<prompt> which of the following drug binds only with the aniotic site of cholinesterase?PhysostigmineNeostigmineEdrophoniumPyridostigmine  <response>: Ref:KD Tripathi pharmacology 7th edition page.no: 105 Edrophonium and Tacrine attach only to the anionic site and dont 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 