system
Medical AI Inquiry: You were designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.
user
CYP 3A4 enzymes are affected by: a) Fexofenadine b) Phenytoin c) Carbamazepine d) Azithromycin e) Penicillin
assistant
The correct answer is  CYP3A4 cary out biotransformation of large number of drugs. The inhibition of this isoenzyme by erythromycin, clarithromycin, ketoconazole, itraconazole etc. is responsible for important drug interactions with terfenadine, astemizole and cisapride. Rifampicin, barbiturates and other anticonvulsants are important inducers.