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Drug overview for DILTIAZEM 24HR ER (diltiazem hcl):
Generic name: DILTIAZEM HCL (dill-TIE-uh-zem)
Drug class: Calcium Channel Blockers
Therapeutic class: Cardiovascular Therapy Agents
Diltiazem is a nondihydropyridine calcium-channel blocking agent (calcium-channel blocker).
Diltiazem is used in the management of Prinzmetal variant angina, chronic stable angina pectoris, supraventricular tachycardias, and hypertension.
Generic name: DILTIAZEM HCL (dill-TIE-uh-zem)
Drug class: Calcium Channel Blockers
Therapeutic class: Cardiovascular Therapy Agents
Diltiazem is a nondihydropyridine calcium-channel blocking agent (calcium-channel blocker).
Diltiazem is used in the management of Prinzmetal variant angina, chronic stable angina pectoris, supraventricular tachycardias, and hypertension.
DRUG IMAGES
DILTIAZEM 24HR ER 360 MG CAP
DILTIAZEM 24HR ER 300 MG CAP
DILTIAZEM 24HR ER 180 MG CAP
DILTIAZEM 24HR ER 120 MG CAP
DILTIAZEM 24HR ER 240 MG CAP
The following indications for DILTIAZEM 24HR ER (diltiazem hcl) have been approved by the FDA:
Indications:
Hypertension
Prevention of anginal pain associated with coronary artery disease
Professional Synonyms:
Elevated blood pressure
Essential hypertension
Hyperpiesia
Hyperpiesis
Hypertensive disorder
Prevention of anginal pain associated with CAD
Systemic arterial hypertension
Indications:
Hypertension
Prevention of anginal pain associated with coronary artery disease
Professional Synonyms:
Elevated blood pressure
Essential hypertension
Hyperpiesia
Hyperpiesis
Hypertensive disorder
Prevention of anginal pain associated with CAD
Systemic arterial hypertension
The following dosing information is available for DILTIAZEM 24HR ER (diltiazem hcl):
Potency of diltiazem hydrochloride preparations is expressed in terms of the hydrochloride. (See Chemistry and Stability: Chemistry.)
Dosage of diltiazem hydrochloride must be carefully adjusted according to individual requirements, tolerance, and response. The manufacturers state that dosage of diltiazem for geriatric patients should be selected carefully because these individuals frequently have decreased hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.
For the management of hypertension in adults receiving diltiazem hydrochloride as monotherapy, the usual initial dosage as the extended-release capsules (Cardizem(R) CD, Cartia XT(R), Dilt-XR(R)) or extended-release tablets (Cardizem(R) LA, Matzim(R) LA) is 180-240 mg once daily. When the extended-release capsules of diltiazem hydrochloride (Tiazac(R), Taztia XT(R)) are used, the usual initial dosage is 120-240 mg once daily. Dosage of the drug should be adjusted according to the patient's blood pressure response.
Some patients may respond to lower initial dosages; the manufacturer of Dilt-XR(R) states that patients 60 years of age or older may respond to an initial dosage of 120 mg daily. The maximum hypotensive effect associated with a given dosage level usually is observed within 14 days. Some manufacturers state that maintenance dosages usually range from 240-360 mg daily, although diltiazem hydrochloride extended-release capsules (Dilt-XR(R)) have been administered during clinical trials in dosages of 180-480 mg once daily, and the diltiazem hydrochloride extended-release capsules (Tiazac(R), Taztia XT(R),Dilt-XR(R)) and the extended-release tablets (Cardizem(R) LA, Matzim(R) LA) may be administered at dosages of 120-540 mg once daily.
Some experts state that the usual maintenance dosage of extended-release diltiazem hydrochloride for the management of hypertension is 120-360 mg once daily.
The manufacturers of Cardizem(R) CD or Cartia XT(R) extended-release capsules or Cardizem(R) LA or Matzim(R) LA extended-release tablets state that patients whose blood pressure is adequately controlled with diltiazem therapy alone or in combination with another antihypertensive agent may be safely switched to Cardizem(R) CD, Cartia XT(R), Cardizem(R) LA, or Matzim(R) LA at the nearest equivalent daily dosage. Subsequent titration of dosage may be necessary depending on the clinical response of the patient. The manufacturers of Cardizem(R) CD or Cartia XT(R) extended-release capsules and Cardizem(R) LA extended-release tablets also state that there is limited clinical experience with diltiazem doses exceeding 360 mg, but doses up to 540 mg have been used during clinical trials; the incidence of adverse effects (especially first-degree AV block, dizziness, sinus bradycardia) increases with increasing dosage.
The manufacturer of Dilt-XR(R) states that although clinical experience is limited, Dilt-XR(R) extended-release capsules have been administered in 540-mg doses with little or no increased risk of adverse effects.
Diltiazem is metabolized extensively by the liver and excreted in urine and bile. Although specific dosage recommendations for patients with impaired renal function are not available, dosage of diltiazem hydrochloride should be titrated cautiously in these patients. However, some evidence suggests that the pharmacokinetics and bioavailability of the oral drug and its major active metabolite deacetyldiltiazem may not be altered substantially in patients with renal failure.
Diltiazem should be used with caution in patients with hepatic impairment, since acute hepatic injury has been reported rarely. (See Cautions: Hepatic Effects.) In addition, systemic clearance and half-life of the drug are increased in patients with liver cirrhosis receiving oral diltiazem; however, the manufacturers make no specific recommendations for dosage adjustment in patients with impaired hepatic function.
Dosage of diltiazem hydrochloride must be carefully adjusted according to individual requirements, tolerance, and response. The manufacturers state that dosage of diltiazem for geriatric patients should be selected carefully because these individuals frequently have decreased hepatic, renal, and/or cardiac function and concomitant disease and drug therapy.
For the management of hypertension in adults receiving diltiazem hydrochloride as monotherapy, the usual initial dosage as the extended-release capsules (Cardizem(R) CD, Cartia XT(R), Dilt-XR(R)) or extended-release tablets (Cardizem(R) LA, Matzim(R) LA) is 180-240 mg once daily. When the extended-release capsules of diltiazem hydrochloride (Tiazac(R), Taztia XT(R)) are used, the usual initial dosage is 120-240 mg once daily. Dosage of the drug should be adjusted according to the patient's blood pressure response.
Some patients may respond to lower initial dosages; the manufacturer of Dilt-XR(R) states that patients 60 years of age or older may respond to an initial dosage of 120 mg daily. The maximum hypotensive effect associated with a given dosage level usually is observed within 14 days. Some manufacturers state that maintenance dosages usually range from 240-360 mg daily, although diltiazem hydrochloride extended-release capsules (Dilt-XR(R)) have been administered during clinical trials in dosages of 180-480 mg once daily, and the diltiazem hydrochloride extended-release capsules (Tiazac(R), Taztia XT(R),Dilt-XR(R)) and the extended-release tablets (Cardizem(R) LA, Matzim(R) LA) may be administered at dosages of 120-540 mg once daily.
Some experts state that the usual maintenance dosage of extended-release diltiazem hydrochloride for the management of hypertension is 120-360 mg once daily.
The manufacturers of Cardizem(R) CD or Cartia XT(R) extended-release capsules or Cardizem(R) LA or Matzim(R) LA extended-release tablets state that patients whose blood pressure is adequately controlled with diltiazem therapy alone or in combination with another antihypertensive agent may be safely switched to Cardizem(R) CD, Cartia XT(R), Cardizem(R) LA, or Matzim(R) LA at the nearest equivalent daily dosage. Subsequent titration of dosage may be necessary depending on the clinical response of the patient. The manufacturers of Cardizem(R) CD or Cartia XT(R) extended-release capsules and Cardizem(R) LA extended-release tablets also state that there is limited clinical experience with diltiazem doses exceeding 360 mg, but doses up to 540 mg have been used during clinical trials; the incidence of adverse effects (especially first-degree AV block, dizziness, sinus bradycardia) increases with increasing dosage.
The manufacturer of Dilt-XR(R) states that although clinical experience is limited, Dilt-XR(R) extended-release capsules have been administered in 540-mg doses with little or no increased risk of adverse effects.
Diltiazem is metabolized extensively by the liver and excreted in urine and bile. Although specific dosage recommendations for patients with impaired renal function are not available, dosage of diltiazem hydrochloride should be titrated cautiously in these patients. However, some evidence suggests that the pharmacokinetics and bioavailability of the oral drug and its major active metabolite deacetyldiltiazem may not be altered substantially in patients with renal failure.
Diltiazem should be used with caution in patients with hepatic impairment, since acute hepatic injury has been reported rarely. (See Cautions: Hepatic Effects.) In addition, systemic clearance and half-life of the drug are increased in patients with liver cirrhosis receiving oral diltiazem; however, the manufacturers make no specific recommendations for dosage adjustment in patients with impaired hepatic function.
Diltiazem hydrochloride is administered by direct IV injection, continuous IV infusion, or orally.
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| DILTIAZEM 24HR ER 120 MG CAP | Maintenance | Adults take 1 capsule (120 mg) by oral route once daily |
| DILTIAZEM 24HR ER 180 MG CAP | Maintenance | Adults take 1 capsule (180 mg) by oral route once daily |
| DILTIAZEM 24HR ER 240 MG CAP | Maintenance | Adults take 1 capsule (240 mg) by oral route once daily |
| DILTIAZEM 24HR ER 300 MG CAP | Maintenance | Adults take 1 capsule (300 mg) by oral route once daily |
| DILTIAZEM 24HR ER 360 MG CAP | Maintenance | Adults take 1 capsule (360 mg) by oral route once daily |
| DRUG LABEL | DOSING TYPE | DOSING INSTRUCTIONS |
|---|---|---|
| DILTIAZEM 24HR ER 120 MG CAP | Maintenance | Adults take 1 capsule (120 mg) by oral route once daily |
| DILTIAZEM 24HR ER 180 MG CAP | Maintenance | Adults take 1 capsule (180 mg) by oral route once daily |
| DILTIAZEM 24HR ER 240 MG CAP | Maintenance | Adults take 1 capsule (240 mg) by oral route once daily |
| DILTIAZEM 24HR ER 300 MG CAP | Maintenance | Adults take 1 capsule (300 mg) by oral route once daily |
| DILTIAZEM 24HR ER 360 MG CAP | Maintenance | Adults take 1 capsule (360 mg) by oral route once daily |
The following drug interaction information is available for DILTIAZEM 24HR ER (diltiazem hcl):
There are 16 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 |
|---|---|
| Vardenafil (Greater Than 5 mg)/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: CYP3A4 inhibitors may inhibit the metabolism of vardenafil by CYP3A4.(1-4) CLINICAL EFFECTS: Concurrent use of CYP3A4 inhibitors may result in increased levels of and adverse effects from vardenafil, including hypotension, visual changes, and sustained erections.(1-4) PREDISPOSING FACTORS: The interaction may be more severe in men older than 75 years.(4) PATIENT MANAGEMENT: The US manufacturer of vardenafil states that a maximum dose of 2.5 mg of vardenafil every 24 hours should not be exceeded in patients taking 400 mg of itraconazole or ketoconazole and that a maximum dose of 5 mg of vardenafil every 24 hours should not be exceeded in patients taking 200 mg of itraconazole or ketoconazole.(1) For moderate CYP3A4 inhibitors, do not exceed a maximum dose of 5 mg of vardenafil every 24 hours.(1) Note that other countries have stricter warnings. The Australian manufacturer of vardenafil states that vardenafil must not be taken with dosages of itraconazole or ketoconazole greater than 200 mg. A maximum dose of 5 mg of vardenafil should not be exceeded if used with lower dosages of itraconazole and ketoconazole.(2) The Canadian manufacturer of vardenafil states that the concurrent use of vardenafil with itraconazole or ketoconazole is contraindicated and that the dosage should not exceed 5 mg in patients taking erythromycin.(3) The UK manufacturer of vardenafil states that the concurrent use of vardenafil with either oral itraconazole or oral ketoconazole is contraindicated in men older than 75 years and should be avoided in all patients. The dosage of vardenafil should not exceed 5 mg in patients taking erythromycin.(4) DISCUSSION: Concurrent use of ketoconazole (200 mg) with vardenafil (5 mg) increased the vardenafil area-under-curve (AUC) and maximum concentration (Cmax) by 10-fold and 4-fold, respectively.(1-4) Concurrent administration of erythromycin (500 mg three times daily) with vardenafil (5 mg) increased the AUC and Cmax of vardenafil by 4-fold and 3-fold, respectively.(1-4) |
VARDENAFIL HCL |
| Simvastatin (Greater Than 10 mg); Lovastatin (Greater Than 20 mg)/Diltiazem 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: Diltiazem may inhibit the metabolism of lovastatin(1) and simvastatin(2-4) by CYP3A4. CLINICAL EFFECTS: Concurrent diltiazem may result in elevated levels of lovastatin(1) or simvastatin,(3) which may result in rhabdomyolysis. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Do not use more than 20 mg of lovastatin in patients receiving diltiazem.(1) Do not use more than 10 mg of simvastatin in patients receiving diltiazem.(2-4) Patients receiving concurrent therapy with diltiazem should be monitored closely for adverse effects of the HMG-CoA reductase inhibitor, including rhabdomyolysis. The dosage of the HMG-CoA reductase inhibitor may need to be reduced or discontinued. Fluvastatin or pravastatin, HMG-CoA reductase inhibitors that are not metabolized by CYP3A4, may be alternatives to atorvastatin, lovastatin, and simvastatin in patients receiving diltiazem. DISCUSSION: In a four-way crossover study in ten subjects, subjects received single doses of lovastatin (20 mg) alone and following two weeks of diltiazem (120 mg twice daily) therapy and single doses of pravastatin (20 mg) alone and following two weeks of diltiazem therapy (120 mg twice daily). Concurrent administration of diltiazem increased lovastatin area-under-curve (AUC) and maximum concentration (Cmax) by 2.6-fold and 3.3-fold, respectively. The increase in lovastatin AUC ranged from 51% to 906%. There were no changes in lovastatin half-life. Concurrent administration of diltiazem had no effect on the AUC, Cmax, or half-life of pravastatin.(5,6) In a study, diltiazem (120 mg twice daily for 10 days) increased the AUC and Cmax of a single dose of simvastatin (80 mg on Day 10) by 3.1-fold and 2.88-fold, respectively. The AUC and Cmax of simvastatin acid increased by 2.69-fold and 2.69-fold, respectively.(3) In a study in Chinese subjects, concurrent diltiazem (60 mg TID) and simvastatin (20 mg daily) enhanced reduction of LDL levels by 1.66% when compared to simvastatin (20 mg alone).(7) In a study in 11 patients with hypercholesterolemia and hypertension, concurrent administration of diltiazem (90 mg daily) and simvastatin (5 mg daily) increased the Cmax and AUC of simvastatin by 97% and 99.5%, respectively, when compared to administration of simvastatin (5 mg daily) alone. Diltiazem Cmax and AUC decreased by 21% and 21%, respectively, when compared to the administration of diltiazem (90 mg) alone. Combination therapy lowered LDL levels by an additional 9% when compared to simvastatin monotherapy.(8) In a study in 10 healthy subjects, diltiazem (120 mg daily for 2 weeks) increased the Cmax and AUC of a single dose of simvastatin (20 mg) by 3.6-fold and 5-fold, respectively. The Cmax of simvastatin acid increased by 3.7-fold.(2,9) A daily dose of 480 mg of diltiazem is expected to increase simvastatin levels 8-fold.(2 In a retrospective review, patients who received simvastatin with concurrent diltiazem experienced a 33.3% reduction in cholesterol levels compared with 24.7% in patients receiving simvastatin without concurrent diltiazem.(10) There are several case reports of myopathy and rhabdomyolysis in patients receiving concurrent simvastatin and diltiazem.(11-16) 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 |
| Lurasidone (Greater Than 80 mg)/Diltiazem; Verapamil SEVERITY LEVEL: 1-Contraindicated Drug Combination: This drug combination is contraindicated and generally should not be dispensed or administered to the same patient. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors such as diltiazem and verapamil may inhibit the metabolism of lurasidone.(1) CLINICAL EFFECTS: Concomitant use of lurasidone with inhibitors of CYP3A4 may lead to orthostatic hypotension, akathisia, acute dystonia, Parkinsonism or other lurasidone toxicities.(1) PREDISPOSING FACTORS: Elderly patients, particularly those with a history of falls or swallowing disorders, and patients with 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 the dose of lurasidone should not exceed 80 mg daily if coadministered with moderate CYP3A4 inhibitors, such as diltiazem or verapamil.(1) If a patient is currently on lurasidone and either diltiazem or verapamil is added to therapy, the dose of lurasidone should be decreased by 50% of the original dose.(1) If a patient is currently on diltiazem or verapamil and lurasidone is added to therapy, the recommended starting dose of lurasidone is 20 mg per day.(1) DISCUSSION: Pretreatment with diltiazem (240 mg daily for 5 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of lurasidone (20 mg) by 2.1-fold, and 2.2-fold, respectively.(1) |
LATUDA, LURASIDONE HCL |
| Simvastatin (Less than or Equal To 10 mg); Lovastatin (Less than or Equal To 20 mg)/Diltiazem (Greater Than 240 mg) 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: Diltiazem may inhibit the metabolism of lovastatin(1,2) and simvastatin(2-6) by CYP3A4. CLINICAL EFFECTS: Concurrent diltiazem may result in elevated levels of lovastatin(1,2) or simvastatin,(2-6) which may result in rhabdomyolysis. 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 more than 20 mg of lovastatin(1) or more than 240 mg of diltiazem(2) in patients receiving concurrent therapy with these agents. Do not use more than 10 mg of simvastatin(2-6) or more than 240 mg of diltiazem(2) in patients receiving concurrent therapy with these agents. Patients receiving concurrent therapy with diltiazem should be monitored closely for adverse effects of the HMG-CoA reductase inhibitor, including rhabdomyolysis. The dosage of the HMG-CoA reductase inhibitor may need to be reduced or discontinued. Fluvastatin or pravastatin, HMG-CoA reductase inhibitors that are not metabolized by CYP3A4, may be alternatives to atorvastatin, lovastatin, and simvastatin in patients receiving diltiazem. DISCUSSION: In a four-way crossover study in ten subjects, subjects received single doses of lovastatin (20 mg) alone and following two weeks of diltiazem (120 mg twice daily) therapy and single doses of pravastatin (20 mg) alone and following two weeks of diltiazem therapy (120 mg twice daily). Concurrent administration of diltiazem increased lovastatin area-under-curve (AUC) and maximum concentration (Cmax) by 2.6-fold and 3.3-fold, respectively. The increase in lovastatin AUC ranged from 51% to 906%. There were no changes in lovastatin half-life. Concurrent administration of diltiazem had no effect on the AUC, Cmax, or half-life of pravastatin.(5,6) In a study, diltiazem (120 mg twice daily for 10 days) increased the AUC and Cmax of a single dose of simvastatin (80 mg on Day 10) by 3.1-fold and 2.88-fold, respectively. The AUC and Cmax of simvastatin acid increased by 2.69-fold and 2.69-fold, respectively.(3) In a study in Chinese subjects, concurrent diltiazem (60 mg TID) and simvastatin (20 mg daily) enhanced reduction of LDL levels by 1.66% when compared to simvastatin (20 mg alone).(7) In a study in 11 patients with hypercholesterolemia and hypertension, concurrent administration of diltiazem (90 mg daily) and simvastatin (5 mg daily) increased the Cmax and AUC of simvastatin by 97% and 99.5%, respectively, when compared to administration of simvastatin (5 mg daily) alone. Diltiazem Cmax and AUC decreased by 21% and 21%, respectively, when compared to the administration of diltiazem (90 mg) alone. Combination therapy lowered LDL levels by an additional 9% when compared to simvastatin monotherapy.(8) In a study in 10 healthy subjects, diltiazem (120 mg daily for 2 weeks) increased the Cmax and AUC of a single dose of simvastatin (20 mg) by 3.6-fold and 5-fold, respectively. The Cmax of simvastatin acid increased by 3.7-fold.(2,9) A daily dose of 480 mg of diltiazem is expected to increase simvastatin levels 8-fold.(2 In a retrospective review, patients who received simvastatin with concurrent diltiazem experienced a 33.3% reduction in cholesterol levels compared with 24.7% in patients receiving simvastatin without concurrent diltiazem.(10) There are several case reports of myopathy and rhabdomyolysis in patients receiving concurrent simvastatin and diltiazem.(11-16) 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, LOVASTATIN, SIMVASTATIN, VYTORIN, ZOCOR |
| 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 |
| Disopyramide/Class IB, II, and IV Antiarrhythmics 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: Disopyramide has been shown to prolong the QTc interval. Concurrent use with other agents that affect the heart rate and rhythm may result in unpredictable effect on heart rhythm.(1-2) CLINICAL EFFECTS: The concurrent use of disopyramide with other agents that affect the heart rate and rhythm may result in in potentially life-threatening cardiac arrhythmias, including torsades de pointes.(1-2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of disopyramide states that concurrent use of disopyramide with antiarrhythmic agents should be reserved for patients with life-threatening arrhythmias who are demonstrably unresponsive to single-agent antiarrhythmic therapy. The Australian manufacturer of disopyramide states that the concurrent use of other antiarrhythmics, such as Class I, II, III, or IV is contraindicated.(1) The US manufacturer of verapamil states that disopyramide should not be administered within 48 hours before or 24 hours after verapamil.(2) 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 combinations of antiarrhythmics are not well researched and concurrent use may result in unpredictable effects, the Australian manufacturer of disopyramide states that the concurrent use of other antiarrhythmics, such as Class I, II, III, or IV is contraindicated.(1) |
DISOPYRAMIDE PHOSPHATE, NORPACE, NORPACE CR |
| 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 |
| 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 |
| Lumateperone (Greater Than 21 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 lumateperone.(1) CLINICAL EFFECTS: Concurrent use of lumateperone with moderate CYP3A4 inhibitors increases lumateperone exposure, which may increase the risk of adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lumateperone recommends decreasing the dosage of lumateperone to 21 mg once daily in patients receiving moderate CYP3A4 inhibitors.(1) 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) Moderate inhibitors of CYP3A4 include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, verapamil, treosulfan and voxelotor.(2,3) |
CAPLYTA |
| 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 |
