Interactions

Drug-Drug

• Ketoconazole inhibits the hepatic P450 3A4 enzyme system, which results in metabolism and possibly effects and/or toxicity from cyclosporine, tacrolimus, corticosteroids (dosage reduction may be necessary), calcium channel blockers, sulfonylurea, oral hypoglycemic agents, quinidine, buspirone, clarithromycin, troleandomycin, erythromycin, cyclophosphamide, phenytoin, warfarin ( risk of bleeding), tamoxifen, tricyclic antidepressants, carbamazepine, nisoldipine, zolpidem, vinca alkaloids, ifosfamide, some benzodiazepines (effect may persist for several days; use of triazolam is contraindicated), alfentanil, fentanyl, sufentanil, donepezil, atorvastatin , lovastatin, simvastatin, amprenavir, indinavir (dosage of indinavir recommended), nelfinavir, ritonavir, saquinavir, quinidine, sildenafil and vardenafil (dosage adjustments may be necessary)

• May alter the effectiveness of hormonal contraceptives (alternative method of contraception recommended)

• Drugs that gastric pH, including antacids, histamine H2 antagonists, didanosine (chewable tablets, because of buffer), and gastric acid–pump inhibitors absorption (wait 2 hr before administration of ketoconazole)

• Sucralfate and isoniazid also bioavailability

• hepatotoxicity with other hepatotoxic agents, including alcohol

• Disulfiram-like reaction may occur with alcohol

• Rifampin or isoniazid may levels and effectiveness

• May absorption and effectiveness of theophylline

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