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Last reviewed: 14 Mar 2025
Last updated: 22 Apr 2024

Summary

Definition

History and exam

Key diagnostic factors

  • presence of risk factors
  • impaired mental status
  • drowsiness, slurred speech, ataxia
  • coma
  • respiratory depression

Other diagnostic factors

  • decreased deep tendon reflexes
  • nystagmus
  • paradoxical stimulation
  • hypothermia
  • rhabdomyolysis

Risk factors

  • depression
  • history of illicit drug or alcohol use
  • history of benzodiazepine use
  • drug administration error
  • comorbidity
  • history of polydrug or unknown substance ingestion
  • suicidal ideation or behaviour
  • older age
  • Severe liver disease
  • drug interaction
  • biogenetic susceptibility

Diagnostic investigations

1st investigations to order

  • pulse oximetry
  • arterial/venous blood gas
  • FBC
  • urea and electrolytes
  • liver function tests
  • ECG
  • creatine kinase
  • plasma paracetamol concentration

Treatment algorithm

Contributors

Expert advisers

Marianne Gillings, BPharm(Hons), MBBS, MRCP(UK), PGDip(MedTox), FRCEM

Consultant in Emergency Medicine

Training Programme Director for the ACCS Emergency Medicine and Acute Medicine programmes

Severn Deanery

Bristol

UK

Disclosures

MG is a member of the RCEM Toxicology Steering Group (unremunerated).

Acknowledgements

BMJ Best Practice would like to gratefully acknowledge the previous expert contributors, whose works have been retained in parts of the content:

Paul M. Gahlinger MD, PhD, MPH

General Practitioner

Paradise Medical Group

Paradise

CA

Euan A. Sandilands MBChB, BSc(Hons), MD, FRCP Edin

Consultant Clinical Toxicologist

Director

National Poisons Information Service (Edinburgh)

Royal Infirmary of Edinburgh

Edinburgh

UK

Peer reviewers

Ruben Thanacoody, MD, FRCP (Edin)

Consultant Physician/Honorary Senior Lecturer

Regional Drugs and Therapeutics Centre

Newcastle-upon-Tyne

UK

Disclosures

RT declares that he has no competing interests.

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