3-Quinuclidinyl Benzilate Poisoning

Author: Christopher P Holstege, MD; Chief Editor: Robert G Darling, MD, FACEP more...

Updated: Mar 16, 2010

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Background
Pathophysiology
Epidemiology
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Background

The chemical warfare agent 3-quinuclidinyl benzilate (QNB, BZ) is an anticholinergic agent that affects both the peripheral and central nervous systems (CNS). It is one of the most potent anticholinergic psychomimetics known, with only small doses necessary to produce incapacitation. It is classified as a hallucinogenic chemical warfare agent. QNB usually is disseminated as an aerosol, and the primary route of absorption is through the respiratory system. Absorption also can occur through the skin or gastrointestinal tract. It is odorless. QNB's pharmacologic activity is similar to other anticholinergic drugs (eg, atropine) but with a much longer duration of action.

Also, see eMedicine's article Chemical Warfare Agents.

Pathophysiology

QNB acts by competitively inhibiting muscarinic receptors. Muscarinic receptors primarily are associated with the parasympathetic nervous system, which innervates numerous organ systems, including the eye, heart, respiratory system, skin, gastrointestinal tract, and bladder. Sweat glands, innervated by the sympathetic nervous system, also are modulated by muscarinic receptors. Effects of QNB by any route of exposure are slow in onset and long in duration. The onset of action is approximately 1 hour, with peak effects occurring 8 hours postexposure. Symptoms gradually subside over 2-4 days. Most of the QNB that enters the body is excreted by the kidneys, making urine the choice for detection.

Frequency

United States

Use of QNB against the United States has never been reported. Currently, the US government is funding numerous programs to prepare the nation for potential chemical terrorist attacks against citizens and the military.

International

Use of QNB has been suggested in a number of international conflicts. In January 1992, soldiers in Mozambique experienced an explosion above their troop formation. Subsequent symptoms resembled those expected from QNB. In July 1995, approximately 15,000 people attempted to walk from the enclave of Srebrenica to the free territory in Bosnia.^[1]Many experienced hallucinations during their march that were suspected to be secondary to QNB.

Mortality/Morbidity

The LD50 (lethal dose to 50% of an exposed population) for BZ is estimated to be similar to that of atropine, which is approximately 100 mg. Other factors, such as the exposed patient's preexisting health status and the time from exposure to medical care, are also important.

Proceed to Clinical Presentation

Contributor Information and Disclosures

Author

Christopher P Holstege, MD Associate Professor of Emergency Medicine and Pediatrics, University of Virginia; Director, Division of Medical Toxicology, Center of Clinical Toxicology; Medical Director, Blue Ridge Poison Ctr, Associate Medical Toxicology Fellowship Director, VA Dept of Health

Christopher P Holstege, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Medical Toxicology, European Association of Poisons Centres and Clinical Toxicologists, Medical Society of Virginia, Society for Academic Emergency Medicine, Society of Toxicology, and Wilderness Medical Society

Disclosure: Nothing to disclose.

Coauthor(s)

Jennifer S Boyle, MD, PharmD Fellow in Toxicology, University of Virginia Health System

Disclosure: Nothing to disclose.

Specialty Editor Board

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, and Michigan State Medical Society

Disclosure: Nothing to disclose.

Francisco Talavera, PharmD, PhD Senior Pharmacy Editor, eMedicine

Disclosure: eMedicine Salary Employment

Rick Kulkarni, MD

Rick Kulkarni, MD is a member of the following medical societies: Alpha Omega Alpha, American Academy of Emergency Medicine, American College of Emergency Physicians, American Medical Association, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: WebMD Salary Employment

John D Halamka, MD, MS Associate Professor of Medicine, Harvard Medical School, Beth Israel Deaconess Medical Center; Chief Information Officer, CareGroup Healthcare System and Harvard Medical School; Attending Physician, Division of Emergency Medicine, Beth Israel Deaconess Medical Center

John D Halamka, MD, MS is a member of the following medical societies: American College of Emergency Physicians, American Medical Informatics Association, Phi Beta Kappa, and Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Robert G Darling, MD, FACEP Adjunct Clinical Assistant Professor of Military and Emergency Medicine, Uniformed Services University of the Health Sciences, F Edward Hebert School of Medicine; Associate Director, Center for Disaster and Humanitarian Assistance Medicine

Robert G Darling, MD, FACEP is a member of the following medical societies: American College of Emergency Physicians, American Medical Association, American Telemedicine Association, and Association of Military Surgeons of the US

Disclosure: Nothing to disclose.

References

Hay A. Surviving the impossible: the long march from Srebrenica. An investigation of the possible use of chemical warfare agents. Med Confl Surviv. Apr-Jun 1998;14(2):120-55. [Medline].
US Army Center for Health Promotion and Preventive Medicine. Psychodelic Agent 3 - Quinuclidinyl Benzilate (BZ). The Deputy for Technical Services' Publication: Detailed Chemical Facts Sheets. 1998;[Full Text].
Byrd GD, Paule RC, Sander LC, et al. Determination of 3-quinuclidinyl benzilate (QNB) and its major metabolites in urine by isotope dilution gas chromatography/mass spectrometry. J Anal Toxicol. May-Jun 1992;16(3):182-7. [Medline].
Gibson RE, Rzeszotarski WJ, Jagoda EM, et al. [125I] 3-quinuclidinyl 4-iodobenzilate: a high affinity, high specific activity radioligand for the M1 and M2-acetylcholine receptors. Life Sci. Jun 4 1984;34(23):2287-96. [Medline].
Glendenning KK. Distribution of muscimol, QNB, and 5HT binding in the vertebrate diencephalon: a comparative study of eight mammals and three non-mammals. Microsc Res Tech. Oct 15 2003;62(3):247-61. [Medline].
Hiramatsu Y, Eckelman WC, Baum BJ. Interaction of iodinated quinuclidinyl benzilate enantiomers with M3 muscarinic receptors. Life Sci. 1994;54(23):1777-83. [Medline].
Holstege CP, Bechtel LK, Reilly TH, Wispelwey BP, Dobmeier SG. Unusual but potential agents of terrorists. Emerg Med Clin North Am. May 2007;25(2):549-66; abstract xi. [Medline].
Hull LA, Rosenblatt DH, Epstein J. 3-Quinuclidinyl benzilate hydrolysis in dilute aqueous solution. J Pharm Sci. Jul 1979;68(7):856-9. [Medline].
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Ketchum JS, Sidell FR. Incapacitating agents. In: Textbook of Military Medicine. 1997:287-305.
McDonough JH Jr, Shih TM. A study of the N-methyl-D-aspartate antagonistic properties of anticholinergic drugs. Pharmacol Biochem Behav. Jun-Jul 1995;51(2-3):249-53. [Medline].
Sorger D, Kampfer I, Schliebs R. Iodo-QNB cortical binding and brain perfusion: effects of a cholinergic basal forebrain lesion in the rat. Nucl Med Biol. Jan 1999;26(1):9-16. [Medline].

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