Uses of GnRH agonists.

Gonadotropin-releasing hormone agonists are a relatively new class of drugs, which, when chronically administered, result in marked reductions in blood levels of testosterone and estrogen. These drugs include leuprolide acetate (Lupron); the first GnRH agonist to be approved in the United States, nafarelin acetate (Synarel); and goserelin acetate (Zoladex). Approved indications for these drugs, depending on the specific agent, include advanced prostate cancer, endometriosis, and precocious puberty. These and other investigational GnRH agonists are also being evaluated in many other diseases, including uterine fibroids, polycystic ovarian disease, breast cancer, fibrocystic breast disease, benign prostatic hypertrophy, and irritable bowel syndrome. Because of their therapeutic potential in many endocrinologic disorders, the GnRH agonists represent one of the most important advances in hormonal therapy in the past few decades. Thus, it appears likely that in the 1990s a greater number of patients will be receiving these agents. This article summarizes the application of GnRH agonist drugs in clinical practice, their side effects, and important information for patient use.