What is triptorelin (Decapeptyl® or Gonapeptyl®)?

Triptorelin is a hormonal therapy drug. It is also called  Decapeptyl® or Gonapeptyl®. It is used to treat prostate cancer.

It is best to read this information with our general information about hormonal therapies and the type of cancer you have. 

Your cancer team will talk to you about this treatment and its possible side effects before you agree (consent) to have treatment. 

Triptorelin can also be used to treat breast cancer. We have separate information about triptorelin (Decapeptyl®) for breast cancer.

More information about this treatment

This information is correct at time of publishing. But sometimes the types of cancer this treatment is used for, or treatment side effects, may change between revision dates.

You can talk to your cancer team if you want more detailed information about this treatment. Or visit the electronic Medicines Compendium (eMC) website, which has patient information leaflets (PIL) for individual drugs.

How triptorelin works

Hormones are chemicals that our bodies make. They act as messengers and help control how cells and organs work. Hormonal therapy drugs change how hormones are made or work in the body.

Prostate cancer needs the hormone testosterone to grow. This is mainly made by the testicles.

Triptorelin stops the testicles from making testosterone. This lowers testosterone levels and may shrink the prostate cancer or stop it growing.

How triptorelin is given

You have triptorelin as an injection. There are 2 types of triptorelin.

  • Decapeptyl® is given as an injection into a muscle (intramuscular). It can be given every 28 days (4 weeks), or as a longer-acting injection every 3 or 6 months.
  • Gonapeptyl® is given as an injection under the skin (subcutaneously) of your tummy, buttock or thigh. Or it can be given as an injection into a muscle (intramuscular). It is given every 28 days (4 weeks).

During your treatment, you will meet someone from your cancer team, such as a:

  • cancer doctor
  • specialist nurse
  • specialist pharmacist.

This is who we mean when we mention doctor, nurse or pharmacist in this information.

Your GP or practice nurse may give triptorelin to you at your GP surgery. Or a district nurse may be able to give it to you at home if you are not able to visit the surgery.

If you are taking any medicines to thin your blood, tell your doctor, nurse or pharmacist. These medicines can make you bruise more easily.

When you start taking triptorelin, you may have another hormonal drug with it. But this is only for a few weeks. Your cancer team will discuss your treatment plan with you.

Injection site

The skin in the area that was injected may become:

  • painful
  • swollen
  • red, if you have white skin
  • darker, if you have black or brown skin.

If this happens, let your doctor know. Painkillers may help.

About side effects

We explain the most common side effects of this treatment here. We also include some that are less common.

You may get some of the side effects we mention, but you are unlikely to get all of them. And you may have some side effects, including rarer ones, that we have not listed here. 

Other cancer treatments may cause different side effects. If you are also having other cancer treatment, you may have other side effects.

When you have this treatment, you will have regular appointments with a doctor, nurse or pharmacist. Always tell them about any side effects you have. They can give you: 

  • drugs to help control most side effects 
  • advice about managing side effects. 

Most side effects can be managed. But sometimes side effects are harder to control. It is important not to stop taking hormonal therapy without telling your doctor. If side effects cannot be managed, your doctor may suggest a different type of hormonal therapy.

Serious and life-threatening side effects

Some cancer treatments can cause serious side effects. Sometimes, these may be life-threatening. Your doctor, nurse or pharmacist can explain the risk of these side effects to you.

Contact the hospital

Your doctor, nurse or pharmacist will give you 24-hour contact numbers for the hospital. If you feel unwell or need advice, you can call at any time of the day or night. Save these numbers in your phone or keep them somewhere safe.

Very common side effects

These side effects happen to 10 or more people in every 100 people (10% or more) who have this treatment.

Sexual effects

It is common to lose your sex drive and have erection difficulties with hormonal therapy. Hormonal therapy may also make your penis shorter and your testicles smaller. 

Your doctor can prescribe drugs and treatments to help with erection difficulties. These will not increase your sex drive. But they might work, even with a low sex drive. 

Things can improve a few months after you stop taking the drug. But it depends on how long you take hormonal therapy, and what other treatments you have had. Some people continue to have problems after treatment ends.

