This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: A.N.S., Subject name: Pharmacology
[{'content': "Which drug is not used now in Alzheimer's disease? \nSelect and explain. \nA. Tacrine, B. Galantamine, C. Donepezil, D. Rivastigmine", 'role': 'user'}, {'content': 'Answer: A \nExplanation: Ans. (A) Tacrine(Ref: KDT 8th/e p119, 518)Because of hepatotoxicity, and requirement of frequent dosing, tacrine is less often used than other agents.', 'role': 'assistant'}]