Imatinib Mesylate (Generic Name)

Other Names: Gleevec®

About This Drug

Imatinib mesylate is used to treat cancer. It is given orally (by mouth).

Possible Side Effects (More Common)

  • Bone marrow depression. This is a decrease in the number of white blood cells, red blood cells, and platelets. This may raise your risk of infection, make you tired and weak (fatigue), and raise your risk of bleeding.
  • Nausea and throwing up (vomiting). Medicines are available to stop or lessen these side effects.
  • Flu-like symptoms: fever, headache, muscle and joint aches, and fatigue (low energy, feeling weak)
  • Swelling of your legs, ankles and/or feet
  • Weight gain
  • Loose bowel movements (diarrhea)
  • Constipation (not able to move bowels)
  • Upset stomach
  • Rash with or without itching
  • Cough
  • Shortness of breath
  • Irritation of your nose and throat
  • Feeling dizzy
  • Loss of appetite
  • Trouble sleeping
  • Changes in your liver function.  Your doctor will monitor your liver function as needed.
  • Night sweats
  • Chest pain or symptoms of a heart attack. Most heart attacks involve discomfort in the center of the chest that lasts more than a few minutes. Or the discomfort may go away and come back. It can feel like uncomfortable pressure, squeezing, fullness, or pain. Sometimes discomfort is felt in one or both arms, the back, neck, jaw, or stomach. If any of these symptoms last 2 minutes, call 911.

Possible Side Effects (Less Common)

  • Flushing
  • Feeling your heart beat rapidly
  • Sensitivity to light (photosensitivity). You may become more sensitive to the light from the sun, sun lamps, and tanning beds. Your eyes may water more, mostly in bright light.
  • Effects on the heart: This drug can weaken the heart and lower heart function. Your heart function will be checked as needed. You may have trouble catching your breath, mainly during activities. You may also have trouble breathing while lying down, and have swelling in your ankles.
  • Bleeding in the brain. Symptoms such as sudden numbness or weakness of your face, arm, or leg, especially on one side of your body; sudden confusion, trouble speaking or understanding; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, loss of balance or coordination; or sudden, severe headache with no known cause.  If you have any of these symptoms for 2 minutes, call 911.

Treating Side Effects

  • Ask your doctor or nurse about medicine that is available to help stop or lessen these symptoms: nausea, vomiting, diarrhea, constipation, upset stomach, gas and bloating, pain, trouble sleeping, cough, nose and throat irritation, depression, anxiety, dry eyes, eye irritation, or headache.
  • If you are constipated, check with your doctor or nurse before you use enemas, laxatives, or suppositories.
  • Drink 6-8 cups of fluids each day unless your doctor has told you to limit your fluid intake due to some other health problem. A cup is 8 ounces of fluid. If you throw up or have loose bowel movements you should drink more fluids so that you do not become dehydrated (lack water in the body due to losing too much fluid).
  • Wear sunglasses and use sunscreen with SPF 30 or higher when you are outdoors even for a short time. Cover up when you are out in the sun. Wear wide-brimmed hats, long-sleeved shirts, and pants. Keep your neck, chest, and back covered.
  • If you get a rash do not put anything on it unless your doctor or nurse says you may. Keep the area around the rash clean and dry. Ask your doctor for medicine if your rash bothers you.

Important Information

  • Take this drug with food and a large glass of water to avoid upset stomach.
  • Swallow the medicine whole.  Do not chew, break or crush it.
  • Missed dose: If you miss a dose, take it as soon as you remember. Do not take it if it is close (within 12 hours) of your next dose. Just take the next dose at your normal time. Do not take more than 1 dose at a time.

Food and Drug Interactions

  • There are known interactions of imatinib mesylate with grapefruit. Do not eat grapefruit or drink grapefruit juice while taking this drug.
  • There are known interactions of imatinib mesylate with other medicines and products like acetaminophen, aspirin, ibuprofen.  Ask your doctor what over-the-counter (OTC) medicines you can take for fever, headache and muscle and joint pain.
  • Talk with your doctor about taking St. John’s Wort, garlic, ginseng, and ginkgo. Tell your doctor and pharmacist about all the medicines and dietary supplements (vitamins, minerals, herbs and others) that you are taking at this time. The safety and use of dietary supplements and alternative diets are often not known. Using these might affect your cancer or interfere with your treatment. Until more is known, you should not use dietary supplements or alternative diets without your cancer doctor's help.

When to Call the Doctor

Call your doctor or nurse right away if you have any of these symptoms:

  • Fever of 100.5 F (38 C) or higher
  • Chills
  • Easy bleeding or bruising 
  • Wheezing or trouble breathing
  • Rash or itching
  • Feeling dizzy or lightheaded
  • Feeling that your heart is beating in a fast or not normal way (palpitations)
  • Loose bowel movements (diarrhea) more than 4 times a day or diarrhea with weakness or lightheadedness
  • Blurred vision or other changes in eyesight
  • Nausea that stops you from eating or drinking
  • Throwing up more than 3 times a day
  • Chest pain or symptoms of a heart attack. Most heart attacks involve pain in the center of the chest that lasts more than a few minutes. The pain may go away and come back. It can feel like pressure, squeezing, fullness, or pain. Sometimes pain is felt in one or both arms, the back, neck, jaw, or stomach. If any of these symptoms last 2 minutes, call 911.
  • Symptoms of bleeding in the brain, such as sudden numbness or weakness of your face, arm, or leg, especially on one side of your body; sudden confusion, trouble speaking or understanding; sudden trouble seeing in one or both eyes; sudden trouble walking, dizziness, loss of balance or coordination; or sudden, severe headache with no known cause.  If you have any of these symptoms for 2 minutes, call 911.
  • Signs of liver problems: dark urine, pale bowel movements, bad stomach pain, feeling very tired and weak, unusual itching, or yellowing of the eyes or skin

Call your doctor or nurse as soon as possible if you have any of these symptoms:

  • Nausea that is not relieved by prescribed medicines
  • Rash that is not relieved by prescribed medicines
  • Heavy menstrual period that lasts longer than normal
  • Swelling of legs, ankles, or feet
  • Weight gain of 5 pounds in one week (fluid retention)
  • Lasting loss of appetite or rapid weight loss of five pounds in a week
  • Fatigue that interferes with your daily activities
  • Headache that does not go away
  • Painful, red, or swollen areas on your hands or feet.
  • No bowel movement for 3 days or you feel uncomfortable
  • Extreme weakness that interferes with normal activities

Reproduction Concerns

  • Pregnancy warning: This drug may have harmful effects on the unborn child, so effective methods of birth control should be used during your cancer treatment.
  • Genetic counseling is available to you to discuss the effects of this drug therapy on future pregnancies. In addition, a genetic counselor can review the potential risks of problems in the fetus due to this medication if an exposure during pregnancy has occurred.
  • Breast feeding warning: Women are advised not to breast feed during treatment because this drug could enter the breast milk and seriously harm the breastfeeding infant.

Revised November 2014

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