This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Gastrointestinal tract, Subject name: Pharmacology
[{'content': 'cimetidine inhibits the metabolism of all the following drugs except: \nSelect and explain. \nA. phenytoin, B. warfarin, C. ketoconazole, D. diazepam', 'role': 'user'}, {'content': 'Answer: C \nExplanation: cimetidine is a potent inhibitor of.microsomal enzymes.it prolongs the half life of warfarin, theophyllin ,phenytoin,oral hypoglycemic agents ,alcohol and benzidiazepines.(ref KDT 6/e p630)', 'role': 'assistant'}]