Benzodiazepine Effects on Arousal Threshold during Sleep.
Interim rept. 1980-1983,
NAVAL HEALTH RESEARCH CENTER SAN DIEGO CA
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In a series of studies, the effects of benzodiazepines on arousal threshold during sleep have been investigated. Two studies, one using flurazepam, 30 mg, over 10 nights and one using triazolam, .5 mg, over 6 nights were conducted in the authors laboratory. A third study at the University of Florida measured the effects of flurazepam, 30 mg, and pentobarbital, 100 mg, each administered on two nights. All drug threshold levels were compared to placebo values. All three studies found that the sedative hypnotics increased arousal threshold to an intermittent pure tone. The placebo groups highest mean arousal threshold was 70-75dB, compared to 100-110dB threshold values for the hypnoptic group. The increase in arousal threshold occurred during the first hours of sleep, reaching a peak around 120-150 minutes post-ingestion. Return to sleep was also more rapid in medicated subjects, and the reduction in sleep latency followed the same time course as did the change in arousal threshold. Arousal threshold and sleep latency did not differ between drug and placebo groups after 3 hours post-administration. The short acting benzodiazepine, triazolam, and flurazepam with its long acting metabolite did not differ in the magnitude of the elevation of arousal threshold, time course of effects across the night, or type of change over nights of consecutive use.