Zolpidem extended-release

Zolpidem extended-release, or controlled-release (CR), is a new formulation of zolpidem, a nonbenzodiazepine hypnotic. It is indicated in the US for the treatment of insomnia, characterised by difficulties with sleep onset and/or sleep maintenance. Zolpidem CR is a dual-layered tablet; one layer releases zolpidem immediately and a second layer provides a slower release of additional zolpidem for maintenance of plasma zolpidem concentrations. Efficacy of zolpidem CR was assessed in two 3-week, randomised, double-blind, placebo-controlled, phase III polysomnography trials in younger adult (aged 18-64 years) or elderly (aged > or =65 years) patients with primary insomnia. Patients received nightly zolpidem CR (12.5mg in younger adult and 6.25mg in elderly patients). Efficacy was assessed objectively on nights 1, 2, 15 and 16. Patients who received zolpidem CR had significantly improved objective latency to persistent sleep, wake time after sleep onset and sleep efficiency on assessment nights compared with placebo recipients. In subjective assessments of sleep quality on day 2 and nights 15 and 22, significantly more zolpidem CR than placebo recipients gave favourable responses on a Patient Global Impression scale in the study in younger adult patients. In the other study, significantly more elderly patients in the zolpidem CR group rated their sleep as improved compared with the placebo group. Zolpidem CR was generally well tolerated and appears to have a tolerability profile similar to that of the original formulation of zolpidem.