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Serotonin syndrome

Last reviewed: 10 Oct 2024
Last updated: 07 Oct 2022

Summary

Definition

History and exam

Key diagnostic factors

  • exposure to a serotonergic drug
  • clonus
  • hyperreflexia
Full details

Other diagnostic factors

  • anxiety
  • agitation
  • confusion
  • tremor, shivering, muscle jerking
  • sweating
  • headache
  • tachycardia
  • hypertonia/rigidity
  • diaphoresis
  • flushing
  • dilated pupils
  • hyperthermia
  • myoclonus
  • startling
Full details

Risk factors

  • exposure to a serotonergic drug
  • exposure to two or more serotonergic drugs
Full details

Diagnostic tests

1st tests to order

  • clinical diagnosis
Full details

Tests to consider

  • CBC
  • creatine phosphokinase
  • ECG
  • blood cultures
  • lumbar puncture
  • CT or MRI head
Full details

Treatment algorithm

ACUTE

severe serotonin toxicity

moderate serotonin toxicity

mild serotonin toxicity

Contributors

Authors

Geoffrey Isbister, BSc, MBBS, FACEM, MD

Clinical Toxicologist

Calvary Mater Newcastle

Associate Professor

University of Newcastle

Newcastle

Australia

Disclosures

GI is an author of several references cited in this monograph.

Peer reviewers

Laura Tormoehlen, MD, FAAN, FACMT

Neurologist and Medical Toxicologist

Associate Professor of Clinical Neurology and Emergency Medicine

Indiana University

Bloomington

IN

Disclosures

LT has been compensated as an expert witness for cases involving serotonergic drugs.

Daniel E Brooks, MD

Medical Director, Banner Poison and Drug Information Center

Phoenix

AZ

Disclosures

DEB declares that he has no competing interests.

Karl Marlowe, MbChB, MSc, PgC-Ed, PgD-CBT, MRCPsych

Consultant Psychiatrist

East London NHS Foundation Trust

London

UK

Disclosures

KM declares that he has no competing interests.

Theodore A. Stern, MD

Chief

Psychiatric Consultation Service

Massachusetts General Hospital

Professor of Psychiatry

Harvard Medical School

Boston

MA

Disclosures

TAS declares that he has no competing interests.

Paul M. Gahlinger, MD

Adjunct Professor

Department of Family and Preventive Medicine

University of Utah

Salt Lake City

UT

Disclosures

PMG declares that he has no competing interests.

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