Each person’s reaction to a cancer drug is different. Some people may have very few side effects, while others may experience more. We have outlined the most common side effects. We have not included those that are very rare, and which are therefore extremely unlikely to affect you. If you notice any effects that you think may be due to the drug but are not listed here, please discuss them with your doctor or nurse.
The side effects of imatinib are generally mild or moderate. They often occur during the first month of treatment and may get better after this initial period. The most common side effects are listed below.
Feeling sick (nausea) This is usually mild. The nausea can be relieved with antisickness (anti-emetic) drugs, which your doctor can prescribe. It can also be reduced by taking the tablet after food.
Diarrhoea This can usually be controlled easily with anti-diarrhoea medication, but let your doctor know if it is severe or if it continues. It is important to drink plenty of fluids if you have diarrhoea.
Headaches Some people have headaches when taking imatinib. Let your doctor know if you get any headaches as painkillers can be given to help.
Leg aches/cramps These can often be eased by taking mild painkillers, which your doctor can prescribe.
Fluid retention This is fairly common and is not harmful, although it can be upsetting. Many people gain weight, or notice swelling around the eyes and ankles due to the retention of fluid. Diuretics (drugs which make you pass more urine) can help to get rid of some of the fluid, but often it settles of its own accord. Let your doctor know if you put on a lot of weight very quickly.
Visual disturbances Imatinib can cause pain in the eyes and deterioration of vision. It may also cause more tears to be produced, which can lead to watery eyes.
Itchy rash If your skin becomes dry, this may be relieved with antihistamine tablets and skin lotion.
Lowered resistance to infection Imatinib can reduce the production of white blood cells by the bone marrow, making you more prone to infection. Your blood cells will be monitored while you are taking imatinib.
Contact your doctor or the hospital straightaway if:
- your temperature goes above 38ºC (100.5ºF)
- you suddenly feel unwell (even with a normal temperature).
You will have a blood test before having more chemotherapy to make sure that your cells have recovered. Occasionally it may be necessary to delay your treatment if the number of blood cells (the blood count) is still low.
Bruising or bleeding Imatinib can reduce the production of platelets (which help the blood to clot). Let your doctor know if you have any unexplained bruising or bleeding.
Anaemia (low number of red blood cells) While having treatment with imatinib you may become anaemic. This may make you feel tired and breathless. You may need to have a transfusion of blood if the number of red blood cells becomes too low.
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.