Chlorpromazine-induced neuroleptic malignant syndrome and its response to diazepam.

We have observed two cases of chlorpromazine-induced neuroleptic malignant syndrome (NMS); both were transiently responsive to intravenous diazepam challenge, but not to blind placebo or amyobarbitol. The interrelationship, via feedback between central dopaminergic and gamma-aminobutyric (GABA) systems is reviewed. A theoretical role for a relative DA-GABA imbalance during NMS and treatment implications are discussed.