Sedative effects and plasma concentrations following single doses of triazolam, diphenhydramine, ethanol and placebo

Twelve, healthy, young men received 0.25 mg triazolam and ethanol placebo, 50 mg diphenhydramine and ethanol placebo, 0.6 g/kg ethanol and placebo pill and ethanol placebo and placebo pill in a double-blind Latin Square design. Each of the four treatments were administered for 2 days at 0900 hours with blood samples drawn on day one at 0830, 1030, 1230, 1430 and 1630 hours, and sleep latency and performance assessed on day two at 1000, 1200, 1400 and 1600 hours. Significant sedative effects of ethanol, triazolam and diphenhydramine relative to placebo were observed on the sleep latency and performance measures with the effects being detected over the full 6.5 hours of assessment. Among the active drugs, triazolam and diphenhydramine had similar sedative effects which differed from that of ethanol. Plasma concentration of each drug declined significantly over the 6.5 hours. Ethanol reached zero, but triazolam and diphenhydramine did not. Continued sedation (sedative effects after plasma concentration reached zero) was observed with ethanol.