| Colchicine (for Cardioprotection)/P-glycoprotein (P-gp) 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: P-glycoprotein (P-gp) inhibitors may affect the transport of colchicine, a P-gp substrate.(1,2) CLINICAL EFFECTS: Concurrent use of a P-gp inhibitor may result in elevated levels of and toxicity from colchicine. Symptoms of colchicine toxicity include abdominal pain; nausea or vomiting; severe diarrhea; muscle weakness or pain; numbness or tingling in the fingers or toes; myelosuppression; 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 or hepatic impairment.(1,2) PATIENT MANAGEMENT: The manufacturer of colchicine used for cardiovascular risk reduction states that concurrent use of colchicine with P-gp inhibitors is contraindicated.(1) DISCUSSION: There are several reports of colchicine toxicity(3-5) and death(6,7) following the addition of clarithromycin to therapy. In a retrospective review of 116 patients who received clarithromycin and colchicine during the same hospitalization, 10.2% (9/88) of patients who received simultaneous therapy died, compared to 3.6% (1/28) of patients who received sequential therapy.(8) An FDA review of 117 colchicine-related deaths that were not attributable to overdose found that 60 deaths (51%) involved concurrent use of clarithromycin.(2) There is one case report of colchicine toxicity with concurrent erythromycin.(9) 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 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 and P-gp inhibitors such as clarithromycin, cyclosporine, diltiazem, erythromycin, and verapamil.(1,2) P-gp inhibitors include abrocitinib, amiodarone, asciminib, asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, cyclosporine, danicopan, daridorexant, diltiazem, diosmin, dronedarone, erythromycin, flibanserin, fluvoxamine, fostamatinib, glecaprevir/pibrentasvir, lapatinib, ledipasvir, mavorixafor, neratinib, osimertinib, pirtobrutinib, propafenone, quinidine, ranolazine, schisandra, selpercatinib, sotorasib, tepotinib, tezacaftor, valbenazine, velpatasvir, vemurafenib, verapamil, vimseltinib, and voclosporin.(1,10,11) |
LODOCO |
| Labetalol/Diltiazem; Verapamil 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: Both labetalol and non-dihydropyridine calcium channel blockers, including diltiazem and verapamil, have negative inotropic and chronotropic effects.(1-4) CLINICAL EFFECTS: Concurrent use of labetalol with non-dihydropyridine calcium channel blockers may result in additive cardiovascular effects, including hypotension, bradycardia, congestive heart failure, conduction abnormalities, and cardiovascular collapse.(1-4) PREDISPOSING FACTORS: Preexisting left ventricular dysfunction and high doses of the beta-blocking agent may predispose patients to adverse responses to this drug combination. Other possible factors include parenteral administration and concurrent administration of other cardio-depressant drugs such as antiarrhythmics. PATIENT MANAGEMENT: The concurrent use of labetalol with non-dihydropyridine calcium channel blockers is contraindicated.(1,2) DISCUSSION: Concurrent use of labetalol with non-dihydropyridine calcium channel blockers may result in hypotension, bradycardia, congestive heart failure, conduction abnormalities, and cardiovascular collapse.(1-4) Excess bradycardia, AV block, and complete heart block have been reported.(3) |
LABETALOL HCL, LABETALOL HCL-WATER |
There are 59 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 |
|---|---|
| Carbamazepine/Selected Calcium Channel Blockers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Diltiazem and verapamil may inhibit the metabolism of carbamazepine. Carbamazepine may induce the metabolism of calcium channel blockers. CLINICAL EFFECTS: Concurrent diltiazem or verapamil may result in elevated levels of and toxicity from carbamazepine. Concurrent carbamazepine may reduce the levels and effectiveness of calcium channel blockers. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Monitor serum carbamazepine levels when starting, stopping, or altering the dose of diltiazem or verapamil. Adjust the dose of carbamazepine accordingly. Monitor the effectiveness of calcium channel blockers in patients maintained on carbamazepine. An alternative antihypertensive agent may be needed. The manufacturer of diltiazem states that coadministration with CYP3A4 inducers should be avoided when possible. DISCUSSION: Neurotoxicity has been reported during concurrent use of carbamazepine and diltiazem or verapamil. Diltiazem has been shown to increase carbamazepine levels by 40% to 72%. Verapamil has been shown to increase carbamazepine levels by 46%. Diltiazem levels have been shown to become undetectable when coadministered with rifampin, a strong CYP3A4 inducer. |
CARBAMAZEPINE, CARBAMAZEPINE ER, CARBATROL, EPITOL, EQUETRO, TEGRETOL, TEGRETOL XR |
| Amiodarone/Diltiazem; Verapamil SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concomitant use of amiodarone with diltiazem or verapamil can contribute to depressant effects on the sinus and atrioventricular node and decreased contractility which can potentiate the electrophysiologic and hemodynamic effects of amiodarone. Diltiazem and verapamil may also increase amiodarone concentrations through CYP3A4 inhibition. Therefore, the effects of these drugs on the heart may be additive.(1-2) CLINICAL EFFECTS: Life-threatening effects, including bradycardia, sinus arrest and atrioventricular blockade may occur. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Carefully monitor patients for cardiac toxicity during combined treatment with amiodarone and diltiazem or verapamil. DISCUSSION: In a single case report, a 61-year-old female patient developed sinus arrest and low cardiac output with decreased urination when amiodarone was added to her treatment regimen of diltiazem and furosemide. After discontinuing diltiazem and amiodarone, the patient was successfully treated with ventricular pacing and pressor agents. The patient was later managed successfully with furosemide and amiodarone.(3) In a study, with severe sinus node dysfunction who were all taking diltiazem, six were concomitantly taking amiodarone and/or beta-blocking agents.(4) |
AMIODARONE HCL, AMIODARONE HCL-D5W, NEXTERONE, PACERONE |
| Selected Calcium Channel Blockers/Rifamycins SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Multiple mechanisms appear to be involved. Rifampin may increase the hepatic metabolism of the calcium channel blockers, increase first-pass hepatic metabolism of oral calcium channel blockers, and decrease the protein binding of calcium channel blockers.(1-8) CLINICAL EFFECTS: Concurrent use of rifampin may decrease levels and effectiveness of the calcium channel blocker.(1-8) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Observe the patient for a decrease in the therapeutic effects of the calcium channel blocker if rifampin is initiated. The dose of the calcium channel blocker may need to be adjusted if rifampin is initiated or discontinued.(1-7) The US manufacturer of diltiazem states that concurrent use should be avoided.(2) The manufacturer of lercanidipine states that concurrent use is not recommended.(10) DISCUSSION: In healthy subjects, pretreatment with rifampin (600 mg daily) reduced the concentration of a single dose of isradipine (5 mg) below a detectable level. The study concluded that the concentrations and effects of isradipine may be either reduced or absent as a result of increased isradipine metabolism.(1) Concurrent administration of rifampin has been shown to lower diltiazem levels below detectable limits.(2) In a study in 5 healthy subjects, pretreatment with rifampin (6 days) decreased the area-under-curve (AUC) of a single oral dose of nilvadipine (4 mg) by 96.5%. Pretreatment with rifampin abolished nilvadipine-induced hypotensive effects and tachycardia.(3) A study in six subjects examined the effects of pretreatment with rifampin (600 mg daily for 15 days) on single doses of verapamil (10 mg intravenously or 120 mg orally). Rifampin significantly decreased the maximum concentration (Cmax) and AUC of oral verapamil and resulted in no changes in the P-R interval. There were small decreases in the AUC of intravenous verapamil.(4) In a study in 8 male subjects, pretreatment with rifampin (600 mg daily for 15 days) increased the systemic clearance of S-verapamil by 1.3-fold and the apparent oral-clearance of S-verapamil by 32-fold. The bioavailability of S-verapamil decreased 25-fold. The effect of oral verapamil on AV conduction was almost abolished. No significant changes were noted for intravenous administration of verapamil.(5) In a study in 16 hypertensive chronic kidney disease patients, amlodipine levels decreased an average of 82% after initiation of rifampin. In eight of the 16 patients, the levels were undetectable.(9) There have been case reports of decreased effectiveness of barnidipine,(6) manidipine,(6) nisoldipine,(6) and verapamil(7,8) during concurrent rifampin therapy. |
PRIFTIN, RIFABUTIN, RIFADIN, RIFAMPIN, TALICIA |
| Eplerenone/Selected 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 eplerenone.(1) CLINICAL EFFECTS: Concurrent use of moderate inhibitors of CYP3A4 may result in a 2-fold increase in eplerenone concentration and toxicity (e.g. hyperkalemia, hypotension).(1) PREDISPOSING FACTORS: Severe renal disease increases the risk for hyperkalemia. PATIENT MANAGEMENT: The starting dose of eplerenone for hypertension should be reduced to 25 mg in patients receiving moderate CYP3A4 inhibitors. For inadequate blood pressure response, dosing may be increased to a maximum of 25 mg twice daily. Do not exceed 25 mg once daily in post-MI CHF patients receiving a moderate CYP3A4 inhibitor.(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) Moderate inhibitors of CYP3A4 include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lefamulin, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, treosulfan and verapamil.(1-3) |
EPLERENONE, INSPRA |
| Selected Macrolides/Selected Calcium Channel Blockers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Some macrolides may inhibit metabolism of calcium channel blockers.(1) In some patients, calcium channel blockers may inhibit the metabolism of the macrolide. Some macrolides have been associated with cardiac arrhythmias, including torsades de pointes.(2) CLINICAL EFFECTS: In some patients, concurrent use may result in elevated levels of and effects from the calcium channel blockers, including hypotension,(2,3) shock,(2) and acute kidney failure.(3) In others, elevated levels of the macrolide may occur, which may increase the risk of sudden death from cardiac causes.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: If possible, avoid the concurrent use of calcium channel blockers with macrolides that inhibit CYP.(1,2) Depending on the infection, azithromycin may be an alternative in patients maintained on calcium channel blockers.(1) If concurrent use is required, monitor patients for and instruct them to report signs of hypotension, cardiac arrhythmias, or renal failure. DISCUSSION: A retrospective review examined sudden cardiac death in Tennessee Medicaid patients. Erythromycin use increased the risk of sudden cardiac death by 1.79-fold. Concurrent use of erythromycin with a potent inhibitor of CYP3A4 (diltiazem, fluconazole, itraconazole, ketoconazole, troleandomycin, or verapamil) increased the risk of sudden cardiac death by 5.35-fold when compared to patients receiving no antibiotic therapy.(2) In a retrospective review of residents of Ontario, Canada aged 66 or older who were receiving calcium channel blockers, use of clarithromycin and erythromycin were associated with an increased risk of hospitalization for hypotension (odds ratio 3.7 and 5.8, respectively). There was no association between use of azithromycin and hospitalization for hypotension.(2) In a retrospective review of residents of Ontario, Canada aged 65 or older who were receiving calcium channel blockers, use of clarithromycin was associated with an increased risk of hospitalization with acute kidney injury when compared to use of azithromycin (0.44% of patients versus 0.22% - odds ratio 1.98). Risk was highest with the use of nifedipine (odds ratio 5.33). Use of clarithromycin was also associated with a higher risk of hospitalization with hypotension (0.12% of patients versus 0.07%, odds ratio 1.60) and all-cause mortality (1.02% of patients versus 0.59%, odds ratio 1.74).(3) In a cross-over study in 12 healthy male subjects, the administration of a single dose of felodipine (10 mg extended-release) after four doses of erythromycin (250 mg) resulted in an increase in felodipine area-under-curve (AUC), maximum concentration (Cmax), and half-life by 149%, 127%, and 61%, respectively. Concurrent administration increased dehydrofelodipine AUC, Cmax, and half-life by 92%, 56%, and 93%, respectively, when compared to felodipine administration alone. Concurrent administration of felodipine and erythromycin decreased felodipine M3 metabolite AUC and Cmax concentrations by 41% and 36%, respectively. The extent of the interaction was extremely variable between subjects.(4) In a case report, a 43 year-old female developed palpitations, flushing, ankle edema, and hypotension 2-4 days after the addition of erythromycin to felodipine therapy. Felodipine levels were found to be elevated.(5) In a case report, a 77 year-old male developed shock, heart block, and multi-organ failure two days after the addition of clarithromycin to nifedipine therapy.(6) In a case report, a 76 year-old female developed hypotension, bradycardia, shortness of breath, and weakness two days after the addition of telithromycin to verapamil therapy.(7) |
CLARITHROMYCIN, CLARITHROMYCIN ER, E.E.S. 200, E.E.S. 400, ERY-TAB, ERYPED 200, ERYPED 400, ERYTHROCIN LACTOBIONATE, ERYTHROCIN STEARATE, ERYTHROMYCIN, ERYTHROMYCIN ESTOLATE, ERYTHROMYCIN ETHYLSUCCINATE, ERYTHROMYCIN LACTOBIONATE, LANSOPRAZOL-AMOXICIL-CLARITHRO, OMECLAMOX-PAK, VOQUEZNA TRIPLE PAK |
| 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 |
| Dantrolene/Calcium Channel Blockers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: The exact mechanism is unknown. Dantrolene may decrease the release of calcium from the sarcoplasmic reticulum, resulting in additive or synergistic effects with calcium channel blockers.(1) CLINICAL EFFECTS: Concurrent use of dantrolene and calcium channel blockers may result in cardiogenic shock.(2-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US, UK, and Australian manufacturers of dantrolene state that concurrent use with calcium channel blockers during the management of malignant hyperthermia crisis is not recommended.(2-4) The Australian and UK manufacturers of diltiazem state that concurrent use of dantrolene infusion with calcium channel blockers is contraindicated.(5-6) DISCUSSION: Cardiogenic shock in patients treated simultaneously with verapamil and dantrolene is rare but has been reported.(2-4,7) Concurrent use of dantrolene and verapamil in swine has been reported to result in cardiogenic shock and hyperkalemia.(8) In dogs, the combination has been reported to cause hyperkalemia.(9) The combination of diltiazem and dantrolene has been reported to cause adverse cardiovascular effects in swine.(10) A study in swine showed no adverse effects from the combination of dantrolene and nifedipine(10) and one patient who experience cardiogenic shock with dantrolene and verapamil had no adverse effects with the combination of dantrolene and nifedipine;(7) however, the US manufacturer cannot endorse the safety of the combination.(2) |
DANTRIUM, DANTROLENE SODIUM, REVONTO, RYANODEX |
| Midazolam; Triazolam/Diltiazem; Verapamil SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Diltiazem and verapamil may inhibit the metabolism of midazolam and triazolam by CYP3A4.(1-7) CLINICAL EFFECTS: Concurrent use of diltiazem or verapamil may result in elevated levels of and clinical effects, including profound sedation, respiratory depression, coma, and/or death, from midazolam and triazolam.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Consider the use of alternative agents to midazolam and triazolam in patients maintained on diltiazem or verapamil. The concurrent use of midazolam or triazolam with diltiazem or verapamil should be approached with caution. The dose of midazolam or triazolam should be reduced and patients should be observed for increased benzodiazepine effects such as prolonged sedation.(1-4) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness. DISCUSSION: In a double-blind, randomized, cross-over study in 9 healthy subjects, pretreatment with diltiazem (60 mg 3 times daily for 2 days) increased the area-under-curve (AUC) of a single oral dose of midazolam (15 mg) by 2.75-fold. Midazolam maximum concentration (Cmax) doubled and half-life (T1/2) was prolonged. These changes were associated with profound and prolonged sedative effects.(1) In a double-blind, randomized, cross-over study in 9 healthy subjects, pretreatment with verapamil (80 mg 3 times daily for 2 days) increased the AUC of a single oral dose of midazolam (15 mg) by 1.9-fold. Midazolam Cmax doubled and T1/2 was prolonged. These changes were associated with profound and prolonged sedative effects.(1) In a randomized, cross-over study in 7 healthy males, pretreatment with diltiazem (180 mg daily for 3 days) increased the AUC, Cmax, and T1/s of a single oral dose of triazolam (0.25 mg) by 1.275-fold, 71%, and 85%, respectively. Pharmacodynamic effects of triazolam were significantly increased as measured by peak saccadic velocity of eye movements (PSV), electroencephalogram (EEG), and visual analogue scale (VAS).(2) In a randomized, double-blind, cross-over study in 10 healthy subjects, pretreatment with diltiazem (60 mg 3 times daily for 2 days) increased the AUC, Cmax, and T1/2 of a single oral dose of triazolam (0.25 mg) by 3-fold, 2-fold, and 2-fold, respectively. These changes were associated with increased and prolonged pharmacodynamic effects.(3) Studies have shown that diltiazem increases midazolam and triazolam AUC by 3-fold to 4-fold, Cmax by 2-fold, and T1/2 by 1.5-fold to 2.5-fold.(4) |
HALCION, MIDAZOLAM, MIDAZOLAM HCL, MIDAZOLAM HCL-0.8% NACL, MIDAZOLAM HCL-0.9% NACL, MIDAZOLAM HCL-D5W, MIDAZOLAM HCL-NACL, MIDAZOLAM-0.9% NACL, MIDAZOLAM-NACL, MKO (MIDAZOLAM-KETAMINE-ONDAN), NAYZILAM, TRIAZOLAM |
| Topotecan/P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of P-glycoprotein may increase the absorption of topotecan.(1) CLINICAL EFFECTS: The concurrent administration of topotecan with an inhibitor of P-glycoprotein may result in elevated levels of topotecan and signs of toxicity. These signs may include but are not limited to anemia, diarrhea, and thrombocytopenia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of topotecan states that the use of topotecan and P-glycoprotein inhibitors should be avoided. If concurrent use is warranted, carefully monitor patients for adverse effects.(1) DISCUSSION: In clinical studies, the combined use of elacridar (100 mg to 1000 mg) increased the area-under-curve (AUC) of topotecan approximately 2.5-fold.(1) Oral cyclosporine (15 mg/kg) increased the AUC of topotecan lactone and total topotecan to 2-fold to 3-fold of the control group, respectively.(1) P-gp inhibitors linked to this monograph include: adagrasib, amiodarone, asciminib, asunaprevir, azithromycin, belumosudil, bosutinib, capmatinib, carvedilol, cimetidine, clarithromycin, cobicistat, conivaptan, cyclosporine, danicopan, daridorexant, diltiazem, diosmin, dronedarone, erythromycin, flibanserin, fostamatinib, ginseng, hydroquinidine, isavuconazonium, itraconazole, ivacaftor, josamycin, ketoconazole, ledipasvir, lonafarnib, mavorixafor, neratinib, osimertinib, pibrentasvir/glecaprevir, pirtobrutinib, propafenone, quinidine, ranolazine, ritonavir, selpercatinib, sotorasib, tezacaftor, tepotinib, tucatinib, valbenazine, velpatasvir, vemurafenib, verapamil, vimseltinib, and voclosporin.(2,3) |
HYCAMTIN |
| 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 |
| 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 |
| Fingolimod/Beta-Blockers; AV Node Blockers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Initiation of fingolimod has a negative chronotropic effect leading to a mean decrease in heart rate of 13 beats per minute (bpm) after the first dose. The first dose has also been associated with heart block. Beta-blockers or agents which slow AV node conduction further increase the risk for symptomatic bradycardia or heart block. CLINICAL EFFECTS: The heart rate lowering effect of fingolimod is biphasic with an initial decrease usually within 6 hours, followed by a second decrease 12 to 24 hours after the first dose. Symptomatic bradycardia and heart block have been observed. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsade de pointes. The cause of death in a patient who died within 24 hour after taking the first dose of fingolimod was not conclusive; however a link to fingolimod or a drug interaction with fingolimod could not be ruled out. Beta-Blockers linked to this monograph are: atenolol, betaxolol, bisoprolol, carvedilol, esmolol, landiolol, labetalol, metoprolol, nadolol, nebivolol, propranolol and timolol. AV Node Blocking agents are:digoxin, diltiazem, flecainide, ivabradine, propafenone and verapamil. PREDISPOSING FACTORS: Pre-existing cardiovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, history of torsades de pointes, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to fingolimod initiation, or factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia, bradycardia, female gender, or advanced age) may increase risk for cardiovascular toxicity due to fingolimod. 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: Fingolimod is contraindicated in patients with Class III/IV heart failure or in patients who have experienced myocardial infarction, unstable angina, stroke, transient ischemic attack (TIA) or decompensated heart failure within the past six months.(1) Patients with pre-existing cardiovascular or cerebrovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, or heart block), severe untreated sleep apnea, or a prolonged QTc interval prior to fingolimod initiation should receive cardiologist consultation to evaluate the risks of fingolimod therapy. Patients receiving agents linked to this monograph should have their physician evaluate the possibility of a switch to agents which do not slow heart rate or cardiac conduction. If fingolimod is initiated, the patient should stay overnight in a medical facility with continuous ECG monitoring after the first dose. Correct hypokalemia or hypomagnesemia prior to starting fingolimod. US monitoring recommendations in addition to continuous ECG with overnight monitoring: Check blood pressure hourly. If heart rate (HR) is < 45 beats per minute (BPM) or if the ECG shows new onset of second degree or higher AV block at the end of the monitoring period, then monitoring should continue until the finding has resolved. If patient requires treatment for symptomatic bradycardia, the first dose monitoring strategy should be repeated for the second dose of fingolimod. If, within the first two weeks of treatment one or more fingolimod doses is missed, then first dose procedures are recommended upon resumption. If during weeks 3 and 4 of fingolimod treatment dose is interrupted more than 7 days, then first dose procedures are recommended upon resumption. United Kingdom recommendations(3): Obtain a 12-lead ECG prior to initiating fingolimod therapy. Consult a cardiologist for pretreatment risk-benefit assessment if patient has a resting heart rate less than 55 bpm, history of syncope, second degree or greater AV block, sick-sinus syndrome, concurrent therapy with beta-blockers, Class Ia, or Class III antiarrhythmics, heart failure or other significant cardiovascular disease. Perform continuous ECG monitoring, measure blood pressure and heart rate every hour, and perform a 12-lead ECG 6 hours after the first dose. Monitoring should be extended beyond 6 hours if symptomatic bradycardia or new onset of second degree AV block, Mobitz Type II or third degree AV block has occurred at any time during the monitoring period. If heart rate 6 hours after the first dose is less than 40 bpm, has decreased more than 20 bpm compared with baseline, or if a new onset second degree AV block, Mobitz Type I (Wenckebach) persists, then monitoring should also be continued. If fingolimod treatment is discontinued for more than two weeks, the effects on heart rate and conduction could recur. Thus, first dose monitoring precautions should be followed upon reintroduction of fingolimod. DISCUSSION: After the first dose of fingolimod, heart rate decrease may begin within an hour. Decline is usually maximal at approximately 6 hours followed by a second decrease 12 to 24 hours after the first dose. The second dose may further decrease heart rate, but the magnitude of change is smaller than the first dose. With continued, chronic dosing, heart rate gradually returns to baseline in about one month.(1,2) Diurnal variation in heart rate and response to exercise are not affected by fingolimod treatment.(2) In a manufacturer sponsored study, fingolimod and atenolol 50 mg daily lowered heart rate 15% more than fingolimod alone. However, additional heart rate lowering was not seen with the combination of extended release diltiazem and fingolimod compared with fingolimod alone.(1) |
