What is triptorelin (Decapeptyl® or Gonapeptyl®)?

Triptorelin (Decapeptyl® or Gonapeptyl®) is a hormonal therapy drug used to treat prostate cancer. It can be given alone, or with radiotherapy or surgery. 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.

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

There are 2 types of triptorelin. They 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® 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) or into a muscle (intramuscular). It is given every 28 days (4 weeks).

Tell your doctor or nurse if you are taking any medicines to thin your blood, as this may increase bruising.

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

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 have not 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 worse. Doctors call this tumour flare.

Your doctor may prescribe another hormonal therapy tablet to prevent or reduce tumour flare. You usually start taking these tablets before starting the hormonal therapy drug to treat the cancer. You may need to 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

Hot flushes are a common side effect of this treatment. During a flush, your neck and face may feel warm and look red. Flushes may last from a few seconds up to 10 minutes. You may have sweats and 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.
  • Wear layers of clothes that you can remove if you feel hot.
  • Use cotton bed sheets and have layers of bedding that you can remove if you feel hot.
  • Keep room temperatures 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. Flushes and sweats usually stop a few months after treatment finishes, but some people continue to have them.

You can read more about coping with hot flushes.

Sexual effects

Most men lose their sex drive and have erection problems during hormonal therapy. Things often return to normal after you stop taking the drug. But some men continue to have problems after treatment is over. Your doctor can prescribe treatments to help with erection problems. But these treatments will not increase your 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 you have headaches, tell your doctor. They may give you painkillers to help.

Dizziness or blurred vision

This treatment can cause dizziness or blurred vision. Do not drive or operate machinery if you have these side effects. Let your doctor or nurse know 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

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 a dietitian can give you more advice.

Muscle strength

You may lose some muscle strength with this treatment. Resistance exercises, such as lifting light weights, may help you to reduce loss of muscle strength. Ask your doctor or nurse for advice.

Mood changes

You may have some mood changes during this treatment. You may feel low or depressed. Let your doctor or nurse know if you notice any changes.

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 may help with the pain and keep your joints flexible. Keeping to a healthy weight may help too. Tell your doctor or nurse if the pain does not get better.

Bone thinning (osteoporosis)

If you take this treatment for several months or more, you may get 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.

Doing regular exercise, such as walking, can improve your bone health. Eating a healthy diet can help too. Your doctor may prescribe drugs called bisphosphonates to help protect your bones. They may also advise you to take calcium and vitamin D supplements.

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 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.

Less common side effects

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 may cause swelling and tenderness of your breast tissue. This is called gynaecomastia. Your doctor can give you advice on preventing and treating this.

Skin changes

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

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

Effects on the heart

This treatment can affect the way your heart works. Your doctor may do tests to see how well your heart is working. You may have these tests before, during, and sometimes after treatment.

Contact a doctor straight away if you:

  • have pain or tightness in your chest
  • feel breathless or dizzy
  • feel your heart is beating too fast or too slowly.

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 pass urine (pee) 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 change your insulin or tablet dose.

Other information

Blood clot risk

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

  • throbbing pain, redness or swelling in a leg or arm
  • suddenly feeling breathless or coughing
  • sharp chest pain, which may be worse when you cough or take a deep breath.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

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

You can help reduce the risk of developing a blood clot by:
  • staying active during treatment
  • drinking plenty of fluids, especially water.

You may be given anticoagulants to help prevent a clot.

Contraception

Your doctor 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 your treatment.

Other medicines

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

  • medicines you have been prescribed
  • medicines you buy in a shop or chemist
  • vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.

Medical and dental treatment

If you need medical treatment for any reason other than cancer, always tell the doctors and nurses 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.