Neuroleptic malignant syndrome complicating antipsychotic treatment of delirium or agitation in medical and surgical patients: case reports and a review of the literature

Psychosomatics. 2009 Jan-Feb;50(1):8-15. doi: 10.1176/appi.psy.50.1.8.


Background: Neuroleptic malignant syndrome (NMS) is a potentially fatal adverse event associated with the use of antipsychotics.

Objective: The authors provide information on the development and outcome of NMS during antipsychotic treatment of delirium or agitation in medically ill patients.

Method: The authors present case reports and a literature review of NMS arising during antipsychotic treatment of delirium.

Results: A total of 25 cases of NMS occurring in patients with delirium or agitation were identified. Most cases involved men with agitated delirium who received relatively high doses of parenteral haloperidol. The signs and symptoms of NMS episodes were similar to those reported in other settings, and most patients had a complete recovery.

Conclusion: Clinicians utilizing antipsychotics in managing delirium or agitation are advised to be vigilant for NMS. Further study is required to determine whether certain patient characteristics or medications present greater risk for this serious adverse event.

Publication types

  • Review

MeSH terms

  • Antipsychotic Agents / adverse effects*
  • Delirium / drug therapy*
  • Humans
  • Neuroleptic Malignant Syndrome / etiology*
  • Psychomotor Agitation / drug therapy*


  • Antipsychotic Agents