FINGOLIMOD, GILENYA, TASCENSO ODT |
| 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 |
| Bosentan/Strong and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Bosentan is metabolized by CYP2C9 and CYP3A4. It is also an inducer of these enzymes. With regular dosing bosentan auto-induces its own metabolism.(1) Strong and moderate CYP3A4 inhibitors may inhibit the CYP3A4 mediated metabolism of bosentan.(1,2) CLINICAL EFFECTS: Concurrent use of bosentan with an inhibitor of CYP3A4 may result in elevated levels of and toxicity from bosentan.(1) PREDISPOSING FACTORS: Concurrent use of bosentan, a CYP3A4 inhibitor and a CYP2C9 inhibitor (e.g. amiodarone, fluconazole, miconazole, oxandrolone, sulfinpyrazone, or phenylbutazone)(3) could lead to blockade of both major metabolic pathways for bosentan, resulting in large increases in bosentan plasma concentrations.(1,3) PATIENT MANAGEMENT: 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) For patients stabilized on bosentan when a CYP3A4 inhibitor is initiated, monitor tolerance to concomitant therapy and adjust bosentan dose if needed. In patients who have been receiving a strong CYP3A4 inhibitor for at least 10 days, start bosentan at 62.5 mg once daily or every other day based upon individual tolerability. Discontinue use of bosentan at least 36 hours prior to initiation of a strong CYP3A4 inhibitor. After at least 10 days following the initiation of a strong CYP3A4 inhibitor, resume bosentan at 62.5 mg once daily or every other day based upon individual tolerability. DISCUSSION: In a study in healthy subjects, concurrent bosentan and ketoconazole (a strong CYP3A4 inhibitor) administration increased bosentan steady-state maximum concentrations (Cmax) and area-under-curve (AUC) by 2.1-fold and 2.3-fold, respectively.(2) Strong CYP3A4 inhibitors linked to this monograph include: adagrasib, boceprevir, ceritinib, clarithromycin, itraconazole, josamycin, ketoconazole, levoketoconazole, mibefradil, mifepristone, nefazodone, posaconazole, ribociclib, telaprevir, telithromycin, troleandomycin, tucatinib, and voriconazole.(3) Moderate CYP3A4 inhibitors linked to this monograph include: aprepitant, berotralstat, clofazimine, conivaptan, diltiazem, dronedarone, erythromycin, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, letermovir, netupitant, nilotinib, schisandra, treosulfan and verapamil.(3) |
BOSENTAN, TRACLEER |
| Guanfacine/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 guanfacine.(1) CLINICAL EFFECTS: The concurrent administration of a strong or moderate CYP3A4 inhibitor may result in elevated levels of guanfacine, which may result in increased adverse effects such as hypotension, bradycardia, loss of consciousness, and drowsiness.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients maintained on guanfacine may need dosage adjustments if strong or moderate inhibitors of CYP3A4 are initiated or discontinued. The manufacturer of extended-release guanfacine recommends a starting dose of extended-release guanfacine initiated at half the recommended level of the weight based dosing in patients receiving strong or moderate inhibitors of CYP3A4. If a patient has been maintained on extended-release guanfacine and is started on a strong or moderate CYP3A4 inhibitor, the dose of extended-release guanfacine should be decreased to half the recommended weight based dose. If a patient has been maintained on extended-release guanfacine and a strong or moderate CYP3A4 inhibitor and the strong or moderate CYP3A4 inhibitor is discontinued, the dose of extended-release guanfacine may need to be increased to the recommended weight based dose based upon patient response. Extended-release guanfacine target dose range for attention deficit hyperactivity disorder is 0.05-0.12 mg/kg/day. Doses above 4 mg/day have not been evaluated in children ages 6-12 years and doses above 7 mg/day have not been evaluated in adolescents ages 13-17 years.(1) DISCUSSION: Ketoconazole (dosage not stated), a strong inhibitor of CYP3A4, increased the maximum concentration (Cmax) and area-under-curve (AUC) of guanfacine (dosage not stated) by approximately 1.75-fold and 3-fold, 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, posaconazole, ribociclib, ritonavir, saquinavir, telaprevir, telithromycin, tipranavir, troleandomycin, tucatinib, and voriconazole.(1-3) Moderate inhibitors of CYP3A4 include: amprenavir, aprepitant, atazanavir, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(1-3) |
GUANFACINE HCL, GUANFACINE HCL ER, INTUNIV |
| Pimozide/Selected 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 pimozide.(1) CLINICAL EFFECTS: Concurrent administration of a moderate inhibitor of CYP3A4 may result in elevated levels of pimozide, which may result in prolongation of the QTc interval and potentially life-threatening ventricular arrhythmias.(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) 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.(3) PATIENT MANAGEMENT: Avoid concurrent use, especially when other risk factors for QT prolongation are present. The manufacturer of pimozide states that concomitant treatment with strong CYP3A4 inhibitors is contraindicated and treatment with less potent inhibitors of CYP3A4 should also be avoided.(1) If concurrent use cannot be avoided, then correct or minimize QT prolonging risk factors, e.g. correct electrolyte disturbances, use the lowest effective dose of pimozide, and discontinue other concurrent QT prolonging agents or CYP3A4 inhibitors if possible. Consider ECG to evaluate baseline and/or concurrent QT prolongation risk. Monitor patients on the combination and counsel patients accordingly. DISCUSSION: Pimozide is metabolized at CYP3A.(1,4) Elevated levels of pimozide may prolong the QTc interval resulting in life-threatening ventricular arrhythmias.(1) Moderate inhibitors of CYP3A4 include: avacopan, berotralstat, clofazimine, conivaptan, diltiazem, duvelisib, fedratinib, fosnetupitant, imatinib, isavuconazonium, lenacapavir, netupitant, schisandra, tofisopam, treosulfan and verapamil.(5,6) |
PIMOZIDE |
| Ergot Alkaloids/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 ergot alkaloids. CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in increased levels of the ergot alkaloid, which may result in clinical signs of ergotism, including vasospasm, dysesthesia, renal ischemia, and peripheral ischemia. PREDISPOSING FACTORS: Patients receiving the maximum recommended (or higher than recommended) dosages of ergot alkaloids may be at a higher risk of adverse effects from this combination. PATIENT MANAGEMENT: When possible, avoid the concurrent use of moderate CYP3A4 inhibitors in patients taking ergot alkaloids. If concurrent use is warranted, consider reducing the dose of the ergot alkaloid during concurrent therapy. Patients receiving concurrent therapy should be monitored for and instructed to report any signs of ergotism. DISCUSSION: Coadministration of dihydroergotamine and ergotamine with potent inhibitors of CYP3A4 such as clarithromycin, erythromycin, indinavir, nelfinavir, ritonavir, and troleandomycin has resulted in ergotism, characterized by vasospasm and ischemia of the extremities. Inhibition of ergot alkaloid metabolism by moderate inhibitors would also be expected, but to a lesser degree. Moderate CYP3A4 inhibitors linked to this monograph are aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lenacapavir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil. |
DIHYDROERGOTAMINE MESYLATE, ERGOLOID MESYLATES, ERGOMAR, ERGOTAMINE TARTRATE, ERGOTAMINE-CAFFEINE, METHYLERGONOVINE MALEATE, METHYSERGIDE MALEATE, MIGERGOT, MIGRANAL, TRUDHESA |
| 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 |
| Rivaroxaban/Selected P-gp and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Diltiazem, dronedarone, and isavuconazonium may inhibit the metabolism of rivaroxaban by CYP3A4 and by P-glycoprotein.(1-5) CLINICAL EFFECTS: Concurrent use of an agent that is both an inhibitor of P-gp and a moderate inhibitor of CYP3A4 may result in elevated levels of and clinical effects of rivaroxaban, including an increased risk of bleeding, in patients with decreased renal function.(1,2) PREDISPOSING FACTORS: It is expected that this interaction will only be clinically significant in patients with decreased renal function.(1) 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 CYP3A4,(6) inhibit anticoagulant/antiplatelet metabolism and/or have an inherent risk for bleeding (NSAIDs). PATIENT MANAGEMENT: The US manufacturer states no precautions are necessary with the concurrent use of agents that are combined moderate inhibitors of CYP3A4 and P-gp inhibitors with rivaroxaban in patients with normal renal function; however, in patients with decreased renal function (CrCL of 15 ml/min to 80 ml/min) these agents should only be used if the benefits of concurrent therapy outweigh the increased risk of bleeding.(1) The Canadian manufacturer states that if such use must be undertaken, caution is required.(3) The UK manufacturer states that concomitant use is not recommended.(7) 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: Clarithromycin (500 mg twice daily) increased the area-under-curve (AUC) and maximum concentration (Cmax) of a single dose of rivaroxaban by 54% and 40%, respectively.(1,2) In a study in 60 healthy males, clarithromycin (500 mg twice daily) increased the AUC and Cmax of a single dose of rivaroxaban (40 mg) by 94% and 92%, respectively.(8) In a case report, a 65 year-old male developed hemoptysis, epistaxis, and intracranial hemorrhage 3 days after the addition of clarithromycin (500 mg twice daily) to rivaroxaban (20 mg daily).(9) A study of 12 healthy volunteers found that cyclosporine increased rivaroxaban AUC and Cmax by 47% and 104%, respectively, compared to rivaroxaban alone. The combination of fluconazole and cyclosporine administered with rivaroxaban increased rivaroxaban AUC and Cmax by 86% and 115%, respectively, compared to rivaroxaban alone.(6) In a review of 9 liver transplant patients, mean rivaroxaban levels were significantly higher in patients treated with cyclosporine than with tacrolimus (131.7 ng/ml versus 20.3 ng/ml).(10) In a review of 23 patients who received concurrent rivaroxaban and dronedarone for an average of 9.1+/-6.7 months, there were no thromboembolic or major bleeding events. One fourth of the patients received a reduced dose of rivaroxaban (15 mg daily), despite having normal renal function.(11) Erythromycin (500 mg three times daily) increased the AUC and Cmax of a single dose of rivaroxaban by 30% and 30%, respectively.(1-3) In patients with mild renal impairment (CrCl of 50 ml/min to 79 ml/min) who were receiving erythromycin, rivaroxaban AUC and Cmax were increased 76% and 56% when compared to administration of rivaroxaban in patients with normal renal function receiving rivaroxaban alone. In patients with moderate renal impairment (CrCl of 30 ml/min to 49 ml/min) who were receiving erythromycin, rivaroxaban AUC and Cmax were increased 99% and 64% when compared to administration of rivaroxaban in patients with normal renal function receiving rivaroxaban alone.(1,12) In a post hoc analysis of the ROCKET-AF trial, concomitant use of non-dihydropyridine calcium channel blockers and rivaroxaban was associated with an increased risk of major bleeding and intracranial hemorrhage. There was no difference in efficacy or safety of rivaroxaban versus warfarin and concomitant use of CCB across renal function subgroups.(13) In a study in subjects who were taking verapamil, the combination of verapamil and mild renal insufficiency produced additive effects on the AUC of a single dose of rivaroxaban (20 mg).(14) A propensity matched cohort evaluated the concurrent use of combined P-gp and moderate CYP3A4 inhibitors with apixaban or rivaroxaban. Combined inhibitors included amiodarone, diltiazem, erythromycin, dronedarone, and verapamil. Bleeding occurred in 26.4% of patients in the inhibitor group compared to 18.4% in the control group (hazard ratio 1.8; 95% CI 1.19-2.73; p=0.006). Although not statistically significant, patients in the inhibitor group also had a higher rate of major bleeding (15% vs 10.3%) and minor bleeding (8.9% vs 5.2%), respectively.(15) A summary of pharmacokinetic interactions with rivaroxaban and dronedarone concluded that concurrent use should be avoided if CrCl < 80 ml/min.(16) These changes are not expected to be clinically significant in patients with normal renal function.(1-3) |
RIVAROXABAN, XARELTO |
| Cobimetinib; Olaparib; Sonidegib/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 cobimetinib, olaparib, and sonidegib.(1-4) CLINICAL EFFECTS: Concurrent use of moderate CYP3A4 inhibitors may increase systemic exposure and the risk for adverse effects from cobimetinib, olaparib, or sonidegib.(1-4) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: When possible, avoid the use of moderate CYP3A4 inhibitors in patients receiving cobimetinib, olaparib, or sonidegib.(1-4) For patients taking cobimetinib 60 mg daily, if concurrent short term use (14 days or less) of a moderate CYP3A4 inhibitor cannot be avoided, reduce cobimetinib dose to 20 mg daily. After discontinuation of the moderate CYP3A4 inhibitor resume the previous 60 mg dose. Patients who are taking cobimetinib 40 mg or 20 mg daily should not receive a moderate or strong CYP3A4 inhibitor.(1) If concomitant use with olaparib cannot be avoided, reduce the olaparib dose. Dosage adjustments are specific to the formulation of olaparib.(2,3) Reduce the dosage of the CAPsule formulation to 200 mg (four 50 mg CAPsules) taken twice daily.(2) Reduce the dosage of the TABlet formulation to 150 mg (one 150 mg TABlet) twice daily). If the CYP3A4 inhibitor is discontinued, resume the dose of olaparib taken prior to initiation of the CYP3A4 inhibitor after 3 to 5 half-lives.(3) If sonidegib and a moderate CYP3A4 inhibitor must be used, administer the moderate CYP3A4 inhibitor for less than 14 days and monitor closely for adverse effects, particularly musculoskeletal adverse reactions.(4) DISCUSSION: In an interaction study, itraconazole (a strong CYP3A4 inhibitor) given 200 mg once daily for 14 days followed by a single dose of cobimetinib 10 mg increased mean cobimetinib AUC 6.7-fold (90% CI 5.6, 8.0). Subsequent simulations showed that predicted steady-state concentrations of cobimetinib at a reduced daily dose of 20 mg given with short term use of a moderate CYP3A4 inhibitor were similar to observed steady-state concentrations at the 60 mg dose without an inhibitor.(1) In simulations using physiologically-based pharmacokinetic (PBPK) models, concurrent use of fluconazole, a moderate CYP3A4 inhibitor, may increase the area-under-curve (AUC) of olaparib by 2.2-fold.(2,3) Based upon PBPK simulations, sonidegib mean steady-state AUC would increase 1.8-fold if administered with a moderate CYP3A4 inhibitor for 14 days and would further increase to 2.8-fold if the moderate CYP3A4 inhibitor is coadministered with sonidegib for 4 months.(4) Moderate CYP3A4 inhibitors linked to this monograph include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(5) |
COTELLIC, LYNPARZA, ODOMZO |
| 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 |
| Pazopanib/Selected Inhibitors of P-gp or BCRP SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Inhibitors of P-glycoprotein (P-gp) or BCRP may increase the absorption of pazopanib.(1) CLINICAL EFFECTS: The concurrent administration of pazopanib with an inhibitor of P-glycoprotein or BCRP may result in elevated levels of pazopanib and signs of toxicity.(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, and/or renal/hepatic dysfunction).(2) PATIENT MANAGEMENT: The US manufacturer of pazopanib states concurrent use of P-gp inhibitors or BCRP inhibitors should be avoided.(1) Monitor patients for increased side effects from pazopanib. 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: Pazopanib is a substrate of P-gp and BCRP. Inhibitors of these transporters are expected to increase pazopanib levels.(1) BCRP inhibitors linked to this monograph include: asciminib, belumosudil, clopidogrel, cyclosporine, darolutamide, eltrombopag, gefitinib, grazoprevir, lazertinib, leflunomide, momelotinib, oteseconazole, rolapitant, roxadustat, tafamidis, teriflunomide, and vadadustat.(1,3-5) P-glycoprotein inhibitors linked to this monograph include: asunaprevir, belumosudil, capmatinib, carvedilol, cyclosporine, danicopan, daridorexant, diltiazem, flibanserin, fostamatinib, ginseng, glecaprevir/pibrentasvir, isavuconazonium, ivacaftor, ledipasvir, neratinib, sofosbuvir/velpatasvir/voxilaprevir, tepotinib, tezacaftor, ticagrelor, valbenazine, verapamil, vimseltinib, and voclosporin.(3,4) |
PAZOPANIB HCL, VOTRIENT |
| 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 |
| Colchicine (for Gout & FMF)/P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: P-glycoprotein (P-gp) inhibitors may affect the transport of colchicine, a P-gp substrate.(1,2) CLINICAL EFFECTS: Concurrent use of a P-gp inhibitor may result in elevated levels of and toxicity from colchicine. Symptoms of colchicine toxicity include abdominal pain; nausea or vomiting; severe diarrhea; muscle weakness or pain; numbness or tingling in the fingers or toes; myelosuppression; 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) and in patients who receive concurrent therapy. PATIENT MANAGEMENT: The concurrent use of colchicine with P-gp inhibitors is contraindicated in patients with renal or hepatic impairment.(1-3) Avoid concurrent use in other patients, if possible.(3) In patients without renal or hepatic impairment who are currently taking or have taken a P-gp inhibitor in the previous 14 days, the dosage of colchicine should be reduced. For gout flares, the recommended dosage is 0.6 mg (1 tablet) for one dose. This dose should be repeated no earlier than in 3 days.(1,2) For gout prophylaxis, if the original dosage was 0.6 mg twice daily, use 0.3 mg daily. If the original dosage was 0.6 mg daily, use 0.3 mg every other day.(3-12) For Familial Mediterranean fever (FMF), the recommended maximum daily dose is 0.6 mg (may be given as 0.3 mg twice a day).(1,2) Patients should be instructed to immediately report any signs of colchicine toxicity, such as abdominal pain, nausea/significant diarrhea, vomiting; muscle weakness/pain; numbness/tingling in fingers/toes; unusual bleeding or bruising, infections, weakness/tiredness, or pale/gray color of the lips/tongue/palms of hands. DISCUSSION: There are several reports of colchicine toxicity(4-6) and death(7,8) following the addition of clarithromycin to therapy. In a retrospective review of 116 patients who received clarithromycin and colchicine during the same hospitalization, 10.2% (9/88) of patients who received simultaneous therapy died, compared to 3.6% (1/28) of patients who received sequential therapy.(9) An FDA review of 117 colchicine-related deaths that were not attributable to overdose found that 60 deaths (51%) involved concurrent use of clarithromycin.(2) There is one case report of colchicine toxicity with concurrent erythromycin.(10) 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 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 and P-gp inhibitors such as clarithromycin, cyclosporine, diltiazem, erythromycin, and verapamil.(1,2) P-gp inhibitors include abrocitinib, amiodarone, asciminib, asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, danicopan, daridorexant, diltiazem, diosmin, dronedarone, erythromycin, flibanserin, fluvoxamine, fostamatinib, glecaprevir/pibrentasvir, lapatinib, ledipasvir, mavorixafor, neratinib, osimertinib, pirtobrutinib, propafenone, quinidine, ranolazine, schisandra, selpercatinib, sotorasib, tepotinib, tezacaftor, valbenazine, velpatasvir, vemurafenib, verapamil, vimseltinib, and voclosporin.(1,11,12) |
COLCHICINE, COLCRYS, GLOPERBA, MITIGARE, PROBENECID-COLCHICINE |
| 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 |
| Neratinib/Strong CYP3A4 Inhibitors;Moderate CYP3A4 & P-gp Dual 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 neratinib.(1) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inhibitors or moderate CYP3A4 and P-glycoprotein (P-gp) dual inhibitors may result in increased systemic exposure to and effects from neratinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the concurrent use of neratinib with strong CYP3A4 inhibitors or moderate CYP3A4 and P-gp dual inhibitors.(1) The Australian and Canadian manufacturer of nirmatrelvir/ritonavir state that concurrent use with neratinib is contraindicated due to the potential for hepatotoxicity and other serious reactions.(2,3) Canadian labeling contraindicates concurrent use of atazanavir/ritonavir and lopinavir/ritonavir with neratinib.(4,5) If concurrent use is warranted, monitor patients closely for increased incidence and severity of diarrhea, abdominal pain, nausea, vomiting, and dehydration. DISCUSSION: Ketoconazole (400 mg daily for 5 days), a strong CYP3A4 inhibitor, increased maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of neratinib by 221% and 381%, respectively.(1) Pharmacokinetic models predicted that verapamil, a moderate CYP3A4 and P-gp dual inhibitor, would increase the Cmax and AUC of neratinib by 203% and 299%, respectively. Fluconazole, a moderate CYP3A4 inhibitor, is not expected to have a significant interaction with neratinib.(1) Strong CYP3A4 inhibitors include: adagrasib, boceprevir, clarithromycin, cobicistat, diltiazem, grapefruit juice, idelalisib, indinavir, itraconazole, ketoconazole, lonafarnib, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, posaconazole, ribociclib, telaprevir, telithromycin, troleandomycin, tucatinib, and voriconazole.(1,6) Moderate CYP3A4 and P-gp dual inhibitors include: atazanavir, conivaptan, diltiazem, dronedarone, erythromycin, isavuconazole, istradefylline, josamycin, nilotinib, and verapamil.(1,6) |
NERLYNX |
| Ibrutinib/Diltiazem SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Agents that are strong or moderate inhibitors of the CYP3A4 isoenzyme may inhibit the metabolism of ibrutinib.(1) Diltiazem is a moderate to strong CYP3A4 inhibitor.(2-4) CLINICAL EFFECTS: Concurrent use of diltiazem may increase levels of and effects from ibrutinib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of ibrutinib recommends avoiding concurrent use with strong and moderate CYP3A4 inhibitors. If concurrent use is warranted with moderate CYP3A4 inhibitor, consider dose modifications.(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) Diltiazem is a moderate to strong CYP3A4 inhibitor.(2-4) DISCUSSION: A pharmacokinetic model simulating human pharmacokinetics and drug interactions in healthy men predicted that diltiazem would increase ibrutinib Cmax and AUC by 5-fold and 5.5-fold, respectively.(2) In a study in 18 healthy subjects, ketoconazole (400 mg daily for 7 days) increased the Cmax and AUC of ibrutinib (single 40 mg dose) by 24-fold and 29-fold, respectively.(1) The coadministration of multiple doses of voriconazole increased ibrutinib's Cmax and AUC by 6.7-fold and 5.7-fold.(1) Simulations under fed conditions suggest that posaconazole may increase ibrutinib's AUC by 7-fold to 10-fold.(1) |
IMBRUVICA |
| 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 |
