Serotonin syndrome

Last reviewed: 23 Apr 2022
Last updated: 31 Dec 2019

Summary

Definition

History and exam

Key diagnostic factors

  • exposure to a serotonergic drug
  • clonus
  • hyperreflexia
More key diagnostic factors

Other diagnostic factors

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

Risk factors

  • exposure to a serotonergic drug
  • genetic predisposition
More risk factors

Diagnostic investigations

1st investigations to order

  • clinical diagnosis
More 1st investigations to order

Investigations to consider

  • CBC
  • creatine phosphokinase
  • urine toxicology screen
  • ECG
More investigations to consider

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

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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