Hypercalcemia in the neuroleptic malignant syndrome.

The neuroleptic malignant syndrome (NMS) developed in a 32-year-old man following fluphenazine enanthate administration. Hypercalcemia was initially present, perhaps reflecting release of calcium from skeletal muscle stores. The elevated serum calcium levels support the existence of a peripheral muscle abnormality in the pathogenesis of the NMS and provides another point of similarity between NMS and malignant hyperthermia.