This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Pharmacology
[{'content': 'Warfarin therapy is prolonged by all except: \nSelect and explain. \nA. Rifampicin, B. Amoxicillin, C. Erythromycin, D. Tetracycline', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Barbiturates (but not benzodiazepines), carbamazepine, rifampicin and griseofulvin induce the metabolism of warfarin.The dose of anticoagulant determined during therapy with these drugs would be higher: if the same is continued after withdrawing the inducer- marked hypoprothrombinemia can occur causing fatal bleeding.\nReference: Essentials of Medical Pharmacology Eighth Edition KD\xa0TRIPATHI\xa0page no 670', 'role': 'assistant'}]