What is triptorelin (Decapeptyl®)?

Triptorelin (Decapeptyl®) is a hormonal therapy drug used to treat breast cancer. It is given with other hormonal therapy drugs after surgery to reduce the risk of breast cancer coming back.

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. 

This information is for anyone having triptorelin as part of treatment for breast cancer. This includes women, people assigned female at birth, men and people assigned male at birth. Triptorelin can also be used to treat prostate cancer. We have separate information about triptorelin (Decapeptyl® or Gonapeptyl®) for prostate cancer

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.

Many breast cancers rely on the hormone oestrogen (or estrogen) to grow. This type of breast cancer is called oestrogen-receptor positive (ER positive) breast cancer. Triptorelin stops the body making oestrogen.

Having triptorelin

Triptorelin (Decapeptyl®) is given as an injection into a muscle (intramuscular). It is given every 28 days (4 weeks). 

The injection 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. 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 will use a different area for each injection. Painkillers may 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.

You may have some rarer side effects that we have not listed here. Always tell your doctor, nurse or pharmacist about any side effects you have.

Your doctor, nurse or pharmacist can give you drugs to help control some side effects. It is important to take them exactly as they tell you. This means the drugs will be more likely to work for you. Your doctor, nurse or pharmacist 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

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.

Vaginal dryness

This treatment can cause vaginal dryness and a lower sex drive. Non-hormonal creams, gels or lubricants may help with vaginal dryness and discomfort. You can buy these from a chemist, or your doctor can prescribe them. We have more information about cancer and sex.

Vaginal bleeding and effects on periods

This treatment can cause vaginal bleeding or change the usual pattern of periods. 

You may have bleeding when you start this treatment, or if you change to it from another treatment. If bleeding continues for more than a few days, tell your doctor or nurse. 

If you have periods, you may find they become irregular, lighter, or sometimes stop altogether during this treatment. This does not always mean you are unable to get pregnant. Even if your periods stop or are irregular when taking this treatment, you still need to use contraception to prevent a pregnancy. Your doctor or nurse can tell you more about this.

Erection problems

It is common to lose your sex drive during treatment with hormonal therapy. This can cause erection problems. Things may return to normal after you stop taking the drug. But some people 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.

Feeling tired (fatigue)

Feeling tired is a common side effect. 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.

Headaches

This treatment may cause headaches. If you have headaches, tell your doctor. They may give you painkillers to help.

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

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.

Loss of muscle strength

You may lose some muscle strength. Resistance exercises, such as lifting weights, may help. 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.

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.

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.

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.

Contraception

Your doctor will advise you not to get pregnant or make someone pregnant while having this treatment. The drugs may harm a developing baby. It is important to use contraception during your treatment and for a while after treatment finishes. Your doctor, nurse or pharmacist can tell you more about this.

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: 

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.

About our information

  • Reviewers

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

    Our cancer information has been awarded the PIF TICK. Created by the Patient Information Forum, this quality mark shows we meet PIF’s 10 criteria for trustworthy health information.

Date reviewed

Reviewed: 01 June 2022
|
Next review: 01 December 2024
Trusted Information Creator - Patient Information Forum
Trusted Information Creator - Patient Information Forum

Our cancer information meets the PIF TICK quality mark.

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