Degarelix (Firmagon)

Degarelix is a type of hormone therapy called a gonadatrophin releasing hormone blocker. It is a treatment for advanced hormone dependent prostate cancer. Hormone dependent means that that the cancer cells need a hormone in order to grow. Degarelix is pronounced deh-ga-rel-ix. It is also called Firmagon.

Prostate cancer depends on testosterone to grow. Drugs that stop the testes making testosterone can slow or stop the growth of prostate cancer cells. Degarelix works by blocking gonadatrophin releasing hormone receptors in the pituitary gland in the brain. The pituitary gland then stops producing luteinising hormone. Luteinising hormone triggers the testes to make testosterone.

You have degarelix as an injection just below the skin (subcutaneously) into the fatty tissue of your tummy (abdomen). The first time you have degarelix you have two injections. Then you have one injection once a month. You continue with the treatment for as long as it is working.

The side effects associated with degarelix are listed below. You can use the links to find out more about each side effect. For general information, see our cancer drug side effects section.

More than 10 in every 100 men have one or more of these.

• Hot flushes and sweats occur in 1 in 4 men (25%)
• Soreness and swelling around the injection site for a day or 2 after the injection
• Weight increase happens in 1 in 10 men (10%)
• Problems getting an erection (impotence) may happen because you don’t produce testosterone
• Less interest in having sex (low libido)

Between 1 and 10 in every 100 people have one or more of these.

• Fatigue during and after treatment – most people find their energy levels are back to normal within 6 months to a year
• Breast tenderness and swelling – this can be distressing so your doctor may suggest a small dose of radiotherapy before treatment to try to prevent it
• Tiredness and breathlessness due to a drop in the number of red blood cells (anaemia)
• Difficulty sleeping
• Dizziness and headaches
• Diarrhoea – drink plenty of fluid and tell your doctor or nurse if diarrhoea becomes severe, or continues for more than 3 days
• Feeling or being sick is usually well controlled with anti sickness drugs
• Pain in your back, joints and bones
• Raised blood pressure
• Urine infections
• Constipation – your doctor or nurse may give you laxatives to help prevent this but do tell them if you are constipated for more than 3 days
• Liver changes that are very mild and unlikely to cause symptoms – the liver will almost certainly go back to normal when treatment finishes, but you will have regular blood tests to check how well your liver is working
• Flu like symptoms such as chills and fever for a few hours after the injection

Fewer than 1 in 100 people have these.

• Swelling of the ankles and legs due to a build up of fluid (oedema) which is usually mild
• Changes in your heart rhythm and blood pressure – your nurse or doctor will check your blood pressure and you will have ECGs regularly
• Shortness of breath
• Skin changes, such as a rash, redness, and itching
• Bone thinning may occur with long term treatment
• You may find that the levels of sugar in your blood change – you will have regular blood tests. If you have diabetes you will need to take extra care when checking your blood sugar
• Sadness that may develop into depression

You won’t get all these side effects. Any that you have may be mild. A side effect may get worse through your course of treatment. Or you may have more side effects as the course goes on. This depends on

• How many times you've had a drug before
• Your general health
• How much of the drug you have (the dose)
• Other drugs you are having

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them.

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and other over the counter remedies – some drugs can react together.

Degarelix is a relatively new drug in cancer treatment. This means that the information about side effects is based on only a few trials. And there is no information available at the moment about possible longer term effects that it may cause. Tell your doctor if you notice anything that is not normal for you.