This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Anti-Ulcer, Subject name: Pharmacology
[{'content': 'Cimetidine inhibits the metabolism of all of the following drugs except. \nSelect and explain. \nA. Phenytoin, B. Warfarin, C. Ketoconazole, D. Diazepam', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. (C) Ketoconazole(Ref: KDT 8th/e p698)Cimetidine is a potent inhibitor of microsomal enzymes. It prolongs the half lives of warfarin, theophylline, phenytoin, oral hypoglycemic agents, alcohol and benzodiazepines.', 'role': 'assistant'}]