This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: C.N.S, Subject name: Pharmacology
[{'content': 'Opioid analgesics used in treatment of cough? \nSelect and explain. \nA. Noscapine, B. Dextromethorphan, C. Codeine, D. Meperidine', 'role': 'user'}, {'content': 'Answer: C \nExplanation: Ans. c (Codeine). (Ref: KD Tripathi, Pharmacology, 5th ed., 424)Codeine or its substitutes are widely used in treatment for suppressing, dry irritating cough.Following are anti-tussives (cough centre supressants).a.Opioidcodeine, pholcodeine, ethyl morphine and morphineb.Non-opioidNoscapine, dextrometharphan, oxeladine, clophedianol,cAnti-histaminicschlorpheniramine, diphenyl hydramine, promethazine.', 'role': 'assistant'}]