The Skeletal Effects of Gonadotropin-Releasing Hormone Antagonists: A Concise Review

Prolonged treatment with Gonadotropin-Releasing Hormone (GnRH) agonists is known to induce bone loss among prostate cancer patients. However, evidence on the skeletal effects of GnRH antagonists is relatively less well-known. This review aims to examine the effects of GnRH antagonists on bone health. GnRH antagonists are an effective treatment for hormone-dependent conditions, such as advanced prostate cancer and endometriosis. They induce a competitive and reversible GnRH-receptor blockage, thereby suppressing the release of gonadotropins and sex hormones. The sex hormone ablation results in undesirable side effects, including accelerated bone loss. In animal studies, treatment with GnRH antagonists is reported to cause deterioration of bone microstructure. Human clinical trials revealed significant bone loss at the spine, hip and femur in patients treated with GnRH antagonists. Thus, osteoporosis and the resultant fragility fractures pose a significant impact on health and quality of life of GnRH antagonist users. Thus, early preventive measures of bone loss are critical in preventing fractures and its associated morbidity in these patients.