Circadian pattern of acute, neuroleptic-induced dystonic reactions

OBJECTIVE: This study examined the timing of acute dystonic reactions in 200 patients taking neuroleptic medication for the first time. METHOD: Two hundred patients received a twice-daily regimen of low-dose neuroleptic. RESULTS: Over 80% of the episodes of acute dystonia occurred between 12:00 noon and 11:00 p.m. The observed circadian variation was not accounted for by sleep, fatigue, or time elapsed from the last dose of medication. CONCLUSIONS: The finding of a diurnal pattern in one of the recognized side effects of neuroleptic medication suggests that the therapeutic efficacy of neuroleptics might similarly vary over the course of the day.