A GnRH antagonist injection for prostate cancer
Degarelix
A hormone treatment given under the skin that rapidly lowers testosterone to treat advanced prostate cancer.
What is Degarelix?
Degarelix is a specialist hormone treatment used for advanced prostate cancer. It works by quickly switching off the body's production of testosterone, the male hormone that fuels prostate cancer growth. It is given as an injection under the skin, usually starting with a larger first dose and then regular maintenance injections. Unlike some older hormone treatments, it lowers testosterone fast without first causing a temporary surge, so it can be useful when a quick effect is needed. Common effects include hot flushes, tiredness, weight gain and reactions where the injection is given.
Education and reference only. This is a plain-language guide to Degarelix — it deliberately contains no doses. Doses depend on the person, the brand and the reason for treatment, and belong with your prescriber. Always check the BNF, the product labelling (SmPC) and follow medical advice.
What it is
Degarelix is a hormone treatment used for advanced prostate cancer. Prostate cancer usually depends on the male hormone testosterone to grow, so lowering testosterone helps control the cancer. Degarelix belongs to a group called GnRH antagonists, which block the signal from the brain that tells the body to make testosterone. It is given as an injection under the skin, generally with a larger starting dose followed by regular maintenance injections. It is prescribed and supervised by a cancer specialist team, often for men who need testosterone brought down quickly.
How it works
The brain releases a signal that tells the body to produce testosterone. Degarelix blocks the receptor for this signal straight away, so testosterone production switches off rapidly. This is different from some older hormone treatments, which first cause a brief surge in testosterone before lowering it; degarelix lowers it quickly without that initial flare. With testosterone reduced to very low levels, the prostate cancer is starved of the hormone it relies on and its growth slows. Because the effect lasts only while the medicine is present, regular injections are needed to keep testosterone suppressed.
Company & origin
Originated / developed by: Specialist manufacturer.
A specialist hormone treatment used in the UK to lower testosterone quickly in advanced prostate cancer, given as an injection under the skin.
Practical use
How to take Degarelix
General, dose-free guidance — always follow your prescriber's and the leaflet's specific instructions.
- It is given as an injection under the skin, usually in the tummy area, by a healthcare professional.
- Expect a larger first dose, often as two injections, followed by regular maintenance injections.
- Keep to the schedule of injections, as missing them allows testosterone to rise again.
- Tell the team if injection-site reactions are troublesome, although they usually settle.
- Discuss looking after your bones and heart health, as long-term low testosterone can affect both.
Weighing it up
Advantages & disadvantages of Degarelix
Advantages
- Lowers testosterone quickly to help control advanced prostate cancer.
- Avoids the temporary testosterone surge, or flare, seen with some other hormone treatments.
- Given as an injection under the skin rather than needing tablets every day.
Disadvantages
- Commonly causes reactions where the injection is given, especially with the first dose.
- Leads to hormone-related effects such as hot flushes, tiredness, weight gain and weaker bones over time.
- Needs regular injections and ongoing specialist supervision.
Practical use
Good to know
A useful feature of degarelix is that it lowers testosterone quickly without the temporary surge, or flare, that some other hormone treatments cause, which can matter when symptoms need controlling fast. The first injection is usually larger and may be given as two injections, after which regular maintenance injections continue. Reactions where the injection is given, such as redness, pain, swelling or a lump, are very common, especially with the first dose, and usually settle. Lowering testosterone leads to expected effects such as hot flushes, tiredness, reduced sex drive, weight gain and, over time, weaker bones, so looking after bone and heart health is part of the plan. Keeping to the schedule of injections matters, because missing them lets testosterone rise again.
Who should not take it / use with caution
- People who have had a serious allergic reaction to degarelix should not have it.
- It is for use in men with prostate cancer and is not used in women or in pregnancy.
- It is used with care in people with significant heart-rhythm problems or heart disease, under specialist guidance.
Monitoring
- Checking testosterone and PSA blood tests to see how well the cancer is being controlled.
- Watching for side effects, including injection-site reactions, bone health and heart-rhythm changes.
- Reviewing liver blood tests and overall response over time.
Side effects
- Reactions where the injection is given, such as redness, pain, swelling or a lump, especially at first.
- Hot flushes, tiredness, reduced sex drive and weight gain.
- Weaker bones over time, and sometimes changes in liver blood tests or the heart's rhythm.
- Rarely but seriously, a severe allergic reaction or significant heart-rhythm changes, which need urgent attention.
Key interactions
- Medicines that affect the heart's rhythm, the QT interval, should be reviewed, so tell your team what you take.
- Give your team a full list of your medicines, although routine interactions are otherwise limited.
- Discuss any heart conditions or heart medicines before and during treatment.
Available as: A powder made up into a solution for injection under the skin.
Answers
Degarelix: frequently asked questions
What is degarelix used for?
It is used to treat advanced prostate cancer by quickly lowering testosterone, the male hormone that fuels prostate cancer growth.
How is it different from other hormone treatments?
It lowers testosterone rapidly without first causing a temporary surge, or flare, which some older hormone treatments do, so it can be useful when a fast effect is needed.
How is it given?
It is given as an injection under the skin, usually a larger first dose followed by regular maintenance injections from a healthcare professional.
Why is the injection site sore?
Reactions where the injection is given, such as redness, pain, swelling or a lump, are very common, especially with the first dose, and usually settle on their own.
What if I miss an injection?
Missing injections lets testosterone rise again, which can let the cancer grow, so keep to the schedule and contact your team if you cannot attend.
Authoritative sources
- BNF
- NICE CKS
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