Understanding Side Effects


What You Can Expect From GLEEVEC

It’s common to be concerned about side effects before starting a new treatment. That’s why it’s important to learn everything you can about GLEEVEC® (imatinib mesylate) tablets so you’re prepared to work closely with your doctor or nurse if a side effect does occur.


The following serious side effects have been reported by patients taking GLEEVEC:


  • Severe fluid retention (holding water), which can cause swelling around the eyes or swelling of the lower legs, lungs, and heart; fatal in rare cases
  • Increased pressure in the heart or brain; fatal in rare cases
  • Low levels of certain blood cells
  • Heart failure
  • Liver problems
  • Hemorrhage (abnormal bleeding)
  • Skin blistering
  • Low levels of thyroid hormone


Your doctor will check you closely for any side effects to stop more serious complications from occurring. Patients with heart disease or risk factors for heart failure should also be monitored carefully.


GLEEVEC is sometimes associated with stomach or intestinal irritation. GLEEVEC should be taken with food and a large glass of water to minimize this problem. There have been rare reports, including deaths, of stomach or intestinal perforation (a small hole or tear).


If you are experiencing any of the above-mentioned side effects, please be sure to speak with your doctor immediately.


Common Side Effects of GLEEVEC


Almost all patients treated with GLEEVEC experience side effects at some time. Some common side effects that you may experience include:


  • Fluid retention (holding water)
  • Muscle cramps, pain, or bone pain
  • Abdominal pain
  • Anorexia (loss of appetite)
  • Vomiting
  • Diarrhea
  • Decreased hemoglobin (decrease in blood cells which carry oxygen)
  • Hemorrhage (abnormal bleeding)
  • Nausea
  • Fatigue
  • Rash


If you are experiencing any of the above-mentioned side effects, please be sure to speak with your doctor immediately.


The severity of some side effects may be reduced with the help of other medicines and advice from your doctor, while others may require stopping GLEEVEC therapy for a while or changing the dose. However, in some cases, GLEEVEC therapy may need to be discontinued.


Tell your doctor if you have a history of heart disease or risk factors for heart disease or if you experience side effects, including fever, shortness of breath, blood in your stools, jaundice (yellowing of the skin and/or eyes), sudden weight gain, or symptoms of heart failure during therapy with GLEEVEC.


After the approval of GLEEVEC, the following adverse events have been reported in patients treated with GLEEVEC: compression of the heart due to increased fluid, swelling of the brain, GI perforation (holes in the stomach or intestine), and sudden lung failure. These events, including some fatalities, may or may not have been drug related.


Take GLEEVEC exactly as prescribed. Do not change your dose or stop taking GLEEVEC unless you are told to do so by your doctor. If you miss a dose, take your dose as soon as possible, unless it is almost time for your next dose. In this case, your missed dose should not be taken. A double dose should not be taken to make up for any missed dose. You should take GLEEVEC with a meal and a large glass of water.


Do not take any other medications without talking to your doctor or pharmacist first, including over-the-counter medications such as Tylenol® (acetaminophen); herbal products (St. John's wort, Hypericum perforatum); or prescription medications including Coumadin® (warfarin sodium); rifampin; erythromycin; metoprolol; ketoconazole; and Dilantin® (phenytoin). Taking these with GLEEVEC may affect how they work, or affect how GLEEVEC works.


You should also tell your doctor if you are taking or plan to take iron supplements. Patients should also avoid grapefruit juice and other foods that may affect how GLEEVEC works.


Tylenol (acetaminophen) is a registered trademark of McNeil Consumer & Specialty Pharmaceuticals, a division of McNeil PPC, Inc. Coumadin (warfarin sodium) is a registered trademark of Bristol-Myers Squibb Company. Dilantin (phenytoin) is a registered trademark of Parke-Davis, a division of Pfizer Inc.


Please see full Prescribing Information, which includes a more complete discussion of the risks associated with GLEEVEC.


You are encouraged to report negative side effects of prescription drugs to the FDA. Visit www.fda.gov/medwatch or call 1-800-FDA-1088.