Hot flushes and sweats

Hot flushes are a common side effect of this treatment. During a flush, your neck and face may feel warm. If you have white skin, your skin may look red. If you have black or brown skin, your skin colour may deepen. Flushes can last up to 5 minutes. You might also have sweats or feel anxious or irritable during a flush. 

Here are some things you can do to reduce the effects of hot flushes:

  • Wear natural fabrics, such as cotton.
  • Wear layers so you can remove clothes as needed. 
  • Use cotton sheets and layers of bedding you can remove. 
  • Try cooling pads or pillows to keep you cool.
  • Keep rooms cool or use a fan.
  • Have cold drinks and avoid caffeine and alcohol. 

You might have fewer hot flushes as your body adjusts to this treatment. You could try therapies to help you cope with hot flushes, such as:

  • talking therapies like cognitive behaviour therapy (CBT)
  • controlled breathing exercises
  • yoga
  • acupuncture. 

If they do not improve, talk to your doctor. Certain drugs can help to improve hot flushes. 

Flushes usually stop a few months after treatment ends. But some people continue to have them.

Back pain

This treatment can cause back pain. If you have any back pain, tell your doctor. They may give you painkillers to help.

Pins and needles in legs

This treatment can cause a tingling feeling, like pins and needles in your legs. Or your legs may feel numb. If you notice these symptoms, contact the hospital on the 24-hour number as soon as possible.

Other side effects

These side effects happen to less than 10 in 100 people (less than 10%) who have this treatment. Some of them are much rarer than this but they are still important to know about. Rare means a side effect that happens to less than 1 in 1,000 people (less than 0.1%).

Tumour flare

When you start taking this treatment your testosterone levels may go up for a very short time. This could cause any symptoms to get temporarily worse. This is sometimes called tumour flare. To prevent this, your doctor gives you another tablet to take before you start and for the first few weeks of treatment. Your doctor, nurse or pharmacist will explain more about this.

Mood changes

You may feel low or depressed, or have mood swings, during this treatment. Talking to family and friends about how you feel might help. If mood changes last for more than a few weeks, tell your doctor, nurse or pharmacist. They can talk to you about different ways to manage low mood or depression.

Generalised weakness

This treatment can cause general weakness and lack of strength. You may feel tired and have no energy. Try to pace yourself and plan your day so you have time to rest between activities.

Being physically active can help to manage tiredness and give you more energy. It also:

  • helps you sleep better
  • reduces stress
  • improves your bone health.

If you feel sleepy, do not drive or operate machinery.

Difficulty sleeping

This treatment can cause sleeping problems (insomnia). If you are finding it difficult to sleep, talk to your nurse or doctor.

Bone thinning (osteoporosis)

Taking this treatment for several months or more can increase the risk of bone thinning. This is called osteoporosis. It can make you more likely to get a broken bone (fracture). 

You may have bone density scans to check your bone health before and during treatment. These scans can diagnose osteoporosis or osteopenia (low bone density) so that it can be monitored. If your scan shows osteoporosis, your doctor usually prescribes:

  • drugs to protect your bones called bisphosphonates
  • calcium and vitamin D supplements. 

Regular exercise where you support your body weight, like walking, running and dancing, can help look after your bones. This is called weight-bearing exercise. Other types of strength exercises are also helpful. If you have any bone thinning or the cancer is affecting your bones, get advice from your cancer team first. 

Eating a healthy diet and not smoking also helps take care of your bones.

Pain

You may get pain in your muscles or joints. If this happens, tell your doctor or nurse. They can give you advice and painkillers or other drugs to help. Being physically active and keeping to a healthy weight may help with the pain. It can keep your joints flexible and reduce stress on them. If the pain does not get better, tell your doctor or nurse. They may talk to you about changing to a different hormonal drug.

Some people may get pain in the arms or legs or in the tummy. Let your doctor, nurse or pharmacist know if you have pain.

Blood pressure changes

Triptorelin may cause low or high blood pressure. If you have ever had any problems with your blood pressure, tell your doctor or nurse. Let them know if you feel dizzy or have any headaches.

