Triptorelin (Decapeptyl® or Gonapeptyl®)

Triptorelin (Decapeptyl® or Gonapeptyl®) is a hormonal therapy drug 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.

Triptorelin is given as an injection. You usually have it at your GP surgery. Your cancer doctor, nurse or pharmacist will tell you how often you will have it.

Like all cancer drugs, triptorelin can cause side effects. Some of the side effects can be serious, so it is important to read the detailed information below.

Your healthcare team can give you advice on how to manage any side effects. Tell your doctor or nurse straight away if you feel unwell or have severe side effects, including any we do not mention here.

Rarely, side effects may be life-threatening. Your cancer doctor or nurse can explain the risk of these side effects to you.

If you need medical attention for any reason other than cancer, always tell the healthcare staff that you are having this treatment.

What is triptorelin?

Triptorelin is a hormonal therapy drug used to treat prostate cancer. It can be given alone or with other types of treatment. It is best to read this information with our general information about hormonal therapies and the type of cancer you have.

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

Tips for talking to your doctor

Find out how to get the most out of your appointments with a GP or doctor.

About our cancer information videos

Tips for talking to your doctor

Find out how to get the most out of your appointments with a GP or doctor.

About our cancer information videos


How triptorelin works

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

Prostate cancer needs the hormone testosterone to grow. Almost all testosterone in men is made by the testicles.

Triptorelin stops the testicles from making testosterone. This reduces testosterone levels and may shrink the prostate cancer or stop it growing. Your doctor or nurse will explain how long you have triptorelin for.

Having triptorelin

The two types of triptorelin are Decapeptyl® and Gonapeptyl®. Both can be given by your practice nurse at your GP surgery. If you are not able to visit the GP surgery, a district nurse can give you it at home.

Decapeptyl®

Decapeptyl® is given as an injection into a muscle (intramuscular). It can be given as a monthly injection or as a longer-acting injection every 3 to 6 months.

Gonapeptyl®

Gonapeptyl® is given as a monthly injection under the skin (subcutaneously) or into a muscle (intramuscular).

Triptorelin can be used on its own or with other types of treatment. It may be used before or after radiotherapy or after surgery.

It may also be used to control prostate cancer that has spread to other parts of the body (advanced or metastatic prostate cancer).

Your doctor or nurse will talk to you about your treatment plan.

If you are taking any medicines to thin your blood, tell your doctor or nurse. These medicines may increase bruising.

Injection site

You may have some pain, swelling, redness or a darker colour around the area that was injected. Let your doctor know if this happens. They may be able to prescribe painkillers to help.


About side effects

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

You may get some of the side effects we mention, but you are unlikely to get all of them. If you are also having treatment with other cancer drugs, you may have some side effects that we haven’t listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor can give you drugs to help control some side effects. It is important to take them exactly as your nurse or pharmacist explains. This means they will be more likely to work for you. Your nurse will give you advice about managing your side effects. After your treatment is over, most side effects start to improve.

Serious and life-threatening side effects

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

Contact the hospital

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

More information

We cannot list every side effect for this treatment. There are some rare side effects that are not listed. You can visit the electronic Medicines Compendium (eMC) for more detailed information.


Common side effects

Tumour flare

When you start this treatment, your testosterone levels may increase for the first few days or weeks. This may make some symptoms that are caused by the cancer worse. Doctors call this tumour flare. Your doctor may prescribe a hormonal therapy for you to take as a tablet to prevent or reduce tumour flare. You usually start taking the hormonal therapy tablets before starting the cancer treatment drug. You usually continue taking them for a few weeks.

Back pain

This treatment can cause back pain. If you have any back pain, weakness, numbness or tingling in your legs, tell your doctor straight away. They may give you painkillers to help.

Hot flushes and sweats

These are common. During a flush, your neck and face may feel warm and look red. Flushes can last for a few seconds or for up to 10 minutes. You may have sweats then feel cold and clammy. Some people feel anxious or irritable during a hot flush.

There are things you can do to try to reduce flushes:

  • Wear clothes made from natural fabrics, such as cotton.
  • Dress in layers of clothes that you can remove as needed.
  • Use cotton sheets and have layers of bedding.
  • Keep the room temperature cool or use a fan.
  • Have cold drinks rather than hot ones. Try to avoid drinks with caffeine in them.

You may have fewer hot flushes and sweats as your body adjusts to hormonal treatment. Or your doctor can prescribe drugs to help. Some people continue to have flushes and sweats, but they usually stop a few months after treatment finishes.

You can read more about coping with hot flushes and managing hormonal symptoms in our information on prostate cancer.

Sexual effects

Most men lose their sex drive and have erection difficulties during hormonal therapy. Things often return to normal after you stop taking the drug, but some men continue to have difficulties after treatment is over.

Your doctor can prescribe treatments to help with erection difficulties. But these treatments will not increase sex drive.

Tiredness

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Difficulty sleeping

This treatment can cause sleeplessness (insomnia) in some people. If you are finding it difficult to sleep, talk to your doctor or specialist nurse.

