 500 mg dose of mefloquine resulted in an increase in the AUC of mefloquine by 79%. The elimination half-life was increased from 322 hours to 448 hours.(1) Strong CYP3A4 inhibitors and protease inhibitors linked to this monograph include: adagrasib, atazanavir, boceprevir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, itraconazole, josamycin, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(3,4) |
MEFLOQUINE HCL |
| Ubrogepant/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of ubrogepant.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in elevated levels of ubrogepant.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer recommends a dosage adjustment of ubrogepant when used concomitantly with moderate CYP3A4 inhibitors. Initial dose of ubrogepant should not exceed 50 mg. A second dose should be avoided within 24 hours of the first dose when used concurrently with moderate CYP3A4 inhibitors.(1) DISCUSSION: Co-administration with verapamil, a moderate CYP3A4 inhibitor, resulted in a 3.5-fold and 2.8-fold increase in area-under-curve (AUC) and concentration maximum (Cmax), respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(2-4) |
UBRELVY |
| Avapritinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of avapritinib.(1) CLINICAL EFFECTS: Concurrent use of avapritinib with a moderate CYP3A4 inhibitor increases avapritinib plasma concentrations, which may increase the incidence and severity of adverse reactions of avapritinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant use of avapritinib with strong or moderate CYP3A4 inhibitors. If coadministration of avapritinib with a moderate CYP3A4 inhibitor cannot be avoided, reduce the dose of avapritinib to 100 mg once daily for treatment of gastrointestinal stromal tumors or 50 mg once daily for treatment of advanced systemic mastocytosis.(1) DISCUSSION: Coadministration of avapritinib 300 mg once daily with fluconazole 200 mg once daily, a moderate CYP3A4 inhibitor, is predicted to increase avapritinib AUC by 210% at steady state.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(2,3) |
AYVAKIT |
| Rimegepant/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Rimegepant is primarily metabolized by CYP3A4. Moderate inhibitors of CYP3A4 may decrease the metabolism of rimegepant.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in increased levels of and toxicity from rimegepant.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of rimegepant recommends avoiding a second dose of rimegepant within 48 hours of a first dose when used concomitantly with moderate CYP3A4 inhibitors.(1) DISCUSSION: In a drug interaction study (n=23), fluconazole, a moderate CYP3A4 inhibitor, increased rimegepant mean area-under-curve from time 0 to infinity (AUC 0-inf) by 1.8-fold (90% confidence interval 1.68-1.93), with no impact on the maximum concentration (Cmax) (1.04-fold; 90% CI 0.94-1.15). (2) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam and treosulfan.(3-4) |
NURTEC ODT |
| Selected Benzodiazepines/Protease Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Protease inhibitors may inhibit the metabolism of benzodiazepines that are metabolized by CYP3A4.(1) CLINICAL EFFECTS: Inhibition of benzodiazepine CYP3A4 metabolism by protease inhibitors may produce increased levels of, as well as increased clinical effects, of benzodiazepines. Toxic effects of increased benzodiazepine levels include profound sedation, respiratory depression, coma, and/or death. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The NIH Guidelines for Use of Antiretroviral Agents advise considering use of alternative benzodiazepines that do not undergo CYP metabolism, like lorazepam, oxazepam, and temazepam.(1) The manufacturers of the protease inhibitors recommend close clinical monitoring for respiratory depression and/or prolonged sedation and consideration of dosage adjustment of the benzodiazepine.(2-5) The manufacturers of some benzodiazepines (i.e., diazepam, estazolam, midazolam) advise caution when they are coadministered with inhibitors of CYP3A4 and to consider dose reduction of the benzodiazepine.(6-8) Monitor patients receiving concurrent therapy with protease inhibitors and benzodiazepines carefully for increased effects including unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness. DISCUSSION: The interaction between most benzodiazepines and protease inhibitors has not been studied. Benzodiazepines are primarily metabolized by CYP3A4 and CYP2C19. Protease inhibitors are moderate to strong inhibitors of CYP3A4, and an elevation in benzodiazepine effects and concentrations with concomitant therapy can be expected. Benzodiazepines linked to this monograph include: brotizolam, chlordiazepoxide, clonazepam, clorazepic acid, diazepam, estazolam, etizolam, flunitrazepam, flurazepam, halazepam, non-oral midazolam, prazepam, and quazepam. Protease inhibitors linked to this monograph include: ritonavir-boosted lopinavir, nirmatrelvir, saquinavir, tipranavir; cobicistat- or ritonavir-boosted darunavir; cobicistat-boosted, ritonavir-boosted or unboosted atazanavir; ritonavir-boosted or unboosted amprenavir, fosamprenavir, indinavir; and nelfinavir. |
CHLORDIAZEPOXIDE HCL, CHLORDIAZEPOXIDE-AMITRIPTYLINE, CHLORDIAZEPOXIDE-CLIDINIUM, CLONAZEPAM, CLORAZEPATE DIPOTASSIUM, DIAZEPAM, DORAL, ESTAZOLAM, FLURAZEPAM HCL, KLONOPIN, LIBRAX, 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, QUAZEPAM, VALIUM, VALTOCO |
| Daridorexant (Less Than or Equal To 25 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of daridorexant.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels of and effects from daridorexant including somnolence, fatigue, CNS depressant effects, daytime impairment, or headache.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The dose of daridorexant should be limited to 25 mg daily when used with a moderate CYP3A4 inhibitor.(1) DISCUSSION: Daridorexant is a CYP3A4 substrate. In a PKPB model, concurrent use of daridorexant with diltiazem, a moderate CYP3A4 inhibitor, increased daridorexant area-under-curve (AUC) and maximum concentration (Cmax) by 2.4-fold and 1.4-fold, respectively.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(2) |
QUVIVIQ |