Weight gain

You may gain weight when you are having this treatment. Eating healthily and being active can help you keep to a healthy weight. Your doctor, nurse or dietitian can give you more advice.

Fluid build-up

Sometimes fluid can build-up in your hands and feet. This can cause swelling. This is known as oedema. Tell your doctor or nurse if you have any swelling. If your ankles and legs swell, it can help to put your legs up on a foot stool or cushion.

Dry mouth

You may get a dry mouth. Drink plenty of fluids, and add sauces and gravies to your food to keep it moist. If you have dry lips, using a lip balm or Vaseline® can help.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor, nurse or pharmacist. They can give you advice about painkillers that may help. Tell them if the headache does not get better, or gets worse.

Dizziness

Triptorelin can cause dizziness. Do not drive or operate machinery if you have this side effect. Tell your doctor or nurse if you notice this side effect.

Feeling sick

Triptorelin can make you feel sick, but this is usually mild. If it does not get better, your doctor can give you anti-sickness drugs to help.

Allergic reaction

This treatment might cause an allergic reaction. But this is not common. Signs of a reaction can include: 

  • a skin rash or itching
  • feeling breathless or wheezy
  • swelling of your face, mouth or throat.

If you feel unwell or have any of these signs, contact the hospital straight away on the 24-hour number. Do not take any more of this treatment until you have checked with them.

Effects on the heart

This treatment might increase certain risk factors for heart problems. Tell your doctor if you have:

  • had any problems with your heart
  • high blood pressure
  • high levels of cholesterol – a fatty substance in your blood. 

They can monitor or treat these if needed. Talk to your doctor if you are worried about this. 

Things you can do to take care of your heart include:

  • not smoking
  • maintaining a healthy weight 
  • being physically active.

Raised blood sugar levels

This treatment can raise your blood sugar levels and increase the risk of diabetes. 

Signs of raised blood sugar include:

  • feeling thirsty
  • needing to pass urine (pee) more often than usual
  • feeling more tired than usual. 

Tell your doctor or nurse if you have these symptoms. They can do tests to check your blood sugar level and give you advice.

If you already have diabetes, your blood sugars may be higher than usual. You may need to check them more often, or make changes to your diabetic treatment. Your diabetic doctor or nurse will talk to you about how to manage this.

Breast swelling or tenderness

This treatment may cause swelling and tenderness of your breast tissue. This is called gynaecomastia. To prevent this, some people have 1 or more low-dose radiotherapy treatments to the chest before treatment starts. Another type of hormonal drug might be used to treat the breast swelling. Your doctor can give you more advice.

Other information

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Contact the hospital straight away on the 24-hour number if you have any of these symptoms during or after treatment:

  • throbbing pain or swelling in a leg or arm
  • reddening of the skin in the area – if you have black or brown skin, this can be harder to notice, but the skin might become darker
  • suddenly feeling breathless or coughing.

Always call 999 if you have:

  • chest pain
  • difficulty breathing.

A blood clot is serious, but it can be treated with drugs called anticoagulants. These thin the blood. Your doctor, nurse or pharmacist can give you more information about preventing and treating blood clots.

Other medicines

Some medicines can affect how this treatment works or be harmful while you are having it. Always tell your cancer doctor, nurse or pharmacist about any drugs you are taking or planning to take, such as: 

Contraception

Your doctor, nurse or pharmacist will advise you not to make someone pregnant while having this treatment. The drug may harm the developing baby. It is important to use effective contraception during treatment and for a while after it finishes.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the healthcare professional that you are having cancer treatment. Give them the contact details for your cancer doctor or cancer team so they can ask for advice.

If you have appointments with a dentist, always tell them you are having cancer treatment. Talk to your cancer team before you have any dental treatment.

About our information

This information has been written, revised and edited by Macmillan Cancer Support’s Cancer Information Development team. It has been reviewed by expert medical and health professionals and people living with cancer.

Date reviewed

Reviewed: 01 June 2024
|
Next review: 01 June 2027
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Trusted Information Creator - Patient Information Forum

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