Neuroleptic malignant syndrome: a review of the literature.

The neuroleptic malignant syndrome (NMS) involves fever, extrapyramidal rigidity, and disturbances of autonomic function and consciousness. It occurs more often with high potency and depot forms, frequently 3 to 9 days after initiation and sometimes years later, and is not related to dose or previous exposure. About 40% of cases had evidence of an affective disorder. NMS apparently results from deficient compensatory mechanisms following blockade of dopaminergic regulation of muscle tone and autonomic function. Possible indicators of vulnerability and various treatments are discussed. Neuroleptic challenge resulted in recurrence of symptoms in about one third of cases. Symptoms sometimes subsided despite continued treatment. Early diagnosis and effective treatment have reduced the risk of such challenge.