Single dose study on buspirone versus diazepam in volunteers. Monitoring psychomotor performance via oculomotor, choice reaction and electromyographic parameters.

The effects of single oral doses of the anxiolytics buspirone (Bespar, 5 mg) and diazepam (5 mg) on psychomotor and cognitive parameters were compared to placebo in 6 healthy male volunteers in a randomised double-blind 3-way crossover design with a 7-day wash-out period in between. Psychomotor and cognitive measurements were taken using the Oculodynamic Test (ODT) for oculomotor, performance and additional cardiorespiratory parameters. Surface electromyogram (EMG, relative activity) and dynamometric measures (force) were registered by an EMG-Force-Chair (EFC), with the measurement of maximal force and EMG-force-slopes. Visual analogue scales with regard to sedation, excitation and anxiety were performed. Intradiurnal assessments were done at -1, +1, +3, +5 h post-dose. The results indicate that 5 mg buspirone behaves more or less like placebo with respect to its objective psychomotor and cognitive side-effect pattern and is significantly less detrimental than diazepam, which displays a clear pattern of psychomotor and cognitive impairment, an alteration of the EMG-force slope, which demonstrates an inefficient-increase in the recruitment of muscle fibers under isometric dynamic conditions for maintaining an experimentally pre-fixed force, and display an increase of subjective sedation and a decrease of subjective excitation in the visual analogue scales. ODT effects of diazepam were maximal at 1 h, EMG-force effects at 3 h.