Drug interactions between amlodipine and Mycelex Troche

amlodipine ↔ clotrimazole

Applies to:amlodipine and Mycelex Troche (clotrimazole)

MONITOR: Coadministration with an azole antifungal agent may increase the plasma concentrations of calcium channel blockers (CCBs) including the dihydropyridines (amlodipine, felodipine, isradipine, lacidipine, nicardipine, nifedipine, nimodipine, nisoldipine), diltiazem, and verapamil. The mechanism is decreased clearance and/or first-pass metabolism of CCBs due to inhibition of CYP450 3A4 enzymatic activity by azole antifungal agents. In a pharmacokinetic study, nisoldipine mean peak plasma concentration (Cmax) and systemic exposure (AUC) increased 11- and 24-fold, respectively, following pretreatment and during concomitant administration with ketoconazole. Significant increases of severalfold in felodipine and nifedipine plasma concentrations have also been observed during coadministration with itraconazole. Theoretically, the interaction may potentiate the risk of ventricular dysfunction, congestive heart failure, and peripheral and pulmonary edema, particularly in patients with preexisting risk factors (e.g., a history of congestive heart failure; cardiac disease such as ischemic and valvular disease; significant pulmonary disease such as chronic obstructive pulmonary disorder; edematous disorders such as renal failure). There have been case reports of leg and ankle edema in patients treated with various itraconazole-dihydropyridine combinations.

MANAGEMENT: Caution is advised if azole antifungal agents must be used concomitantly with CCBs. Close monitoring of clinical response and tolerance is recommended, and the CCB dosage adjusted as necessary. Patients should be advised to seek medical attention if they experience edema or swelling of the lower extremities; sudden, unexplained weight gain; difficulty breathing; chest pain or tightness; or hypotension as indicated by dizziness, fainting, or orthostasis.