This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: All India exam, Subject name: Medicine
[{'content': 'All of the following agents are used for prophylaxis of migraine, except \nSelect and explain. \nA. Propanalol, B. Valproate, C. Topiramate, D. Ethosuxamide', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Prophylaxis of a migraineThe drugs approved by the FDA for the prophylactic treatment of a migraine include propranolol, timolol, sodium valproate, topiramate, and methysergide (not available in the United States).Also amitriptyline, noriptyline, flunarizine, phenelzine, gabapentin, and cyproheptadine.Onabotulinum toxin type A for a chronic migraine.Phenelzine and methysergide are usually reserved for recalcitrant cases because of their serious potential side effects.Ref: Harrison; 19th edition', 'role': 'assistant'}]