Glivec 400mg Tablet belongs to the class of medicines known as tyrosine kinase inhibitors. It is used in the treatment of blood cancer (chronic myeloid leukaemia and Acute lymphocytic leukemia) and gastrointestinal stromal tumor. Glivec 400mg Tablet should be taken with food, but better to have it same time every day to get the most benefit. You should continue to take it as long as your doctor advises for it. The duration of treatment varies according to your need and response to treatment. Taking it in the wrong way or taking too much can cause very serious side effects. It may take several weeks or months for you to see or feel the benefits but do not stop taking it unless your doctor tells you to. The most common side effects of this medicine include edema, nausea, vomiting, muscle cramps, musculoskeletal pain, diarrhea, rash, fatigue, and abdominal pain. Let your doctor know if you experience unexpected rapid weight gain. Your doctor may advise for regular monitoring of blood cells and liver function while you are taking this medicine. Do not drive or do anything requiring mental focus if you experience dizziness and blurry vision. Many other medicines can affect, or be affected by, this medicine so let your healthcare team know all medications you are using. This medicine is not recommended during pregnancy or while breastfeeding. The use of effective contraception by both males and females during treatment is important to avoid pregnancy.