Convulsions and Bizarre Behavior in Monkeys Receiving Chlorpromazine

Abstract

The fact that convulsions did not occur at the 25 mg/kg dose level indicates roughly that the greater the dose of chlorpromazine, the greater is the likelihood of seizures. Although the doses used in the experiments were quite high and exceeded the usual clinical dosages, they are comparable to the human dosage regimen (3400 mg of chlorpromazine in one day) reported by one clinic. Species difference prohibits quantitative extrapolation of these data to the clinic. However, the current widespread use of chlorpromazine warrants speculation as regards at least 2 clinical situations [long dash]in epilepsy, and in management of barbiturate and alcohol withdrawal. Use of chlorpromazine or any other compound with convulsant properties may be hazardous in these situations. Chronic administration of chlorpromazine in doses ranging between 44 and 77 mg/kg caused major convulsions in 4 nonepileptic monkeys and induced behavior suggestive of hallucinations in 3 of the same animals. Possible clinical significance of these findings was discussed.