This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Cardiovascular system, Subject name: Pharmacology
[{'content': 'Drugs causing constipation are All except \nSelect and explain. \nA. Verapamil, B. Quinidine, C. MAO inhibitor, D. Tricyclic antidepressants', 'role': 'user'}, {'content': 'Answer: B \nExplanation: Refer kDT 6/e p530,655 drugs causing constipation are Verapamil MAO inhibitor Tricyclic antidepressants Ferrous sulfate other impoant drugs which cause constipation are Ganglion blockers Opioid Calcium carbonate Sedatives Anti histamine Laxative abuse itself Quinidine causes diarrhoea', 'role': 'assistant'}]