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': 'Propranolol is contra-indicated in a patient of angina pectoris, when he is already receiving: \nSelect and explain. \nA. Nifedipine, B. Isosorbide mononitrate, C. Aspirin, D. Verapamil', 'role': 'user'}, {'content': 'Answer: D \nExplanation: Verapamil has maximum depressant action on the heart and it causes vasodilation by causing blockade of calcium channel. It is indicated for the treatment of angina, PSVT, hypertension and hypertrophic obstructive cardiomyopathy (HOCM).\nBoth verapamil and propranolol decrease the conduction through the AV node and their concomitant\xa0use can result in heart block.', 'role': 'assistant'}]