Imatinib Mesylate

Imantinib (Gleevec®)

About This Drug

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

Possible Side Effects

  • Nausea and throwing up (vomiting)
  • Loose bowel movements (diarrhea)
  • Pain in your abdomen
  • Swelling of your legs, ankles and/or feet
  • Rash 
  • Muscles, joint or bone pain
  • Muscle cramps
  • Tiredness

Note: Each of the side effects above was reported in 30% or greater of patients treated with imatinib. Not all possible side effects are included above.

Warnings and Precautions 

  • 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.
  • Abnormal bleeding. Symptoms may be coughing up blood, throwing up blood (may look like coffee grounds), red or black tarry bowel movements, abnormally heavy menstrual flow, nosebleeds or any other unusual bleeding.
  • Congestive heart failure. You may be short of breath. Your arms, hands, legs and feet may swell.
  • Effects on the heart. This drug may weaken the heart and lower heart function. Your heart function will be checked as needed. 
  • Changes in your liver function. Your doctor will check your liver function as needed.
  • Small holes or tears in the lining of your stomach or your intestines can happen. 
  • Severe skin reactions. You may develop blisters on your skin that are filled with fluid or a severe red rash all over your body.
  • Tumor lysis syndrome. This drug may act on your cancer cells very quickly. This may affect how your kidneys work. Your doctor will monitor your kidney function. 
  • Changes in your thyroid function. Your doctor will check your thyroid function as needed.
  • Severe swelling of your legs, ankles, feet and/or severe weight gain that can affect your heart and/or other organs.

Important Information 

  • This drug may impair your ability to drive or use machinery. Use caution and tell your nurse or doctor if you feel dizzy, very sleepy, or have blurred vision

How to Take your Medication 

  • 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.
  • If you have difficulty with swallowing your medication, you can dissolve the tablet in a glass of water or apple juice. 100 mg tablets should be dissolved in approximately 50 mL of liquid, and 400 mg tablets should be dissolved in 200 mL of liquid. The liquid should be stirred with a spoon and taken immediately once tablet has dissolved. 
  • Missed dose: If you vomit or miss a dose, take your next dose at the regular time.  Do not take 2 doses at the same time.
  • Handling: Wash your hands after handling your medicine, your caretakers should not handle your medicine with bare hands and should wear latex gloves. 
  • This drug is excreted in the urine, stool, vomit, semen, and vaginal secretions.  Talk to your doctor and/or your nurse about the necessary precautions to take during this time.
  • Storage: Store this medicine in the original container at room temperature. Discuss with your nurse or your doctor how to dispose of unused medicine.

Treating Side Effects

  • 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).
  • To help with nausea and vomiting, eat small, frequent meals instead of three large meals a day. Choose foods and drinks that are at room temperature. Ask your nurse or doctor about other helpful tips and medicine that is available to help or stop lessen these symptoms.
  • If you get diarrhea, eat low-fiber foods that are high in protein and calories and avoid foods that can irritate your digestive tracts or lead to cramping. Ask your nurse or doctor about medicine that can lessen or stop your diarrhea. 
  • Manage tiredness by pacing your activities for the day. Be sure to include periods of rest between energy-draining activities
  • Keeping your pain under control is important to your well-being. Please tell your doctor or nurse if you are experiencing pain. 
  • 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.

Food and Drug Interactions

  • Do not eat grapefruit or drink grapefruit juice while taking this medicine.  Grapefruit and grapefruit juice may raise the levels of imatinib in your body. This could make side effects worse.
  • Check with your doctor or pharmacist about all other prescription medicines and dietary supplements you are taking before starting this medicine as there are a lot of known drug interactions with imatinib.
  • There are known interactions of imatinib with other medicines and products like acetaminophen, 
    aspirin, and 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. 

When to Call the Doctor

Call your doctor or nurse if you have any of these symptoms and/or any new or unusual symptoms:

  • Fever of 100.5 F (38 C) or higher
  • Chills
  • Feeling dizzy or lightheaded
  • Fatigue that interferes with your daily activities
  • Feeling that your heart is beating in a fast or not normal way (palpitations)
  • Wheezing or trouble breathing
  • Nausea that is not relieved by prescribed medicine, or that stops you from eating or drinking or throwing up more than 3 times a day
  • Lasting loss of appetite or rapid weight loss of five pounds in a week
  • Loose bowel movements (diarrhea) more than 4 times a day or diarrhea with weakness or lightheadedness
  • Severe abdominal pain
  • 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
  • Decreased urine
  • Easy bleeding or bruising
  • Heavy menstrual period that lasts longer than normal
  • Blood in your urine, vomit (bright red or coffee-ground) and/or stools ( bright red, or black/tarry)
  • Coughing up blood
  • Rash or itching, or rash that worsens, and/or is not relieved by prescribed medicine
  • Swelling of legs, ankles, or feet
  • Weight gain of 5 pounds in one week (fluid retention)
  • Pain in your muscles or joints that is not relieved by prescribed medication

Reproduction Warnings 

  • Pregnancy: This drug may have harmful effects on the unborn baby, so effective methods of birth control should be used by both men and women during your cancer treatment and for at least 14 days after treatment. If you suspect you may be pregnant, please notify your nurse or doctor right away. 
  • Breast feeding: Women should not breast feed during treatment and for 1 month after treatment because this drug could enter the breast milk and badly harm a breast feeding baby.

Revised May 2017