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Irinotecan (Campto)

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This page tells you about the chemotherapy drug irinotecan and its possible side effects. There are sections about


What irinotecan is

Irinotecan (Campto) is a chemotherapy drug. It is a treatment for bowel cancer. It is usually combined with other anti cancer drugs.


How irinotecan works

Irinotecan works by blocking an enzyme, called topoisomerase I. Cells needs this enzyme to divide and grow into 2 new cells. If this enzyme is blocked by irinotecan, then the cell's DNA gets tangled up and the cancer cells can't divide. DNA is the genetic code that is in the heart of all animal and plant cells. It controls everything the cell does.


How you have irinotecan

You have it into your bloodstream (intravenously) through a drip. You can have it through a thin, short tube (a cannula) put into a vein in your arm each time you have treatment. Or you may have it through a central line, a portacath, or a PICC line. These are long, plastic tubes that give the drugs directly into a large vein in your chest. You have the tube put in before or during your course of treatment and it stays in place as long as you need it. Each treatment usually takes between 30 to 90 minutes.

You can read our information about having chemotherapy into a vein.

You usually have chemotherapy as a course of several cycles of treatment. So you have the treatment and then a break with no treatment. The treatment plan for irinotecan depends on your type of bowel cancer and whether it has spread. 

We've listed the side effects associated with irinotecan below. You can use the links to find out more about each side effect. If there is no link, go to the cancer drug side effects section or use the search box at the top of the page.


Common side effects

More than 10 in every 100 people have one or more of the side effects listed below.

  • Increased sweating
  • Increased saliva production
  • Watery eyes
  • Abdominal cramps
  • Diarrhoea can occasionally become severe –  if it happens within 24 hours of having the treatment you should contact your doctor straight away. They will prescribe a suitable treatment. If the diarrhoea starts more than 24 hours after the treatment you should immediately take anti diarrhoea medicines given to you by your nurse. It is important that you take this medicine exactly as it has been prescribed for you. Make sure you follow any special advice you have been given about how to cope with diarrhoea. Contact your nurse if you are worried. Tell them straight away if the diarrhoea lasts for more than 48 hours after treatment, or if you also have nausea and vomiting or a high temperature

If you get any of the above effects while having treatment, let your chemotherapy nurse know as they can give atropine to reduce these effects.

Other common side effects include

  • An increased risk of getting an infection from a drop in white blood cells – it is harder to fight infections and you can become very ill. You may have headaches, aching muscles, a cough, a sore throat, pain passing urine, or you may feel cold and shivery. If you have a severe infection this can be life threatening. Contact your treatment centre straight away if you have any of these effects or if your temperature goes above 38°C. You will have regular blood tests to check your blood cell levels
  • Tiredness and breathlessness due to a drop in red blood cells (anaemia) – you may need a blood transfusion
  • Bruising more easily due to a drop in platelets – you may have nosebleeds, or bleeding gums after brushing your teeth. Or you may have lots of tiny red spots or bruises on your arms or legs (known as petechia)
  • Tiredness and weakness (fatigue) during and after treatment – most people find their energy levels are back to normal from 6 months to a year after treatment ends
  • Feeling or being sick
  • Loss of appetite – this is usually mild, lasting for a day or so
  • Hair loss or hair thinning – a cold cap may help to stop you losing your hair, but they are not recommended for everyone so you need to talk to your doctor about it

Occasional side effects

Between 1 and 10 in every 100 people have one or more of these effects.

  • Mouth sores and ulcers
  • Muscle cramps and twitches
  • Liver changes that are very mild and unlikely to cause symptoms – these will almost certainly go back to normal when treatment finishes. You will have regular blood tests to check how well your liver is working
  • Skin rashes, which may be itchy
  • Women may stop having periods (amenorrhoea), but this may only be temporary
  • Loss of fertility – you may not be able to become pregnant or father a child after this treatment. 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
  • Dizziness – do not drive or operate machinery if you have this
  • Temporary eyesight changes
  • Pins and needles
  • Constipation
  • Inflammation around the drip site caused by drugs leaking into the tissues. Tell your nurse or doctor if you have any stinging or burning, leakage of fluid, or redness or swelling around your drip site during or after treatment
  • Temporary speech problems
  • High blood pressure – you will have regular blood pressure checks

Important points to remember

You may have a few of the side effects mentioned on this page. They may be mild or more severe. A side effect may get better or worse through your course of treatment, or more side effects may develop as the course goes on. This depends on

  • How many times you've had the drug before
  • Your general health
  • The amount of the drug you have (the dose)
  • Other drugs you are having

Coping with side effects

Talk to your doctor, pharmacist or nurse about all your side effects so they can help you manage them. They can give you advice or reassure you. Your nurse will give you a contact number to ring if you have any questions or problems. If in doubt, call them.

Other medicines

Tell your doctor about any other medicines you are taking, including vitamins, herbal supplements and over the counter remedies. Some drugs can react together.

Pregnancy and contraception

Irinotecan may have a harmful effect on a developing baby so you should not become pregnant or father a child whilst taking this drug. Talk to your doctor or nurse about contraception before beginning treatment if there is any possibility that you or your partner could become pregnant. Women need to continue with reliable contraception for a month after treatment ends and men need to continue for 3 months.


Do not breastfeed during this treatment because the drug may come through in the breast milk.


Immunisations and chemotherapy

You should not have immunisations with live vaccines while you are having chemotherapy or for at least 6 months afterwards. In the UK, these include rubella, mumps, measles (usually given together as MMR), BCG, yellow fever and Zostavax (shingles vaccine).

You can have other vaccines, but they may not give you as much protection as usual until your immune system has fully recovered from your chemotherapy. It is safe to have the flu vaccine.

It is safe for you to be in contact with other people who've had live vaccines as injections. There can be problems with vaccines you take by mouth (oral vaccines), but not many people in the UK have these now. So there is usually no problem in being with any baby or child who has recently had any vaccination in the UK. You might need to make sure that you aren't in contact with anyone who has had oral polio, cholera or typhoid vaccination recently, particularly if you live abroad.


More information about irinotecan

This information does not list all the very rare side effects of this treatment that are very unlikely to affect you. For further information look at the Electronic Medicines Compendium website at

If you have a side effect not mentioned here that you think may be due to this treatment you can report it to the Medicines Health and Regulatory Authority (MHRA) at


Related information

You can read our information about bowel cancer and its treatment.

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Updated: 12 February 2015