| Mitapivat (Less Than or Equal To 20 mg)/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of mitapivat.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels of and effects from mitapivat including decreased estrone and estradiol levels in males, increased urate, back pain, and arthralgias.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of moderate CYP3A4 inhibitors with mitapivat should be monitored closely for increased risk of adverse reactions. Mitapivat dose should not exceed 20 mg twice daily with concurrent moderate CYP3A4 inhibitors.(1) DISCUSSION: Mitapivat is a CYP3A4 substrate. In a pharmacokinetic study with mitapivat 5, 20, or 50 mg twice daily dosing, fluconazole increased mitapivat area-under-curve (AUC) and concentration maximum (Cmax) by 2.6-fold and 1.6-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, erythromycin, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(2)(2) |
PYRUKYND |
| Pacritinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents that inhibit the CYP3A4 isoenzyme may inhibit the metabolism of pacritinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase levels of and effects from pacritinib.(1) Elevated levels of pacritinib may result in QTc prolongation, which may result in potentially life-threatening cardiac arrhythmias, including torsades de pointes (TdP). Other toxicities include bleeding, diarrhea, thrombocytopenia, major adverse cardiovascular events, thrombosis, and infection.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The manufacturer of pacritinib recommends monitoring patients concomitantly receiving moderate CYP3A4 inhibitors (e.g., fluconazole) for increased adverse reactions and considering pacritinib dose modifications based on safety.(1) When concurrent therapy is warranted monitor for prolongation of the QTc interval.(1) Consider obtaining serum calcium, magnesium, and potassium levels and monitoring EKG at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. If patients develop QTc prolongation >500 msec or >60 msec from baseline, hold pacritinib. If QTc prolongation resolves to <=480 msec or to baseline within 1 week, resume pacritinib at the same dose. If time to resolution of the QTc interval takes greater than 1 week to resolve, reduce the pacritinib dose according to labeling.(1) DISCUSSION: Fluconazole (200 mg once daily for 7 days, a moderate CYP3A4 inhibitor) increased maximum concentration (Cmax) and area-under-curve (AUC) of pacritinib (200 mg twice daily at steady state) by 41% and 45%, respectively.(1) Concomitant use of pacritinib with doses of fluconazole greater than 200 mg once daily have not been studied.(1) Clarithromycin (500 mg twice daily for 5 days, a strong CYP3A4 inhibitor) increased maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of pacritinib (400 mg) by 80% and 30%, respectively.(1) In a 24 week clinical study, patients treated with pacritinib 200 mg twice daily had a change in QTc from baseline of 11 msec (90% CI: 5-17).(1) Pacritinib has been associated with QTc interval prolongation. In clinical trials, patients with QTc prolongation >500 msec occurred in 1.4% of patients in the treatment arm compared to 1% in the control arm. The treatment arm had a greater incidence of an increase in QTc > 60 msec from baseline than the control arm (1.9% vs 1%, respectively). QTc prolongation adverse reactions were higher in the treatment arm than the control group (3.8% vs 2%, respectively).(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, schisandra, tofisopam, treosulfan, verapamil and voxelotor.(3,4) |
VONJO |
| Selected Protease Inhibitors/Nirmatrelvir-Ritonavir SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Nirmatrelvir-ritonavir may inhibit the metabolism of amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir.(1-11) CLINICAL EFFECTS: Concurrent administration of nirmatrelvir-ritonavir with amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir may increase levels and toxicity of the protease inhibitors.(1-11) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of nirmatrelvir-ritonavir states that no dose adjustment is needed when coadministered with other ritonavir- or cobicistat-containing products. Patients on ritonavir-boosted or cobicistat-boosted HIV regimens should continue their HIV therapy while on nirmatrelvir-ritonavir. Monitor patients closely for adverse effects.(1,2) DISCUSSION: Nirmatrelvir-ritonavir is a strong CYP3A4 inhibitor and may increase the levels of CYP3A4 substrates, including amprenavir, atazanavir, darunavir, fosamprenavir, indinavir, lopinavir, nelfinavir, saquinavir, and tipranavir.(1-11) |
PAXLOVID |
| Mometasone/Selected CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: CYP3A4 inhibitors may inhibit the metabolism of mometasone.(1-14,17) CLINICAL EFFECTS: Concurrent use of CYP3A4 inhibitors may result in increased systemic exposure to and effects from mometasone, including Cushing's syndrome and adrenal suppression.(1-14,17) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Use caution when using concurrent therapy with mometasone and CYP3A4 inhibitors. Alternative corticosteroids that are less affected by CYP3A4 inhibitors should be considered, like beclomethasone and prednisolone.(14) If concurrent therapy is warranted, patients should be closely monitored for systemic effects. The corticosteroid may need to be discontinued. DISCUSSION: In a study in 24 healthy subjects, inhaled mometasone furoate (400 mcg delivered by a dry powder inhaler twice daily for 9 days) with ketoconazole (200 mg on Days 4 to 9) increased systemic mometasone furoate concentrations from <150 pg/mL on Day 3 prior to coadministration of ketoconazole to a peak plasma concentrations of mometasone furoate >200 pg/mL on Day 9 (211-324 pg/mL).(14) There have been several case reports of Cushing's syndrome in patients treated concurrently with ritonavir and nasal fluticasone and mometasone.(15) A review of corticosteroid use patients on protease inhibitors detailed the interactions that can result in accumulation of corticosteroids, leading to adrenal suppression and Cushing's syndrome.(16) Selected CYP3A4 inhibitors linked to this monograph include: atazanavir, boceprevir, ceritinib, cobicistat, darunavir, fosamprenavir, idelalisib, indinavir, lenacapavir, lonafarnib, lopinavir, mibefradil, nelfinavir, nirmatrelvir, paritaprevir, saquinavir, telaprevir, tipranavir, and tucatinib.(17) |
ASMANEX, ASMANEX HFA, DULERA, MOMETASONE FUROATE, RYALTRIS, SINUVA |
