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.