For treatment of insomnia. It is an orexin receptor antagonist. The orexin neuropeptide signaling system is a central promoter of wakefulness. Orexin producing neuronal cell bodies are localized specifically in the hypothalamus and project to the wakefulness mediating neurons of the brain. Suvorexant is thought to suppress wake drive by blocking the binding of the wake-promoting neuropeptides orexin A and orexin B to OX1R and OX2R reversibly.