Four cases of neuroleptic malignant syndrome.

The neuroleptic malignant syndrome (NMS) is a relatively uncommon, sometimes fatal, idiosyncratic drug reaction usually associated with the administration of neuroleptic drugs. The syndrome is characterized by generalized rigidity, fever, altered consciousness or mutism, tremor, autonomic dysfunction, tachypnea, elevated serum creatinine phosphokinase, leukocytosis and myoglobinuria. We report four cases of NMS; one following levodopa/bromocriptine withdrawal, two related to neuroleptic administration and one following heroin use. There are no previous reports linking heroin to NMS. The syndrome is thought to result from acute dopaminergic blockage or dopamine depletion. Levodopa, bromocriptine or both are recommended as specific treatment for this condition.