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Triptorelin (Decapeptyl SR, Gonapeptyl Depot)

Find out what triptorelin is, how you have it and other important information about having triptorelin.

What it is

Triptorelin is a hormone drug that you might have as a treatment for prostate cancer that is:

  • advanced (spread to other parts of your body)
  • locally advanced with or without radiotherapy or surgery

Researchers are also looking into using triptorelin as a treatment for breast cancer. 

How it works

Triptorelin is a gonadotrophin releasing hormone blocker. This means it lowers the level of testosterone (the male sex hormone). It stops the release of lutenising hormone from the pituitary gland. 

Prostate cancer depends on testosterone to grow. So triptorelin can shrink the cancer or slow its growth. 

In women, it stops the ovaries from producing oestrogen.

Some breast cancers depend on oestrogen to grow. Lowering the level of oestrogen can slow or stop the growth of the cancer.

How you have it

You have triptorelin as an injection either

  • into a muscle (usually in your buttock)
  • just under the skin of your tummy

When you have it

You might have it either

  • once a month
  • every 3 months
  • every 6 months

Tests during treatment

You have blood tests before starting treatment and during your treatment. They check your levels of blood cells and other substances in the blood. They also check how well your liver and kidneys are working.

Side effects

Important information

Other medicines, foods and drink

Cancer drugs can interact with some other medicines and herbal products. Tell your doctor or pharmacist about any medicines you are taking. This includes vitamins, herbal supplements and over the counter remedies.

Pregnancy and contraception

This treatment might harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment and for a few months afterwards. Talk to your doctor or nurse about effective contraception before starting treatment.


Don’t breastfeed during this treatment because the drug may come through in your breast milk.

Treatment for other conditions

Always tell other doctors, nurses or dentists that you’re having this treatment if you need treatment for anything else, including teeth problems.

More information about this treatment

For further information about this treatment go to the electronic Medicines Compendium (eMC) website.

You can report any side effect you have to the Medicines Health and Regulatory Authority (MHRA) as part of their Yellow Card Scheme.

Information and help

Dangoor sponsorship

About Cancer generously supported by Dangoor Education since 2010.