Paracetamol overdose in adults

Last reviewed: 3 May 2023
Last updated: 16 May 2023



History and exam

Other diagnostic factors

  • nausea and vomiting
  • risk factors
  • right upper quadrant abdominal pain
  • jaundice
  • hepatomegaly
  • altered conscious level
  • asterixis
  • loin pain
Full details

Risk factors

  • history of self-harm
  • history of frequent or repeated use of medications for pain relief
  • glutathione deficiency
  • drugs that induce liver enzymes (cytochrome P450 inducers)
  • low bodyweight (<50 kg)
Full details

Diagnostic investigations

1st investigations to order

  • serum paracetamol concentration
  • liver function tests
  • prothrombin time and INR
  • blood glucose
  • urea, creatinine, and electrolytes
  • venous or arterial blood gas
  • full blood count
Full details

Investigations to consider

  • salicylate level
  • urinalysis
  • urine drug screen
Full details

Treatment algorithm


acute single overdose

staggered overdose

therapeutic excess


Expert advisers

Alexander Alexiou, MB, BS, BSc, DCH, FRCEM, DipIMC RCSEd

Consultant in Emergency Medicine

Royal London Hospital

Consultant in Physician Response Unit

Barts Health NHS Trust/London Air Ambulance




AA declares that he has no competing interests.


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

Johann Grundlingh MBChB, FCEM, FFICM, EDICM, DFMS, DipMedTox, MMedTox, MSB, ERT, MEWI, MBA

Emergency Medicine Consultant

Royal London Hospital

Barts Health NHS Trust

Honorary senior lecturer

Queen Mary University



Clarissa Ribeiro

Senior Clinical Fellow

Newham University Hospital

Barts Health NHS Trust



Daniel K. Colby MD

Assistant Professor

Department of Emergency Medicine

UC Davis Health


Alastair Newton MB ChB, FCEM

Consultant in Emergency Medicine

The Prince Charles Hospital




JG, CR, DKC and AN declare that they have no competing interests.

Peer reviewers

Ruben Thanacoody, MD, FRCP (Edin)

Consultant Physician and Clinical Toxicologist

Regional Drugs and Therapeutics Centre

Newcastle upon Tyne



RT was an investigator in the Scottish and Newcastle Antiemetic Pre-treatment for paracetamol poisoning (SNAP) study. RT declares that he has no other competing interests.


Annabel Sidwell

Section Editor, BMJ Best Practice


AS declares that she has no competing interests.

Tannaz Aliabadi-Oglesby

Lead Section Editor, BMJ Best Practice


TAO declares that she has no competing interests.

Rachel Wheeler

Lead Section Editor, BMJ Best Practice


RW declares that she has no competing interests.

Susan Mayor

Lead Section Editor, BMJ Best Practice


SM works as a freelance medical journalist and editor, video editorial director and presenter, and communications trainer. In this capacity, she has been paid, and continues to be paid, by a wide range of organisations for providing these skills on a professional basis. These include: NHS organisations, including the National Institute for Health and Care Excellence, NHS Choices, NHS Kidney Care, and others; publishers and medical education companies, including the BMJ Group, the Lancet group, Medscape, and others; professional organisations, including the British Thoracic Oncology Group, the European Society for Medical Oncology, the National Confidential Enquiry into Patient Outcome and Death, and others; charities and patients’ organisations, including the Roy Castle Lung Cancer Foundation and others; pharmaceutical companies, including Bayer, Boehringer Ingelheim, Novartis, and others; and communications agencies, including Publicis, Red Healthcare and others. She has no stock options or shares in any pharmaceutical or healthcare companies; however, she invests in a personal pension, which may invest in these types of companies. She is managing director of Susan Mayor Limited, the company name under which she provides medical writing and communications services.

Julie Costello

Comorbidities Editor, BMJ Best Practice


JC declares that she has no competing interests.

Adam Mitchell

Drug Editor, BMJ Best Practice


AM declares that he has no competing interests.

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