Imatinib

Imatinib comes as tablets or capsules. The nurse or pharmacist will give you them to take home. Always take them exactly as explained. This is important to make sure they work as well as possible for you. 

During treatment you will see a haematologist (doctor who treats blood cancers) or a cancer doctor, a specialist nurse and a specialist pharmacist. This is who we mean when we mention doctor, nurse or pharmacist in this information.

Before or on the day of treatment, a nurse or person trained to take blood (phlebotomist) will take a blood sample from you. This is to check that your blood cells are at a safe level for you to have your treatment. 

You keep taking imatinib for as long as your doctor tells you. Do not stop taking it without talking to your doctor.

You usually take imatinib once or twice a day, depending on the dose your doctor prescribes. You should take it with a meal. The tablets or capsules must be swallowed whole with a glass of water. They should not be chewed, opened or crushed. Take them at the same time every day.

If you find it hard to swallow the tablets or capsules, tell your doctor, nurse or pharmacist. They may suggest that you dissolve them in still water or apple juice. They will give you clear instructions on how to do this. 

If you forget to take imatinib, you should take the missed dose as soon as possible. If it is nearly time for your next dose, skip the missed dose and continue with your usual schedule and let your doctor or nurse know. Do not take a double dose unless your doctor tells you to.

Other things to remember about your tablets or capsules:

• Keep them in the original package and at room temperature, away from heat.
• Keep them safe and out of sight and reach of children.
• If you are sick just after taking the capsules or tablets, contact the hospital. Do not take another dose.
• If your treatment is stopped, return any unused imatinib to the pharmacist.

This treatment can reduce the number of white blood cells in your blood. These cells fight infection. If the number of white blood cells is low, you are more likely to get an infection. A low white blood cell count is sometimes called neutropenia.

An infection can be very serious when the number of white blood cells is low. It is important to get any infection treated as soon as possible. Contact the hospital straight away on the 24-hour contact number you have been given if:

• your temperature goes over 37.5°C (99.5°F)
• you suddenly feel unwell, even with a normal temperature
• you have symptoms of an infection
• your temperature goes below 36°C (96.8°F).

Symptoms of an infection include:

• feeling shivery and shaking
• a sore throat
• a cough
• breathlessness
• diarrhoea
• needing to pass urine (pee) a lot, or discomfort when you pass urine.

It is important to follow any specific advice your cancer treatment team gives you.

You will have regular blood tests during treatment. If needed, your doctor may reduce or delay your treatment for a short time, until your cell count increases.

This treatment can reduce the number of platelets in your blood. Platelets are cells that help the blood to clot.

If the number of platelets is low, you may bruise or bleed easily. You may have:

• nosebleeds
• bleeding gums
• heavy periods
• blood in your urine (pee) or stools (poo)
• tiny red or purple spots on the skin that may look like a rash.

Tell your doctor if you have any unexplained bruising or bleeding. You may need a drip to give you extra platelets. This is called a platelet transfusion.

This treatment can reduce the number of red blood cells in your blood. Red blood cells carry oxygen around the body. If the number of red blood cells is low, this is called anaemia. You may have symptoms such as:

• pale skin
• lack of energy
• feeling breathless
• feeling dizzy and light-headed.

Tell your doctor or nurse if you have these symptoms.

If you are very anaemic, you may need a drip to give you extra red blood cells. This is called a blood transfusion.

This is usually mild. Your doctor can prescribe anti-sickness (anti-emetic) drugs to prevent or reduce sickness and vomiting. Taking imatinib with food also helps. Tell your doctor if the sickness isn't controlled or if it continues. They can give you other anti-sickness drugs that may work better for you.

This treatment may cause diarrhoea. Diarrhoea means passing more stools (poo) than is usual for you, or having watery or loose stools. If you have a stoma, it will be more active than usual.

If you have diarrhoea:

• try to drink at least 2 litres (3½ pints) of fluids each day
• avoid alcohol, caffeine, milk products, high-fat foods and high-fibre foods
• contact the hospital for advice.

Some people have indigestion or wind when taking imatinib. They may also have acid reflux, which is when acid comes up from the stomach and into the gullet. If this happens, tell your doctor.

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

You may gain weight or develop swelling around the eyes and ankles because of fluid build-up. Your doctor may prescribe drugs that make you pass more urine (diuretics) to help get rid of some fluid. But it often improves by itself.

If you put on weight very quickly it is important to let your doctor know straightaway.

Some people develop an itchy rash. If this happens, it is important to tell your doctor. They can advise you about creams or lotions to use, or prescribe medicines to relieve itching. 

If you have a severe rash or any blistering or peeling contact your doctor immediately.  You should also tell them straight away if you feel any flu-like symptoms, for example, a high temperature or pain in your joints.

Your skin may be more sensitive to sun while taking imatinib. Use a sun cream with a sun protection factor (SPF) of at least 30 when you are in the sun. Cover up with clothing and a hat.

Feeling tired is a common side effect. Try to pace yourself and plan your day so you have time to rest. Gentle exercise, like short walks, can give you more energy. If you feel sleepy, do not drive or operate machinery.

Cancer and some cancer treatments can increase the risk of a blood clot. Symptoms of a blood clot include:

• throbbing pain, redness or swelling in a leg or arm
• suddenly feeling breathless or coughing
• sharp chest pain, which may be worse when you cough or take a deep breath.

If you have any of these symptoms, contact the hospital straight away on the 24-hour contact number you have been given. If you cannot get through to your doctor, call the NHS urgent advice number on 111.

A blood clot is serious, but it can be treated with drugs that thin the blood (anticoagulants). Your doctor or nurse can give you more information.

You can help reduce the risk of developing a blood clot by:

• staying active during treatment
• drinking plenty of fluids, especially water.

You may be given anticoagulants to help prevent a clot.

Some medicines can affect how this treatment works or be harmful when you are having it. Always tell your cancer doctor about any drugs you are taking or planning to take, such as:

• medicines you have been prescribed
• medicines you buy in a shop or chemist
• vitamins, herbal drugs and complementary therapies.

Tell other doctors, pharmacists or dentists who prescribe or give you medicines that you are having this cancer treatment.

You can visit the electronic Medicines Compendium (eMC) for more detailed information about your treatment.

Some brands of imatinib contain a small amount of lactose. If you have a lactose intolerance, talk to your doctor before you start taking this.

If you have had a liver infection called hepatitis B in the past, this treatment can make it active again. Your doctor or nurse will talk to you about this. They will test you for hepatitis B.

Vaccinations can reduce your risk of getting certain infections. Your doctor or nurse may talk to you about having vaccinations.

Doctors usually recommend that people with cancer have a flu vaccination and a coronavirus (covid) vaccination. These are both inactivated vaccinations that can help reduce the risk of infection. People with weak immune systems can have these, as they are not live vaccinations. 

If your immune system is weak, you need to avoid live vaccinations. This is because they can make you unwell. Live vaccines contain a very weak version of the illness they are vaccinating you against. Your cancer doctor or GP can tell you more about live and inactivated vaccinations.

Some cancer drugs can affect whether you can get pregnant or make someone pregnant. If you are worried about this, it is important to talk with your doctor before you start treatment.

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.

You are advised not to breastfeed while having this treatment, or for some time after treatment finishes. This is because the drugs could be passed to the baby through breast milk.

Your doctor or nurse can give you more information.

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.