This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Autonomic nervous system, Subject name: Pharmacology
[{'content': 'which of the following drug binds only with the aniotic site of cholinesterase? \nSelect and explain. \nA. Physostigmine, B. Neostigmine, C. Edrophonium, D. Pyridostigmine', 'role': 'user'}, {'content': "Answer: C \nExplanation: Ref:KD Tripathi pharmacology 7th edition (page.no: 105) Edrophonium and Tacrine attach only to the anionic site and don't form a covalent bond with the enzyme. so, edrophonium is a very sho-acting drug. While organophosphates attach only to the esteratic site forming a covalent bond. Carbamates (physostigmine, pyridostigmine, neostigmine) carbamylate the esteratic site of the enzyme", 'role': 'assistant'}]