| 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 |
| Siponimod/Agents That Cause Bradycardia SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Initiation of siponimod has caused transient decreases in heart rate and atrioventricular conduction delays after the first dose. Decreases in heart rate start within the first hour and maximal decrease in heart rate was seen at approximately 3-4 hours. The first dose has also been associated with heart block. Additional agents that cause bradycardia further increase the risk for symptomatic bradycardia.(1) CLINICAL EFFECTS: The heart rate lowering effect of siponimod is transient and is usually seen with the first dose. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsade de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, history of torsades de pointes, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to siponimod initiation, or factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia, bradycardia, female gender, or advanced age) may increase risk for cardiovascular toxicity due to siponimod.(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 prescribing information states siponimod treatment should generally not be initiated in patients who are concurrent therapy with additional agents that cause bradycardia. If treatment with siponimod is considered, advice from a cardiologist should be sought regarding switching to non-heart rate lowering drugs or recommendations for monitoring for treatment initiation. Treatment initiation recommendations include: - Obtain an ECG in all patients to determine whether preexisting conduction abnormalities are present. - In all patients, a dose titration is recommended for initiation of siponimod treatment to help reduce cardiac effects. - In patients with sinus bradycardia (HR less than 55 bpm), first- or second-degree [Mobitz type I] AV block, or a history of myocardial infarction or heart failure with onset > 6 months prior to initiation, ECG testing and first dose monitoring is recommended. - Since significant bradycardia may be poorly tolerated in patients with history of cardiac arrest, cerebrovascular disease, uncontrolled hypertension, or severe untreated sleep apnea, siponimod is not recommended in these patients. If treatment is considered, advice from a cardiologist should be sought prior to initiation of treatment in order to determine the most appropriate monitoring strategy. - Use of siponimod in patients with a history of recurrent syncope or symptomatic bradycardia should be based on an overall benefit-risk assessment. If treatment is considered, advice from a cardiologist should be sought prior to initiation of treatment in order to determine the most appropriate monitoring. - If a titration dose is missed or if 4 or more consecutive daily doses are missed during maintenance treatment, reinitiate Day 1 of the dose titration and follow titration monitoring recommendations.(1) DISCUSSION: Initiation of siponimod treatment has been associated with transient atrioventricular (AV) conduction delays that follow a similar temporal pattern as the observed decrease in heart rate during dose titration. The AV conduction delays manifested in most of the cases as first-degree AV block (prolonged PR interval on ECG), which occurred in 5.1% of siponimod treated patients and in 1.9 % of patients receiving placebo in Study 1. Second-degree AV blocks, usually Mobitz type I (Wenckebach), have been observed at the time of treatment initiation with siponimod in less than 1.7% of patients in clinical trials. The conduction abnormalities typically were transient, asymptomatic, resolved within 24 hours, rarely required treatment with atropine, and did not require discontinuation of siponimod treatment.(1) |
MAYZENT |
| Crizotinib/Agents That Cause Bradycardia SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Crizotinib may cause symptomatic bradycardia. Additional agents that cause bradycardia further increase the risk for symptomatic bradycardia.(1) CLINICAL EFFECTS: Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsade de pointes.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of crizotinib recommends avoiding concurrent use of crizotinib and other agents known to cause bradycardia to the extent possible. If combination therapy is required, monitor heart rate and blood pressure regularly. If bradycardia occurs, withhold crizotinib until heart rate recovers to 60 bpm or above, or patient is asymptomatic. Re-evaluate the use of the concomitant medication. If the concomitant medication is discontinued or its dose is reduced, resume crizotinib at the previous dose upon patient's recovery. If the concomitant medication is not discontinued or dose adjusted, resume crizotinib at a reduced dose upon patient's recovery. If life-threatening bradycardia occurs, discontinue or reduce the dose of the concomitant medication. Upon the patient's recovery, lower the dose of crizotinib to 250 mg daily. Monitor blood pressure and heart rate frequently.(1) DISCUSSION: Across clinical trials, bradycardia occurred in 13 % of patients on crizotinib, and grade 3 syncope occurred in 2.4 % of patients on crizotinib compared with 0.6 % on chemotherapy.(1) Agents that may cause bradycardia and linked to this monograph include: beta-blockers, non-dihydropyridine calcium channel blockers, clonidine, and digoxin.(1) |
XALKORI |
| 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 |
| Selected Sensitive 3A4 Substrates that Inhibit 3A4/Oral Lefamulin SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Lefamulin is considered a moderate inhibitor of CYP3A4. FDA defines a moderate inhibitor as a drug which increases the area-under-curve (AUC) of a sensitive substrate by 2- to 5-fold.(1,2) Moderate inhibitors of CYP3A4 may inhibit the metabolism of oral lefamulin.(1,2) CLINICAL EFFECTS: Concurrent use of oral lefamulin with a sensitive CYP3A4 substrate that also inhibits CYP3A4 may lead to increased serum levels and adverse effects of lefamulin and the sensitive substrate, including 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).(4) PATIENT MANAGEMENT: If oral lefamulin must be coadministered with a sensitive CYP3A4 substrate, it is recommended to closely monitor for adverse effects of the CYP3A4 substrate and of lefamulin.(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 study, oral lefamulin tablets administered concomitantly with and at 2 or 4 hours before oral midazolam (a CYP3A4 substrate) increased the area-under-curve (AUC) and maximum concentration (Cmax) of midazolam by 200% and 100%, respectively. No clinically significant effect on midazolam pharmacokinetics was observed when co-administered with lefamulin injection.(1) 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) Sensitive CYP3A4 substrates linked to this monograph include: aprepitant, atazanavir, darunavir, diltiazem, isavuconazonium, and verapamil.(1,3) |
XENLETA |
| 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 |
| Relugolix/P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Relugolix is a substrate of the intestinal P-glycoprotein (P-gp) efflux transporter. Inhibitors of P-gp may increase the absorption of relugolix.(1) CLINICAL EFFECTS: The concurrent administration of relugolix with an inhibitor of P-glycoprotein may result in elevated levels of relugolix and adverse effects, including hot flashes, skin flushing, musculoskeletal pain, hyperglycemia, acute renal injury, transaminitis, arrhythmias, and hemorrhage.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The US manufacturer of relugolix states that the coadministration of relugolix with P-gp inhibitors should be avoided. If the P-gp inhibitor is to be used short-term, relugolix may be held for up to 2 weeks. If treatment with relugolix is interrupted for longer than 7 days, resume relugolix with a loading dose of 360 mg on the first day, followed by 120 mg once daily.(1) If coadministration with a P-gp inhibitor cannot be avoided, relugolix should be taken at least 6 hours before the P-gp inhibitor. Monitor the patient more frequently for adverse events.(1) DISCUSSION: Coadministration of relugolix with erythromycin (a P-gp and moderate CYP3A4 inhibitor) increased the area-under-curve (AUC) and maximum concentration (Cmax) of relugolix by 6.2-fold. Voriconazole (a strong CYP3A4 inhibitor) did not have a clinically significant effect on the pharmacokinetics of relugolix.(1) P-gp inhibitors linked to this monograph include: amiodarone, asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, clarithromycin, cobicistat, conivaptan, curcumin, cyclosporine, daclatasvir, danicopan, daridorexant, diltiazem, diosmin, dronedarone, eliglustat, erythromycin, flibanserin, fluvoxamine, fostamatinib, ginkgo, ginseng, glecaprevir/pibrentasvir, indinavir, itraconazole, ivacaftor, josamycin, ketoconazole, lapatinib, lonafarnib, mavorixafor, mibefradil, mifepristone, neratinib, osimertinib, paroxetine, pirtobrutinib, propafenone, quinidine, quinine, ranolazine, ritonavir, sarecycline, schisandra, selpercatinib, simeprevir, sotorasib, telaprevir, telithromycin, tepotinib, tezacaftor, tucatinib, valbenazine, velpatasvir, vemurafenib, verapamil, vimseltinib, and voclosporin.(2,3) |
MYFEMBREE, ORGOVYX |
| 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 |
| Ponesimod/Agents That Cause Bradycardia SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Initiation of ponesimod has caused transient decreases in heart rate and atrioventricular conduction delays after the first dose. Decreases in heart rate start within the first hour and maximal decrease in heart rate was seen at approximately 2-4 hours. The first dose has also been associated with heart block. Additional agents that cause bradycardia further increase the risk for symptomatic bradycardia.(1) CLINICAL EFFECTS: The heart rate lowering effect of ponesimod is transient and is usually seen with the first dose. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsade de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, history of torsades de pointes, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to siponimod initiation, or factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia, bradycardia, female gender, or advanced age) may increase risk for cardiovascular toxicity due to siponimod.(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 prescribing information states ponesimod treatment should generally not be initiated in patients who are on concurrent therapy with additional agents that cause bradycardia. If treatment with ponesimod is considered, advice from a cardiologist should be sought regarding switching to non-heart rate lowering drugs or monitoring during treatment initiation. Treatment initiation recommendations include: - Obtain an ECG in all patients to determine whether preexisting conduction abnormalities are present. - In all patients, a dose titration is recommended for initiation of ponesimod treatment to help reduce cardiac effects. - In patients with sinus bradycardia (HR less than 55 bpm), first- or second-degree [Mobitz type I] AV block, or a history of myocardial infarction or heart failure with onset > 6 months prior to initiation, ECG testing and first dose monitoring is recommended. - Since significant bradycardia may be poorly tolerated in patients with history of cardiac arrest, cerebrovascular disease, uncontrolled hypertension, or severe untreated sleep apnea, ponesimod is not recommended in these patients. If treatment is considered, advice from a cardiologist should be sought prior to initiation of treatment in order to determine the most appropriate monitoring strategy. - Use of ponesimod in patients with a history of recurrent syncope or symptomatic bradycardia should be based on an overall benefit-risk assessment. If treatment is considered, advice from a cardiologist should be sought prior to initiation of treatment in order to determine the most appropriate monitoring. - If a titration dose is missed or if 4 or more consecutive daily doses are missed during maintenance treatment, reinitiate Day 1 of the dose titration and follow titration monitoring recommendations.(1) DISCUSSION: Initiation of ponesimod treatment has been associated with transient atrioventricular (AV) conduction delays that follow a similar temporal pattern as the observed decrease in heart rate during dose titration. The AV conduction delays manifested in most of the cases as first-degree AV block (prolonged PR interval on ECG), which occurred in 3.4% of ponesimod treated patients and in 1.2% of patients receiving teriflunomide in Study 1. Second-degree or third-degree AV blocks have not been reported in patients in clinical trials. The conduction abnormalities typically were transient, asymptomatic, resolved within 24 hours, and did not require discontinuation of ponesimod treatment.(1) |
PONVORY |
| Alprazolam/Selected 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 alprazolam.(1) CLINICAL EFFECTS: Concurrent use may result in increased pharmacologic or toxic effects of alprazolam. Toxic effects include profound sedation, respiratory depression, coma, and/or death.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid concomitant use with moderate CYP3A4 inhibitors. Consider reducing the dose of alprazolam when coadministered with a moderate CYP3A4 inhibitor. If fluvoxamine is concurrently administered with alprazolam, the manufacturer of fluvoxamine recommends that the initial dose of alprazolam be reduced by 50%, followed by titration to the lowest effective dose.(2) If concurrent use is necessary, monitor patients for unusual dizziness or lightheadedness, extreme sleepiness, slowed or difficult breathing, or unresponsiveness. DISCUSSION: Coadministration of cimetidine, a moderate CYP3A4 inhibitor, increased the maximum concentration (Cmax) of alprazolam by 82%.(1) Coadministration with erythromycin, a moderate CYP3A4 inhibitor, increased the area-under-curve (AUC) of alprazolam by 1.61-fold.(1) Coadministration of fluvoxamine 100 mg daily and alprazolam 1 mg given 4 times per day resulted in a 2-fold increase of AUC, Cmax, and half-life of alprazolam.(2) Selected moderate CYP3A4 inhibitors linked to this monograph include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil.(3,4) |
ALPRAZOLAM, ALPRAZOLAM ER, ALPRAZOLAM INTENSOL, ALPRAZOLAM ODT, ALPRAZOLAM XR, XANAX, XANAX XR |
| Doxorubicin/P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: P-glycoprotein (P-gp) inhibition may increase doxorubicin cellular concentration, as well as decrease biliary or renal elimination.(1) CLINICAL EFFECTS: Increased cellular or systemic levels of doxorubicin may result in doxorubicin toxicity, including cardiomyopathy, myelosuppression, or hepatic impairment.(1) PREDISPOSING FACTORS: The interaction magnitude may be greater in patients with impaired renal or hepatic function. PATIENT MANAGEMENT: Avoid the concurrent use of P-gp inhibitors in patients undergoing therapy with doxorubicin.(1) Consider alternatives with no or minimal inhibition. If concurrent therapy is warranted, monitor the patient closely for signs and symptoms of doxorubicin toxicity. DISCUSSION: Doxorubicin is a substrate of P-gp.(1) Clinical studies have identified and evaluated the concurrent use of doxorubicin and P-gp inhibitors as a target to overcome P-gp mediated multidrug resistance.(2,3) P-gp inhibitors linked to this monograph include: amiodarone, asciminib, asunaprevir, azithromycin, belumosudil, capmatinib, cimetidine, cyclosporine, daclatasvir, danicopan, daridorexant, diltiazem, diosmin, dronedarone, eliglustat, erythromycin, flibanserin, fluvoxamine, fostamatinib, ginkgo, ginseng, glecaprevir/pibrentasvir, hydroquinidine, istradefylline, ivacaftor, lapatinib, ledipasvir, mavorixafor, neratinib, osimertinib, paroxetine, pirtobrutinib, propafenone, quercetin, quinidine, quinine, ranolazine, sarecycline, schisandra, selpercatinib, simeprevir, sofosbuvir/velpatasvir/voxilaprevir, sotorasib, tepotinib, tezacaftor, valbenazine, vemurafenib, verapamil, vimseltinib, and voclosporin.(4,5) |
ADRIAMYCIN, CAELYX, DOXIL, DOXORUBICIN HCL, DOXORUBICIN HCL LIPOSOME |
| Eliglustat/Dual CYP3A4 & Weak CYP2D6 Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Dual strong or moderate CYP3A4 and weak CYP2D6 inhibitors may inhibit the metabolism of eliglustat.(1) CLINICAL EFFECTS: Concurrent use of an agent that is a dual strong or moderate CYP3A4 and weak CYP2D6 inhibitor 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: Prescribing information has no specific recommendation on the use of eliglustat with drugs that are dual strong or moderate CYP3A4 and weak CYP2D6 inhibitors. 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 CYP2D6 metabolizers is contraindicated.(1) The concurrent use of eliglustat with strong inhibitors of CYP3A4 in intermediate and poor CYP2D6 metabolizers is contraindicated.(1) The concurrent use of eliglustat with moderate inhibitors of CYP3A4 in intermediate and poor CYP2D6 metabolizers should be avoided.(1) The dosage of eliglustat with strong or moderate inhibitors of CYP3A4 in extensive CYP2D6 metabolizers 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 CYP2D6 metabolizers.(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) Dual strong CYP3A4 and weak CYP2D6 inhibitors include: cobicistat.(1,3,4) Dual moderate CYP3A4 and weak CYP2D6 inhibitors include: diltiazem, fedratinib, fluvoxamine, imatinib, and verapamil.(1,3,4) |
CERDELGA |
| 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 |
| 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 |
| 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 |
| 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 |
| Etrasimod/Agents That Cause Bradycardia SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Initiation of etrasimod has caused transient decreases in heart rate and atrioventricular conduction delays after the first dose. The first dose has also been associated with heart block. Additional agents that cause bradycardia further increase the risk for symptomatic bradycardia.(1) CLINICAL EFFECTS: The heart rate lowering effect of etrasimod is transient and is usually seen with the first dose. Bradycardia may be associated with an increase in the QTc interval, increasing the risk for torsade de pointes.(1) PREDISPOSING FACTORS: Pre-existing cardiovascular disease (e.g. heart failure, ischemic heart disease, history of myocardial infarction, stroke, history of torsades de pointes, or heart block), severe untreated sleep apnea, a prolonged QTc interval prior to etrasimod initiation, or factors associated with QTc prolongation (e.g. hypokalemia, hypomagnesemia, bradycardia, female gender, or advanced age) may increase risk for cardiovascular toxicity due to etrasimod.(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 prescribing information for etrasimod treatment states that advice from a cardiologist should be sought before initiating etrasimod treatment in patients currently taking additional agents that cause bradycardia or in patients with preexisting heart and cerebrovascular conditions, with resting heart rate of less than 50 bpm, history of symptomatic bradycardia, recurrent cardiogenic syncope, severe untreated sleep apnea, or history of Mobitz type 1 second-degree AV block (unless has functioning pacemaker).(1) Monitor blood pressure during treatment.(1) DISCUSSION: Initiation of etrasimod treatment has been associated with transient atrioventricular (AV) conduction delays. The AV conduction delays manifested as first or second degree AV block (prolonged PR interval on ECG), which occurred in 0.7% of etrasimod treated patients in UC-1 and in 0.8% of patients in UC-2 and UC-3 compared to 0% for placebo in all studies.(1) |
VELSIPITY |
| 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 |
| Vincristine/P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: P-glycoprotein (P-gp) inhibitors may inhibit cellular efflux of vincristine.(1) CLINICAL EFFECTS: Concurrent administration of a P-gp inhibitor may result in elevated levels of and toxicity from vincristine including myelosuppression, neurologic toxicity, tumor lysis syndrome, hepatotoxicity, constipation, or bowel obstruction.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Avoid the use of P-gp inhibitors in patients undergoing therapy with vincristine.(1) Consider alternatives with no or minimal P-gp inhibition. The manufacturer of vincristine states that concomitant use of P-gp inhibitors should be avoided.(1) The manufacturer of lopinavir/ritonavir states that patients who develop significant hematological or gastrointestinal toxicity on concomitant vincristine should temporarily hold lopinavir/ritonavir, or use alternative medications that do not inhibit CYP3A4 or P-gp.(2) DISCUSSION: Vincristine is a substrate of P-gp. Inhibitors of P-gp may increase toxicity of vincristine.(1) There are several case reports of neurotoxicity with concurrent administration of vincristine and itraconazole.(3-5) There is a case report of neurotoxicity with concurrent administration of lopinavir-ritonavir with vincristine.(6) In a prospective study in 22 children receiving various chemotherapy with prophylactic itraconazole oral solution (0.5 ml/kg per day), two children receiving vincristine developed non-alcoholic steatohepatitis (NASH) and one child developed syndrome of inappropriate anti-diuretic hormone secretion (SIADH).(7) Strong inhibitors of P-gp linked to this monograph include: abrocitinib, amiodarone, Asian ginseng (Panax ginseng), asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, cyclosporine, danicopan, daridorexant, diltiazem, diosmin, dronedarone, elagolix, eliglustat, erythromycin, flibanserin, fluvoxamine, fostamatinib, ginkgo biloba, glecaprevir and pibrentasvir, isavuconazonium, ivacaftor, lapatinib, mavorixafor, milk thistle (Silybum marianum), neratinib, osimertinib, pirtobrutinib, propafenone, quercetin, quinidine, ranolazine, rolapitant, Schisandra chinensis, selpercatinib, sofosbuvir, sotorasib, tepotinib, tezacaftor, valbenazine, velpatasvir, vemurafenib, venetoclax, verapamil, vilazodone, vimseltinib, and voclosporin.(8,9) |
VINCASAR PFS, VINCRISTINE SULFATE |
| Mavacamten/Diltiazem; Verapamil SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors such as diltiazem and verapamil may decrease the metabolism of mavacamten.(1-3) The combination of mavacamten, diltiazem or verapamil, and a beta blocker may result in an increased risk of additive negative inotropic effects.(1) CLINICAL EFFECTS: Concurrent use of diltiazem or verapamil may increase the plasma levels and the incidence and severity of adverse reactions of mavacamten.(1) Concurrent use of mavacamten and diltiazem or verapamil with a beta blocker may increase the incidence and severity of heart failure.(1) PREDISPOSING FACTORS: CYP2C19 poor metabolizers may experience an increased incidence or severity of adverse effects.(1) Patients established on treatment with a beta blocker may experience an increased incidence or severity of heart failure symptoms.(1) PATIENT MANAGEMENT: The US manufacturer of mavacamten makes the recommendations below for concurrent use with CYP3A4 inhibitors such as diltiazem and verapamil: Initiate 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) Avoid concomitant use of mavacamten in patients on verapamil with a beta blocker, or diltiazem with a beta blocker as these medications and combinations increase the risk of left ventricular systolic dysfunction and heart failure symptoms and clinical experience is limited.(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. If starting a moderate CYP3A4 inhibitor in a patient who is a poor CYP2C19 metabolizer, reduce mavacamten 5 mg to 2.5 mg. If CYP2C19 phenotype is unknown, consider a starting dose of mavacamten of 2.5 mg daily.(3) DISCUSSION: Concomitant use of mavacamten (25 mg) with verapamil sustained release (240 mg) increased mavacamten area-under-curve (AUC) by 16% and maximum concentration (Cmax) by 52% in intermediate metabolizers and normal metabolizers of CYP2C19.(1) Concomitant use of mavacamten with diltiazem in CYP2C19 poor metabolizers is predicted to increase mavacamten AUC and Cmax up to 55% and 42%, respectively.(1) |
