Controlled clinical investigation of trimeprazine as a sleep-inducer in normal subjects

Summary The effects of acute introduction and withdrawal of trimeprazine (Vallergan), an antihistaminic phenothiazine derivative with known sedative effects, were investigated by a single blind polygraphic study in 8 healthy volunteers. A baseline placebo was given on Nights 1–3, followed either by 10 mg or 20 mg of the drug on Nights 4–6, and then withdrawal effects were recorded on Nights 7–9. The subjective effects of the drug and EEG sleep variables were determined on these nights. The results showed that the drug might have had dose related effects. REM-sleep was increased by 10 mg doses, which also caused an increase in SW sleep. There was no significant change after the 20 mg dose. Significant REM rebound was not observed after withdrawal of either dose. These characteristics may be of value in the treatment of certain aspects of sleep disturbances.Partly supported by grant from Pharma Rhodia Laboratories, Denmark