A comparison of the residual effects of zaleplon and zolpidem following administration 5 to 2 h before awakening

Aims To compare the duration of the residual hypnotic and sedative effects of zaleplon with those of zolpidem and placebo following nocturnal administ ration at various times before morning awakening. Methods Zaleplon 10 mg, zolpidem 10 mg, or placebo was administered double- blind to 36 healthy subjects under standardized conditions in a six-period, incomplete-block, crossover study. Subjects were gently awakened and given medication at predetermined times 5, 4, 3, or 2 h before morning awakening , which occurred 8 h after bedtime. When the subjects awoke in the morning, a battery of subjective and objective assessments of residual effects of h ypnotics was administered. Results No residual effects were demonstrated after zaleplon 10 mg, when ad ministered as little as 2 h before waking, on either subjective or objectiv e assessments, whereas zolpidem 10 mg showed significant residual effects o n DSST and memory (immediate and delayed free recall) after administration up to 5 h before waking and choice reaction time, critical flicker fusion t hreshold and Sternberg memory scanning after administration up to 4 h befor e waking. Residual effects of zolpidem were apparent in all objective and s ubjective measurements when the drug was administered later in the night. Conclusions The present results demonstrate that zaleplon at the dose of 10 mg is free of residual hypnotic or sedative effects when administered noct urnally as little as 2 h before waking in normal subjects. In contrast, res idual effects of zolpidem are still apparent on objective assessments up to 5 h after nocturnal administration, longer than has been reported from stu dies involving daytime administration.