A phase 3 trial of doxepin HCl (SILENOR) in doses of 3 mg and 6 mg yielded positive results in the treatment of insomnia. Researchers measured sleep using the 8-hour Wake After Sleep Onset (WASO), which uses polysomnography in a sleep laboratory. Mean WASO improved by 26 minutes with the 3-mg dose and by 31 minutes with the 6-mg dose, compared with placebo. Total sleep time was 374 minutes for placebo, 415 minutes for the 3-mg dose, and 421 minutes for the 6-mg dose. At 4 weeks, results had lasted significantly longer for SILENOR, compared with placebo. Sleep efficiency also was statistically significantly higher for the SILENOR groups, compared with placebo. Another important sleep measure, Latency to Persistent Sleep, showed significantly improved outcomes45 minutes for placebo and 27 minutes for both SILENOR groups. SILENOR was well-tolerated, and side effects were comparable to those with placebo. Rebound insomnia, withdrawal effects, memory impairment, weight gain, and anticholinergic effects were not observed.
Ms. Farley is a freelance medical writer based in Wakefield, RI.