High Quality Content by WIKIPEDIA articles! Flesinoxan (DU-29,373) is a potent and selective 5-HT1A receptor partial/near-full agonist of the phenylpiperazine class. Originally developed as an antihypertensive agent, it was later found to possess antidepressant and anxiolytic effects in animals. As a result, it was investigated in human clinical trials for the treatment of major depressive disorder and generalized anxiety disorder and was found to have robust efficacy with very high tolerability, but for unclear reasons development was halted and it was never marketed. In patients it enhances REM sleep latency, decreases body temperature, and increases ACTH, cortisol, prolactin, and growth hormone secretion.