Dystonia and pseudoparkinsonism usually are easily treated with concomitant benztropine, diphenhydramine, lorazepam, or amantadine. In rare patients, an alternate antipsychotic may be necessary. NMS does not appear to be dose-related. 3- 30 days after the onset of the syndrome. Several predisposing factors may contribute to the development of NMS including heat stress, physical exhaustion, dehydration, and organic brain disease.
NMS occurs more frequently in young men.
The phenothiazine should be immediately discontinued and appropriate supportive therapy initiated as soon as symptoms of NMS are discovered. Hypothermia and hyperthermia have been reported with phenothiazines independent of the neuroleptic malignant syndrome and may be caused by the effect of the phenothiazine on the hypothalamic control of temperature regulation. Hyperpyrexia and heat stroke unrelated to NMS also have occurred. It can develop during long-term therapy or following discontinuation of phenothiazine therapy, and it is observed more frequently in elderly women. The incidence of TD may be higher in patients with bipolar disorder than with schizophrenia.