Which of the following drugs is an inhibitor of cytochrome p450 enzymes?: (A) Ketoconazole, (B) Rifampicin, (C) Phenytoin, (D) Phenobarbitone
Answer is A. Ans. (A) Ketoconazole(Ref: KDT 8th/e p30)Ketoconazole is a powerful microsomal enzyme inhibitor whereas rifampicin, phenobarbitone and phenytoin are enzyme inducers.