| Lumateperone (<=10.5 mg)/Strong CYP3A4 Inhib; Protease Inhib SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong inhibitors of CYP3A4 and protease inhibitors may inhibit the metabolism of lumateperone.(1,2) CLINICAL EFFECTS: Concurrent use of lumateperone with strong CYP3A4 inhibitors or protease inhibitors increases lumateperone exposure, which may increase the risk of adverse reactions.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lumateperone recommends decreasing the dosage of lumateperone to 10.5 mg once daily in patients receiving strong CYP3A4 inhibitors.(1) The US Department of Health and Human Services HIV guidelines state that protease inhibitors should not be coadministered with lumateperone.(2) DISCUSSION: Coadministration of lumateperone with itraconazole, a strong CYP3A4 inhibitor, resulted in a 4-fold and 3.5-fold increase in area-under-curve (AUC) and concentration maximum (Cmax), respectively.(1) Coadministration of lumateperone with diltiazem, a moderate CYP3A4 inhibitor, resulted in a 2.5-fold and 2-fold increase AUC and Cmax, respectively.(1) Strong inhibitors of CYP3A4 include: adagrasib, amprenavir, atazanavir, boceprevir, ceritinib, clarithromycin, cobicistat, darunavir, fosamprenavir, grapefruit, idelalisib, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir/ritonavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, posaconazole, ribociclib, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(2-4) |
CAPLYTA |
| Tadalafil (PAH)/Select Protease Inhibitors; Cobicistat SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: The protease inhibitors may inhibit the metabolism of tadalafil.(1-10) CLINICAL EFFECTS: The concurrent administration of a protease inhibitor may result in elevated levels of tadalafil, which may result in increased adverse effects such as hypotension, visual changes, and priapism.(1-10) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturers of the protease inhibitors state that in patients who have received a protease inhibitor for at least one week, the initial dosage of tadalafil for the treatment of primary pulmonary hypertension should be 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(2-10) The US manufacturers of the protease inhibitors state that in patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be discontinued for 24 hours before beginning protease inhibitor therapy other than nelfinavir without concurrent ritonavir. After one week, tadalafil may be resumed at a dosage of 20 mg daily. The dosage may be increased to 40 mg daily based upon tolerability.(2-10) In patients who have been receiving tadalafil for the treatment of primary pulmonary hypertension, tadalafil should be adjusted to 20 mg daily prior to beginning therapy with nelfinavir without concurrent ritonavir. The dosage may be increased to 40 mg daily based upon tolerability.(7) The US manufacturers of tadalafil(1) and the protease inhibitors(2-10) state that the recommended dose of as needed tadalafil for the treatment of erectile dysfunction is 10 mg of tadalafil every 72 hours in patients receiving concurrent therapy. The US manufacturer of tadalafil states that the recommended dose of daily tadalafil for the treatment of erectile dysfunction in patients taking potent inhibitors of CYP3A4 is 2.5 mg.(1) Patients should be counseled that they are at an increased risk of tadalafil adverse effects, including hypotension, syncope, visual changes, and priapism. Patients experiencing these effects should report them promptly to their physician. DISCUSSION: Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (500 mg or 600 mg twice daily) increased tadalafil area-under-curve (AUC) by 32% and decreased tadalafil concentration maximum (Cmax) by 30%. Concurrent administration of tipranavir/ritonavir (500/200 mg twice daily for 17 doses) had no significant effects on the AUC of a single dose of tadalafil (10 mg). Tadalafil Cmax decreased 30%. Tipranavir Cmax, AUC, and concentration minimum (Cmin) decreased by 10%, 15%, and 19%, respectively. Administration of a single dose of tipranavir/ritonavir (500/200 mg) increased the AUC of a single dose of tadalafil (10 mg) by 2.33-fold. Tadalafil Cmax decreased 22%. Concurrent administration of a single dose of tadalafil (20 mg) with ritonavir (200 mg twice daily) increased tadalafil AUC by 124%. |
ADCIRCA, ALYQ, OPSYNVI, TADALAFIL, TADLIQ |
| Larotrectinib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Agents which inhibit the CYP3A4 enzyme may inhibit the metabolism of larotrectinib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase systemic exposure and the risk for larotrectinib toxicities such as neurotoxicity or hepatotoxicity.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving a moderate CYP3A4 inhibitor concurrently with larotrectinib should be monitored for adverse effects more frequently. A dose reduction may be needed based on the severity of adverse effects. Refer to prescribing information for dosage modifications. DISCUSSION: In a drug interaction study in healthy subjects, coadministration of itraconazole (a strong CYP3A4 inhibitor) with a single dose of larotrectinib (100 mg) increased larotrectinib maximum concentration (Cmax) and area-under-the-curve (AUC) by 2.8 and 4.3-fold, respectively.(1) Fluconazole (a moderate CYP3A4 inhibitor) is predicted to increase the AUC and Cmax of larotrectinib by 2.7-fold and 1.9-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2,3) |
VITRAKVI |
| Palovarotene/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of palovarotene.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in elevated levels of and toxicity from palovarotene, including rash, alopecia, skin exfoliation, photosensitivity, reduction in bone mass, hyperostosis, and night blindness.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of moderate CYP3A4 inhibitors with palovarotene should be avoided. If concurrent use cannot be avoided, reduce the dose of palovarotene by half, according to the US prescribing information.(1) DISCUSSION: In a clinical trial, erythromycin, a moderate CYP3A4 inhibitor, increased the maximum concentration (Cmax) and area-under-curve (AUC) of palovarotene by 1.6- and 2.5-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, voxelotor.(3,4) |
SOHONOS |
