Efficacy and tolerability of indiplon in older adults with primary insomnia

ObjectiveTo evaluate the efficacy and safety of indiplon in elderly patients with primary insomnia.Patients and methodsElderly patients, 65–80 years (N = 358; 55% female; mean age, 71 years) who met the criteria for primary insomnia according to the Diagnostic and Statistical Manual of Mental Disorders, fourth edition (DSM-IV) for three months were randomized to two weeks of double-blind nightly treatment with 5 mg or 10 mg indiplon or placebo. Daily self-assessments by the patients included latency to sleep onset (LSO), total sleep time (TST), number of awakenings (NAW), wake time after sleep onset (WASO), and sleep quality. Data were collected between July, 2002, and October, 2003, at 52 clinical research sites in North America.ResultsTreatment with indiplon was associated with significant reduction in LSO at Week 1 for the 5 mg (34.6 ± 1.8 min) and 10 mg doses (30.4 ± 1.6 min) relative to placebo (47.4 ± 2.5 min; p < 0.0001 for both comparisons). During Week 2, LSO remained shorter on both indiplon doses compared to placebo (5 mg, p = 0.016; and 10 mg, p = 0.0028). During both study weeks, treatment with indiplon was also associated with significant improvement, relative to placebo, in TST, NAW, WASO, and sleep quality. The frequency of adverse events was similar in the indiplon 5 mg and placebo groups; somnolence, nausea, depression and decreased appetite were slightly more common in the indiplon 10 mg group.ConclusionIn elderly patients with primary insomnia, indiplon 5 mg and 10 mg were efficacious in inducing and maintaining sleep and improving sleep quality during the two weeks of treatment. Indiplon 5 mg was well-tolerated, with no serious adverse events and no significant changes in electrocardiogram (ECG) or routine clinical laboratory evaluations; the 10 mg dose produced slightly greater efficacy as well as somewhat increased adverse events.