CAMZYOS |
| Encorafenib/CYP3A4 Inhibitors and Substrates SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Encorafenib is a CYP3A4 substrate and a strong CYP3A4 inducer. Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of encorafenib. Also, the metabolism of sensitive substrates of CYP3A4 may be induced by encorafenib.(1) CLINICAL EFFECTS: Concomitant use of encorafenib with agents that are both strong or moderate CYP3A4 inhibitors and CYP3A4 substrates may result in increased levels and effects from encorafenib including QT prolongation. Concomitant use may also result in decreased levels and effectiveness of the CYP3A4 substrate.(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) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of encorafenib with strong or moderate CYP3A4 inhibitors that are also CYP3A4 substrates.(1) The US manufacturer of encorafenib states that it should be avoided with CYP3A4 substrates for which decreased plasma concentrations may result in decreased therapeutic efficacy. If coadministration cannot be avoided, refer to the CYP3A4 substrate prescribing information for recommendations.(1) In addition, concurrent use of strong or moderate CYP3A4 inhibitors with encorafenib should be avoided.(1) The net effect of this two-way interaction is unknown and optimal doses of the drugs when used concurrently have not been determined. The manufacturer provides recommendations for dose modification when encorafenib is used with a CYP3A4 inhibitor, but the recommendations may not apply when there is a two-way interaction. Dose modifications mentioned below are informational only. 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 encorafenib 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 450 mg daily with binimetinib 45 mg twice daily decreased the AUC and Cmax of single dose of midazolam 2 mg, a sensitive CYP3A4 substrate, by 82% and 74%, respectively, relative to midazolam 2 mg alone.(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) Agents that are both strong CYP3A4 inhibitors and CYP3A4 substrates linked to this monograph include: idelalisib, itraconazole, mifepristone, and tucatinib.(3) Agents that are both moderate CYP3A4 inhibitors and CYP3A4 substrates linked to this monograph include: aprepitant, darunavir, diltiazem, duvelisib, fedratinib, fosnetupitant, imatinib, netupitant, verapamil and voxelotor.(3) |
BRAFTOVI |
| Ivosidenib/CYP3A4 Inhibitors and Substrates SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Ivosidenib is a CYP3A4 substrate and a strong CYP3A4 inducer. Strong and moderate inhibitors of CYP3A4 may inhibit the metabolism of ivosidenib. Also, the metabolism of sensitive substrates of CYP3A4 may be induced by ivosidenib.(1) CLINICAL EFFECTS: Concomitant use of ivosidenib with agents that are both strong or moderate CYP3A4 inhibitors and CYP3A4 substrates may result in increased levels and effects from ivosidenib including QT prolongation. Concomitant use may also result in decreased levels and effectiveness of the CYP3A4 substrate.(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) Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: Avoid concomitant use of ivosidenib with strong or moderate CYP3A4 inhibitors that are also CYP3A4 substrates. Consider an alternative concomitant medication with less potential for CYP3A4 interaction.(1) The US manufacturer of ivosidenib states that if coadministration with a sensitive CYP3A4 substrate cannot be avoided, monitor patients for loss of therapeutic effect of these drugs.(1) The net effect of this two-way interaction is unknown and optimal doses of the drugs when used concurrently have not been determined. The manufacturer provides recommendations for dose modification when ivosidenib is used with a CYP3A4 inhibitor, but the recommendations may not apply when there is a two-way interaction. Dose modifications mentioned below are informational only. If coadministration of a strong CYP3A4 inhibitor cannot be avoided, reduce ivosidenib dose to 250 mg once daily. After the inhibitor has been discontinued for at least 5 half-lives, resume the ivosidenib dose that was taken prior initiating the CYP3A4 inhibitor (500 mg once daily).(1) No dose adjustment is recommended for ivosidenib when coadministered with moderate CYP3A4 inhibitors.(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 ivosidenib and QTc interval prolongation adverse reactions include: - QTc interval greater than 480 msec (millisecond) and less than 500 msec: Monitor and supplement electrolyte levels as clinically indicated. Review and adjust concomitant medications with known QTc interval-prolonging effects. Withhold ivosidenib until after the QT interval returns to less than or equal to 480 msec. Resume ivosidenib at a dose of 500 mg once daily. Monitor ECGs at least weekly for 2 weeks following resolution of QTc prolongation. - QTc interval greater than 500 msec: Monitor and supplement electrolyte levels as clinically indicated. Review and adjust concomitant medications with known QTc interval-prolonging effects. Withhold ivosidenib until after the QT interval returns to within 30 msec of baseline or less than or equal to 480 msec. Resume ivosidenib at a reduced dose of 250 mg once daily. Monitor ECGs at least weekly for 2 weeks following resolution of QTc prolongation. Consider re-escalating the dose of ivosidenib to 500 mg daily if an alternative etiology for QTc prolongation can be identified. - QTc interval prolongation with signs/symptoms of life-threatening arrhythmia: Permanently discontinue ivosidenib.(1) See ivosidenib prescribing information for additional information regarding dose reductions.(1) 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) In a PBPK model, ivosidenib 500 mg for 15 days was predicted to decrease the AUC and Cmax of midazolam 5 mg by 82% and 73%, respectively.(3) In clinical trials of ivosidenib, 9% of patients experienced a QTc interval greater than 500 msec and 14% of patients had an increased from baseline QTc interval of greater than 60 msec. Patients with a baseline QTc of equal to or greater than 450 msec without pre-existing bundle branch block, or with a history of long QT syndrome were excluded from this trial.(1) Agents that are both strong CYP3A4 inhibitors and CYP3A4 substrates linked to this monograph include: mifepristone.(4) Agents that are both moderate CYP3A4 inhibitors and CYP3A4 substrates linked to this monograph include: aprepitant, darunavir, diltiazem, duvelisib, fosnetupitant, netupitant, and verapamil.(4) |
TIBSOVO |
| Diltiazem/Selected Strong CYP3A4 Inducers SEVERITY LEVEL: 2-Severe Interaction: Action is required to reduce the risk of severe adverse interaction. MECHANISM OF ACTION: Concurrent use of strong CYP3A4 inducers may accelerate the CYP3A4-mediated metabolism of diltiazem.(1) Diltiazem is a CYP3A4 inhibitor and may inhibit the metabolism of phenytoin.(2) CLINICAL EFFECTS: Concurrent use of strong CYP3A4 inducers may decrease the levels and effectiveness of diltiazem.(1) Concurrent use of diltiazem may also result in elevated levels of and toxicity from phenytoin.(2) PREDISPOSING FACTORS: Higher doses of diltiazem may increase the risk of elevated phenytoin levels. Induction effects may be more likely with regular use of the inducer for longer than 1-2 weeks. PATIENT MANAGEMENT: The manufacturer of diltiazem states that coadministration of CYP3A4 inducers should be avoided.(1) Observe the patient for a decrease in the therapeutic effects of diltiazem if a strong CYP3A4 inducer is initiated. The dose of diltiazem may need to be adjusted if an inducer is initiated or discontinued. Monitor phenytoin levels when initiating or discontinuing diltiazem in patients maintained on phenytoin.(2) DISCUSSION: Concurrent administration of rifampin, a strong CYP3A4 inducer, has been shown to lower diltiazem levels below detectable limits.(1) A study in six subjects examined the effects of pretreatment with rifampin (600 mg daily for 15 days) on single doses of verapamil (10 mg intravenously or 120 mg orally). Rifampin significantly decreased the maximum concentration (Cmax) and area-under-curve (AUC) of oral verapamil and resulted in no changes in the P-R interval. There were small decreases in the AUC of intravenous verapamil.(3) In a study in 8 male subjects, pretreatment with rifampin (600 mg daily for 15 days) increased the systemic clearance of S-verapamil by 1.3-fold and the apparent oral-clearance of S-verapamil by 32-fold. The bioavailability of S-verapamil decreased 25-fold. The effect of oral verapamil on AV conduction was almost abolished. No significant changes were noted with intravenous administration of verapamil.(4) In one case report, a patient established on phenytoin treatment (250 mg twice daily) experienced signs of phenytoin toxicity after initiating high-dose diltiazem (90 mg every 2 hours for a total of 4 doses, then 120 mg every 4 hours for a total of 4 doses and then 240 mg of sustained release formulation every 8 hours). Serum phenytoin concentration was raised at 41 mcg/ml and phenytoin was held and reloaded at a lower maintenance dose (150 mg twice daily), whilst the patient continued treatment on diltiazem. Subsequent serum phenytoin concentrations were within range (17.1 and 14.8 mcg/ml).(2) Strong CYP3A4 inducers linked to this monograph include: apalutamide, enzalutamide, fosphenytoin, lumacaftor, mitotane, phenobarbital, phenytoin, and primidone.(5,6) |
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, ERLEADA, FIORICET, FIORICET WITH CODEINE, FOSPHENYTOIN SODIUM, LYSODREN, MITOTANE, MYSOLINE, ORKAMBI, PENTOBARBITAL SODIUM, PHENOBARBITAL, PHENOBARBITAL SODIUM, PHENOBARBITAL-BELLADONNA, PHENOBARBITAL-HYOSC-ATROP-SCOP, PHENOHYTRO, PHENYTEK, PHENYTOIN, PHENYTOIN SODIUM, PHENYTOIN SODIUM EXTENDED, PRIMIDONE, SEZABY, TENCON, XTANDI |
| 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 58 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 |
|---|---|
| Selected Beta-blockers/Selected Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Synergistic pharmacologic activity. CLINICAL EFFECTS: May see an increase in the therapeutic and toxic effects of both drugs. Concurrent use in patients with low heart rates may unmask sick sinus syndrome. PREDISPOSING FACTORS: Preexisting left ventricular dysfunction and high doses of the beta-blocking agent may predispose patients to adverse responses to this drug combination. Other possible factors include parenteral administration and concurrent administration of other cardio-depressant drugs such as antiarrhythmics. PATIENT MANAGEMENT: Monitor the patient for signs of increased cardio-depressant effects and hypotension. Adjust the dose accordingly. DISCUSSION: Coadministration of these classes of drugs may be effective in the treatment of angina pectoris and hypertension. Patients should be screened in order to determine who should receive this combination of agents. The concurrent use of mibefradil and beta-blockers in patients with low heart rates may unmask underlying sick sinus syndrome. One or more of the drug pairs linked to this monograph have been included in a list of interactions that could be considered for classification as "non-interruptive" 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. |
ACEBUTOLOL HCL, ATENOLOL, ATENOLOL-CHLORTHALIDONE, BETAPACE, BETAPACE AF, BETIMOL, BISOPROLOL FUMARATE, BISOPROLOL-HYDROCHLOROTHIAZIDE, BRIMONIDINE TARTRATE-TIMOLOL, BYSTOLIC, CARVEDILOL, CARVEDILOL ER, COMBIGAN, COREG, COREG CR, CORGARD, COSOPT, COSOPT PF, DORZOLAMIDE-TIMOLOL, HEMANGEOL, INDERAL LA, INDERAL XL, INNOPRAN XL, ISTALOL, KAPSPARGO SPRINKLE, LOPRESSOR, METOPROLOL SUCCINATE, METOPROLOL TARTRATE, METOPROLOL-HYDROCHLOROTHIAZIDE, NADOLOL, NEBIVOLOL HCL, PINDOLOL, PROPRANOLOL HCL, PROPRANOLOL HCL ER, PROPRANOLOL-HYDROCHLOROTHIAZID, SOTALOL, SOTALOL AF, SOTALOL HCL, SOTYLIZE, TENORETIC 100, TENORETIC 50, TENORMIN, TIMOLOL, TIMOLOL MALEATE, TIMOLOL-BIMATOPROST, TIMOLOL-BRIMONI-DORZOL-BIMATOP, TIMOLOL-BRIMONIDIN-DORZOLAMIDE, TIMOLOL-DORZOLAMIDE-BIMATOPRST, TIMOPTIC OCUDOSE, TOPROL XL |
| Calcium Channel Blockers/Quinidine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Diltiazem, a moderate CYP3A4 inhibitor, may inhibit the metabolism of quinidine. Verapamil, a moderate CYP3A4 inhibitor and P-gp inhibitor, may inhibit the metabolism of quinidine. Verapamil and quinidine may slow A-V conduction and prolong the refractory period. CLINICAL EFFECTS: Concurrent administration of diltiazem may result in elevated levels of and effects from quinidine, including the risk of QT prolongation. Concurrent administration of quinidine and verapamil may result in result in hypotension and elevated levels of quinidine. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving concurrent diltiazem or verapamil should be monitored for increased effects of quinidine. DISCUSSION: Concurrent diltiazem has been shown to increase the area-under-curve (AUC) and half-life (T1/2) of quinidine by 51% and 36%, respectively. Quinidine clearance decreased by 33%. No significant pharmacodynamic effects were noted. There are several case reports documenting hypotension during concurrent quinidine and verapamil. In a study in 6 subjects, concurrent verapamil decreased quinidine clearance by 35.2%. |
NUEDEXTA, QUINIDINE GLUCONATE, QUINIDINE SULFATE |
| Digoxin/Selected Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Calcium channel blockers may inhibit the renal clearance of digoxin through an unknown mechanism. CLINICAL EFFECTS: Plasma digoxin concentrations may be elevated. In addition, the negative chronotropic effects of digoxin and bepridil are additive, resulting in a cumulative decrease in heart rate. Symptoms of digoxin toxicity can include anorexia, nausea, vomiting, headache, fatigue, malaise, drowsiness, generalized muscle weakness, disorientation, hallucinations, visual disturbances, and arrhythmias. PREDISPOSING FACTORS: Low body weight, advanced age, impaired renal function, hypokalemia, hypercalcemia, and/or hypomagnesemia may increase the risk of digoxin toxicity. PATIENT MANAGEMENT: If concurrent therapy is warranted, monitor serum digoxin levels and observe the patient for symptoms of digoxin toxicity. Upon adding a calcium channel blocker, digoxin should first be decreased in anticipation of interaction, then adjust the dosage accordingly. The dosage of digoxin may need to be decreased by 15-50% or the frequency of administration may be reduced. DISCUSSION: The effect of bepridil on steady-state serum digoxin levels was studied in a randomized, double-blind investigation. Concurrent administration of bepridil and digoxin produced a 34% increase in serum digoxin levels compared to administration of digoxin alone. Concomitant administration of both drugs was associated with additive negative chronotropic effects. Information on the effects of diltiazem on digoxin concentrations are conflicting. Several studies have reported that concurrent use of digoxin and diltiazem led to an increased steady state digoxin level as well as an increased digoxin area-under-curve (AUC) and decreased renal clearance, and reduced volume of distribution. However, one of these studies reported no significant change in digoxin half-life, peak concentration (Cmax), time to Cmax (Tmax), or volume of distribution, and seven other studies reported no effect of diltiazem on serum digoxin concentrations or renal digoxin clearance. Concomitant isradipine administration significantly decreased (by 9%) the the digoxin volume of distribution and increased (by 25%) digoxin Cmax; however, the digoxin steady state serum concentration, AUC, and renal clearance were not affected. In patients with congestive heart failure on digoxin therapy, the addition of felodipine resulted in a significant increase in digoxin Cmax attained following oral administration. This increase was most notable in patients with high felodipine serum concentrations. Digoxin trough levels and six hour post-dose levels were unaffected; as were digoxin AUC measurements. There is one case report of an interaction between nifedipine and digoxin; however, a study in 28 patients found no effect of nifedipine on digoxin. A study in ten subjects showed that nisoldipine increased digoxin levels by 15%. Information on the effects of nicardipine on digoxin kinetics is conflicting. One study in twenty patients showed no effect of nicardipine on digoxin. One study in ten subjects showed a significant increase in digoxin levels: however, this was seen in only one subject. Concurrent nitrendipine has been shown to increase digoxin serum levels by 57% and digoxin AUC by 15%. Concurrent diltiazem has been shown to increase digoxin serum concentration by 20%. Concurrent nifedipine has been shown to increase digoxin serum concentration by 45%. |
DIGITEK, DIGOXIN, DIGOXIN MICRONIZED, LANOXIN, LANOXIN PEDIATRIC |
| Cyclosporine/Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Calcium channel blockers may inhibit the metabolism of cyclosporine by CYP3A4. CLINICAL EFFECTS: Concurrent use of calcium channel blockers may result in elevated levels of and toxicity from cyclosporine. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Monitor cyclosporine levels when initiating or discontinuing calcium channel blockers. DISCUSSION: Concurrent administration of cyclosporine and amlodipine, diltiazem, nicardipine, or verapamil has caused elevated cyclosporine levels. Renal toxicity was seen in some cases. Upon discontinuation of the calcium channel blocker, cyclosporine concentrations have returned to baseline levels. With concurrent diltiazem administration, cyclosporine dosage decreases of 15% to 48% were required. A prospective study in 11 renal transplant patients showed a 40% increase in trough cyclosporine levels when given concomitantly with amlodipine.(29) |
CYCLOSPORINE, CYCLOSPORINE MODIFIED, GENGRAF, NEORAL, SANDIMMUNE |
| Selected Calcium Channel Blockers/Cimetidine SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Cimetidine may decrease the metabolism of diltiazem, felodipine, isradipine, nicardipine, nifedipine, nisoldipine, and nitrendipine. CLINICAL EFFECTS: The pharmacological effects of the calcium channel blocker may be increased. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Observe the patient for changes in clinical response to the calcium channel blocker when starting or stopping cimetidine. The dosage of the calcium channel blocker may need to be adjusted. Ideally, suggest an alternative H-2 antagonist such as famotidine, nizatidine, or ranitidine. DISCUSSION: Significant effects have been observed during concurrent administration of nifedipine or felodipine with cimetidine. During combined administration of nifedipine and cimetidine in six healthy volunteers, the area-under-curve (AUC) of nifedipine was increased by 80% compared to nifedipine alone. Increased heart rate and a drop in mean arterial pressure 14 mmHg were also reported. Ranitidine showed only a nonsignificant 25% rise in peak plasma levels of nifedipine and no effects on blood pressure. Similar results were reported in another study where concurrent administration of felodipine and cimetidine resulted in an increase in felodipine AUC and maximum concentration (Cmax) by 50%. Concurrent administration of cimetidine has also been shown to increase the AUC and Cmax of diltiazem by 53% and 58%, respectively. The manufacturers of isradipine and nicardipine recommend carefully monitoring patients receiving concurrent therapy with cimetidine. The manufacturer of isradipine states that concurrent therapy with cimetidine has been shown to increase the AUC of isradipine by 50%. The manufacturer of nifedipine states that careful titration is necessary in patients receiving concurrent therapy. The manufacturers of felodipine and diltiazem state that dosage adjustments may be necessary in patients receiving concurrent therapy. Ranitidine has much less affinity for CYP metabolism than cimetidine and would therefore be expected to have less of an effect on calcium channel blocker metabolism. Studies have shown that nizatidine and famotidine do not inhibit CYP3A4 metabolism. |
CIMETIDINE |
| Atorvastatin/Diltiazem SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Diltiazem may inhibit the metabolism of atorvastatin by CYP3A4.(1) CLINICAL EFFECTS: Concurrent diltiazem may result in elevated levels of atorvastatin,(1) which may result in rhabdomyolysis. 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: Patients receiving concurrent therapy with diltiazem should be monitored closely for adverse effects of the HMG-CoA reductase inhibitor, including rhabdomyolysis. The dosage of the HMG-CoA reductase inhibitor may need to be reduced or discontinued. Fluvastatin or pravastatin, HMG-CoA reductase inhibitors that are not metabolized by CYP3A4, may be alternatives to atorvastatin, lovastatin, and simvastatin in patients receiving diltiazem. DISCUSSION: There is a case report of rhabdomyolysis following the addition of diltiazem to a patient maintained on atorvastatin.(1) In a PKPB model, concurrent use of atorvastatin (20 mg daily) with diltiazem (180 mg twice daily for 3 weeks) increased the simulated Cmax ratio and AUC ratio of atorvastatin by 1.32 and 1.77, respectively, and increased the simulated Cmax ratio and AUC ratio of atorvastatin lactone by 2.66 and 3.24, respectively.(2) |
AMLODIPINE-ATORVASTATIN, ATORVALIQ, ATORVASTATIN CALCIUM, CADUET, LIPITOR |
| 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 |
| 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) |
ATAZANAVIR SULFATE, DARUNAVIR, EVOTAZ, FOSAMPRENAVIR CALCIUM, PREZCOBIX, PREZISTA, REYATAZ, SYMTUZA |
| Sirolimus;Temsirolimus/Selected Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Some calcium channel blockers may inhibit the metabolism of sirolimus and temsirolimus by CYP3A4.(1-3) CLINICAL EFFECTS: Concurrent use of calcium channel blockers may result in elevated levels of and side effects from sirolimus and temsirolimus.(1-3) Concurrent sirolimus and verapamil may result in elevated levels of and effects from verapamil.(1) Sirolimus is the active metabolite of temsirolimus,(3) therefore, temsirolimus should be expected to act in the same manner as sirolimus. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients maintained on sirolimus should be closely monitored if calcium channel blockers such as diltiazem, nicardipine, or verapamil are initiated or discontinued. The dosage of sirolimus or tacrolimus may need to be adjusted or the calcium channel blocker may need to be discontinued. Patients receiving concurrent sirolimus and verapamil should be observed for increased verapamil effects. 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.(4) Sirolimus is the active metabolite of temsirolimus,(3) therefore, temsirolimus is expected to act in the same manner as sirolimus. DISCUSSION: In an open, randomized, cross-over trial in 18 healthy subjects, concurrent single doses of diltiazem (120 mg) and sirolimus (10 mg) increased sirolimus area-under-curve (AUC) and maximum concentration (Cmax) by 60% and by 43%, respectively. Sirolimus apparent oral clearance and volume of distribution decreased by 38% and 45%, respectively. There were no effects on diltiazem pharmacokinetics or pharmacodynamics.(1,2) In a study in 24 healthy subjects, concurrent single doses of nifedipine (60 mg) and sirolimus (10 mg) had no effect on sirolimus levels.(1) Nicardipine may increase sirolimus levels.(1) In a study in 26 healthy subjects, concurrent sirolimus (2 mg daily) with verapamil (180 mg twice daily) increased sirolimus AUC and Cmax by 2.2-fold and 2.3-fold, respectively. The AUC and Cmax of the active S-enantiomer of verapamil each increased by 1.5-fold. Verapamil time to Cmax (Tmax) was increased by 1.2 hours.(1) Sirolimus is the active metabolite of temsirolimus,(2) therefore, temsirolimus is expected to act in the same manner as sirolimus. In a study in 25 healthy subjects, concurrent sirolimus with verapamil increased sirolimus Cmax and AUC 130% and 120%, respectively.(5) |
