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Cholinesterase Inhibitors: Including Insecticides and Chemical Warfare Nerve Agents
How to Use This Course

Course: WB 1098
CE Original Date: October 16, 2007
CE Renewal Date: October 16, 2010
CE Expiration Date: October 16, 2012
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The goal of Case Studies in Environmental Medicine (CSEM) is to increase the primary care provider's knowledge of hazardous substances in the environment and to aid in the evaluation of potentially exposed patients. This CSEM focuses on cholinesterase inhibitors, including pesticides and chemical warfare nerve agents.

Available Versions

Two versions of the Cholinesterase Inhibitors, Including Insecticides and Chemical Warfare Nerve Agents CSEM are available.


To make the most effective use of this course, we recommend that you:

  • Take the Initial Check to assess your current knowledge about cholinesterase inhibitors.
  • Read the title, learning objectives, text, and key points in each section.
  • Complete the progress check exercises at the end of each section and check your answers.
  • Complete and submit your assessment and posttest responses online if you wish to obtain continuing education credit. Continuing education certificates can be printed immediately upon completion.

Instructional Format

This course is designed to help you learn efficiently. Topics are clearly labeled so that you can skip sections or quickly scan sections you are already familiar with. This labeling will also allow you to use this training material as a handy reference. To help you identify and absorb important content quickly, each section is structured as follows:

Section Element


Serves as a "focus question" that you should be able to answer after completing the section

Learning Objectives

Describes specific content addressed in each section and focuses your attention on important points


Provides the information you need to answer the focus question(s) and achieve the learning objectives

Key Points

Highlights important issues and helps you review

Progress Check exercises

Enables you to test yourself to determine whether you have mastered the learning objectives

Progress Check answers

Provides feedback to ensure you understand the content and can locate information in the text

Learning Objectives

Upon completion of the Cholinesterase Inhibitors, Including Insecticides and Chemical Warfare Nerve Agents CSEM, you should be able to

Topic Objectives

Community preparedness

  • Identify key community agencies that should be involved in planning, training, and exercises for hazardous materials emergencies and disasters, such as those due to exposure to cholinesterase inhibitors
  • Describe the consequences that result when many patients exposed to hazardous materials, such as cholinesterase inhibitors, transport themselves to the hospital.

What are cholinesterase inhibitors?

  • Describe how cholinesterase inhibitors, including organophosphorus compounds (e.g., pesticides, nerve agents) and carbamates block the ability of acetylcholinesterase to break down acetylcholine.

What types of pathology do cholinesterase inhibitors cause?

  • Identify the 4 major types of pathology caused by cholinesterase inhibitors

What is the cholinergic toxidrome?

  • Describe what causes the cholinergic toxidrome.
  • Identify generally where cholinergic receptors are found.
  • Identify the differences between nicotinic and muscarinic receptors.
  • Identify why excessive levels of acetylcholine (the cholinergic toxidrome) cause different signs and symptoms depending on whether cholinergic receptors involved are of the muscarinic or nicotinic type.

Clinical findings are due to a mixture of nicotinic and muscarinic effects

  • Describe factors that account for variation in the clinical presentation of cholinesterase toxicity.
  • Describe the CNS effects cholinesterase inhibitor toxicity.
  • Describe what is known about the nicotinic and muscarinic effects of cholinesterase toxicity on the central nervous system.
  • Identify 4 factors contributing to respiratory failure and death in cases of cholinesterase inhibitor toxicity.

Effects on routine laboratory tests

  • Describe what routine laboratory tests can be altered by acute cholinesterase inhibitor toxicity.

Differential diagnosis

  • Identify other medical conditions that can be mimicked by the cholinergic toxidrome.

Signs and symptoms: Differences in pediatric cases

  • Identify how the in clinical presentation in pediatric cases of the cholinergic toxidrome differs from that in adults.

Who is at risk for exposure? The exposure history

  • Identify potential sources of exposure to cholinesterase inhibitors.
  • Identify the important elements to include in an exposure history when evaluating patients who might be suffering from cholinesterase inhibitor toxicity.

RBC and serum cholinesterase levels

  • Describe the usefulness and limitations of laboratory analysis of RBC and serum cholinesterase levels.

Direct measurement of cholinesterase inhibitors and their metabolic byproducts

  • Describe the usefulness and limitations of laboratory analysis for the presence of cholinesterase inhibitors themselves and their breakdown products in biological specimens.

Management Strategy 1: Prevention of secondary exposure

  • Describe 5 key strategies for preventing secondary exposure from patients contaminated with cholinesterase inhibitors.

Management strategy 2: Supportive care

  • Identify the most important organ system requiring supportive care in patients suffering from the cholinergic toxidrome.

Management strategy 3: Medications - Atropine


  • The mechanism by which atropine counters the effects of the cholinergic toxidrome.
  • Findings against which to titrate atropine dosage.
  • The preferred routes of administration of atropine.
  • The type of cholinesterase inhibitor toxicity that may require extremely high doses of atropine.

Management strategy 3: Medications - 2-PAM


  • How 2-PAM works as an antidote.
  • How 2-PAM influences the body's response to atropine and vice-versa.
  • What “aging” is, as it relates to 2-PAM, and how the process can affect response to treatment.
  • Situations that delay the onset of toxicity and aging of cholinesterase inhibitors.
  • Reasons for treatment failure with 2-PAM.
  • The recommendations for use of 2-PAM in carbamate poisoning.

Management strategy 3: Medications - Diazepam


  • Why seizure prevention and control is important in the management of the cholinergic toxidrome.
  • The difference in the risk of seizures between adults and pediatric cases of the cholinergic toxidrome.

Syrup of ipecac, gastric lavage, cathartics, and activated charcoal

  • Describe the roles of the following treatment modalities in the management of poisoning due to cholinesterase inhibitors:
    • Syrup of ipecac.
    • Gastric lavage.
    • Cathartics.
    • Activated charcoal.

Public health and medico legal issues

  • Describe the importance of notifying public health authorities and other emergency response agencies in poisonings due to cholinesterase inhibitor.

The intermediate syndrome

Describe the

  • Clinical findings in the intermediate syndrome.
  • Significance of the intermediate syndrome in regards to morbidity and mortality due to cholinesterase inhibitor poisoning.
  • Treatment and prognosis for intermediate syndrome.

Organophosphate-induced delayed neuropathy (OPIDN)

Identify the

  • Clinical findings in OPIDN compared to the intermediate syndrome.
  • Available treatments for OPIDN.
  • Current knowledge about the cause of OPIDN.

Organophosphorus ester-induced chronic neurotoxicity (OPICN)


  • Our current level of understanding about the association of OPICN and asymptomatic exposures to cholinesterase inhibitors.
  • Current treatment options.

Other issues related to cholinesterase inhibitor toxicity

  • Describe our current knowledge about the association of cholinesterase inhibitor exposure with
    • Cancer risks.
    • Fetal effects.
    • Gulf War I illness.
    • Immune system effects.
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