Medscape is available in 5 Language Editions – Choose your Edition here.


Agent 15 Poisoning Medication

  • Author: Geoffrey M Fitzgerald, MD; Chief Editor: Duane C Caneva, MD, MSc  more...
Updated: Apr 10, 2015

Medication Summary

In the past, physostigmine was used to reverse the effects of anticholinergic intoxicants. However, numerous adverse effects from its use are reported. For this reason, its role as an antidote is controversial, and benzodiazepines generally are considered to be the safest medications for treating patients with anticholinergic-mediated agitation or delirium. Physostigmine use is reserved for patients with intractable seizures, tachycardia, or agitation. Physostigmine does not shorten the clinical course of anticholinergic toxicity. Neostigmine and pyridostigmine lack the central antimuscarinic activity needed to make them effective antidotes.


Cholinesterase inhibitors

Class Summary

Physostigmine is a carbamate that increases the concentration of acetylcholine in synapses and neuromuscular junctions through acetylcholinesterase inhibition.

Physostigmine (Antilirium)


Increased concentration of acetylcholine can improve patient's delirium dramatically; for reasons that are not entirely clear, appears to have less effect if administered within 4 h postexposure.



Class Summary

By binding to specific receptor-sites these agents appear to potentiate effects of GABA and facilitate inhibitory GABA neurotransmission and other inhibitory transmitters.

Diazepam (Valium, Diazemuls, Diastat)


Depresses all levels of CNS (eg, limbic and reticular formation), possibly by increasing activity of GABA.

Contributor Information and Disclosures

Geoffrey M Fitzgerald, MD Consulting Staff, Concord Emergency Medical Associates

Disclosure: Nothing to disclose.


David P Sole, DO Associate, Department of Emergency Medicine, Faculty, Emergency Medicine Residency Program, Geisinger Medical Center; Clinical Assistant Professor (Adjunct) of Emergency Medicine, Temple University School of Medicine

David P Sole, DO is a member of the following medical societies: American College of Emergency Physicians

Disclosure: Nothing to disclose.

Specialty Editor Board

Francisco Talavera, PharmD, PhD Adjunct Assistant Professor, University of Nebraska Medical Center College of Pharmacy; Editor-in-Chief, Medscape Drug Reference

Disclosure: Received salary from Medscape for employment. for: Medscape.

Chief Editor

Duane C Caneva, MD, MSc Senior Medical Advisor to Customs and Border Protection, Department of Homeland Security (DHS) Office of Health Affairs; Federal Co-Chair, Health, Medical, Responder Safety Subgroup, Interagency Board (IAB)

Disclosure: Nothing to disclose.

Additional Contributors

Suzanne White, MD Medical Director, Regional Poison Control Center at Children's Hospital, Program Director of Medical Toxicology, Associate Professor, Departments of Emergency Medicine and Pediatrics, Wayne State University School of Medicine

Suzanne White, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Clinical Toxicology, American College of Epidemiology, American College of Medical Toxicology, American Medical Association, Michigan State Medical Society

Disclosure: Nothing to disclose.

  1. Goldfrank L, Flomenbaum N, Lewin N, et al. Anticholinergic poisoning. J Toxicol Clin Toxicol. 1982 Mar. 19(1):17-25. [Medline].

  2. Bowen TE. Emergency War Surgery. Revisionist Press; 1988. 93-94.

  3. Burns MJ, Linden CH, Graudins A, et al. A comparison of physostigmine and benzodiazepines for the treatment of anticholinergic poisoning. Ann Emerg Med. 2000 Apr. 35(4):374-81. [Medline].

  4. Goldfrank LR, Flomenbaum NE. Goldfrank's Toxicologic Emergencies. Appleton & Lange; 1998.

  5. Ketchum JS, Sidell FR. Incapacitating agents. Textbook of Military Medicine, Warfare, Weaponry and the Casualty: Medical Aspects of Chemical and Biological Warfare. United States Government Printing Office; 1997. 287-306.

  6. Schneir AB, Offerman SR, Ly BT, Davis JM, Baldwin RT, Williams SR, et al. Complications of diagnostic physostigmine administration to emergency department patients. Ann Emerg Med. 2003 Jul. 42(1):14-9. [Medline].

  7. Shannon M. Toxicology reviews: physostigmine. Pediatr Emerg Care. 1998 Jun. 14(3):224-6. [Medline].

  8. Tintinalli JE. Anticholinergic toxicity. Emergency Medicine: A Comprehensive Study Guide. McGraw Hill; 2000. 1182-1185.

All material on this website is protected by copyright, Copyright © 1994-2016 by WebMD LLC. This website also contains material copyrighted by 3rd parties.