SIROLIMUS, TEMSIROLIMUS, TORISEL |
| Loperamide/CYP3A4; CYP2C8; P-glycoprotein (P-gp) Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Inhibitors of CYP3A4, CYP2C8, and/or P-gp may increase loperamide systemic absorption and facilitate entry into central nervous system (CNS).(1) CLINICAL EFFECTS: Concurrent use of inhibitors of CYP3A4, CYP2C8, and/or P-gp may increase levels of loperamide, resulting in respiratory depression.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Use loperamide with caution in patients receiving inhibitors of CYP3A4, CYP2C8, and/or P-gp. Consider lower doses of loperamide in these patients and monitor for adverse effects. The manufacturer of lonafarnib recommends starting loperamide at a dose of 1 mg and slowly increasing the dose as needed.(2) DISCUSSION: In a randomized, cross-over study in 12 healthy subjects, itraconazole (100 mg twice daily for 5 days - first dose 200 mg), gemfibrozil (600 mg twice daily), and the combination of itraconazole and gemfibrozil (same dosages) increased the area-under-curve (AUC) of single doses of loperamide (4 mg) by 2.9-fold, 1.6-fold, and 4.2-fold, respectively.(3) In a study of healthy subjects, lonafarnib (100 mg twice daily for 5 days) increased the AUC and maximum concentration (Cmax) of single dose loperamide (2 mg) by 299% and 214%, respectively.(3) In a study in 18 healthy males, quinidine increased the AUC of a single dose of loperamide by 2.2-fold and markedly decreased pupil size.(4) In a study in 8 healthy subjects, subjects experienced respiratory depression when a single dose of loperamide (16 mg) was administered with a single dose of quinidine (600 mg) but not when loperamide was administered alone.(6) Loperamide plasma levels increased 2-fold to 3-fold.(5) |
LOPERAMIDE |
| 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 |
| Tamoxifen/Selected Weak CYP2D6 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Inhibitors of CYP2D6 may inhibit the conversion of tamoxifen to endoxifen (an active metabolite of tamoxifen).(1-2) The role of endoxifen in tamoxifen's efficacy has been debated and may involve a minimum concentration level.(3-5) CLINICAL EFFECTS: Concurrent use of inhibitors of CYP2D6 may decrease the effectiveness of tamoxifen in preventing breast cancer recurrence. PREDISPOSING FACTORS: Concurrent use of weak CYP2D6 inhibitors in patients who are CYP2D6 intermediate metabolizers should be avoided. Patients who are CYP2D6 poor metabolizers lack CYP2D6 function and are not affected by CYP2D6 inhibition. PATIENT MANAGEMENT: Although data on this interaction are conflicting, it may be prudent to use alternatives to CYP2D6 inhibitors when possible in patients taking tamoxifen. The US manufacturer of tamoxifen states that the impact on the efficacy of tamoxifen by strong CYP2D6 inhibitors is uncertain and makes no recommendation regarding coadministration with inhibitors of CYP2D6.(12) The manufacturer of paroxetine (a strong CYP2D6 inhibitor) states that alternative agents with little or no CYP2D6 inhibition should be considered.(13) The National Comprehensive Cancer Network's breast cancer guidelines advises caution when coadministering strong CYP2D6 inhibitors with tamoxifen.(14) If concurrent therapy is warranted, the risks versus benefits should be discussed with the patient. DISCUSSION: Some studies have suggested that administration of fluoxetine, paroxetine, and quinidine with tamoxifen or a CYP2D6 poor metabolizer phenotype may result in a decrease in the formation of endoxifen (an active metabolite of tamoxifen) and a shorter time to breast cancer recurrence.(1-2,9) A retrospective study of 630 breast cancer patients found an increasing risk of breast cancer mortality with increasing durations of coadministration of tamoxifen and paroxetine. In the adjusted analysis, absolute increases of 25%, 50%, and 75% in the proportion of time of overlapping use of tamoxifen with paroxetine was associated with 24%, 54%, and 91% increase in the risk of death from breast cancer, respectively.(16) The CYP2D6 genotype of the patient may have a role in the effects of this interaction. Patients with wild-type CYP2D6 genotype may be affected to a greater extent by this interaction. Patients with a variant CYP2D6 genotype may have lower baseline levels of endoxifen and may be affected to a lesser extent by this interaction.(6-10) In a retrospective review, 1,325 patients treated with tamoxifen for breast cancer were classified as being poor 2D6 metabolizers (lacking functional CYP2D6 enzymes), intermediate metabolizers (heterozygous alleles), or extensive metabolizers (possessing 2 functional alleles). After a mean follow-up period of 6.3 years, the recurrence rates were 14.9%, 20.9%, and 29.0%, in extensive metabolizers, intermediate metabolizers, and poor metabolizers, respectively.(11) In October of 2006, the Advisory Committee Pharmaceutical Science, Clinical Pharmacology Subcommittee of the US Food and Drug Administration recommended that the US tamoxifen labeling be updated to include information about the increased risk of breast cancer recurrence in poor CYP2D6 metabolizers (either by genotype or drug interaction).(17-18) The labeling changes were never made due to ongoing uncertainty about the effects of CYP2D6 genotypes on tamoxifen efficacy. In contrast to the above information, two studies have shown no relationship between CYP2D6 genotype and breast cancer outcome.(19-21) As well, a number of studies found no association between use of CYP2D6 inhibitors and/or antidepressants in patients on tamoxifen and breast cancer recurrence,(22-26) though the studies were limited by problematic selection of CYP2D6 inhibitors and short follow-up. Weak inhibitors of CYP2D6 include: alogliptin, artesunate, celecoxib, cimetidine, clobazam, cobicistat, delavirdine, diltiazem, dimenhydrinate, diphenhydramine, dronabinol, dupilumab, echinacea, enasidenib, fedratinib, felodipine, fluvoxamine, gefitinib, hydralazine, imatinib, labetalol, lorcaserin, nicardipine, osilodrostat, ranitidine, ritonavir, sertraline, verapamil and viloxazine.(27) |
SOLTAMOX, TAMOXIFEN CITRATE |
| Buspirone/Diltiazem; Verapamil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Diltiazem and verapamil may inhibit the metabolism of buspirone by CYP3A4.(1) CLINICAL EFFECTS: Concurrent use of diltiazem(1,2) or verapamil(1) may result in increased levels of and effects from buspirone, including lightheadedness, asthenia, dizziness, and somnolence.(3) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving concurrent therapy with buspirone and either diltiazem or verapamil should be monitored for adverse effects. The dosage of buspirone may need to be adjusted.(1,2) DISCUSSION: In a randomized, 3-way cross-over study in 9 healthy subjects, concurrent diltiazem (60 mg 3 times daily) and verapamil (80 mg 3 times daily) increased the area-under-curve (AUC) of a single dose of buspirone (10 mg) by 5.5-fold and 3.4-fold, respectively. Buspirone maximum concentration (Cmax) increased by 4.1-fold and 3.4-fold, respectively. Overall drug effects were increased with concurrent diltiazem and verapamil. (1) |
BUSPIRONE HCL |
| 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 |
| Tacrolimus/Selected Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Some calcium channel blockers may inhibit the metabolism of tacrolimus by CYP3A4.(1-13) CLINICAL EFFECTS: Concurrent use of calcium channel blockers may result in elevated levels of and side effects from tacrolimus, including nephrotoxicity, neurotoxicity, and prolongation of the QTc interval and life-threatening cardiac arrhythmias, including torsades de pointes.(1-13) 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. 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). PATIENT MANAGEMENT: Patients maintained on tacrolimus should be closely monitored if calcium channel blockers such as amlodipine, diltiazem, felodipine, nifedipine, or verapamil are initiated or discontinued. The dosage of tacrolimus may need to be adjusted or the calcium channel blocker may need to be discontinued. When concurrent therapy of selected calcium channel blockers and tacrolimus is warranted, consider obtaining serum calcium, magnesium, and potassium levels and monitoring ECG at baseline and at regular intervals. Correct any electrolyte abnormalities. Instruct patients to report any irregular heartbeat, dizziness, or fainting. DISCUSSION: A study of 9 healthy volunteers who are CYP3A5 expressers found that concomitant tacrolimus and amlodipine resulted in increased tacrolimus AUC by 2.44-fold and 4.1-fold in a single-dose and a 7-day multi-dose study, respectively, compared to tacrolimus alone. No interaction was observed in CYP3A5 non-expressers.(2) However, a case report of a 4-year-old renal transplant patient who is a CYP3A5 non-expresser on tacrolimus and started on amlodipine described increased tacrolimus trough level and AUC from 3.7 to 12.2 ng/mL and 211 to 638 h/ng/mL, respectively.(3) A non-randomized study in 2 liver and 2 renal transplant recipients examined the effects of diltiazem on tacrolimus. In the 2 kidney recipients, concurrent diltiazem at a dosage of 20 mg daily increased tacrolimus AUC by 26% and by 67%. Diltiazem at a dosage of 180 mg increased tacrolimus AUC by 48% and by 177%. In the 2 liver recipients, no tacrolimus increases were seen until diltiazem dosage reached 60 mg daily. One subject received 120 mg of diltiazem daily and tacrolimus AUC was increased by 18%. The other subject received 180 mg diltiazem daily and tacrolimus AUC increased 22%.(4) There is one case report of elevated tacrolimus levels and toxicity in a liver transplant patient 3 days after the addition of diltiazem to his regimen.(5) There is one case report of elevated tacrolimus levels in a renal transplant patient.(6) In contrast, a retrospective review of renal transplant patients found no difference in tacrolimus-related side effects or tacrolimus exposure in patients treated with diltiazem versus those not treated with diltiazem.(7) There is one report of increased tacrolimus levels with concurrent felodipine in a renal transplant patient.(8) A retrospective review examined the effects of nifedipine on tacrolimus dosing requirements in renal transplant patients. In patients who received concurrent nifedipine (n=22), tacrolimus daily dosing requirements were 26%, 29%, and 38% lower at 3, 6, and 12 months post-transplant when compared to patients not taking nifedipine (n=28).(9) In a study of liver transplant patients, nifedipine improved kidney function as indicated by lowering of serum creatinine levels at 6 and 12 months.(10) In vitro studies in human tissue found that tacrolimus metabolism was inhibited by nifedipine and verapamil.(12,13) |
ASTAGRAF XL, ENVARSUS XR, PROGRAF, TACROLIMUS, TACROLIMUS XL |
| Selected Calcium Channel Blockers/Selected Strong CYP3A4 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 first-pass and elimination metabolism of calcium channel blockers by CYP3A4. CLINICAL EFFECTS: The concurrent use of strong CYP3A4 inhibitors with calcium channel blockers metabolized by CYP3A4 may result in elevated levels of the calcium channel blocker and risk of adverse effects, including hypotension and bradycardia. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The concurrent use of strong CYP3A4 inhibitors with calcium channel blockers should be approached with caution. When these agents are used concurrently, the dose of the calcium channel blocker may need to be adjusted or an alternative agent considered. Monitor patients for increased calcium channel blocker effects. If the strong CYP3A4 inhibitor is discontinued, the dose of the calcium channel blocker may need to be increased and patients should be observed for decreased effects. DISCUSSION: A double-blind, randomized, two-phase crossover study in nine subjects examined the effects of itraconazole on felodipine. The half-life of felodipine increased by 71% during concurrent itraconazole. In seven of the nine subjects, the maximum concentration (Cmax) of felodipine when administered with placebo was lower than the 32-hour concentration of felodipine when administered with itraconazole. Concurrent use also resulted in significantly greater effects on both blood pressure and heart rate.(10,11) A randomized cross-over trial in seven subjects examined the effects of ketoconazole (200 mg daily for 4 days) on nisoldipine (5 mg daily). The concurrent use of ketoconazole increased the nisoldipine area-under-curve (AUC) and Cmax by 24-fold and 11-fold, respectively. Increases in the M9 nisoldipine metabolite were similar.(7) PKPB modeling of nifedipine and ritonavir noted a decreased systolic blood pressure > 40 mmHg.(8) There are several case reports of patients developing increased levels of calcium channel blockers and adverse effects with concurrent strong CYP3A4 inhibitors.(9-16) Strong CYP3A4 inhibitors include: adagrasib, ceritinib, cobicistat, grapefruit, idelalisib, indinavir, itraconazole, ketoconazole, levoketoconazole, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, posaconazole, ribociclib, saquinavir, tipranavir, troleandomycin, tucatinib, and voriconazole.(17,18) |
APTIVUS, EVOTAZ, GENVOYA, ITRACONAZOLE, ITRACONAZOLE MICRONIZED, KALETRA, KETOCONAZOLE, KISQALI, KORLYM, KRAZATI, LOPINAVIR-RITONAVIR, MIFEPREX, MIFEPRISTONE, NEFAZODONE HCL, NOXAFIL, POSACONAZOLE, PREZCOBIX, RECORLEV, SPORANOX, STRIBILD, SYMTUZA, TOLSURA, TUKYSA, TYBOST, VFEND, VFEND IV, VIRACEPT, VORICONAZOLE, ZYDELIG, ZYKADIA |
| Dronedarone/Diltiazem; Nifedipine; Verapamil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Dronedarone my inhibit the metabolism of diltiazem, nifedipine, and verapamil by CYP3A4. Diltiazem and verapamil may inhibit the metabolism of dronedarone by CYP3A4. Calcium channel blockers may potentiate dronedarone conduction effects by depressing the sinus and AV nodes.(1) CLINICAL EFFECTS: Concurrent use may result in elevated levels and effects of both dronedarone and the calcium channel blocker. Calcium channel blockers may also potentiate dronedarone's conduction effects. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Give low initial doses of the calcium channel blockers. The dosage of the calcium channel blocker should only be increased after ECG verification of good tolerability.(1) DISCUSSION: Concurrent use of diltiazem and verapamil with dronedarone (exact dosages not stated) increased dronedarone exposure by 1.7-fold and 1.4-fold, respectively.(1) Concurrent use of dronedarone with diltiazem, nifedipine, or verapamil (exact dosages not stated) increased exposure of the calcium channel blocker by 1.4-fold to 1.5-fold.(1) |
MULTAQ |
| 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 |
| Lurasidone (Less Than or Equal To 80 mg)/Diltiazem; Verapamil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Moderate CYP3A4 inhibitors such as diltiazem or verapamil may inhibit the metabolism of lurasidone.(1) CLINICAL EFFECTS: Concomitant use of lurasidone with inhibitors of CYP3A4 may lead to orthostatic hypotension, akathisia, acute dystonia, Parkinsonism or other lurasidone toxicities.(1) PREDISPOSING FACTORS: Elderly patients, particularly those with a history of falls or swallowing disorders, and patients with 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 the dose of lurasidone should not exceed 80 mg daily if coadministered with moderate CYP3A4 inhibitors, such as diltiazem or verapamil.(1) If a patient is currently on lurasidone and either diltiazem or verapamil is added to therapy, the dose of lurasidone should be decreased by 50% of the original dose.(1) If a patient is currently on diltiazem or verapamil and lurasidone is added to therapy, the recommended starting dose of lurasidone is 20 mg per day.(1) DISCUSSION: Pretreatment with diltiazem (240 mg daily for 5 days) increased the maximum concentration (Cmax) and area-under-curve (AUC) of a single dose of lurasidone (20 mg) by 2.1-fold, and 2.2-fold, respectively.(1) |
LATUDA, LURASIDONE HCL |
| Vardenafil (Less Than or Equal To 5 mg)/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 vardenafil by CYP3A4.(1-4) CLINICAL EFFECTS: Concurrent use of CYP3A4 inhibitors may result in increased levels of and adverse effects from vardenafil, including hypotension, visual changes, and sustained erections.(1-4) PREDISPOSING FACTORS: The interaction may be more severe in men older than 75 years.(4) PATIENT MANAGEMENT: The US manufacturer of vardenafil states that a maximum dose of 2.5 mg of vardenafil every 24 hours should not be exceeded in patients taking 400 mg of itraconazole or ketoconazole and that a maximum dose of 5 mg of vardenafil every 24 hours should not be exceeded in patients taking 200 mg of itraconazole or ketoconazole.(1) For moderate CYP3A4 inhibitors, do not exceed a maximum dose of 5 mg of vardenafil every 24 hours.(1) Patients receiving concurrent therapy should be monitored for increased vardenafil effects. Note that other countries have stricter warnings. The Australian manufacturer of vardenafil states that vardenafil must not be taken with dosages of itraconazole or ketoconazole greater than 200 mg. A maximum dose of 5 mg of vardenafil should not be exceeded if used with lower dosages of itraconazole and ketoconazole.(2) The Canadian manufacturer of vardenafil states that the concurrent use of vardenafil with itraconazole or ketoconazole is contraindicated and that the dosage should not exceed 5 mg in patients taking erythromycin.(3) The UK manufacturer of vardenafil states that the concurrent use of vardenafil with either oral itraconazole or oral ketoconazole is contraindicated in men older than 75 years and should be avoided in all patients. The dosage of vardenafil should not exceed 5 mg in patients taking erythromycin.(4)) DISCUSSION: Concurrent use of ketoconazole (200 mg) with vardenafil (5 mg) increased the vardenafil area-under-curve (AUC) and maximum concentration (Cmax) by 10-fold and 4-fold, respectively.(1-4) Concurrent administration of erythromycin (500 mg three times daily) with vardenafil (5 mg) increased the AUC and Cmax of vardenafil by 4-fold and 3-fold, respectively.(1-4) |
VARDENAFIL HCL |
| Simvastatin (Less Than or Equal To 10 mg); Lovastatin (Less Than or Equal To 20 mg)/Diltiazem (Less than or Equal To 240 mg) SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Diltiazem may inhibit the metabolism of lovastatin(1,2) and simvastatin(2-6) by CYP3A4. CLINICAL EFFECTS: Concurrent diltiazem may result in elevated levels of lovastatin(1,2) or simvastatin,(2-6) which may result in rhabdomyolysis. 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 more than 20 mg of lovastatin(1) or more than 240 mg of diltiazem(2) in patients receiving concurrent therapy with these agents. Do not use more than 10 mg of simvastatin(2-6) or more than 240 mg of diltiazem(2) in patients receiving concurrent therapy with these agents. Patients receiving concurrent therapy with diltiazem should be monitored closely for adverse effects of the HMG-CoA reductase inhibitor, including rhabdomyolysis. The dosage of the HMG-CoA reductase inhibitor may need to be reduced or discontinued. Fluvastatin or pravastatin, HMG-CoA reductase inhibitors that are not metabolized by CYP3A4, may be alternatives to atorvastatin, lovastatin, and simvastatin in patients receiving diltiazem. DISCUSSION: In a four-way crossover study in ten subjects, subjects received single doses of lovastatin (20 mg) alone and following two weeks of diltiazem (120 mg twice daily) therapy and single doses of pravastatin (20 mg) alone and following two weeks of diltiazem therapy (120 mg twice daily). Concurrent administration of diltiazem increased lovastatin area-under-curve (AUC) and maximum concentration (Cmax) by 2.6-fold and 3.3-fold, respectively. The increase in lovastatin AUC ranged from 51% to 906%. There were no changes in lovastatin half-life. Concurrent administration of diltiazem had no effect on the AUC, Cmax, or half-life of pravastatin.(5,6) In a study, diltiazem (120 mg twice daily for 10 days) increased the AUC and Cmax of a single dose of simvastatin (80 mg on Day 10) by 3.1-fold and 2.88-fold, respectively. The AUC and Cmax of simvastatin acid increased by 2.69-fold and 2.69-fold, respectively.(3) In a study in Chinese subjects, concurrent diltiazem (60 mg TID) and simvastatin (20 mg daily) enhanced reduction of LDL levels by 1.66% when compared to simvastatin (20 mg alone).(7) In a study in 11 patients with hypercholesterolemia and hypertension, concurrent administration of diltiazem (90 mg daily) and simvastatin (5 mg daily) increased the Cmax and AUC of simvastatin by 97% and 99.5%, respectively, when compared to administration of simvastatin (5 mg daily) alone. Diltiazem Cmax and AUC decreased by 21% and 21%, respectively, when compared to the administration of diltiazem (90 mg) alone. Combination therapy lowered LDL levels by an additional 9% when compared to simvastatin monotherapy.(8) In a study in 10 healthy subjects, diltiazem (120 mg daily for 2 weeks) increased the Cmax and AUC of a single dose of simvastatin (20 mg) by 3.6-fold and 5-fold, respectively. The Cmax of simvastatin acid increased by 3.7-fold.(2,9) A daily dose of 480 mg of diltiazem is expected to increase simvastatin levels 8-fold.(2 In a retrospective review, patients who received simvastatin with concurrent diltiazem experienced a 33.3% reduction in cholesterol levels compared with 24.7% in patients receiving simvastatin without concurrent diltiazem.(10) There are several case reports of myopathy and rhabdomyolysis in patients receiving concurrent simvastatin and diltiazem.(11-16) |
ALTOPREV, EZETIMIBE-SIMVASTATIN, LOVASTATIN, SIMVASTATIN, VYTORIN, ZOCOR |
| 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 |
| Tamsulosin/Diltiazem;Dronedarone;Verapamil SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tamsulosin is primarily metabolized by CYP3A4 and CYP2D6. Diltiazem, dronedarone, and verapamil are both moderate inhibitors of CYP3A4 and weak inhibitors of CYP2D6(1,2) and so may delay tamsulosin metabolism via both major pathways. The pharmacodynamic effects of diltiazem and verapamil on blood pressure may further increase the risk for hypotension from tamsulosin. CLINICAL EFFECTS: Co-administration of diltiazem, dronedarone, or verapamil may cause an increase in tamsulosin levels and effects, including symptomatic hypotension. PREDISPOSING FACTORS: The interaction may be more severe in poor metabolizers of CYP2D6 or in patients receiving additional agents which inhibit CYP3A4 or CYP2D6. PATIENT MANAGEMENT: The manufacturer of tamsulosin states there is a potential for a significant increase in exposure when tamsulosin is co-administered with both CYP3A4 and CYP2D6 inhibitors.(3) The risk for hypotension from tamsulosin is more likely after starting or increasing the dose of either drug.(3) Monitor for orthostatic hypotension prior to a dose increase and delay dose adjustment if needed. Monitor patients after a dose increase, particularly those with a history of hypotension, orthostasis or falls. Instruct patient to report episodes of dizziness, lightheadedness or feeling faint.(3) DISCUSSION: An open label, multicenter, prospective trial evaluated the safety of tamsulosin 0.4 mg daily over 24 weeks in 1784 patients. The most commonly reported adverse effects were dizziness, headache, abnormal ejaculation and hypotension. Patients receiving verapamil had an approximately 3-fold (odds ratio 3.166, 95% confidence interval 1.513, 6.58) increase in the risk for adverse events.(4) |
DUTASTERIDE-TAMSULOSIN, FLOMAX, JALYN, TAMSULOSIN HCL |
| 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 |
