Core53: Drug-induced adverse reaction: neuroleptic malignant syndrome

🌡️ High-yield / 要点：Neuroleptic malignant syndrome is classically triggered by dopamine blockade or dopamine agonist withdrawal. Key causes: antipsychotics, metoclopramide, stopping dopamine agonists.

Definition / 定義

• Neuroleptic malignant syndrome / NMS = rare, severe drug-induced reaction related to impaired dopaminergic signaling.
• It is most associated with dopamine receptor blockade.

Inducing drugs / 原因薬

Trigger	Examples / notes
Typical antipsychotics	First-generation antipsychotics
Atypical antipsychotics	Second-generation antipsychotics can also cause NMS
Anti-dopaminergic antiemetics	Metoclopramide
Dopamine agonist withdrawal	Stopping dopaminergic therapy can precipitate NMS-like syndrome

Clinical idea / 臨床的ポイント

• Suspect NMS in a patient with severe systemic symptoms after antipsychotic exposure or dopamine agonist withdrawal.
• High-yield contrast:
  • Serotonin syndrome = serotonergic excess.
  • NMS = dopamine blockade/withdrawal.
• NMS typically evolves more slowly than serotonin syndrome.

Treatment / 治療

• Stop the causative drug.
• Supportive care and cooling.
• Dantrolene for hyperthermia/rigidity.
• Benzodiazepines for muscle rigidity/agitation.
• Dopamine agonists may be used.

Remember / 覚え方

• NMS = Neuroleptic = dopamine blockade
• Metoclopramide can trigger NMS
• Treatment: stop trigger + cooling/support + dantrolene ± dopamine agonist