Degarelix (Firmagon®)

Last Modified: August 21, 2011

Pronounced: DEG-a-REL-ix
Classification: Antiandrogen

About Degarelix

Degarelix is a man-made form of a protein that blocks the production of gonadotropin-releasing hormone (GnRH) by the pituitary gland. GnRH stimulates the testes to produce testosterone. By blocking GnRH, Degarelix reduces the body's level of testosterone. Testosterone affects the growth of the prostate gland and any cancer cells that may be present.

How to Take Degarelix

Degarelix is given as a subcutaneous injection (under the skin) every 4 weeks. Two injections are given for the first dose. Subsequent doses are one injection. The injection is designed to slowly release the medication over the next 4 weeks.

Possible Side Effects of Degarelix

There are a number of things you can do to manage the side effects of Degarelix. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Hot Flashes

Most men find that hot flashes decrease after a period of time on the medication. There are a few things you can do to help with hot flashes. Several medications have been studied, including some low doses of antidepressants (such as venlafaxine and Paxil), and certain hormone therapies (medroxyprogesterone acetate and cyproterone acetate). Non-medical recommendations include: keeping well-hydrated with eight glasses of water daily, wearing cotton or lightweight, breathable fabrics, dressing in layers, exercising on a regular basis (generally walking exercise is best), practicing relaxation exercises, and avoiding triggers such as warm rooms, spicy foods, caffeinated beverages, nicotine and alcohol.

Weakening of the bones (osteoporosis)

Men who take hormone therapy for extended periods of time are at risk for bone thinning (osteoporosis). You may be advised to take calcium and vitamin D supplements to help prevent bone loss. You may have a bone density scan (DEXA scan) to assess your bone health. If your physician determines that you are at high risk of developing osteoporosis, they may recommend additional treatment with a type of medication called a bisphosphonate to help strengthen the bones. Learn more about bone health after cancer therapy.


While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink's section on fatigue for helpful tips on dealing with this side effect.

Sexual and Reproductive Changes

This drug can affect your reproductive system, resulting in sperm production becoming irregular or stopping permanently. In addition, you may experience erectile dysfunction or a decreased desire for sex during treatment. Talk to your urologist about options for treating erectile dysfunction.

Exposure of an unborn child to this medication could cause birth defects, so you should not father a child while on this medication. Effective birth control is necessary during treatment, even if you believe your sperm is affected. You may want to consider sperm banking if you may wish to have a child in the future. Discuss these options with your oncology team. See OncoLink's section on sexuality for helpful tips for dealing with these side effects.

Breast Tenderness or Increase in Breast Tissue

An increase in breast tissue (gynecomastia) or breast tenderness may develop. Your healthcare team can suggest medications to relieve the tenderness. In rare cases, radiation can be given to relieve severe tenderness.

Other Side Effects

Some men experience weight gain, for which exercise and dietary changes may be helpful. Injection site reactions (redness, swelling and pain) have also been reported. In clinical trials, some patients had increases in blood tests that evaluate liver function. These abnormalities resolved when the medication was stopped.


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