This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.V.S, Subject name: Pharmacology
[{'content': 'First dose hypotension is caused by : \nSelect and explain. \nA. Prazosin, B. Clonidine, C. Sodium nitroprusside, D. Propranolol', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' Prazosin Prazosin is a highly selective alpha1 blocker*It dilates arterioles more than veins*It is effective orally *It causes first dose hypotension *It is primarily used as an antihypertensiveIts initial dose should be low", 'role': 'assistant'}]