ACUTE EFFECTS OF ZOLPIDEM AND FLUNITRAZEPAM ON SLEEP, MEMORY AND DRIVING PERFORMANCE, COMPARED TO THOSE OF PARTIAL SLEEP-DEPRIVATION AND PLACEBOE

The aims of the present study were to determine whether the imidazopyr idine zolpidem and the benzodiazepine flunitrazepam differentially aff ect the sleep architecture, and whether zolpidem had any residual effe cts on driving performance or memory functions the morning after night ly drug administration. These effects were compared with flunitrazepam , partial sleep deprivation and placebo. Seventeen women who complaine d of chronic sleep disturbances underwent four experimental sessions o n separate nights at weekly intervals - initially, during partial slee p deprivation, and after single doses of zolpidem 10 mg, flunitrazepam 2 mg and placebo administered in a double-blind, crossover design. Po lysomnographic recordings were made each night, and verbal learning an d driving tests were performed the following morning and subjective as sessments of sleep quality, daytime sleepiness and activation, effort to perform the tests and driving quality determined by questionnaire. Polysomnographic recording showed that zolpidem and flunitrazepam sign ificantly shortened sleep onset latency. Zolpidem respected the overal l sleep architecture, without disturbance of NREM 3/4 sleep and REM sl eep. Flunitrazepam significantly decreased REM sleep over the whole ni ght. Zolpidem and flunitrazepam both enhanced deep NREM 3/4 sleep duri ng the first two hours of sleep. Subjectively, flunitrazepam improved sleep quality and duration, but subjects reported feeling significantl y more drowsy and less active during the day than after placebo. Both hypnotics significantly reduced the recalled frequency of nocturnal aw akenings. Psychometric tests showed that flunitrazepam caused signific ant memory impairment the next morning, whereas zolpidem did not produ ce any disturbance of memory function. Driving performance was not dis turbed by any drug treatment or partial sleep deprivation. We conclude that zolpidem 10 mg is an effective hypnotic which causes no psychome tric dysfunction the next day. Sleep architecture remained unaffected by zolpidem and cyclicity was maintained without enhancement of durati on.