Comparison of the effects of zaleplon, zolpidem, and triazolam on memory, learning, and psychomotor performance

Twenty-four healthy male and female subjects, who participated in this rand omized, double-blind, crossover study, received single nighttime doses of z aleplon 10 mg (therapeutic dose), zaleplon 20 mg, zolpidem 10 mg (therapeut ic dose), zolpidem 20 mg, triazolam 0.25 mg (positive control), and placebo . Subjective behavioral ratings and psychomotor tests were completed before and 1.25 and 8.25 hours after administration of the study drug. The Immedi ate and Delayed Word Recall tests and the Digit Span Test were used to asse ss memory. The Digit-Symbol Substitution Test, Paired Associates Learning T est, and Divided Attention Test were used to assess other cognitive skills. Zaleplon 10 mg did not produce any significant changes in memory or learni ng compared with placebo. All other active treatments, including zolpidem 1 0 mg, caused psychomotor impairment at the 1.25-hour test battery. Zolpidem 20 mg (twice the therapeutic dose) produced more psychomotor impairment at the 1.25-hour assessment than did any of the other active treatments, incl uding zaleplon 20 mg. At the 8.25-hour time point, test scores for subjects who received zaleplon 10 mg and 20 mg did not differ from the test scores for those who received placebo. However, cognitive impairment persisted up to the 8.25-hour observation for subjects who were administered triazolam 0 .25 mg and zolpidem 20 mg. Adverse events associated with the use of zalepl on were transient and mild-to-moderate in severity. Overall, this study sho ws that zaleplon is a safe hypnotic that does not affect memory, learning, or psychomotor skills associated with vigilance.