Eptapirone is a potent, selective and efficacious 5-HT1A receptor agonist. In rats, it is readily bioavailable after oral administration. Likely, because of its high efficacy at 5-HT1A receptors, Eptapirone exerted powerful antidepressant- and anxiolytic-like activity in animal models. Eptapirone given in the evening suppresses REM (rapid eye movement) sleep more than buspirone and implies a greater central effect on serotonin receptors, which is consistent with the preclinical data that indicate it has greater efficacy than buspirone. It has little effect on other sleep stages. Eptapirone has been in phase I clinical trials for the treatment of anxiety and major depressive disorder. However, this research has been discontinued.