They are used in the treatment of prostate cancer, endometriosis, uterine fibroids, female infertility in assisted reproduction, and for other indications.

[1] In patients with advanced disease, this surge in testosterone can lead to a flare-up of the tumour, which can precipitate a range of clinical symptoms such as bone pain, urethral obstruction, and spinal cord compression.

As testosterone surge does not occur with GnRH antagonists, there is no need for patients to receive an antiandrogen as flare protection during prostate cancer treatment.

The reduction in testosterone levels that occurs during GnRH antagonist therapy subsequently reduces the size of the prostate cancer.

Degarelix is a GnRH antagonist that is approved for use in patients with advanced hormone-sensitive prostate cancer throughout Europe and also in the United States.

[2] GnRH antagonists are also used for short periods in the prevention of premature LH surge and endogenous ovulation in patients undergoing ovarian hyperstimulation with FSH in preparation for in-vitro fertilization (IVF).

[12][13][14][15] Currently approved GnRH antagonists include the peptide molecules abarelix, cetrorelix, degarelix, and ganirelix and the small-molecule compounds elagolix and relugolix.