Headaches

This treatment may cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers.

Skin changes

This treatment may affect your skin. Your doctor or nurse can tell you what to expect. If your skin feels dry, try using an unperfumed moisturising cream every day. This treatment can cause a rash, which may be itchy.

Always tell your doctor or nurse about any skin changes. They can give you advice and may give you creams or medicines to help. Any changes to your skin are usually temporary and improve when treatment finishes.

Dizziness, blurred vision, drowsiness

This treatment can cause dizziness, blurred vision or drowsiness. Do not drive or operate machinery if you have these side effects. Talk to your doctor or nurse if you notice any of these effects.

Feeling sick

This treatment 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. Some men may get pain in their lower tummy. Let your doctor know if this happens to you.

Weight gain and loss of muscle strength

You may gain weight, particularly around your waist, and you may lose some muscle strength. Eating a healthy diet and exercising regularly can help control your weight. Resistance exercises, such as lifting weights, may help you to reduce the loss of muscle strength. Ask your doctor or nurse for advice.

Mood changes

Some people have mood changes and feel low or depressed when having this treatment. Let your doctor or nurse know if you notice any changes. There are professionals, who are trained to help you manage your feelings.

Memory and concentration

You may notice changes in your memory or ability to concentrate. To help you keep track of things, try using:

  • a notebook
  • notes on your phone
  • a calendar.

Muscle or joint pain

You may get pain in your muscles or joints. If this happens, tell your doctor so they can give you painkillers. Being physically active and keeping to a healthy weight may help with the pain and keeps your joints flexible. Let your doctor or nurse know if it does not get better.

Bone thinning (osteoporosis)

Taking this treatment for several months or more can cause bone thinning. This is called osteoporosis. This can increase your risk of a broken bone (fracture). You may have bone density scans to check your bone health before and during treatment.

Taking regular exercise, such as walking and eating a healthy diet helps look after your bones. Your doctor may prescribe drugs called bisphosphonates to help protect your bones. They may also advise you to take calcium and vitamin D supplements.

Build-up of fluid (oedema)

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 footstool 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.

Blood pressure changes

This treatment may cause high blood pressure. Tell your doctor or nurse if you have ever had any problems with your blood pressure. Let them know if you feel dizzy or have any headaches.

Amrik reading a book

Alan on treatment and side effects

'The thought that I would not be able to carry on with these activities was extremely upsetting.'

Sex and impotence after prostate cancer

Brian talks about the impact of prostate cancer and impotence on his sex life. He explains how, in the face of these challenges, his relationship with Elizabeth remained strong.

About our cancer information videos

Sex and impotence after prostate cancer

Brian talks about the impact of prostate cancer and impotence on his sex life. He explains how, in the face of these challenges, his relationship with Elizabeth remained strong.

About our cancer information videos

Coping with fatigue

Denton describes how he coped with fatigue (tiredness) during his treatment for prostate cancer.

About our cancer information videos

Coping with fatigue

Denton describes how he coped with fatigue (tiredness) during his treatment for prostate cancer.

About our cancer information videos


Less common side effects of triptorelin

Allergic reaction

Some people have an allergic reaction while having this treatment. Signs of a reaction can include:

  • feeling hot or flushed
  • a skin rash
  • itching
  • shivering
  • feeling dizzy
  • a headache
  • feeling breathless.

If you feel unwell or have any of these signs, tell a doctor or nurse straight away. Do not take any more of this treatment until you have spoken to them.

Breast swelling or tenderness

This treatment can cause swelling and tenderness of your breast tissue. This is called gynaecomastia. Your doctor can give you advice on how this can be prevented or treated.

Risk of heart changes

There may be an increased risk of developing changes in heart rhythm or heart disease when taking this treatment. Let your doctor know if you feel your heart is beating too fast or too slowly.

Contact a doctor straight away if you have pain or tightness in your chest or feel breathless or dizzy. Other conditions can cause these symptoms, but it is important to get them checked by a doctor.

Raised blood sugar levels

This treatment can raise your blood sugar levels. If you have a raised blood sugar level, you may:

  • feel thirsty
  • need to pee (pass urine) more often
  • feel tired.

Tell your doctor or nurse if you have these symptoms.

If you have diabetes, your blood sugar levels may be higher than usual. Your doctor will talk to you about how to manage this. You may need to adjust your insulin or tablet dose.

Blood clot risk

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

  • pain, redness or swelling in a leg or arm
  • breathlessness
  • chest pain. 

If you have any of these symptoms, contact a doctor straight away. 

A blood clot is serious, but can be treated with drugs that thin the blood. Your doctor or nurse can give you more information.


Other information

Other medicines

Some medicines can affect the hormonal treatment or be harmful when you are having it. This includes medicines you can buy in a shop or chemist. Tell your cancer doctor about any drugs you are taking, including vitamins, herbal drugs and complementary therapies.

Medical and dental treatment

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

If you think you need dental treatment, talk to your cancer doctor or nurse. Always tell your dentist you are having cancer treatment.