Comparison studies of chlorazepate administered as a divided daily dose and as a single dose at night.

The residual effects of dipotassium chlorazepate administered as either a single daily dose of 20 mg at bedtime or a divided daily dose (5 + 5 + 10 mg) were studied in a placebo-controlled, double-blind trial comprising 12 out-patients. The following tests were used to determine changes in perceptual wakefulness, performance ability, fine motor skills, and coordination: critical flicker fusion test, car driving in a simulator, and the "bead and needle tests." In addition, the patients underwent a clinical assessment and also filled out a self-rating scale for judging factors related to the tests. No significant differences were found between the dosage schedules or between the active medication and the placebo. The clinical results were not dependent on the dosage schedule.