| Etrasimod/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Strong and moderate inhibitors of CYP3A4 may impair the CYP3A4-mediated metabolism of etrasimod.(1) Etrasimod is metabolized by CYP2C8, CYP2C9, and CYP3A4.(1) CLINICAL EFFECTS: In patients who are poor metabolizers of CYP2C9 or are also taking a strong or moderate CYP2C9 inhibitor, concurrent use of a strong or moderate inhibitor of CYP3A4 may result in elevated levels of and clinical effects from etrasimod including immunosuppression, decreased lung function, bradycardia, and AV conduction delays. PREDISPOSING FACTORS: CYP2C9 poor metabolizers (e.g., *2/*3, *3/*3) may have decreased clearance of etrasimod when etrasimod is used concomitantly with strong or moderate inhibitors of CYP3A4. Patients who are also taking a strong or moderate CYP2C9 inhibitor may also have decreased etrasimod clearance.(1) PATIENT MANAGEMENT: Concomitant use of etrasimod with strong or moderate CYP3A4 inhibitors in patients who are CYP2C9 poor metabolizers is not recommended.(1) Concomitant use with strong or moderate CYP3A4 inhibitors in patients who are also taking a strong or moderate CYP2C9 inhibitor is not recommended. (1) DISCUSSION: CYP2C9 activity is decreased in individuals with genetic variants such as CYP2C9*2 and CYP2C9*3 alleles. The impact of CYP2C9 genetic variants on the pharmacokinetics of etrasimod has not been directly evaluated. Increased exposure of etrasimod in patients who are CYP2C9 poor metabolizers is expected with concomitant use of moderate to strong inhibitors of CYP3A4.(1) Concomitant use of etrasimod with steady-state fluconazole (a moderate CYP2C9 and CYP3A4 inhibitor) increased etrasimod area-under-curve (AUC) by 84%.(1) Strong inhibitors of CYP3A4 include: boceprevir, cobicistat, grapefruit, indinavir, itraconazole, josamycin, ketoconazole, mibefradil, nefazodone, nelfinavir, nirmatrelvir/ritonavir, paritaprevir, telaprevir, tipranavir, troleandomycin, and tucatinib.(2,3) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, darunavir, fluvoxamine, fosamprenavir, fosnetupitant, isavuconazonium, letermovir, lenacapavir, netupitant, schisandra, tofisopam, and voxelotor.(2,3) |
VELSIPITY |
| Capivasertib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the CYP3A4 metabolism of capivasertib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may result in increased systemic exposure to and effects from capivasertib, hyperglycemia, severe diarrhea, and cutaneous adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concomitant use of capivasertib with moderate CYP3A4 inhibitors requires a dose reduction of capivasertib. Reduce the capivasertib dose to 320 mg twice daily for 4 days followed by 3 days off.(1) After discontinuation of the strong CYP3A4 inhibitor for 3 to 5 half-lives of the inhibitor, resume the capivasertib dosage that was taken prior to initiating the strong CYP3A4 inhibitor.(1) DISCUSSION: Itraconazole (strong CYP3A4 inhibitor) is predicted to increase capivasertib area-under-curve (AUC) by up to 1.7-fold and maximum concentration (Cmax) by up to 1.4-fold.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, voxelotor.(2,3) |
TRUQAP |
| Finerenone/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of finerenone.(1) CLINICAL EFFECTS: Concurrent use of finerenone with a moderate inhibitor of CYP3A4 increases finerenone concentrations and may increase the risk of toxicity (e.g., hyperkalemia, hypotension).(1) PREDISPOSING FACTORS: Severe renal disease and concurrent use of potassium supplements increase the risk for hyperkalemia. PATIENT MANAGEMENT: The manufacturer of finerenone states that use with moderate CYP3A4 inhibitors should be closely monitored. Check serum potassium during drug initiation or dosage adjustment of either finerenone or the moderate CYP3A4 inhibitor. Dose adjustment of finerenone may be necessary.(1) DISCUSSION: Concurrent use of finerenone with erythromycin, a moderate CYP3A4 inhibitor, increased finerenone area-under-curve (AUC) by 248% and maximum concentration (Cmax) by 88%.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, voxelotor.(2,3) |
KERENDIA |
| Macitentan/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Macitentan is primarily metabolized by CYP3A4, with minor contributions from CYP2C8, CYP2C9, and CYP2C19. Moderate inhibitors of CYP3A4 may inhibit the metabolism of macitentan.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in elevated levels and increased effects of macitentan, including hepatotoxicity and fluid retention.(1) PREDISPOSING FACTORS: Concomitant use of a moderate CYP2C9 inhibitor increases the magnitude of this interaction and the risk of adverse events. PATIENT MANAGEMENT: The manufacturer of macitentan states that concurrent use of both a moderate CYP2C9 inhibitor and a moderate CYP3A4 inhibitor should be avoided.(1) While the manufacturer does not provide recommendations for concurrent use of a moderate CYP3A4 inhibitor alone, it would be prudent to use caution and monitor for adverse effects. DISCUSSION: Based on pharmacokinetic (PBPK) modeling, dual moderate inhibitors of CYP2C9 and CYP3A4 such as fluconazole are predicted to increase macitentan exposure by 4-fold.(1) Pretreatment with ketoconazole increased the area-under-curve (AUC) and maximum concentration (Cmax) of macitentan by approximately 2.3 and 1.3-fold, respectively.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2) |
OPSUMIT, OPSYNVI |
| Lonafarnib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of lonafarnib.(1) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors with lonafarnib may increase the risk of adverse reactions including QT prolongation and potentially life-threatening cardiac arrhythmias like torsades de pointes, nausea and vomiting, increased liver enzymes, myelosuppression, and hypertension.(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(2) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The use of lonafarnib with moderate CYP3A4 inhibitors should be approached with caution. No dose adjustment of lonafarnib is recommended when moderate CYP3A4 inhibitors are added to steady-state lonafarnib. When initiating lonafarnib therapy in a patient already taking a moderate CYP3A4 inhibitor, monitor the patient closely for the first 7 days of therapy. If the patient does not tolerate lonafarnib, consider an alternative that is not a moderate CYP3A4 inhibitor.(1) Lonafarnib dose modification recommendation: if the QTc interval is greater than or equal to 500 msec, withhold lonafarnib until the QTc interval is less than 470 msec, then resume lonafarnib at the same dosage.(1) If concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities.(1) Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: With coadministration of a single oral dose of 50 mg lonafarnib following 200 mg ketoconazole (a strong CYP3A4 inhibitor) once daily for 5 days, the area-under-curve (AUC) and maximum concentration (Cmax) were increased by 425% and 270%, respectively.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, berotralstat, clofazimine, darunavir, diltiazem, duvelisib, fedratinib, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nirogacestat, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2,3) |
