Pimozide attentuates d-amphetamine-induced sleep changes in man.

Pretreatment with pimozide (mean dose = 13 mg/day) blocked the effect of d-amphetamine (20 mg base, administered by intravenous bolus infusion at 0815) on all-night EEG sleep patterns in seven hospitalized psychiatric patients. Each patient was studied for five nights (2 nights baseline, 1 night on the day of the infusion, and 2 nights recovery) with and without pretreatment with pimozide. Without treatment with pimozide, d-amphetamine significantly reduced duration of total sleep, REM and nonREM sleep, Stage I, and Stage II. With coadministration of pimozide, d-amphetamine had no effect on sleep. These results suggest that the d-amphetamine induced changes in sleep are mediated by dopaminergic neurons.