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MD Pharmacology NMC syllabus ~5 min read Recent advances last updated on 2026-06-20

Anticholinesterases and Organophosphate Poisoning

Cholinesterase inhibitors, their therapeutic uses, and the toxicology and management of organophosphate / carbamate poisoning

Past RGUHS + DNB + MPMSU + MUHS · 17 RGUHSMay '25 MPMSUMay '25 DNBOct '23 MPMSUMay '19 RGUHSNov '18 RGUHSMay '18 RGUHSNov '17 MUHSSummer '16 MPMSU2014 MPMSU2014 MUHSWinter '14 MUHSWinter '14 RGUHSOct '10 RGUHSMay '10 MPMSU2010 RGUHSMay '09 MPMSU2009

Introduction

  • Definition — Anticholinesterases (anti-ChEs) inhibit cholinesterase, protect acetylcholine (ACh) from hydrolysis, and so amplify cholinergic transmission throughout the CNS and PNS.
  • Two enzymes — They inhibit both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE, pseudocholinesterase) — hence "anti-ChE", not simply "AChE inhibitor".
  • Therapeutic span — Used in myasthenia gravis, glaucoma, post-operative ileus/bladder atony, reversal of competitive neuromuscular block, Alzheimer's disease, and as the antidote to antimuscarinic poisoning.
  • Toxicological importance — The class includes the single most important toxicology problem — organophosphate (OP) and carbamate insecticide poisoning plus chemical-warfare nerve agents (sarin, soman, VX).
  • Prototype — Physostigmine (Calabar-bean alkaloid, the original miotic/antidote) and neostigmine (synthetic, myasthenia gravis) are the prototypes.
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Anticholinesterases Op Poisoning

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