ZOKINVY |
| Mavorixafor/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors may inhibit the metabolism of mavorixafor.(1) Mavorixafor is also a substrate of P-glycoprotein (P-gp). P-gp inhibitors may increase mavorixafor exposure.(1) Many CYP3A4 inhibitors also inhibit P-glycoprotein (P-gp), including cimetidine, diltiazem, fluvoxamine, isavuconazonium, schisandra, and verapamil.(2) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase the levels and effects of mavorixafor, including thrombocytopenia and QTc prolongation, which may result in potentially life-threatening cardiac arrhythmias like torsades de pointes (TdP).(1) PREDISPOSING FACTORS: The risk of QT prolongation or torsades de pointes may be increased in patients with cardiovascular disease (e.g. heart failure, myocardial infarction, history of torsades de pointes, congenital long QT syndrome), hypokalemia, hypomagnesemia, hypocalcemia, bradycardia, female gender, or advanced age.(3) Concurrent use of more than one drug known to cause QT prolongation or higher systemic concentrations of either QT prolonging drug are additional risk factors for torsades de pointes. Factors which may increase systemic drug concentrations include rapid infusion of an intravenous dose or impaired metabolism or elimination of the drug (e.g. coadministration with an agent which inhibits its metabolism or elimination, genetic impairment in drug metabolism or elimination, and/or renal/hepatic dysfunction).(3) PATIENT MANAGEMENT: When used concomitantly with moderate CYP3A4 inhibitors, monitor more frequently for mavorixafor adverse effects and reduce the dose in 100 mg increments, if necessary, but not to a dose less than 200 mg.(1) When concurrent therapy is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring EKG at baseline and regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: There are no clinical studies for the combination of mavorixafor and moderate CYP3A4 inhibitors. In a study with healthy subjects, itraconazole 200 mg daily (a strong CYP3A4 and P-gp inhibitor) increased the exposure to single-dose mavorixafor 200 mg similar to that from single-dose mavorixafor 400 mg alone. This suggests that itraconazole increased mavorixafor exposure by about 2-fold.(1) A study in healthy volunteers found that ritonavir 100 mg twice daily (a strong CYP3A4 inhibitor and P-gp inhibitor) increased the area-under-curve (AUC) and maximum concentration (Cmax) of single-dose mavorixafor 200 mg by 60% and 39%, respectively.(4) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, cimetidine, clofazimine, conivaptan, darunavir, diltiazem, duvelisib, fedratinib, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, schisandra, tofisopam, treosulfan, verapamil and voxelotor.(2,5) |
XOLREMDI |
| Oliceridine/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Oliceridine is metabolized equally by CYP2D6 and CYP3A4. Oliceridine metabolism may be inhibited by inhibitors of CYP2D6 or CYP3A4.(1) CLINICAL EFFECTS: The concurrent administration of a strong or moderate CYP2D6 or strong or moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from oliceridine including profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: Patients with CYP2D6 poor metabolizer phenotype may be affected to a greater extent by CYP3A4 inhibitors. Inhibition of both CYP2D6 and CYP3A4 pathways may result in a greater increase in the levels of and toxcity of oliceridine.(1) PATIENT MANAGEMENT: Caution should be used when administering oliceridine to patients taking strong or moderate inhibitors of CYP2D6 or CYP3A4. Dosage adjustments should be made if warranted. Closely monitor these patients for respiratory depression and sedation at frequent intervals and evaluate subsequent doses based on response. If concomitant use of a strong or moderate CYP2D6 or CYP3A4 inhibitor is necessary, less frequent dosing of oliceridine may be required. If a strong or moderate CYP2D6 or CYP3A4 inhibitor is discontinued, increase of the oliceridine dosage may be necessary. Monitor for signs of opioid withdrawal. Patients receiving concurrent therapy with both a strong or moderate CYP3A4 inhibitor and CYP2D6 inhibitors may be at greater risk of adverse effects. Patient who are CYP2D6 normal metabolizers taking a CYP2D6 inhibitor and a strong CYP3A4 inhibitor may require less frequent dosing of oliceridine.(1) Respiratory depression can occur at any time during opioid therapy, especially during therapy initiation and following dosage increases. Consider this risk when using concurrently with agents that may increase opioid drug levels.(2) Discuss naloxone with all patients when prescribing or renewing an opioid analgesic or medicine to treat opioid use disorder (OUD). Consider prescribing naloxone to patients prescribed medicines to treat OUD or opioid analgesics (such as those taking CNS depressants) who are at increased risk of opioid overdose and when a patient has household members/close contacts at risk for accidental overdose.(3) DISCUSSION: In a study of four healthy subjects who are CYP2D6 poor metabolizers, itraconazole (200 mg daily for 5 days) increased the area-under-curve (AUC) of single-dose oliceridine (0.25 mg) by 80%.(1) In a study of subjects who were not CYP2D6 poor metabolizers, ketoconazole (200 mg for 2 doses 10 hours apart) did not affect the pharmacokinetics of oliceridine.(1) Moderate CYP3A4 inhibitors include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, Schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(4) |
OLINVYK |
