Activity of the hypnotics, flunitrazepam and triazolam, in man.

1 Effects of flunitrazepam and triazolam (0.25 and 0.5 mg) on sleep and on performance were studied in six healthy adult males. Sleep was assessed by electroencephalography and analogue scales, and performance by a visuo-motor coordination task. 2 Over the same dose range triazolam had a more pronounced effect than flunitrazepam. Total sleep time was increased by 0.25 and 0.5 mg triazolam, and by 0.5 mg flunitrazepam. Both drugs decreased awake activity and drowsy sleep, though the effect of flunitrazepam was limited to the 0.5 mg dose and restricted to the first 6 h after sleep onset. There were no changes in slow wave sleep. 3 Latency to the first period of rapid eye movement (REM) sleep was increased with 0.5 mg triazolam, and when doses were combined (0.25-0.5 mg) the latencies with both drugs were increased. Both doses of triazolam reduced the duration and percentage of REM sleep during the early part of the night, though the whole night duration of REM sleep was not changed. 4 After the morning ingestion of 0.25 mg flunitrazepam performance was impaired for 2.0 h, but there were no residual effects when 0.25 or 0.5 mg were taken at night. With the morning ingestion of 0.25 mg triazolam performance was impaired from 0.5 to at least 5.0 h after ingestion. There were no residual effects with 0.25 mg overnight, but with 0.5 mg triazolam there was an effect on performance 10 h after ingestion with recovery within 1.5 h (11.5 h of ingestion). 5 Triazolam (0.25 mg) and 0.5 mg flunitrazepam provide useful hypnotic activity when impaired performance the next day is to be avoided. The activity of 0.5 mg triazolam is accompanied by only limited residual sequelae compared with some other benzodiazepines of comparable efficacy, and so may prove to be useful when a more powerful effect is required.