Abstract

Neuroleptic malignant syndrome is thought to be a result of dopamine D2 receptor blockade in the striatum of the basal ganglia. Risperidone, a benzisoxazole derivative antipsychotic, has high serotonin 5-HT2 receptor blockade and dose-related D2 receptor blockade. The high ratio is believed to impart the low frequency of extrapyramidal symptoms with risperidone at low dosages. With this low frequency of extrapyramidal symptoms, it was thought the frequency of neuroleptic malignant syndrome might also be lowered. A 73-year-old woman developed neuroleptic malignant syndrome after monotherapy with risperidone. The syndrome reversed after discontinuing risperidone and starting treatment with dantrolene and bromocriptine. It appears that the protection from extrapyramidal side effects observed with risperidone does not ensure protection from neuroleptic malignant syndrome.