Sleep laboratory and clinical studies of the effects of triazolam, flunitrazepam and flurazepam in insomniac patients.

Polysomnographic recordings allow the recognition of three normal sleep stages: wakefulness, NREM and REM sleep. There are quantitative changes in these stages from childhood to old age. Most characteristic are progressive decreases in total sleep time, stage 4 NREM sleep and REM sleep. Insomnia can be defined as an alteration of both the quantity and quality of sleep. It can be associated with psychophysiological factors, psychiatric disorders, use of drugs and alcohol, sleep apnea, sleep-related myoclonus and restless legs, medical, toxic and environmental conditions, or REM sleep interruptions. At present, the benzodiazepines are the most frequently prescribed hypnotics. Their efficacy has been evaluated in the sleep laboratory and by means of sleep questionnaires (clinical studies). Their derivatives are grouped according to their pharmacokinetic profiles as short acting (triazolam), intermediate acting (flunitrazepam) and long acting (flurazepam). At the EEG level these compounds induce an increase in fast frequencies and in the number of sleep spindles. Slow wave activity is markedly decreased. All of the derivatives effectively and significantly induce and maintain sleep. Total sleep time increase is related to an imcrement of stage 2 sleep while REM sleep and stages 3 + 4 sleep are consistently reduced. Triazolam withdrawal is followed by a rebound insomnia. In contrast, under the same circumstances, flurazepam has a carry-over effect.