ABSTRACT
Background: Insomnia often responds to the orexin receptor antagonist suvorexant. This study aimed to evaluate the efficacy and adverse events of suvorexant for Chinese patients with primary insomnia over 6 months. Methods: A total of 120 patients with primary insomnia were assigned randomly to two groups that received placebo or suvorexant (40 mg) for 6 months. The primary outcomes were the total sleep time (sTST), time to sleep onset (sTSO), and sleep quality (sQUAL). The secondary outcomes were the Insomnia Severity Index (ISI) score and adverse events. Results: A total of 111 patients completed the study and all of them were included in the final analysis. Suvorexant showed greater efficacy than the placebo in enhancing sTST, sTSO, sQUAL and ISI score at months 1 and 6. Serious adverse events were documented in 2 patients (3.3%) in the suvorexant group and 1 patients (1.7%) in the placebo group. The most common adverse event was somnolence, which occurred in 7 patients (11.7%) in the suvorexant group and 2 patients (3.3%) in the placebo group. No death related to suvorexant treatment was recorded. Conclusions: Suvorexant was efficacious and well-tolerated in a group of Chinese patients with primary insomnia over 6 months.