¹HPRU Medical Research Centre, University of Surrey, Sanofi-Synthelabo Research, Guildford, United Kingdom

Abstract

Aims/Background: To assess the residual psychomotor and cognitive effects and safety of the new zolpidem modified-release (MR) formulation 8h after a single nocturnal dose in healthy elderly subjects.

Methods: A randomized, double-blind, placebo- and reference controlled, 4-way crossover study in 24 volunteers (65 to 78 years old, 10 male) comparing zolpidem MR 6.25 mg and 12.5 mg or flurazepam 30 mg to placebo. Tests included Critical Flicker Fusion (CFF), Choice Reaction Time (CRT), Compensatory Tracking Time (CTT), Immediate and Delayed Word Recall (WR_i, WR_d), and Digit Symbol Substitution Test (DSST). Subjective sleep quality was evaluated using the Leeds Sleep Questionaire (LSEQ). Blood hematology and biochemistry, vital signs monitoring and adverse event recording evaluated safety.

Results: Neither zolpidem MR doses demonstrated a significant difference in performance vs. placebo for CFF, CRT, total reaction time, CTT, WR_i, WR_d, and DSST, 8h postdose. Flurazepam significantly impaired performance with respect to placebo on all tests. The LSEQ assessment showed no negative effects on awakening.

Conclusion: The results demonstrate that a single dose of zolpidem MR 6.25 mg or 12.5 mg has no residual effects on CNS integrative capacity, sensorimotor or psychomotor performance, immediate and delayed memory recall compared with placebo in healthy elderly subject. Zolpidem MR was well tolerated at both doses with no serious adverse safety events observed.