Definition:

Neuroleptic malignant syndrome (NMS) is a rare but potentially life-threatening side effect to antipsychotic drugs characterized by fever, altered mental status, muscle rigidity, and autonomic dysfunction. NMS is classically associated with the use of high-potency antipsychotics (AP), such as butyrophenones and phenothiazines, but has also been described with newer agents, commonly described as atypical AP (risperidone, olanzapine, quetiapine), other D2-receptor antagonists (metoclopramide), and following withdrawal of anti dopaminergic agents. Although the precise pathophysiologic mechanism underlying NMS remains unknown, a reduction in dopaminergic activity in the brain probably by dopamine D2 receptor blockade in the striatum and hypothalamus is generally assumed as a potential cause. Laboratory findings include elevation of serum creatine phosphokinase (CK), liver enzymes, and leukocitosis. Treatment includes immediately stopping the offending agent and implementing supportive measures, as well as pharmacological interventions in more severe cases.