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Anticholinergic Chemical-Warfare Compounds


James M. Madsen

, MD, MPH, University of Florida

Reviewed/Revised Jan 2023

Anticholinergic drugs have been used as chemical-warfare (CW) agents. They are classified as incapacitating agents (ie, designed not to cause serious injury or death but rather to cause sufficient disorientation to prevent military personnel from carrying out their missions). One anticholinergic chemical-warfare agent is 3-quinuclidinyl benzilate, North Atlantic Treaty Organization (NATO) code BZ.

BZ is a solid that can be disseminated by heat-generating artillery rounds without being inactivated. It can persist in the environment for 3 to 4 weeks. Mass casualties due to BZ exposure would likely result from inhalation of aerosolized BZ, although the compound can also be dissolved in a solvent and placed on an environmental surface from which it can be absorbed through the skin following contact.

Pathophysiology of Anticholinergic Chemical-Warfare Injuries

BZ binds to muscarinic cholinergic receptors in the central nervous system (CNS), smooth muscle, and exocrine glands and blocks acetylcholine (ACh) at these sites. The decrease in cholinergic stimulation produces the anticholinergic toxidrome (see table Common Toxic Syndromes Common Toxic Syndromes Common Toxic Syndromes ).

Symptoms and Signs of Anticholinergic Chemical-Warfare Injuries

Patients have dry mouth and skin, dilated pupils (causing blurring of vision), usually tachycardia, and may develop hyperthermia. Cholinergic blockade in the CNS causes first lethargy and then characteristic anticholinergic illusions and hallucinations; hallucinations may be visual or auditory and are typically concrete and easily describable (eg, voices of known contacts, imaginary television programs, sharing of imaginary cigarettes, odd shapes) in contrast to the abstract, geometric, and ineffable nature of psychedelic hallucinations. Anticholinergic visual hallucinations may also be lilliputian (ie, items hallucinated decrease in size over time—eg, a cow transforms into a dog and then into a mouse or a butterfly). Speech may be slurred, and patients exhibit stereotypical picking or plucking motions (woolgathering) and may confabulate. Stupor and coma may last hours to days, with gradual recovery.

Diagnosis of Anticholinergic Chemical-Warfare Injuries

  • Clinical evaluation

  • Sometimes diagnostic challenge with physostigmine

Diagnosis is made by recognizing the typical anticholinergic toxidrome. No common laboratory tests detect BZ exposure. Although many drugs and plants have anticholinergic effects (see table Common Toxic Syndromes Common Toxic Syndromes Common Toxic Syndromes ), the simultaneous appearance of an anticholinergic toxidrome in many individuals who did not all ingest an anticholinergic drug or plant suggests an intentional or CW exposure. Physostigmine, a cholinergic drug, can be used as a diagnostic challenge; reduction of anticholinergic manifestations after physostigmine is given strongly suggests an anticholinergic compound.


Most patients exposed to BZ can be triaged as delayed.

Treatment of Anticholinergic Chemical-Warfare Injuries

  • Supportive care, including cooling as needed

  • Rarely physostigmine

Patients are usually quiet but may become disruptive and may need to be reassured and in some cases restrained. Patients with elevated body temperature require cooling (see Heatstroke: Cooling techniques Cooling techniques Heatstroke is hyperthermia accompanied by a systemic inflammatory response causing multiple organ dysfunction that may result in death. Symptoms include temperature > 40° C and altered mental... read more ). Most patients do not require drug treatment, but those who are disruptive or who are markedly distressed as a result of hallucinations may benefit from being given physostigmine slowly; dose is 0.5 to 20 mg IV in adults and 0.02 mg/kg IV in children (see table ). Exceeding recommended doses may cause cholinergic effects, including seizures.

The views expressed in this chapter are those of the author and do not reflect the official policy of the Department of Army, Department of Defense, or the US Government.

Drugs Mentioned In This Article

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NOTE: This is the Professional Version. CONSUMERS: View Consumer Version
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