Effects of diazepam and triazolam on auditory and visual thresholds and reaction times in the baboon

Adult male baboons were trained on a psychophysical procedure that measured detection thresholds and reaction times for pure tone and white light stimuli. Intramuscular injections of diazepam or triazolam were given 30 min before session onset; stimulus intensity was randomly varied from trial to trial, and four to five estimates of sensory thresholds and reaction times were obtained throughout each session. Diazepam produced dose-related elevations of both auditory and visual thresholds and reaction times. Effects of a single high dose of diazepam were apparent 4-5 days after administration. Triazolam was approximately 100 times more potent than diazepam in elevating reaction times and visual thresholds, but did not elevate auditory thresholds. There were no residual effects of triazolam on the day after dosing. These results suggest that diazepam and triazolam produce qualitatively similar effects on basic psychophysical function, but that they can be differentiated on the basis of sensory modality changes and post-drug recovery time.