Abarelix acetate is a synthetic third generation gonadotropin-releasing hormone receptor (GnRHR) antagonist. It increases histamine release from rat peritoneal mast cells in vitro and from a human skin model ex vivo. In vivo, abarelix decreases plasma luteinizing hormone (LH) levels six hours post-treatment in castrated rats, with levels returning to baseline within 24 hours.3 Abarelix (2 mg/kg) also transiently decreases plasma testosterone levels in intact rats, with levels returning to baseline within seven days post-treatment. Formulations containing abarelix have previously been used in the treatment of advanced prostate cancer.
