Fatal hyperpyrexia after withdrawal of levodopa

We studied a patient affected with idiopathic Parkinson's disease and levodopa-induced dyskinesias. Fatal hyperpyrexia followed simultaneous levodopa withdrawal and a decrease in the dosage of diphenhydramine. The clinical features were those of the neuroleptic malignant syndrome. The rapid decrease in dopaminergic activity may have been important in causing the syndrome.