14th February 2025

Overview of neuroleptic malignant syndrome (NMS)

Rather than a psychiatric presentation, NMS is an uncommon iatrogenic condition resulting from the medications used to treat psychiatric conditions. It is a medical emergency and requires rapid intervention.

The single most important diagnostic factor is the presence of relevant psychotropic drug treatment:

• Presence of dopamine modulator therapy, especially if started or increased in the last 10 days: 
  • Antipsychotics, especially first generation, e.g. haloperidol
  • Antidepressants, especially tricyclic antidepressants, e.g. amitriptyline, imipramine
  • Metoclopramide, lithium, amantadine, tolcapone
• Cessation of dopamine agonists, usually Parkinson’s treatments, e.g. levodopa, bromocriptine, ropinirole

Risk factors include male sex and pre-existing brain pathology, e.g. Parkinson’s, dementia, delirium, traumatic injury.