| Tretinoin/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of tretinoin.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in increased levels of and effects from tretinoin including hepatotoxicity and hyperlipidemia.(1) Retinoids, including tretinoin, have been associated with intracranial hypertension, especially in pediatric patients. Early signs and symptoms include papilledema, headache, nausea, vomiting, and visual disturbances.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of tretinoin recommends monitoring patients taking a moderate CYP3A4 inhibitor in combination with tretinoin more frequently for adverse reactions.(1) Evaluate patients with symptoms for intracranial hypertension (such as papilledema, headache, nausea, vomiting, and visual disturbances), and, if present, institute care in concert with neurological assessment. Consider interruption, dose reduction, or discontinuation of tretinoin as appropriate.(1) DISCUSSION: In 13 patients on tretinoin for 4 weeks, single-dose ketoconazole (400 to 1200 mg) (strong CYP3A4 inhibitor) increased tretinoin area-under-curve (AUC) by 72%.(1) There are no clinical pharmacokinetic studies on the combination of tretinoin with a moderate CYP3A4 inhibitor. The US manufacturer of tretinoin states increased tretinoin toxicity following concomitant use of tretinoin with certain antimycotics that are moderate CYP3A4 inhibitors has been reported post-marketing.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, and treosulfan.(2-3) |
RETINOIC ACID, TRETINOIN, TRETINOIN ACID |
| Vanzacaftor-Tezacaftor-Deutivacaftor/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate inhibitors of CYP3A4 may inhibit the metabolism of vanzacaftor-tezacaftor-deutivacaftor. Vanzacaftor, tezacaftor, and deutivacaftor are CYP3A substrates.(1) CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from vanzacaftor-tezacaftor-deutivacaftor, such as hepatotoxicity.(1) PREDISPOSING FACTORS: This interaction may be more severe in patients with hepatic impairment.(1) PATIENT MANAGEMENT: The US manufacturer of vanzacaftor-tezacaftor-deutivacaftor states that concurrent use with moderate CYP3A4 inhibitors requires a dose adjustment. If concurrent use is warranted, the following dose adjustments are recommended: -For age 6 to less than 12 years old AND less than 40 kg - Two tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg every other day; -For age 6 to less than 12 years old AND greater than or equal to 40 kg - One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day; -For age 12 years and older AND any weight - One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day.(1) DISCUSSION: Concurrent administration with itraconazole (200 mg every 12 hours on Day 1, followed by 200 mg daily, a strong inhibitor of CYP3A4) with tezacaftor (25 mg daily)-ivacaftor (50 mg daily) increased tezacaftor area-under-curve (AUC) and concentration maximum (Cmax) by 4-fold and 2.83-fold, respectively.(1) Concurrent administration with itraconazole (200 mg daily, a strong inhibitor of CYP3A4) with single-dose elexacaftor 20 mg-tezacaftor 50 mg-deutivacaftor 50 mg increased tezacaftor AUC and Cmax by 4.51-fold and 1.48-fold and deutivacaftor AUC and Cmax by 11.1-fold and 1.96-fold.(1) Concurrent administration with itraconazole (200 mg daily, a strong inhibitor of CYP3A4) with vanzacaftor (5 mg single dose) increased vanzacaftor AUC and Cmax by 6.37-fold and 1.55-fold, respectively.(1) Concurrent administration with fluconazole (200 mg daily, a moderate inhibitor of CYP3A4) with vanzacaftor (20 mg daily)-tezacaftor (100 mg daily)-deutivacaftor (250 mg daily) is predicted to increase vanzacaftor AUC and Cmax by 2.55-fold and 2.48-fold and deutivacaftor by 3.13-fold and 2.27-fold, respectively.(1) Concurrent administration with erythromycin (500 mg four times daily, a moderate inhibitor of CYP3A4) with vanzacaftor (20 mg daily)-tezacaftor (100 mg daily)-deutivacaftor (250 mg daily) is predicted to increase vanzacaftor AUC and Cmax by 3.29-fold and 3.19-fold and deutivacaftor by 4.13-fold and 2.89-fold, respectively.(1) Concurrent administration with verapamil (80 mg three times daily, a moderate inhibitor of CYP3A4) with vanzacaftor (20 mg daily)-tezacaftor (100 mg daily)-deutivacaftor (250 mg daily) is predicted to increase vanzacaftor AUC and Cmax by 3.93-fold and 3.8-fold and deutivacaftor by 5.11-fold and 3.43-fold, respectively.(1) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, Schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2-4) |
ALYFTREK |
| Suzetrigine/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Suzetrigine and M6-SUZ (active metabolite of suzetrigine) are CYP3A4 substrates. Moderate CYP3A4 inhibitors increase suzetrigine and M6-SUZ exposures, which may cause suzetrigine adverse reactions.(1) CLINICAL EFFECTS: The concurrent administration of a moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from suzetrigine including pruritis, muscle spasms, increased blood creatine phosphokinase, and rash.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: When possible, avoid the use of moderate CYP3A4 inhibitors with suzetrigine. The US manufacturer of suzetrigine states when suzetrigine is administered to patients taking moderate CYP3A4 inhibitors reduce the suzetrigine dose as follows: -Dose 1: The recommended starting dose of suzetrigine is 100 mg orally. -Dose 2, 3, and 4: Starting 12 hours after the initial dose, take 50 mg of suzetrigine orally every 12 hours. -Dose 5 and Subsequent Doses: Starting 12 hours after Dose 4, take 50 mg of suzetrigine orally every 24 hours.(1) DISCUSSION: In a PKPB model, concomitant administration of fluconazole (a moderate CYP3A4 inhibitor) with suzetrigine with the recommended dosage modification is predicted to increase the area-under-curve (AUC) of suzetrigine and active metabolite M6-SUZ by 1.5-fold and 1.2-fold, respectively, while the maximum concentration (Cmax) of suzetrigine and M6-SUZ by 1.4-fold and 1.1-fold, respectively, when compared to the regular recommended dosage in the absence of fluconazole.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosamprenavir, fosnetupitant, imatinib, isavuconazole, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2-3) |
JOURNAVX |
The following contraindication information is available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
Drug contraindication overview.
