Neuroleptic malignant syndrome

Last reviewed: 7 Jan 2023
Last updated: 08 Sep 2021



History and exam

Key diagnostic factors

  • presence of risk factors
  • hyperthermia
  • muscle rigidity
  • altered mental status
  • sympathetic nervous system lability
  • hypermetabolism
Full details

Risk factors

  • exposure to antipsychotic medications
  • structural brain abnormality
  • abrupt withdrawal of dopaminergic drugs
  • older age
  • pre-existing agitation
  • akathisia
  • male sex
  • iron deficiency
  • catatonia
  • pre-existing dehydration
  • exposure to other dopamine antagonists
Full details

Diagnostic investigations

1st investigations to order

  • serum creatine kinase (CK)
  • blood gas
  • blood glucose
  • urea, electrolytes, and creatinine
  • FBC
  • liver function tests
  • clotting screen
  • ECG
  • myoglobin levels and urinalysis
Full details

Investigations to consider

  • brain CT scan
  • urine culture
  • blood culture
  • chest x-ray
  • toxicology screen
  • lumbar puncture
  • serum iron
  • EEG
Full details

Treatment algorithm


acute episode


after resolution of NMS


Expert advisers

Jonathan Mitchell, MBChB, MRCPsych

Consultant Psychiatrist

Sheffield Health and Social Care NHS Foundation Trust




JM declares that he has no competing interests.

Melvyn Jenkins-Welch, BSc(Hons), MBBS, MSc, FRCA, FFICM

Consultant Critical Care Medicine

Cardiff and Vale ULHB




MJW declares that he has no competing interests.


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

Ronald J. Gurrera, MD

Associate Professor

Harvard Medical School



Disclosures: RJG is a member of the Neuroleptic Malignant Syndrome Professional Advisory Board, and has given expert testimony in medical malpractice tort claims in which NMS was alleged. He is an author of several references cited in this topic.

Peer reviewers

Nigel Langford, MD, MRCP, MRPharmS

Consultant Physician in Clinical Pharmacology and Therapeutics/Acute and General Internal Medicine

Leicester Royal Infirmary

Honorary Senior Lecturer

University of Leicester




NL has worked as a clinical pharmacologist expert witness at criminal, civil, family and coroners courts; given lectures, published articles, and written book chapters.


Annabel Sidwell

Section Editor and Comorbidities 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.

Adam Mitchell

Drug Editor, BMJ Best Practice


AM declares that he has no competing interests.

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