Imatinib (Glivec®) for chronic myeloid leukaemia

It works by blocking (inhibiting) signals within the leukaemia cells that make them grow and divide. Blocking the signals makes the cells die.

The National Institute for Health and Clinical Excellence (NICE)| has recommended imatinib as the first treatment to be considered in the chronic phase of CML. Imatinib can also be used in the accelerated or blast crisis phases of CML, as long as it hasn’t been used before.

Imatinib comes as a tablet. You take the tablet every day for as long as it’s working to control the leukaemia. 

Side effects

The side effects are usually mild and treatable. They may be more noticeable in the first four weeks of treatment and then begin to settle after this.

Side effects generally go away when treatment is stopped, so if you have severe side effects your doctor may ask you to stop taking imatinib for a few days. After a short break, you may be able to start taking it again without having the same problems. Occasionally some people need to stop taking imatinib altogether because their side effects are too severe.

Always let your doctor know if you notice any new side effects or if your side effects get worse. Side effects may include:

Feeling sick (nausea) and indigestion This is usually mild. It can be reduced by taking the tablet with a large glass of water after a main meal. If you continue to have problems with nausea, your doctor may prescribe anti-sickness medicine for you.

Diarrhoea This can usually be controlled with anti-diarrhoeal medicine. It’s important to drink plenty of fluids if you have diarrhoea. Let your doctor know if it’s severe.

Loss of appetite A dietitian or specialist nurse at your hospital can give advice and tips on boosting appetite, coping with eating difficulties and maintaining weight.

Headaches Let your haematologist know if you are having headaches. They can advise you on what painkillers to take.

Muscle cramps, bone and joint pains You may get cramps or pain in your hands, the calves of your legs and in your feet. Sometimes these lessen after a few weeks. Your haematologist can advise on what types of painkillers may help. They may also prescribe quinine, calcium or magnesium supplements to help if cramps are severe.

Build up of fluid in the tissues (oedema) This is fairly common. You may notice swelling around your eyes, especially in the morning. You may also notice swelling in other areas such as your ankles. Cutting down on the amount of salt in your diet can help. Your doctor may prescribe tablets to make you pass more urine (diuretics). It’s important to contact your doctor straight away if you gain a lot of weight quickly or if you feel breathless as this can be a sign of a more serious fluid build up.

Eye changes Your eyes may produce more tears than normal, making them watery. Some people have painful eyes or blurred vision.

Skin changes Imatinib can cause a skin rash. Usually it’s mild but sometimes it can be more severe. If the rash is itchy or your skin feels dry, antihistamine tablets and skin lotion may help. Speak to your doctor if you have a rash or other skin changes as they may prescribe additional treatments.

Some people notice changes in the colour (pigment) of their skin, with some areas becoming lighter or not tanning so well. This may be more noticeable if you have darker skin. Your skin may also become more sensitive to sunlight. It can help to use a sunscreen or cover up in the sun if you are affected.

Effects on your blood cells Imatinib can lower the numbers of healthy blood cells that are being made in your bone marrow. This is more common if you start taking it when the CML is in accelerated or blast phase. You’ll have regular blood tests while you are taking imatinib to monitor the levels of your blood cells. If your blood cell numbers are low this can cause:

Lowered resistance to infection if your white blood cell numbers are low. Contact your doctor or the hospital straight away if your temperature goes above 38°C (100.5°F) or you suddenly feel unwell (even with a normal temperature).

Bruising or bleeding if your platelet (cells which help the blood to clot) numbers are low. Let your doctor know if you have any unexplained bruising or bleeding.

Anaemia (too few red blood cells) You may feel tired and breathless. You may need to have a transfusion of blood if the number of red cells in your blood is too low.

If your blood cell numbers fall too low your doctor may stop your treatment for a few days to let them recover, or you may be prescribed injections of substances called growth factors. Growth factors| work by boosting the numbers of white blood cells (G-CSF) or red blood cells (erythropoietin|) your bone marrow can make.

Contraception and fertility

Imatinib is quite a new drug so there isn’t a lot of experience of women becoming pregnant or men fathering children while taking it. But there is a slightly increased risk of damage to the developing baby if imatinib is taken during pregnancy. So, it’s strongly recommended that you use contraception while taking it.

If you are taking imatinib and wish to father a child or become pregnant it’s important to discuss this with your haematologist.  They can discuss your treatment options with you. 

Taking other medicines

Some medicines can be affected by, or interact with, how imatinib works. This includes herbal medicines such as St John’s Wort and some commonly used painkillers such as paracetamol. So, it’s important to always check with your doctor before taking any medicines.