*History of clinically important hypersensitivity reaction (e.g., Stevens-Johnson syndrome) to fosamprenavir, amprenavir (active metabolite of fosamprenavir; no longer commercially available in the US), or any ingredient in the formulation. *Concomitant use with drugs highly dependent on cytochrome P-450 (CYP) isoenzyme 3A4 for metabolism and for which elevated plasma concentrations are associated with serious and/or life-threatening events. These drugs and other contraindicated drugs (which may lead to reduced efficacy of fosamprenavir and possible resistance) include: alfuzosin, cisapride, delavirdine, ergot derivatives (dihydroergotamine, ergonovine, ergotamine, methylergonovine), pimozide, sildenafil used for treatment of pulmonary arterial hypertension, lomitapide, lovastatin, simvastatin, midazolam, triazolam, rifampin, St.
John's wort (Hypericum perforatum), flecainide (when used with fosamprenavir plus ritonavir), propafenone (when used with fosamprenavir plus ritonavir), and lurasidone (when used with fosamprenavir plus ritonavir). Unless otherwise noted, these contraindications apply to the use of fosamprenavir with or without ritonavir. When fosamprenavir is used in combination with ritonavir, consult the full prescribing information for ritonavir for additional considerations.
*History of clinically important hypersensitivity reaction (e.g., Stevens-Johnson syndrome) to fosamprenavir, amprenavir (active metabolite of fosamprenavir; no longer commercially available in the US), or any ingredient in the formulation. *Concomitant use with drugs highly dependent on cytochrome P-450 (CYP) isoenzyme 3A4 for metabolism and for which elevated plasma concentrations are associated with serious and/or life-threatening events. These drugs and other contraindicated drugs (which may lead to reduced efficacy of fosamprenavir and possible resistance) include: alfuzosin, cisapride, delavirdine, ergot derivatives (dihydroergotamine, ergonovine, ergotamine, methylergonovine), pimozide, sildenafil used for treatment of pulmonary arterial hypertension, lomitapide, lovastatin, simvastatin, midazolam, triazolam, rifampin, St.
John's wort (Hypericum perforatum), flecainide (when used with fosamprenavir plus ritonavir), propafenone (when used with fosamprenavir plus ritonavir), and lurasidone (when used with fosamprenavir plus ritonavir). Unless otherwise noted, these contraindications apply to the use of fosamprenavir with or without ritonavir. When fosamprenavir is used in combination with ritonavir, consult the full prescribing information for ritonavir for additional considerations.
There are 1 contraindications.
Absolute contraindication.
| Contraindication List |
|---|
| Lactation |
There are 6 severe contraindications.
Adequate patient monitoring is recommended for safer drug use.
| Severe List |
|---|
| Child-pugh class A hepatic impairment |
| Child-pugh class B hepatic impairment |
| Child-pugh class C hepatic impairment |
| Disease of liver |
| Kidney stone |
| Severe hepatic disease |
There are 6 moderate contraindications.
Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.
| Moderate List |
|---|
| Coronary artery disease |
| Diabetes mellitus |
| Hemolytic anemia |
| Hemophilia |
| Hypercholesterolemia |
| Hypertriglyceridemia |
The following adverse reaction information is available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
Adverse reaction overview.
The most common adverse effects (incidence >=4%) in adults receiving fosamprenavir are diarrhea, nausea, vomiting, headache, and rash. Vomiting and neutropenia were reported more frequently in pediatric patients compared to adults.
The most common adverse effects (incidence >=4%) in adults receiving fosamprenavir are diarrhea, nausea, vomiting, headache, and rash. Vomiting and neutropenia were reported more frequently in pediatric patients compared to adults.
There are 11 severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
| None. |
Abnormal hepatic function tests |
| Rare/Very Rare |
|---|
|
Acute myocardial infarction Angioedema Diabetes mellitus Graves' disease Guillain-barre syndrome Hemolytic anemia Kidney stone Neutropenic disorder Polymyositis Stevens-johnson syndrome |
There are 12 less severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Diarrhea Headache disorder Lipodystrophy associated with human immunodeficiency virus infection Nausea Skin rash Vomiting |
Acute abdominal pain Fatigue Hyperglycemia Hypertriglyceridemia |
| Rare/Very Rare |
|---|
|
Hypercholesterolemia Oral hypoesthesia |
The following precautions are available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
Three open-label studies have evaluated the safety, efficacy, and pharmacokinetics of fosamprenavir (with and without ritonavir) in PI-naive and PI-experienced HIV-1-infected pediatric patients 4 weeks to <18 years of age and weighing >=3 kg. Pharmacokinetics, safety, tolerability, and efficacy of fosamprenavir have not been established in pediatric patients younger than 4 weeks of age. Treatment with fosamprenavir is not recommended in PI-experienced pediatric patients younger than 6 months of age.
Do not use once-daily regimens of fosamprenavir (with or without low-dose ritonavir) in pediatric patients. Do not use twice-daily regimens of fosamprenavir (without low-dose ritonavir) in pediatric patients <2 years of age.
Contraindicated
Severe Precaution
Management or Monitoring Precaution
Do not use once-daily regimens of fosamprenavir (with or without low-dose ritonavir) in pediatric patients. Do not use twice-daily regimens of fosamprenavir (without low-dose ritonavir) in pediatric patients <2 years of age.
Contraindicated
| None |
Severe Precaution
| None |
Management or Monitoring Precaution
| None |
The Antiretroviral Pregnancy Registry (APR) monitors pregnancy outcomes in women exposed to fosamprenavir during pregnancy. Clinicians are encouraged to register patients in the APR by calling 800-258-4263 or visiting https://www.apregistry.com.
