Degarelix (Firmagon)

How does degarelix work?

Degarelix is a treatment for hormone dependent prostate cancer. Prostate cancer depends on ​testosterone​ to grow. Hormone therapy blocks or lowers the amount of testosterone in the body.

Degarelix works by blocking messages from a part of the brain called the hypothalamus that tells the ​pituitary gland​ to produce luteinising hormone. Luteinising hormone tells the ​testicles​ to produce testosterone. So degarelix stops the testicles making testosterone.

This type of hormone therapy is called a gonadotrophin-releasing hormone antagonist or GnRH blocker.

How do you have degarelix?

You have degarelix as an injection just under the skin (subcutaneously) into the fatty tissue of your tummy (abdomen). 

How often do you have degarelix?

When you start treatment, you have 2 injections on the same day. Then you have one injection a month. 

How long you continue having degarelix for will depend on your situation. Your healthcare team will let you know more about this.

Tests

You might have blood tests before starting treatment and regularly during your treatment. The tests check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

What are the side effects of degarelix?

Side effects can vary from person to person. They also depend on what other treatment you are having. 

When to contact your team

Your doctor, nurse, or pharmacist will go through the possible side effects. They will monitor you closely during treatment and check how you are at your appointments. Contact your advice line as soon as possible if:

• you have severe side effects 

• your side effects aren’t getting any better

• your side effects are getting worse

We haven't listed all the side effects here. Talk to your healthcare team if you have any new symptoms that you think might be a side effect of your treatment.

Remember it is very unlikely that you will have all of these side effects, but you might have some of them at the same time.

Common side effects

These side effects happen in more than 10 in 100 people (more than 10%). You might have one or more of them. They include:

Hot flushes

We have some tips for coping with hot flushes and the possible treatments. Talk to your doctor if your hot flushes are hard to cope with. They might be able to prescribe you some medicines.

Soreness and swelling around the injection site

Tell your nurse if you notice any signs of pain, redness or irritation around the injection site. Less commonly this medicine can cause swelling, thickening or hardening of the tissue, or you might develop a small round lump (nodule).

Occasional side effects

These side effects happen in between 1 and 10 out of every 100 people (between 1 and 10%). You might have one or more of them. They include:

• a drop in ​red blood cells​ that can cause breathlessness, tiredness and looking pale

• weight gain, rarely you may lose weight

• difficulty sleeping or getting to sleep

• headaches

• feeling dizzy

• diarrhoea

• feeling sick. Some people can be sick, but this is rare

• high levels of liver ​enzymes​ in the blood. Rarely, your bilirubin might also go up. You have regular blood tests to check this

• excessive sweating including night sweats

• skin problems such as a rash. Rarely you might have raised, itchy bumps (hives), reddening or itching of the skin

• discomfort or pain in your muscles, bones, or joints

• breast swelling (gynaecomastia) - talk to your doctor if this becomes a problem

• your testicles become smaller

• you might have problems getting or maintaining an erection (erectile dysfunction) - talk to your doctor or nurse if this becomes a problem

• high temperature

• chills

• tiredness (fatigue)

• flu-like symptoms such as high temperature, feeling achy, cough, sore throat, and headache

Rare side effects

These side effects happen in fewer than 1 in 100 people (less than 1%). You might have one or more of them. They include:

• an allergic reaction that can cause a rash, shortness of breath, redness or swelling of the face and dizziness. Some allergic reactions can be life threatening, alert your nurse or doctor if you notice any of these symptoms

• high blood sugar levels, symptoms can include headaches, feeling thirsty and blurred vision. If you have ​diabetes you may need to check your blood sugar levels more often than usual. This treatment can also cause diabetes​

• high levels of a fatty substance called cholesterol in the blood, you have regular blood tests to check this

• loss of appetite

• high or low levels of calcium in the blood, you have regular blood tests to check this

• feeling very low and sad (depression)

• a decrease in your sex drive

• changes in concentration, memory or being able to think clearly

• reduced sense of touch

• blurred vision

• heart problems including changes to your heart rhythm, palpitations or changes to an ECG. Rarely this treatment can cause a heart attack or heart failure. Symptoms can include shortness of breath, chest pain, pressure or discomfort, feeling lightheaded, fainting, fast heartbeat, swelling of the legs and ankles, feeling tired and weak. Call 999 if you have any chest pain or shortness of breath

• a high or low blood pressure. Symptoms can include feeling dizzy, faint, headaches, nosebleeds, blurred or double vision, or shortness of breath. Let your healthcare team know if you have any of these symptoms.

• difficulty breathing

• constipation

• pain or discomfort in your abdomen, testicles, breasts and the area between your hips (pelvis)

• dry mouth

• hair loss or thinning

• weakened bones that are fragile and more likely to break (osteoporosis)

• muscle problems such as weakness, pain and spasms. Very rarely this treatment can cause your muscles to breakdown (rhabdomyolysis). This can be serious if not treated quickly. Symptoms include muscle pain or weakness, dark urine, tiredness, dehydration and confusion

• swollen or stiff joints

• problems peeing, such as leaking (incontinence), waking to pass at night, having an urgency to go, passing small amounts often, difficulty or pain when you pee

• problems with how well your kidneys work – you have regular blood tests to check this

• itching, burning or irritation of your penis and scrotum

• unable to ​ejaculate​  

• a general feeling of discomfort, illness or unease the cause of which is not easy to identify

• swelling of your hands and feet

Coping with side effects

We have more information about side effects and tips on how to cope with them.

Read more about how to cope with side effects

What else do you need to know?

Other medicines, foods and drink

Cancer drugs can interact with medicines, herbal products, and some food and drinks. We are unable to list all the possible interactions that may happen. An example is grapefruit or grapefruit juice which can increase the side effects of certain drugs.

Tell your healthcare team about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies. Also let them know about any other medical conditions or allergies you may have.

Loss of fertility

This treatment might stop you being able to father a child.

Talk to your doctor before starting treatment if you think you may want to have a baby in the future. You may be able to store sperm before starting treatment.

Treatment for other conditions

If you are having tests or treatment for anything else, always mention your cancer treatment. For example, if you are visiting your dentist.

More information about this treatment

For further information about this treatment and possible side effects go to the electronic Medicines Compendium (eMC) website. You can find the patient information leaflet on this website.

eMC website

You can report any side effect you have to the Medicines and Healthcare products Regulatory Agency (MHRA) as part of their Yellow Card Scheme.

Report a side effect to the MHRA