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': 'Reduces blood pressure primarily by directly decreasing hea rate alone - \nSelect and explain. \nA. Propranolol, B. Prazosin, C. Alpha methyl dopa, D. Nitroprusside sodium', 'role': 'user'}, {'content': "Answer: A \nExplanation: Ans. is 'a' i.e., Propranolol o Methyldopa is useful in the treatment of mild to moderately severe hypeension. It lowers blood pressure chiefly by reducing peripheral vascular resistance, with a variable reduction in hea rate and cardiac output. o Prazosin and nitroprusside are vasodilators and produce reflex tachycardia instead of causing bradycardia. o Propranolol is a non selective beta blocker and acts mainly by decreasing hea rate.", 'role': 'assistant'}]