Which of the following drug is an inhibitor of cytochrome p450 enzyme: (A) Ketoconazole, (B) Rifampecin, (C) Phenytoin, (D) Phenobarbitone
Answer is A. Ketoconazole is a powerful microsomal enzyme inhibitor where as rifampicin,phenobarbitone and Phenytoin are enzyme inducers Refer KDT 7-e p26