A 25-week trial of 1,018 patients in the US measured total sleep time, number of awakenings and other subjective sleep measures in a placebo group and a group given single-dose extended release zolpidem.
The 669 patients in the zolpidem group self-administered 12.5mg of the drug in slow-release form for a minimum of three nights a week to a maximum of seven nights a week.
By the end of the trial 92.3% of zolpidem patients said the drug helped them sleep, compared with just under 60% of the placebo group. Zolpidem is currently available in the UK in a quick release, 5mg form.
Sleep (2008) 31: 79-90