In animal reproduction studies, no major adverse developmental outcomes were observed following oral administration of fosamprenavir. Systemic exposure to amprenavir (fosamprenavir's active metabolite) in rabbits or rats was less than or up to 2 times, respectively, the exposures in humans at the maximum recommended human dose (MRHD) with or without ritonavir. However, abortions were observed following oral administration of amprenavir in pregnant rabbits at doses that produced approximately one-twentieth the human exposure at the MRHD.
In the pre- and postnatal development study in rats, toxicities to the offspring were observed at maternal systemic exposures to amprenavir that were approximately 2 times the exposure in humans at the MRHD of fosamprenavir alone, or approximately the same as those seen in humans at the MRHD of fosamprenavir in combination with ritonavir. There are limited data on use of fosamprenavir in pregnancy. Data are insufficient to date to adequately assess the risk of birth defects and miscarriage in pregnant women receiving fosamprenavir.
Based on prospective reports to the APR of 146 live births following exposures to fosamprenavir, 2 birth defects each were reported with first- and second/third- trimester exposures. The safety, efficacy, and pharmacokinetics of fosamprenavir 700 mg twice daily in combination with ritonavir 100 mg twice daily were studied in a clinical trial of HIV-1-infected pregnant women during the second and third trimesters and postpartum. The use of this regimen should only be considered in pregnant patients who are already on a stable twice-daily regimen of fosamprenavir 700 mg twice daily plus ritonavir 100 mg prior to pregnancy, and who are virologically suppressed (HIV-1 RNA <50 copies per mL). Total amprenavir exposures (AUC) were lower during pregnancy compared with the postpartum period; thus, closely monitor viral load to ensure viral suppression is maintained.
In animal reproduction studies, no major adverse developmental outcomes were observed following oral administration of fosamprenavir. Systemic exposure to amprenavir (fosamprenavir's active metabolite) in rabbits or rats was less than or up to 2 times, respectively, the exposures in humans at the maximum recommended human dose (MRHD) with or without ritonavir. However, abortions were observed following oral administration of amprenavir in pregnant rabbits at doses that produced approximately one-twentieth the human exposure at the MRHD.
In the pre- and postnatal development study in rats, toxicities to the offspring were observed at maternal systemic exposures to amprenavir that were approximately 2 times the exposure in humans at the MRHD of fosamprenavir alone, or approximately the same as those seen in humans at the MRHD of fosamprenavir in combination with ritonavir. There are limited data on use of fosamprenavir in pregnancy. Data are insufficient to date to adequately assess the risk of birth defects and miscarriage in pregnant women receiving fosamprenavir.
Based on prospective reports to the APR of 146 live births following exposures to fosamprenavir, 2 birth defects each were reported with first- and second/third- trimester exposures. The safety, efficacy, and pharmacokinetics of fosamprenavir 700 mg twice daily in combination with ritonavir 100 mg twice daily were studied in a clinical trial of HIV-1-infected pregnant women during the second and third trimesters and postpartum. The use of this regimen should only be considered in pregnant patients who are already on a stable twice-daily regimen of fosamprenavir 700 mg twice daily plus ritonavir 100 mg prior to pregnancy, and who are virologically suppressed (HIV-1 RNA <50 copies per mL). Total amprenavir exposures (AUC) were lower during pregnancy compared with the postpartum period; thus, closely monitor viral load to ensure viral suppression is maintained.
Amprenavir is distributed into milk in rats. It is not known whether amprenavir is distributed into human milk, affects human milk production, or affects the breast-fed infant. The HHS perinatal HIV transmission guideline provides updated recommendations on infant feeding.
The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant. Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery.
The guideline states that patients with HIV should receive evidence-based, patient-centered counseling to support shared decision making about infant feeding. During counseling, patients should be informed that feeding with appropriate formula or pasteurized donor human milk from a milk bank eliminates the risk of postnatal HIV transmission to the infant. Additionally, achieving and maintaining viral suppression with antiretroviral therapy during pregnancy and postpartum reduces the risk of breastfeeding HIV transmission to <1%, but does not completely eliminate the risk. Replacement feeding with formula or banked pasteurized donor milk is recommended when patients with HIV are not on antiretroviral therapy and/or do not have a suppressed viral load during pregnancy (at a minimum throughout the third trimester), as well as at delivery.
Experience in patients >=65 years of age is insufficient to determine whether they respond differently from younger adults. Select dosage with caution because of age-related decreases in hepatic, renal, and/or cardiac function and potential for concomitant disease and drug therapy. The pharmacokinetics of fosamprenavir have not been studied in patients >65 years of age.
The following prioritized warning is available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium):
No warning message for this drug.
No warning message for this drug.
The following icd codes are available for FOSAMPRENAVIR CALCIUM (fosamprenavir calcium)'s list of indications:
| HIV infection | |
| B20 | Human immunodeficiency virus [HIv] disease |
| B97.35 | Human immunodeficiency virus, type 2 [HIV 2] as the cause of diseases classified elsewhere |
| O98.7 | Human immunodeficiency virus [HIv] disease complicating pregnancy, childbirth and the puerperium |
| O98.71 | Human immunodeficiency virus [HIv] disease complicating pregnancy |
| O98.711 | Human immunodeficiency virus [HIv] disease complicating pregnancy, first trimester |
| O98.712 | Human immunodeficiency virus [HIv] disease complicating pregnancy, second trimester |
| O98.713 | Human immunodeficiency virus [HIv] disease complicating pregnancy, third trimester |
| O98.719 | Human immunodeficiency virus [HIv] disease complicating pregnancy, unspecified trimester |
| O98.72 | Human immunodeficiency virus [HIv] disease complicating childbirth |
| O98.73 | Human immunodeficiency virus [HIv] disease complicating the puerperium |
| Z21 | Asymptomatic human immunodeficiency virus [HIv] infection status |
Formulary Reference Tool