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Irinotecan is a chemotherapy drug| that is usually given to treat cancer of the colon and rectum|. This information should ideally be read with our general information about chemotherapy| and your type of cancer|.
Irinotecan is a clear yellow fluid.
Irinotecan may be given as a drip (infusion) in one of the following ways:
Chemotherapy is usually given as a course of several sessions (cycles) of treatment over a few months. The length of your treatment and the number of cycles you have will depend on the type of cancer| you're being treated for. Irinotecan is often given alongside other chemotherapy drugs as part of a combination regimen|. Your nurse or doctor will discuss your treatment plan| with you.
Before you have your treatment your doctor will arrange for you to have blood tests. You'll usually be given anti-sickness drugs before and/or during your treatment.
Each person's reaction to chemotherapy is different. Some people have very few side effects while others may experience more. The side effects described below won't affect everyone who has irinotecan and may be different if you are having more than one type of chemotherapy drug.
We have outlined the most common side effects but haven't included those that are rare and therefore unlikely to affect you. If you notice any effects that aren't listed below, discuss them with your doctor, chemotherapy nurse or pharmacist.
Irinotecan can cause increased sweating, increased production of saliva, stomach cramps and diarrhoea|. This is a particular group of side effects known as acute cholinergic syndrome. They happen because irinotecan can cause the cells in the body to release too much of a chemical called acetylcholine. The side effects tend to occur during, or within the first 24 hours after, an infusion of irinotecan.
These symptoms can usually be prevented or controlled by a drug called atropine. Atropine is given as an injection under the skin (subcutaneously), which can be repeated if necessary.
Diarrhoea can occur as a delayed side effect (occurring more than 24 hours after an infusion). It can usually be easily controlled but may occasionally be severe.
If you get diarrhoea and abdominal cramps, start taking the anti-diarrhoea medicine you have been given (usually loperamide tablets or capsules). These should be taken exactly as instructed by the hospital treating you and may be different from the instructions provided on any printed leaflets from the manufacturer.
Normally your doctor will tell you to take two tablets or capsules when the diarrhoea starts, and then one every two hours until you have not had a loose bowel movement for 12 hours.
If loperamide doesn't work quickly and if you still have diarrhoea after 48 hours, it's important that you contact the hospital.
You may become dehydrated if you have several episodes of diarrhoea. In some situations, you may be asked to take liquids to re-hydrate you and replace any salts you may have lost.
Antibiotics are also sometimes given if diarrhoea occurs.
This may begin soon after the treatment is given and can last for up to 24 hours. Your doctor can prescribe very effective anti-sickness (anti-emetic) drugs to prevent, or greatly reduce, nausea and vomiting|. If the sickness isn't controlled, or if it continues, tell your doctor; they can prescribe other anti-sickness drugs that may be more effective.
Some anti-sickness drugs can cause constipation|. Let your doctor or nurse know if this is a problem.
Irinotecan can reduce the number of white blood cells, which help fight infection. White blood cells are produced by the bone marrow. If the number of your white blood cells is low you'll be more prone to infections|. A low white blood cell count is called neutropenia.
Neutropenia can begin a few days after treatment, and your resistance to infection usually reaches its lowest point around eight days after chemotherapy. The number of white blood cells in your blood will then increase steadily and usually return to normal before your next cycle of chemotherapy is due.
You'll have a blood test before having more chemotherapy to check the numbers of white blood cells in your blood. Occasionally, it may be necessary to delay your treatment if the number of your blood cells (blood count) is still low.
Irinotecan can reduce the production of platelets, which help the blood to clot. Tell your doctor if you have any unexplained bruising or bleeding, such as nosebleeds, bleeding gums, blood spots or rashes on the skin. You may need to have a platelet transfusion| if your platelet count is low.
Irinotecan can reduce the number of red blood cells, which carry oxygen around the body. A low red blood cell count is called anaemia. This may make you feel tired| and breathless|. Tell your doctor or nurse if you have these symptoms. You may need to have a blood transfusion| if the number of red blood cells becomes too low.
Your hair may fall out completely or just thin. This usually starts 3-4 weeks after starting treatment, although it may occur earlier. You may also have thinning and loss of eyelashes, eyebrows and other body hair|. Hair loss is temporary, and your hair will grow back once the treatment has finished. Your hair may grow back straighter, curlier, finer or a slightly different colour than it was before. Your nurse can give you advice about coping with hair loss|.
Feeling tired| is a common side effect of chemotherapy, especially towards the end of treatment and for some weeks after it’s over. It’s important to try to pace yourself and get as much rest as you need. Try to balance this with some gentle exercise, such as short walks, which will help. If tiredness is making you feel sleepy, don’t drive or operate machinery.
Your mouth may become sore or dry|, or you may notice small ulcers during this treatment. Drinking plenty of fluids, and cleaning your teeth regularly and gently with a soft toothbrush, can help reduce the risk of this happening. Some people find sucking on ice soothing. Tell your nurse or doctor if you have any of these problems, as they can prescribe mouthwashes and medicine to prevent or clear mouth infections.
Some people lose their appetite while they’re having chemotherapy. This can be mild and may only last a few days. If it doesn’t improve you can ask to see a dietitian or specialist nurse at your hospital. They can give you advice on improving your appet|ite and keeping to a healthy weight|. You may want to read our information about eating well|.
You may notice that food tastes different|. Normal taste usually comes back after treatment finishes. A dietitian or specialist nurse at your hospital can give you advice about ways of coping with this side effect.
Tell your doctor if you have muscle cramps so that suitable painkillers| can be prescribed.
Treatment with irinotecan may cause changes in the way your liver| works, although it will return to normal when the treatment finishes. You're very unlikely to notice any problems, but your doctor will take regular blood samples to check your liver is working properly.
Irinotecan can cause a rash, which may be itchy. Your doctor can prescribe medicine to help with this.
It’s important to let your doctor know straight away if you feel unwell or have any severe side effects, even if they’re not mentioned above.
Some medicines, including those you can buy in a shop or chemist, can be harmful to take when you're having chemotherapy. Tell your doctor about any medicines you're taking, including over-the-counter drugs, complementary therapies| and herbal drugs|.
Your ability to become pregnant or father a child may be affected by having this treatment. It's important to discuss fertility| with your doctor before starting treatment.
It's not advisable to become pregnant or father a child while having irinotecan, as it may harm the developing baby. It’s important to use effective contraception while having this drug and for at least a few months afterwards. You can discuss this with your doctor or nurse.
It’s not known whether chemotherapy drugs can be present in semen or vaginal fluids. To protect your partner, it’s safest to either avoid sex or use a barrier form of contraception for about 48 hours after chemotherapy.
If you’re admitted to hospital for a reason not related to the cancer, it’s important to tell the doctors and nurses looking after you that you're having chemotherapy treatment. You should tell them the name of your cancer specialist so that they can ask for advice.
It’s a good idea to know who you should contact if you have any problems or troublesome side effects when you’re at home. Your chemotherapy nurse or doctor will give you details of who to contact for advice. This should include ‘out-of hours’ contact details if you need to call someone at evenings, overnight or at the weekend.
This section is based on our irinotecan fact sheet, which has been compiled using information from a number of reliable sources, including:
For answers, support or just a chat, call the Macmillan Support Line free (Monday to Friday, 9am-8pm)
If you have any questions about cancer, need support or just want someone to talk to, ask Macmillan.
Watch our slideshow with tips for coping with a poor appetite
Watch our slideshow with tips for coping with a sore mouth
Watch our video about coping with fatigue
Watch our slideshow about avoiding infection when you have reduced immunity