This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Central Nervous system, Subject name: Pharmacology
[{'content': 'Which drug has more analgesic effects than morphine? \nSelect and explain. \nA. Heroin, B. Apomorphine, C. Codeine, D. Pethidine', 'role': 'user'}, {'content': 'Answer: A \nExplanation: Codeine is less potent than morphine as an analgesic(60mg codeine=10 mg morphine). 100 mg pethidine= 10 mg morphine.Heroin is conveed to morphine in the body and has higher lipid solubility than morphine. Ref KD Tripathi 8th ed.', 'role': 'assistant'}]