| Nintedanib/Dual CYP3A4 & P-gp Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Nintedanib is a substrate for the P-glycoprotein (P-gp) transporter and is metabolized to a minor extent by CYP3A4. CLINICAL EFFECTS: Concurrent use of an agent that is both an inhibitor of P-gp and CYP3A4 may result in elevated levels of and clinical effects of nintedanib. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of nintedanib recommends close monitoring for nintedanib patients receiving drugs which are both P-gp and CYP3A4 inhibitors. In an interaction study ketoconazole increased exposure to nintedanib by 60%. Nintedanib therapy may need to be interrupted or the dose may need to be reduced.(1) DISCUSSION: In an interaction study coadministration with ketoconazole, a P-gp and CYP3A4 inhibitor, increased nintedanib exposure (area-under-curve, AUC) and maximum concentration (Cmax) by 1.61-fold and 1.83 fold respectively.(1) Strong CYP3A4 & P-gp inhibitors include: adagrasib, boceprevir, clarithromycin, cobicistat, grapefruit, indinavir, itraconazole, josamycin, ketoconazole, levoketoconazole, lonafarnib, lopinavir, mibefradil, mifepristone, nefazodone, nelfinavir, nirmatrelvir, paritaprevir, posaconazole, ritonavir, saquinavir, telaprevir, telithromycin, tipranavir, and tucatinib. Moderate CYP3A4 & P-gp inhibitors include: conivaptan, diltiazem, dronedarone, erythromycin, fluvoxamine, isavuconazonium, schisandra, and verapamil. Weak CYP3A4 & P-gp inhibitors include: amiodarone, azithromycin, cimetidine, cyclosporine, daclatasvir, daridorexant, diosmin, flibanserin, fluvoxamine, fostamatinib, glecaprevir/pibrentasvir, ivacaftor, lapatinib, mavorixafor, and ranolazine.(2) |
OFEV |
| Apixaban/P-gp and Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Cimetidine, diltiazem, dronedarone, erythromycin, isavuconazonium and verapamil may inhibit the metabolism of apixaban by CYP3A4 and by P-glycoprotein.(1,2) CLINICAL EFFECTS: Concurrent use of an agent that is both an inhibitor of P-gp and a moderate inhibitor of CYP3A4 may result in elevated levels of and clinical effects of apixaban, including an increased risk of bleeding.(1,2) PREDISPOSING FACTORS: This interaction may be more clinically significant in patients with decreased renal function.(1) 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 Australian(1), Canadian(2), UK(3), and US(4) manufacturers state concurrent use of agents that are P-gp and moderate CYP3A4 inhibitors are expected to increase apixaban levels to a lesser extent than agents that are P-gp and strong CYP3A4 inhibitors. No dose adjustment of apixaban is necessary. Use caution when administering apixaban with moderate inhibitors of CYP3A4. 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: Concurrent ketoconazole (400 mg daily, a strong inhibitor of CYP3A4) increased the area-under-curve (AUC) and maximum concentration (Cmax) of apixaban by 2-fold and 1.6-fold, respectively.(1) A propensity matched cohort evaluated the concurrent use of combined P-gp and moderate CYP3A4 inhibitors with apixaban or rivaroxaban. Combined inhibitors included amiodarone, diltiazem, erythromycin, dronedarone, and verapamil. Bleeding occurred in 26.4% of patients in the inhibitor group compared to 18.4% in the control group (hazard ratio 1.8; 95% CI 1.19-2.73; p=0.006). Although not statistically significant, patients in the inhibitor group also had a higher rate of major bleeding (15% vs 10.3%) and minor bleeding (8.9% vs 5.2%), respectively.(6) A summary of pharmacokinetic interactions with apixaban and calcium-channel blockers, including diltiazem and verapamil, concluded that concurrent use is considered safe based on a lesser increase in apixaban exposure with moderate CYP3A4 inhibitors.(7) A population cohort study of 48,422 patients evaluated overall and gastrointestinal major, moderate or minor bleeding in patients on concurrent therapy with apixaban and diltiazem or verapamil. Concurrent therapy was not associated with increased bleeding rates compared to patients receiving amlodipine or metoprolol.(8) A retrospective study of two propensity matched cohorts of 1681 patients each found a bleeding rate of 1.31 and 2.14 per 100 years at risk with apixaban and warfarin, respectively, when used concurrently with dronedarone in patients with atrial fibrillation. The hazard ratio with apixaban and dronedarone was 0.66 compared to warfarin and dronedarone.(9) An observational study of 29 patients evaluated concurrent administration of apixaban (5 mg) with diltiazem or diltiazem with atorvastatin or rosuvastatin. Administration of apixaban with diltiazem and rosuvastatin resulted in a greater than 1.5-fold increate in apixaban concentrations. Concurrent administration of apixaban with diltiazem alone or diltiazem with atorvastatin did not result in a statistically significant increase in apixaban concentration.(11) P-gp and moderate CYP3A4 inhibitors linked to this monograph are: conivaptan, diltiazem, dronedarone, erythromycin, isavuconazonium and verapamil.(10) |
ELIQUIS |
| Brexpiprazole/Moderate CYP3A4 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: This interaction is expected to be more severe in patients who are CYP2D6 poor metabolizers, or who receive concomitant treatment with a strong or moderate CYP2D6 inhibitor (e.g. bupropion, fluoxetine, paroxetine, quinidine) in addition to treatment with a moderate CYP3A4 inhibitor. PATIENT MANAGEMENT: The US manufacturer of brexpiprazole recommends the following dose adjustments for patients who are receiving a moderate CYP3A4 inhibitor: - in patients taking a moderate 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. The dose of brexpiprazole should be adjusted to its original level if the CYP3A4 inhibitor is discontinued.(1) No empiric dosage adjustment is recommended in other patients. DISCUSSION: Coadministration of ketoconazole, a strong inhibitor of CYP3A4, increased the area-under-curve (AUC) of brexpiprazole approximately 2-fold.(1) Moderate CYP3A4 inhibitors linked to this monograph include aprepitant, avacopan, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan and verapamil. |
REXULTI |
| Edoxaban (Greater Than 30 mg)/Select P-gp Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Edoxaban is a substrate for P-glycoprotein (P-gp). Inhibitors of P-gp may increase intestinal absorption and decrease renal tubular elimination of edoxaban.(1,2) CLINICAL EFFECTS: Concurrent use with selected P-gp inhibitors may result in higher systemic concentrations of edoxaban which may increase the risk for bleeding.(1,2) PREDISPOSING FACTORS: Bleeding risk may be increased in patients with creatinine clearance below 50 mL per minute(1-4). Use of multiple agents which increase edoxaban exposure or affect hemostasis would be expected to increase the risk for bleeding. 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: Management recommendations between approving regulatory agencies (FDA or European Medicines Agency, EMA) are conflicting. EMA approved prescribing information specifically states that dosage adjustments are not required solely for concomitant use with amiodarone, quinidine, or verapamil regardless of indication.(3,4) Potential interactions with azithromycin, clarithromycin, or oral itraconazole are not described.(3) FDA approved prescribing recommendations for edoxaban are indication specific:(2) - For prevention of stroke or embolic events due to nonvalvular atrial fibrillation, no edoxaban dose adjustments are recommended during concomitant therapy with P-glycoprotein inhibitors. - For treatment of deep vein thrombosis (DVT) or pulmonary embolism (PE), the edoxaban dose should be reduced to 30 mg daily during concomitant use with azithromycin, clarithromycin, oral itraconazole, quinidine or verapamil. The manufacturer of vimseltinib states concurrent use with P-gp substrates should be avoided. If concurrent use cannot be avoided, take vimseltinib at least 4 hours prior to edoxaban.(6) Monitor patients receiving anticoagulant therapy for signs of blood loss, including decreased hemoglobin and/or 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. anti Factor Xa inhibition) 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. Discontinue edoxaban in patients with active bleeding. DISCUSSION: Edoxaban in vivo interaction studies have been performed for quinidine and verapamil. In vivo interaction studies have not been conducted for the remaining P-gp inhibitors linked to this monograph.(1,4) In an interaction study, the effect of repeat administration of quinidine (300 mg TID) on a single oral dose of edoxaban 60 mg was evaluated in healthy subjects. Both peak (Cmax) and total systemic exposure (AUC) to edoxaban and to the active M4 metabolite increased approximately 1.75-fold.(1) In an interaction study, the effect of repeat administration of verapamil (240 mg Verapamil SR Tablets (Calan SR) QD for 11 Days) on a single oral dose of edoxaban 60 mg on the morning of Day 10 was evaluated in healthy subjects. Total and peak systemic exposure to edoxaban increased 1.53-fold and 1.53-fold, respectively. Total and peak systemic exposure to the active M4 metabolite increased 1.31-fold and 1.28-fold, respectively.(1) Based upon the above results, patients in the DVT/PE trial had a 50% dose reduction (from 60 mg to 30 mg) during concomitant therapy with P-glycoprotein inhibitors. Approximately 0.5% of these patients required a dose reduction solely due to P-gp inhibitor use. This low rate of concurrent therapy was too small to allow for detailed statistical evaluation. Almost all of these patients were receiving quinidine or verapamil. In these patients, both trough edoxaban concentrations (Ctrough) used to evaluate bleeding risk, and total edoxaban exposure (AUC or area-under-curve) used to evaluate treatment efficacy, were lower than patients who did not require any edoxaban dose adjustment. In this DVT/PE comparator trial, subgroup analysis revealed that warfarin had numerically better efficacy than edoxaban in patients receiving P-gp inhibitors. Based upon the overall lower exposure to edoxaban in P-gp dose adjusted subjects, both EMA and FDA Office of Clinical Pharmacology (OCP) concluded that the edoxaban 50% dose reduction overcorrected for the difference in exposure.(1,4) Consequently, EMA recommended no edoxaban dose adjustments for patients receiving concomitant therapy with quinidine or verapamil.(3,4) A summary of pharmacokinetic interactions with edoxaban and verapamil concluded that if concurrent use is considered safe.(7) P-gp inhibitors linked to this interaction are: amiodarone, asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, clarithromycin, cobicistat, conivaptan, daclatasvir, danicopan, daridorexant, diltiazem, diosmin, flibanserin, fostamatinib, ginseng, glecaprevir/pibrentasvir, hydroquinidine, oral itraconazole, indinavir, ivacaftor, josamycin, ledipasvir, lonafarnib, neratinib, osimertinib, pirtobrutinib, propafenone, quinidine, ranolazine, telaprevir, telithromycin, tezacaftor, tepotinib, tucatinib, valbenazine, velpatasvir, vemurafenib, verapamil, vimseltinib, and voclosporin.(8) |
SAVAYSA |
| Bromocriptine/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 bromocriptine. CLINICAL EFFECTS: Concurrent use of a moderate CYP3A4 inhibitor may result in increased levels of bromocriptine, which may result in increased side effects of these agents. PREDISPOSING FACTORS: Patients receiving the maximum recommended (or higher than recommended) dosages of ergotamine derivatives may be at a higher risk of adverse effects from this combination. PATIENT MANAGEMENT: Use caution with concurrent therapy with bromocriptine with azole antifungals. The US manufacturer of bromocriptine states use caution when co-administering drugs that are inhibitors of CYP3A4. Bromocriptine dose should not exceed 1.6 mg per day when used with a moderate CYP3A4 inhibitor. Concomitant use of strong CYP3A4 inhibitors should be avoided. Ensure adequate washout of strong CYP3A4 inhibitor drug before initiating bromocriptine.(1) DISCUSSION: A study in five healthy subjects found that concurrent administration of erythromycin and bromocriptine resulted in a 268% increase in area-under-curve (AUC) for bromocriptine and a 4.6-fold increase in bromocriptine maximum concentration (Cmax).(2) Inhibition of ergotamine derivative metabolism by moderate inhibitors would also be expected, but to a lesser degree. Moderate CYP3A4 inhibitors linked to this monograph are aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, ledipasvir, lenacapavir, letermovir, netupitant, nilotinib, schisandra, stiripentol, tofisopam, treosulfan and verapamil.(3,4) |
BROMOCRIPTINE MESYLATE, CYCLOSET |
| Quetiapine/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 quetiapine. Quetiapine is a sensitive substrate for CYP3A4 and so an approximately 2-fold or higher increase in exposure (AUC, area-under-curve) is possible when quetiapine is given with a moderate CYP3A4 inhibitor.(1-4) CLINICAL EFFECTS: Concurrent use of a strong or moderate CYP3A4 inhibitor may result in elevated levels of and toxicity from quetiapine, including potentially life-threatening cardiac arrhythmias such as torsades de pointes.(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.(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: Monitor patients when moderate inhibitors of CYP3A4 are co-prescribed with quetiapine as the magnitude of the interaction is highly variable between patients.(6) Use of higher doses of either the CYP3A4 inhibitor or quetiapine are other factors which may affect the magnitude of this interaction. Decrease the quetiapine dose if needed. 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 in 19 Chinese patients with schizophrenia, patients received quetiapine (200 mg twice daily) alone and with erythromycin (500 mg 3 times daily, a moderate inhibitor of CYP3A4). Erythromycin increased the quetiapine maximum concentration (Cmax)by 68%(range approximately 20-130%), area-under-curve (AUC) 129% (range approximately 20-300%), and half-life by 92% (range approximately 0-250%). Quetiapine clearance decreased 52% (range approximately -15 to -80%).(6) Moderate inhibitors of CYP3A4 include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, diltiazem, duvelisib, fedratinib, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nirogacestat, schisandra, schisandra sphenanthera, tofisopam, treosulfan and verapamil.(4) |
QUETIAPINE FUMARATE, QUETIAPINE FUMARATE ER, SEROQUEL, SEROQUEL XR |
| Selected MAOIs/Selected Antihypertensive Agents SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Both MAOIs and antihypertensive agents may increase the risk of postural hypotension.(1,2) CLINICAL EFFECTS: Postural hypotension may occur with concurrent therapy of MAOIs and antihypertensive agents.(1,2) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of phenelzine states all patients should be followed closely for symptoms of postural hypotension. Hypotensive side effects have occurred in patients who have been hypertensive and normotensive, as well as hypotensive at initiation of phenelzine.(1) The manufacturer of tranylcypromine states hypotension has been observed most commonly but not exclusively in patients with pre-existing hypertension. Tranylcypromine doses greater than 30 mg daily have a major side effect of postural hypotension and can lead to syncope. Gradual dose titration is recommended to decrease risk of postural hypotension. Combined use with other agents known to cause hypotension have shown to have additive side effects and should be monitored closely.(2) Monitor the patient for signs and symptoms of postural hypotension including dizziness, lightheadedness, or weakness, especially upon standing. Monitor blood pressure as well as orthostatic vitals and adjust antihypertensive therapy, including decreasing the dose, dividing doses, or scheduling doses at bedtime, as needed to maintain goal blood pressure. If blood pressure remains hypotensive, consider decreasing the dose of phenelzine or tranylcypromine. In some cases, discontinuation of one or both agents may be necessary.(3) Normotensive patients on stable antihypertensive therapy who are started on either phenelzine or tranylcypromine may be at increased risk for hypotension. Hypertensive patients on stable phenelzine or tranylcypromine who require antihypertensive therapy would be at decreased risk for hypotension. DISCUSSION: A review article describes the pharmacology of phenelzine and tranylcypromine as non-selective MAOIs which inhibit both type A and type B substrates. Orthostatic hypotension is described as the most common MAOI side effect and usually occurs between initiation and the first 3-4 weeks of therapy.(3) In a double-blind study, 71 patients were randomized to receive a 4-week trial of either tranylcypromine, amitriptyline, or the combination. The number of patients reporting dizziness at 4 weeks was not different between the three treatment groups (tranylcypromine 52.4%; amitriptyline 65%; combination 66.7%). Blood pressure (BP) assessment noted a significant drop in standing BP in the tranylcypromine group compared to baseline (systolic BP change = -10 mmHg; p<0.02 and diastolic BP change = -9 mmHg; p<0.02). Combination therapy also had a significant drop in standing BP compared to baseline (systolic BP change = -9 mmHg; p<0.02). Patients receiving amitriptyline had no significant change in BP from baseline at 4 weeks. All three groups had a trend toward increasing orthostatic hypotension in BP changes from lying to standing. The change in orthostatic hypotension was significant in the amitriptyline group with an average systolic BP orthostatic drop of -9 mmHg (p<0.05).(4) A randomized, double-blind study of 16 inpatients with major depressive disorder were treated with either phenelzine or tranylcypromine. Cardiovascular assessments were completed at baseline and after 6 weeks of treatment. After 6 weeks, 5/7 patients (71%) who received phenelzine had a decrease in standing systolic BP greater than 20 mmHg from baseline. Head-up tilt systolic and diastolic BP decreased from baseline in patients on phenelzine (98/61 mmHg v. 127/65 mmHg, respectively; systolic change p=0.02 and diastolic change p=0.02). After 6 weeks, 6/9 patients (67%) who received tranylcypromine had a decrease in standing systolic BP greater than 20 mmHg from baseline. Head-up tilt systolic and diastolic BP decreased from baseline in patients on tranylcypromine (113/71 mmHg v. 133/69 mmHg, respectively; systolic change p=0.09 and diastolic change p=0.07).(5) Selected MAOIs linked to this monograph include: phenelzine and tranylcypromine. Selected antihypertensive agents include: ACE inhibitors, alpha blockers, ARBs, beta blockers, calcium channel blockers, aprocitentan, clonidine, hydralazine and sparsentan. |
NARDIL, PARNATE, PHENELZINE SULFATE, TRANYLCYPROMINE SULFATE |
| Tizanidine/Selected Antihypertensives SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Tizanidine is an alpha-2 agonist. Concurrent use with antihypertensive agents may result in additive effects on blood pressure.(1) CLINICAL EFFECTS: Concurrent use of antihypertensives and tizanidine may result in hypotension.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Patients receiving concurrent therapy should be monitored for hypotension. The risk of hypotension may be decreased by careful titration of tizanidine dosages and monitoring for hypotension prior to dose advancement. Counsel patients about the risk of orthostatic hypotension.(1) DISCUSSION: Severe hypotension has been reported following the addition of tizanidine to existing lisinopril therapy.(2-4) |
TIZANIDINE HCL, ZANAFLEX |
| 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 |
| Edoxaban (Less Than or Equal To 30 mg)/Select P-gp Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Edoxaban is a substrate for P-glycoprotein (P-gp). Inhibitors of P-gp may increase intestinal absorption and decrease renal tubular elimination of edoxaban.(1,2) CLINICAL EFFECTS: Concurrent use with selected P-gp inhibitors may result in higher systemic concentrations of edoxaban which may increase the risk for bleeding.(1,2) PREDISPOSING FACTORS: Bleeding risk may be increased in patients with creatinine clearance below 50 mL per minute(1-4). Use of multiple agents which increase edoxaban exposure or affect hemostasis would be expected to increase the risk for bleeding. 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: Management recommendations between approving regulatory agencies (FDA or European Medicines Agency, EMA) are conflicting. EMA approved prescribing information specifically states that dosage adjustments are not required solely for concomitant use with amiodarone, quinidine, or verapamil regardless of indication.(3,4) Potential interactions with azithromycin, clarithromycin, or oral itraconazole are not described.(3) FDA approved prescribing recommendations for edoxaban are indication specific:(2) - For prevention of stroke or embolic events due to nonvalvular atrial fibrillation, no edoxaban dose adjustments are recommended during concomitant therapy with P-glycoprotein inhibitors. - For treatment of deep vein thrombosis (DVT) or pulmonary embolism (PE), the edoxaban dose should be reduced to 30 mg daily during concomitant use with azithromycin, clarithromycin, oral itraconazole, quinidine or verapamil. The manufacturer of vimseltinib states concurrent use with P-gp substrates should be avoided. If concurrent use cannot be avoided, take vimseltinib at least 4 hours prior to edoxaban.(6) Monitor patients receiving anticoagulant therapy for signs of blood loss, including decreased hemoglobin and/or 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. anti Factor Xa inhibition) 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. Discontinue edoxaban in patients with active bleeding. DISCUSSION: Edoxaban in vivo interaction studies have been performed for quinidine and verapamil. In vivo interaction studies have not been conducted for the remaining P-gp inhibitors linked to this monograph.(1,4) In an interaction study, the effect of repeat administration of quinidine (300 mg TID) on a single oral dose of edoxaban 60 mg was evaluated in healthy subjects. Both peak (Cmax) and total systemic exposure (AUC) to edoxaban and to the active M4 metabolite increased approximately 1.75-fold.(1) In an interaction study, the effect of repeat administration of verapamil (240 mg Verapamil SR Tablets (Calan SR) QD for 11 Days) on a single oral dose of edoxaban 60 mg on the morning of Day 10 was evaluated in healthy subjects. Total and peak systemic exposure to edoxaban increased 1.53-fold and 1.53-fold, respectively. Total and peak systemic exposure to the active M4 metabolite increased 1.31-fold and 1.28-fold, respectively.(1) Based upon the above results, patients in the DVT/PE trial had a 50% dose reduction (from 60 mg to 30 mg) during concomitant therapy with P-glycoprotein inhibitors. Approximately 0.5% of these patients required a dose reduction solely due to P-gp inhibitor use. This low rate of concurrent therapy was too small to allow for detailed statistical evaluation. Almost all of these patients were receiving quinidine or verapamil. In these patients, both trough edoxaban concentrations (Ctrough) used to evaluate bleeding risk, and total edoxaban exposure (AUC or area-under-curve) used to evaluate treatment efficacy, were lower than patients who did not require any edoxaban dose adjustment. In this DVT/PE comparator trial, subgroup analysis revealed that warfarin had numerically better efficacy than edoxaban in patients receiving P-gp inhibitors. Based upon the overall lower exposure to edoxaban in P-gp dose adjusted subjects, both EMA and FDA Office of Clinical Pharmacology (OCP) concluded that the edoxaban 50% dose reduction overcorrected for the difference in exposure.(1,4) Consequently, EMA recommended no edoxaban dose adjustments for patients receiving concomitant therapy with quinidine or verapamil.(3,4) A summary of pharmacokinetic interactions with edoxaban and verapamil concluded that if concurrent use is considered safe.(7) P-gp inhibitors linked to this interaction are: amiodarone, asunaprevir, azithromycin, belumosudil, capmatinib, carvedilol, cimetidine, clarithromycin, cobicistat, conivaptan, daclatasvir, danicopan, daridorexant, diltiazem, diosmin, flibanserin, fostamatinib, ginseng, glecaprevir/pibrentasvir, hydroquinidine, indinavir, oral itraconazole, ivacaftor, josamycin, ledipasvir, lonafarnib, mavorixafor, neratinib, osimertinib, pirtobrutinib, propafenone, quinidine, ranolazine, telaprevir, telithromycin, tezacaftor, tepotinib, tucatinib, valbenazine, velpatasvir, vemurafenib, verapamil vimseltinib, and voclosporin.(8) |
