Comparison of psychomotor performance after intravenous and rectal diazepam

Twenty-four healthy subjects participated in a triple crossover study in which some of the widely used psychomotor tests were applied as indicators of psychomotor ability. Diazepam was administered in doses of 10 mg intravenously, 10 mg rectally, and 35 mg rectally. Plasma levels of diazepam and performance decrement in the Trieger dot test (DOT), the perceptual speed test (PST), the digit symbol substitution test (DSST), and continuous reaction time were measured up to 12 hr after administration. The psychomotor effects were quite similar after administration of 10 mg diazepam intravenously and rectally. When the 35-mg rectal administration was compared to the 10-mg administrations, performance was still affected at 12 hr.