Quantitative pharmaco-EEG and performance after administration of brotizolam to healthy volunteers.

The activity of brotizolam (0.1, 0.3 and 0.5 mg) was studied in normal subjects using quantitative pharmaco-EEG, psychometric and clinical evaluation. Power spectral density analysis showed no changes after placebo, while brotizolam increased beta-activity, decreased alpha-activity and increased the average frequency (anxiolytic pharmaco-EEG profile). In addition, 0.3 and 0.5 mg brotizolam augmented delta-activity indicating hypnotic activity. The highest dose (0.5 mg) of brotizolam decreased attention, concentration, psychomotor performance and affectivity, and increased reaction time. The lower doses of brotizolam also caused a decrease in attention and concentration, but tended to improve psychomotor performance, shorten reaction time, and did not influence mood or affectivity. Brotizolam (0.1 mg) is the minimal effective psychoactive dose with a tranquillizing effect, while 0.5 mg and to some extent 0.3 mg induce a sedative effect and may be regarded as hypnotic doses.