<p>Suvorexant is a highly selective antagonist for orexin receptors OX1R and OX2R. The mechanism by which Suvorexant exerts its therapeutic efect in insomnia is presumed to be through antagonism of orexin receptors. The orexin neuropeptide signaling system is a central promoter of wakefulness. Blocking the binding of wake-promoting neuropeptides orexin A and orexin B to receptors OX1R and OX2R is thought to suppress wake drive.</p>