A randomized placebo-controlled polysomnographic study of eszopiclone in Japanese patients with primary insomnia

Abstract

Objectives: To evaluate the efficacy and dose-response effect of eszopiclone on sleep latency and sleep maintenance in Japanese patients with primary insomnia.

Methods: In this randomized, double-blind, five-way crossover study, 72 patients received placebo, eszopiclone 1mg, 2mg, and 3mg, and zolpidem 10mg in random order for two consecutive nights with a washout period between treatments. Objective sleep measures from polysomnography (PSG) and subjective patient reports were collected.

Results: All active treatments produced significant improvement in objective and subjective sleep latency compared with placebo (P<0.05 for all comparisons); linear dose-response relationships were observed for eszopiclone. PSG-determined wake time after sleep onset (WASO), sleep efficiency, and number of awakenings (NA), and patient-reported measures of WASO, NA, sleep quality, sleep depth, and daytime functioning significantly improved following treatment with eszopiclone 2mg and 3mg and zolpidem 10mg versus placebo (P<0.05). Eszopiclone at all doses increased total sleep time and stage 2 sleep time (P<0.001 for both comparisons), but did not alter REM or slow-wave sleep. Eszopiclone was generally well tolerated; the most frequently reported adverse event was mild dysgeusia.

Conclusions: In Japanese patients with primary insomnia, eszopiclone 2mg and 3mg significantly improved PSG-determined and patient-reported sleep latency and sleep maintenance relative to placebo.

Trial registration: ClinicalTrials.gov NCT00770510.