Elagolix (formerly NBI56418; ABT620; NBI-56418; ABT-620; trade name: Orilissa) is a potent, specific, orally bioavailable, non-peptide antagonist of the gonadotropin-releasing hormone receptor (GnRHR) used for pain management. It inhibits GnRHR with a Kd of 54 pM. Elagolix was given FDA approval on July 23, 2018, to treat endometriosis-related moderate to severe pain. A short-acting GnRH antagonist, elagolix suppresses ovarian estrogen production in a dose-dependent manner, resulting in partial suppression at lower doses and complete suppression at higher doses. Because Elagolix is non-peptide and readily absorbed through the mouth, it is considered the leader of a new class of GnRH inhibitors known as second-generation inhibitors.