Lemborexant, sold under the brand name Dayvigo, is an orexin antagonist medication which is used in the treatment of insomnia.

[3][8] It is indicated specifically for the treatment of insomnia characterized by difficulties with sleep onset and/or maintenance in adults.

[3][8] Side effects of lemborexant include somnolence, fatigue, headache, and abnormal dreams.

[3] A major systematic review and network meta-analysis of medications for the treatment of insomnia published in 2022 found that lemborexant had an effect size (standardized mean difference (SMD)) against placebo for treatment of insomnia at 4 weeks of 0.36 (95% CITooltip confidence interval 0.08 to 0.63) and at 3 months of 0.41 (95% CI 0.04 to 0.78).

[14] Lemborexant had similar effect sizes at 4 weeks as the other evaluated and marketed orexin receptor antagonists suvorexant (SMD 0.31, 95% CI 0.01 to 0.62) and daridorexant (SMD 0.23, 95% CI –0.01 to 0.48), whereas benzodiazepines and Z-drugs generally showed larger effect sizes (e.g., SMDs of 0.45 to 0.83) than lemborexant and the other orexin receptor antagonists.

[14] However, the review concluded that lemborexant and eszopiclone among all of the insomnia medications assessed had the best profiles overall in terms of efficacy, tolerability, and acceptability.

[3] A high-fat and high-calorie meal has been found to delay the time to peak levels by 2 hours.

[21][7] In June 2016, Eisai initiated Phase III clinical trials in the United States, France, Germany, Italy, Japan, Poland, Spain and the UK.