Almorexant HCl (ACT-078573)是口服有效的双重orexin receptor 拮抗剂，其作用于受体 OX1 和 OX2 的 Information Almorexant HCl (ACT-078573) is an orally active, dualorexin receptorantagonist withIC50of 6.6 nM and 3.4 nM for OX1 and OX2 receptor, respectively. Phase 3. Targets OX2 receptor ; OX1 receptor 3.4 nM; 6.6 nM In vitro Almorexant inhibits the increase in intracellular Ca 2+ induced by 10 nM human orexin-A in Chinese hamster ovary cells with IC50 of 16 nM (rat) and 13 nM (human) for the OX1 receptor and 15 nM (rat) and 8 nM (human) for the OX2 receptor. In vivo Almorexant (300 mg/kg p.o.) decreases alertness, and increases electrophysiological indices of both non-REM and REM sleep in male Wistar rats. In dogs, Almorexant (100 mg/kg p.o.) causes somnolence and increases surrogate markers of REM sleep. Almorexant induces a robust antidepressant-like effect and the restoration of stress-related HPA axis defect independently from a neurogenic action. In addition, Almorexant also reduces ethanol self-administration in high-drinking rodent models.