SAVAYSA |
| Lacosamide/Beta-Blockers; Calcium Channel Blockers SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Lacosamide may enhance the slow inactivation of voltage-gated sodium channels and may cause dose-dependent bradycardia, prolongation of the PR interval, atrioventricular (AV) block, or ventricular tachyarrhythmia.(1) CLINICAL EFFECTS: Concurrent use of lacosamide and agents that affect cardiac conduction (beta-blockers, calcium channel blockers) may increase the risk of bradycardia, prolongation of the PR interval, atrioventricular (AV) block, or ventricular tachyarrhythmia.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Lacosamide should be used with caution in patients on concomitant medications that affect cardiac conduction, including beta-blockers and calcium channel blockers.(1) If concurrent use is needed, obtain an ECG before lacosamide therapy and after lacosamide dose is titrated to steady-state.(1) Patients should be monitored closely when lacosamide is given intravenously.(1) DISCUSSION: In a clinical trial in patients with partial-onset seizures, asymptomatic first-degree atrioventricular (AV) block occurred in 4/944 (0.4%) of patient who received lacosamide compared to 0/364 (0%) with placebo.(1) In a clinical trial in patients with diabetic neuropathy, asymptomatic first-degree AV block occurred in 5/1023 (0.5%) of patients who received lacosamide compared to 0/291 (0%) with placebo.(1) Second-degree and complete AV block have been reported in patients with seizures.(1) One case of profound bradycardia was observed in a patient during a 15-minute infusion of 150 mg of lacosamide.(1) Two postmarketing reports of third-degree AV block in patients with significant cardiac history and also receiving metoprolol and amlodipine during infusion of lacosamide injection at doses higher than recommended have been reported.(1) A case report of an 88 year old female taking bisoprolol documented complete AV block after initiation of lacosamide. The patient required pacemaker implementation.(2) |
LACOSAMIDE, MOTPOLY XR, VIMPAT |
| Abemaciclib/Moderate CYP3A4 Inhibitors SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Abemaciclib is a substrate of CYP3A4. Moderate inhibitors of CYP3A4 may inhibit the metabolism of abemaciclib.(1) CLINICAL EFFECTS: Concurrent use of a moderate inhibitor of CYP3A4 may result in increased levels and toxicity from abemaciclib.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of abemaciclib recommends monitoring for adverse reactions and consider a dose reduction of abemaciclib dose in 50 mg decrements as detailed in prescribing information (based on starting dose, previous dose reductions, and combination or monotherapy use) with concurrent use of moderate CYP3A4 inhibitors.(1) Monitor patient for signs and symptoms of abemaciclib toxicity with concurrent use. DISCUSSION: Abemaciclib is a substrate of CYP3A4.(1) Concurrent administration of verapamil and diltiazem (moderate CYP3A4 inhibitors) are predicted to increase the relative adjusted unbound area-under-curve (AUC) of abemaciclib and its active metabolites (M2, M18, and M20) by approximately 1.6-fold and 2.4-fold, respectively.(1) Concurrent administration of ketoconazole (a strong CYP3A4 inhibitor) is predicted to increase the AUC of abemaciclib up to 16-fold.(1) Concurrent administration of itraconazole (a strong CYP3A4 inhibitor) is predicted to increase the relative potency adjusted unbound AUC of abemaciclib and its active metabolites (M2, M18, and M20) by 2.2-fold.(1) Concurrent administration of clarithromycin (500 mg twice daily, a strong CYP3A4 inhibitor) with a single dose of 50 mg of abemaciclib increased the relative potency adjusted unbound AUC of abemaciclib and its active metabolites (M2, M18, and M20) by 2.5-fold.(1) Moderate CYP3A4 inhibitors linked to this monograph include: amprenavir, aprepitant, avacopan, berotralstat, clofazimine, conivaptan, darunavir, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, lenacapavir, letermovir, netupitant, nilotinib, nirogacestat, schisandra, tofisopam, treosulfan and verapamil.(2,3) |
VERZENIO |
| Apomorphine/Selected Antihypertensives and Vasodilators SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Apomorphine causes dose-dependent decreases in blood pressure. Concurrent use with antihypertensive agents may result in additive effects on blood pressure.(1) CLINICAL EFFECTS: Concurrent use of antihypertensives and apomorphine may result in orthostatic hypotension with or without dizziness, nausea, or syncope.(1) PREDISPOSING FACTORS: The risk of orthostatic hypotension may be increased during dose escalation of apomorphine and in patients with renal or hepatic impairment.(1) PATIENT MANAGEMENT: Patients receiving concurrent therapy should be monitored for hypotension. Counsel patients about the risk of orthostatic hypotension.(1) DISCUSSION: Healthy volunteers who took sublingual nitroglycerin (0.4 mg) concomitantly with apomorphine experienced a mean largest decrease in supine systolic blood pressure (SBP) of 9.7 mm Hg and in supine diastolic blood pressure (DBP) of 9.3 mm Hg, and a mean largest decrease in standing SBP and DBP of 14.3 mm Hg and 13.5 mm Hg, respectively. The maximum decrease in SBP and DBP was 65 mm Hg and 43 mm Hg, respectively. When apomorphine was taken alone, the mean largest decrease in supine SBP and DBP was 6.1 mm Hg and 7.3 mm Hg, respectively, and in standing SBP and DBP was 6.7 mm Hg and 8.4 mm Hg, respectively.(1) |
APOKYN, APOMORPHINE HCL, ONAPGO |
| 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 |
| 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 |
| 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 Calcium Channel Blockers/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 calcium channel blockers by CYP3A4.(1,2) CLINICAL EFFECTS: Concurrent use of nirmatrelvir-ritonavir may result in elevated levels of and toxicity from calcium channel blockers. PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: Concurrent use of nirmatrelvir-ritonavir and selected calcium channel blockers should be approached with caution. Monitor patients receiving concurrent therapy with nirmatrelvir-ritonavir and either amlodipine, diltiazem, felodipine, nicardipine, nifedipine, or verapamil for increased calcium channel blocker effects. The dosage of the calcium channel blocker may need to be adjusted.(1,2) The Journal of American College of Cardiology recommends a 50% reduction in the dose amlodipine for 8 days with the initiation of nirmatrelvir-ritonavir. Close monitoring of blood pressure and dose reduction or temporary discontinuation of calcium channel blockers may be needed. Resume calcium channel blockers 3 days after the last dose of nirmatrelvir-ritonavir.(3) DISCUSSION: Nirmatrelvir-ritonavir is a strong CYP3A4 inhibitor and may increase the levels of calcium channel blockers that are CYP3A4 substrates.(1,2) In a case report of a 80-year old female on verapamil, on day 2 of concurrent nirmatrelvir-ritonavir the patient presented to the hospital with symptomatic bradycardia (heart rate of 28 beats per minute and blood pressure of 58/35 mmHg) requiring hospitalization, medical management, and a temporary transvenous pacer.(4) |
PAXLOVID |
| Lumateperone (Less Than or Equal To 21 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 lumateperone.(1) CLINICAL EFFECTS: Concurrent use of lumateperone with moderate CYP3A4 inhibitors increases lumateperone exposure, which may increase the risk of adverse reactions.(1) PREDISPOSING FACTORS: None determined. PATIENT MANAGEMENT: The manufacturer of lumateperone recommends decreasing the dosage of lumateperone to 21 mg once daily in patients receiving moderate CYP3A4 inhibitors.(1) 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) Moderate inhibitors of CYP3A4 include: aprepitant, avacopan, berotralstat, clofazimine, conivaptan, crizotinib, diltiazem, dronedarone, duvelisib, erythromycin, fedratinib, fluconazole, fluvoxamine, fosnetupitant, imatinib, isavuconazonium, oral lefamulin, lenacapavir, letermovir, netupitant, nilotinib, schisandra, tofisopam, treosulfan, verapamil, and voxelotor.(2,3) |
CAPLYTA |
| 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 |
| Dabigatran/Diltiazem SEVERITY LEVEL: 3-Moderate Interaction: Assess the risk to the patient and take action as needed. MECHANISM OF ACTION: Dabigatran etexilate is a substrate for the P-glycoprotein (P-gp) system. Diltiazem is a P-gp inhibitor. Inhibition of intestinal P-gp leads to increased absorption of dabigatran.(1-3) CLINICAL EFFECTS: The concurrent use dabigatran with diltiazem may lead to elevated plasma levels of dabigatran, increasing the risk for bleeding. PREDISPOSING FACTORS: Factors associated with an increased risk for bleeding include renal impairment, concomitant use of P-gp inhibitors, patient age >74 years, coexisting conditions (e.g. recent trauma) or use of drugs (e.g. NSAIDs) associated with bleeding risk, and patient weight < 50 kg.(1-4) PATIENT MANAGEMENT: Assess renal function and evaluate patient for other pre-existing risk factors for bleeding prior to initiating concurrent therapy. Caution and close monitoring is warranted with concurrent use of dabigatran and diltiazem. The US manufacturer of dabigatran states that the concurrent use of dabigatran and P-gp inhibitors should be avoided in atrial fibrillation patients with severe renal impairment (CrCl less than 30 ml/min) and in patients with moderate renal impairment (CrCl less than 50 ml/min) being treated for or undergoing prophylaxis for deep vein thrombosis (DVT) or pulmonary embolism (PE). The interaction with P-gp inhibitors can be minimized by taking dabigatran several hours apart from the P-gp inhibitor dose.(1) The concomitant use of dabigatran with P-gp inhibitors has not been studied in pediatric patients but may increase exposure to dabigatran.(1) While the US manufacturer of dabigatran states that no dosage adjustment is necessary in other patients,(1) the Canadian manufacturer of dabigatran states that concomitant use of strong P-gp inhibitors such as but not limited to cyclosporine, itraconazole, nelfinavir, posaconazole, ritonavir, saquinavir, tacrolimus and tipranavir may be expected to increase systemic exposure to dabigatran and should be used with caution.(2) The UK manufacturer of dabigatran also states when dabigatran is used in atrial fibrillation patients and for treatment of DVT and PE concurrently with mild to moderate P-gp inhibitors, the dose of dabigatran should be reduced from 150 mg twice daily to 110 mg twice daily, taken simultaneously with the P-gp inhibitor. When used for VTE prophylaxis after orthopedic surgery concurrently with amiodarone, quinidine, or verapamil, the dabigatran loading dose should be reduced from 110 mg to 75 mg, and the maintenance dose should be reduced from 220 mg daily to 150 mg daily, taken simultaneously with the P-gp inhibitor. For patients with CLcr 30-50 mL/min on concurrent verapamil or other moderate P-gp inhibitor, consider further lowering the dabigatran dose to 75 mg daily.(3) Concomitant administration of P-gp inhibitors is expected to result in increased dabigatran plasma concentrations. If not otherwise specifically described, close clinical surveillance is required when dabigatran is co-administered with strong P-gp inhibitors. Dose reductions may be required in combination with some P-gp inhibitors.(3) If concurrent therapy is warranted, monitor patients for signs of blood loss, including decreased hemoglobin and/or hematocrit, fecal occult blood, and/or decreased blood pressure and promptly evaluate patients with any symptoms. Consider regular monitoring of hemoglobin, platelet levels, and/or activated partial thromboplastin time (aPTT) or ecarin clotting time (ECT). 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: A retrospective cohort study included data from 9,886 individuals evaluating rates of adverse bleeding with standard doses of oral anticoagulants with concurrent verapamil or diltiazem in patients with nonvalvular atrial fibrillation and normal kidney function. Concurrent dabigatran use with verapamil or diltiazem was associated with increased overall bleeding (hazard ratio (HR) 1.52; 95% confidence interval (CI), 1.05-2.20, p<0.05) and increased overall gastrointestinal (GI) bleeding (HR 2.16; 95% CI, 1.30-3.60, p<0.05) when compared to amlodipine. When compared to metoprolol, concomitant dabigatran use with verapamil or diltiazem was also associated with increased overall bleeding (HR, 1.43; 95% CI, 1.02-2.00, p<0.05) and increased overall GI bleeding (HR, 2.32; 95% CI, 1.42-3.79, p<0.05). No association was found between increased bleeding of any kind and concurrent use of rivaroxaban or apixaban with verapamil or diltiazem.(5) A summary of pharmacokinetic interactions with dabigatran and amiodarone or verapamil concluded that concurrent use is considered safe if CrCl is greater than 50 ml/min but should be avoided if CrCl is less than 50 ml/min in VTE and less than 30 ml/min for NVAF. Concurrent use with diltiazem was considered safe.(6) In a study of 4,544 patients with atrial fibrillation, the association between the concomitant use of diltiazem and direct oral anticoagulants (DOACs) (rivaroxaban, apixaban, and dabigatran) with bleeding was evaluated. The study reported that DOAC patients taking diltiazem were associated with a higher risk of any bleeding-related hospitalizations (unadjusted risk difference, 2.4; 95% CI, 0.6-4.2 events per 100 person-years; adjusted HR, 1.56, 95% CI, 1.15-2.12), as well as major bleeding (unadjusted risk difference, 1.4 [95% CI, 0.1-2.6 events per 100 person-years]; adjusted HR, 1.84 [95% CI, 1.18-2.85]). Increased risk of bleeding with diltiazem was observed in both patients with and without chronic kidney disease (estimated glomerular filtration rate <60 mL/min per 1.73 m2).(7) In a retrospective cohort study, the association of novel oral anticoagulants (NOACs) with or without concomitant medication with risk of major bleeding was assessed in 91,330 patients with nonvalvular atrial fibrillation. Concurrent use of amiodarone, fluconazole, rifampin, and phenytoin with NOACs had a significant increase in adjusted incidence rates per 1000 person-years of major bleeding than NOACs alone. Compared with NOAC use alone, the adjusted incidence rate for major bleeding was significantly lower for concurrent use of atorvastatin, digoxin, and erythromycin or clarithromycin and was not significantly different for concurrent use of verapamil; diltiazem; cyclosporine; ketoconazole, itraconazole, voriconazole, or posaconazole; and dronedarone.(8) A retrospective cohort study included patients taking DOACs (dabigatran, apixaban, rivaroxaban) who were prescribed amiodarone, verapamil, or diltiazem compared to amlodipine or metoprolol. The study evaluated the association between hospitalization or emergency room visit due to major hemorrhage and concomitant administration of DOACs with either a moderate P-gp inhibitor or agents with no P-gp activity. Results of the study show the weighted risk of major hemorrhage was not increased with amiodarone, verapamil, or diltiazem initiation in DOAC users, compared to metoprolol or amlodipine, during the full follow-up period (HR; 95% confidence interval]: amiodarone HR 0.77 [0.61-0.97]; verapamil HR 1.32 [0.88-1.98]; diltiazem HR 0.99 [0.85-1.15], respectively).(9) |
DABIGATRAN ETEXILATE, PRADAXA |
| 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 |
| 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 DILTIAZEM 24HR ER (diltiazem hcl):
Drug contraindication overview.
No enhanced Contraindications information available for this drug.
No enhanced Contraindications information available for this drug.
There are 3 contraindications.
Absolute contraindication.
| Contraindication List |
|---|
| Complete atrioventricular block |
| Second degree atrioventricular heart block |
| Severe hypotension |
There are 6 severe contraindications.
Adequate patient monitoring is recommended for safer drug use.
| Severe List |
|---|
| Bradycardia |
| Chronic heart failure |
| Chronic idiopathic constipation |
| Hypotension |
| Sick sinus syndrome |
| Wolff-parkinson-white pattern |
There are 4 moderate contraindications.
Clinically significant contraindication, where the condition can be managed or treated before the drug may be given safely.
| Moderate List |
|---|
| Asthma |
| Disease of liver |
| Kidney disease with reduction in glomerular filtration rate (GFr) |
| Myasthenia gravis |
The following adverse reaction information is available for DILTIAZEM 24HR ER (diltiazem hcl):
Adverse reaction overview.
No enhanced Common Adverse Effects information available for this drug.
No enhanced Common Adverse Effects information available for this drug.
There are 33 severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Peripheral edema |
Atrioventricular block Bradycardia |
| Rare/Very Rare |
|---|
|
Abnormal ECG Abnormal hepatic function tests Acute generalized exanthematous pustulosis Angioedema Asthma exacerbation Asystole Bronchospastic pulmonary disease Bundle branch block Chronic heart failure Dyspnea Erythema multiforme Exfoliative dermatitis Extrapyramidal disease Gingival hyperplasia Hemolytic anemia Hyperbilirubinemia Hypersensitivity angiitis Hyperuricemia Hypotension Leukopenia Myopathy Purpura Retinal disorder Stevens-johnson syndrome Tachycardia Thrombocytopenic disorder Toxic amblyopia Toxic epidermal necrolysis Ventricular premature beats Worsening of chronic heart failure |
There are 49 less severe adverse reactions.
| More Frequent | Less Frequent |
|---|---|
|
Fatigue Headache disorder Sinusitis |
Constipation Diarrhea Dizziness Dyspepsia Edema Flushing General weakness Insomnia Nausea Orthostatic hypotension Skin rash |
| Rare/Very Rare |
|---|
|
Abnormal sexual function Acute abdominal pain Alopecia Anorexia Depression Diplopia Dream disorder Drowsy Dysgeusia Epistaxis Gait abnormality Gynecomastia Hallucinations Hyperglycemia Lichenoid dermatitis drug eruption Memory impairment Nasal congestion Nervousness Nocturia Palpitations Paresthesia Periorbital edema Personality disorders Petechiae Phototoxicity Polydipsia Polyuria Pruritus of skin Syncope Tinnitus Tremor Urticaria Vomiting Weight gain Xerostomia |
The following precautions are available for DILTIAZEM 24HR ER (diltiazem hcl):
No enhanced Pediatric Use information available for this drug.
Contraindicated
Severe Precaution
Management or Monitoring Precaution
Contraindicated
| None |
Severe Precaution
| None |
Management or Monitoring Precaution
| None |
Diltiazem has produced embryocidal and fetocidal effects, skeletal abnormalities, and reductions in early individual pup weights and survival rates during reproduction studies in mice, rats, and rabbits when given in dosages 5-10 times the usual human daily dosage, and an increased incidence of stillbirths at dosages 20 times or more the usual human dosage. There are no adequate and controlled studies to date with diltiazem in pregnant women, and the drug should be used during pregnancy only when the potential benefits justify the possible risks to the fetus.
Because diltiazem is distributed into milk, the manufacturers state that women receiving the drug should not breastfeed their infants; an alternative method of infant feeding should be used if diltiazem therapy is considered necessary in nursing women.
No enhanced Geriatric Use information available for this drug.
The following prioritized warning is available for DILTIAZEM 24HR ER (diltiazem hcl):
No warning message for this drug.
No warning message for this drug.
The following icd codes are available for DILTIAZEM 24HR ER (diltiazem hcl)'s list of indications:
| Hypertension | |
| I10 | Essential (primary) hypertension |
| I11 | Hypertensive heart disease |
| I11.0 | Hypertensive heart disease with heart failure |
| I11.9 | Hypertensive heart disease without heart failure |
| I12 | Hypertensive chronic kidney disease |
| I12.0 | Hypertensive chronic kidney disease with stage 5 chronic kidney disease or end stage renal disease |
| I12.9 | Hypertensive chronic kidney disease with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease |
| I13 | Hypertensive heart and chronic kidney disease |
| I13.0 | Hypertensive heart and chronic kidney disease with heart failure and stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease |
| I13.1 | Hypertensive heart and chronic kidney disease without heart failure |
| I13.10 | Hypertensive heart and chronic kidney disease without heart failure, with stage 1 through stage 4 chronic kidney disease, or unspecified chronic kidney disease |
| I13.11 | Hypertensive heart and chronic kidney disease without heart failure, with stage 5 chronic kidney disease, or end stage renal disease |
| I13.2 | Hypertensive heart and chronic kidney disease with heart failure and with stage 5 chronic kidney disease, or end stage renal disease |
| I15.1 | Hypertension secondary to other renal disorders |
| Prevention of anginal pain in coronary artery disease | |
| I20.2 | Refractory angina pectoris |
| I20.81 | Angina pectoris with coronary microvascular dysfunction |
| I20.89 | Other forms of angina pectoris |
| I20.9 | Angina pectoris, unspecified |
| I25.112 | Atherosclerotic heart disease of native coronary artery with refractory angina pectoris |
| I25.118 | Atherosclerotic heart disease of native coronary artery with other forms of angina pectoris |
| I25.119 | Atherosclerotic heart disease of native coronary artery with unspecified angina pectoris |
| I25.702 | Atherosclerosis of coronary artery bypass graft(s), unspecified, with refractory angina pectoris |
| I25.708 | Atherosclerosis of coronary artery bypass graft(s), unspecified, with other forms of angina pectoris |
| I25.709 | Atherosclerosis of coronary artery bypass graft(s), unspecified, with unspecified angina pectoris |
| I25.712 | Atherosclerosis of autologous vein coronary artery bypass graft(s) with refractory angina pectoris |
| I25.718 | Atherosclerosis of autologous vein coronary artery bypass graft(s) with other forms of angina pectoris |
| I25.719 | Atherosclerosis of autologous vein coronary artery bypass graft(s) with unspecified angina pectoris |
| I25.722 | Atherosclerosis of autologous artery coronary artery bypass graft(s) with refractory angina pectoris |
| I25.728 | Atherosclerosis of autologous artery coronary artery bypass graft(s) with other forms of angina pectoris |
| I25.729 | Atherosclerosis of autologous artery coronary artery bypass graft(s) with unspecified angina pectoris |
| I25.732 | Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with refractory angina pectoris |
| I25.738 | Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with other forms of angina pectoris |
| I25.739 | Atherosclerosis of nonautologous biological coronary artery bypass graft(s) with unspecified angina pectoris |
| I25.752 | Atherosclerosis of native coronary artery of transplanted heart with refractory angina pectoris |
| I25.758 | Atherosclerosis of native coronary artery of transplanted heart with other forms of angina pectoris |
| I25.759 | Atherosclerosis of native coronary artery of transplanted heart with unspecified angina pectoris |
| I25.762 | Atherosclerosis of bypass graft of coronary artery of transplanted heart with refractory angina pectoris |
| I25.768 | Atherosclerosis of bypass graft of coronary artery of transplanted heart with other forms of angina pectoris |
| I25.769 | Atherosclerosis of bypass graft of coronary artery of transplanted heart with unspecified angina pectoris |
| I25.792 | Atherosclerosis of other coronary artery bypass graft(s) with refractory angina pectoris |
| I25.798 | Atherosclerosis of other coronary artery bypass graft(s) with other forms of angina pectoris |
| I25.799 | Atherosclerosis of other coronary artery bypass graft(s) with unspecified angina pectoris |
Formulary Reference Tool