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Anticholinergic Toxicity Workup

  • Author: Mityanand Ramnarine, MD, FACEP; Chief Editor: Asim Tarabar, MD  more...
Updated: Jul 28, 2016

Laboratory Studies


No specific diagnostic studies exist for anticholinergic overdoses. Serum drug concentrations are not helpful and results rarely are available to aid in initial management. However, screening for acetaminophen and salicylate is indicated in all intentional poisonings because combination medication preparations and multiple ingestions often occur. In addition, studies that may be helpful include the following:

  • Blood and urine cultures in febrile patients
  • Serum chemistry and electrolyte analysis, which may provide clues to the intoxicating agents and co-ingestants
  • Creatine kinase (CK) level in patients with psychomotor agitation, to rule out associated rhabdomyolysis
  • Electrolyte and arterial blood gas (ABG) analysis when bicarbonate therapy has been instituted for agents that also produce type 1A cardiac conduction disturbances; blood pH should be 7.45-7.55
  • Urine pregnancy test on all females of childbearing age.

Imaging Studies

Consider a computed tomography (CT) or magnetic resonance imaging (MRI) scan of the brain in patients with altered mental status that is insufficiently explained by the ingested agent or in patients that are unresponsive to appropriate intervention.


Other Tests


Immediately perform an electrocardiogram (ECG) on all patients with suspected toxic ingestions.




Consider lumbar puncture (LP) in all patients with fever and altered mental status.

Contributor Information and Disclosures

Mityanand Ramnarine, MD, FACEP Assistant Professor of Emergency Medicine, Program Director, Emergency/Internal Medicine/Critical Care, Hofstra Northwell School of Medicine at Hofstra University; Attending Physician, Department of Emergency Medicine, Long Island Jewish Medical Center

Mityanand Ramnarine, MD, FACEP is a member of the following medical societies: Alpha Omega Alpha, American College of Emergency Physicians, American College of Physicians, American Medical Association

Disclosure: Nothing to disclose.


Danish A Ahmad, MD Resident Physician, Departments of Emergency Medicine and Internal Medicine, Long Island Jewish Medical Center

Disclosure: Nothing to disclose.

Specialty Editor Board

John T VanDeVoort, PharmD Regional Director of Pharmacy, Sacred Heart and St Joseph's Hospitals

John T VanDeVoort, PharmD is a member of the following medical societies: American Society of Health-System Pharmacists

Disclosure: Nothing to disclose.

Michael J Burns, MD Instructor, Department of Emergency Medicine, Harvard University Medical School, Beth Israel Deaconess Medical Center

Michael J Burns, MD is a member of the following medical societies: American Academy of Clinical Toxicology, American College of Emergency Physicians, American College of Medical Toxicology, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

Chief Editor

Asim Tarabar, MD Assistant Professor, Director, Medical Toxicology, Department of Emergency Medicine, Yale University School of Medicine; Consulting Staff, Department of Emergency Medicine, Yale-New Haven Hospital

Disclosure: Nothing to disclose.

Additional Contributors

David C Lee, MD Research Director, Department of Emergency Medicine, Associate Professor, North Shore University Hospital and New York University Medical School

David C Lee, MD is a member of the following medical societies: American Academy of Emergency Medicine, American College of Emergency Physicians, American College of Medical Toxicology, Society for Academic Emergency Medicine

Disclosure: Nothing to disclose.

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