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Interferon (Intron A)

Find out what interferon is, how you have it and other important information about this biological therapy for cancer. 

What it is

Interferon is also called interferon alfa. It is used to treat several different types of cancer, including:

  • kidney cancer (renal cell cancer)
  • malignant melanoma
  • multiple myeloma
  • some types of leukaemia

It is also used to treat conditions other than cancer. 

    How it works

    Interferon works in several ways.

    It interferes with cancer cells and stops them growing and multiplying.

    It also stimulates the immune system by encouraging killer T cells and other cells to attack cancer cells. It can encourage cancer cells to send out chemicals that attract immune system cells to them.

    How you have it

    You usually have interferon as an injection just under the skin (subcutaneously) into the abdomen (tummy) or thigh. How often you have it depends on which cancer you have. You might have it daily, although it is more common to have it 3 times a week.

    A nurse may teach you to give the injection yourself at home if you are having interferon for some weeks or months. Or a family member can learn how to do it. You need to keep your interferon in the fridge.

    Sometimes you have interferon into your bloodstream.

    Into your bloodstream

    You have the treatment through a drip into your arm. A nurse puts a small tube (a cannula) into one of your veins and connects the drip to it.

    You might need a central line. This is a long plastic tube that gives the drugs into a large vein, either in your chest or through a vein in your arm. It stays in while you’re having treatment, which may be for a few months.


    You have blood tests before 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, food 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 drug may harm a baby developing in the womb. It is important not to become pregnant or father a child while you are having treatment. Talk to your doctor or nurse about effective contraception before starting treatment.

    Women must not become pregnant for at least 4 months after the end of treatment. Men should not father a child for at least 7 months after treatment. 


    You may not be able to become pregnant or father a child after treatment with this drug. Talk to your doctor before starting treatment if you think you may want to have a baby in the future. Men may be able to store sperm before starting treatment. Women may be able to store eggs or ovarian tissue but this is rare.

    Breast feeding

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

    Treatment for other conditions

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

    Children and adolescents

    Children and young people may grow and develop more slowly during interferon treatment.


    Don’t have immunisations with live vaccines while you’re having treatment and for at least 6 months afterwards.

    In the UK, live vaccines include rubella, mumps, measles, BCG, yellow fever and shingles vaccine (Zostavax).

    You can:

    • have other vaccines, but they might not give you as much protection as usual
    • have the flu vaccine (as an injection)
    • be in contact with other people who've had live vaccines as injections

    Avoid close contact with people who’ve recently had live vaccines taken by mouth (oral vaccines) such as oral polio or the typhoid vaccine.

    This also includes the rotavirus vaccine given to babies. The virus is in the baby’s poo for up to 2 weeks and could make you ill. So, avoid changing their nappies for 2 weeks after their vaccination if possible. Or wear disposable gloves and wash your hands well afterwards.

    You should also avoid close contact with children who have had the flu vaccine nasal spray if your immune system is severely weakened. 

    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

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    About Cancer generously supported by Dangoor Education since 2010.