Imatinib (Gleevec®)
Pronounce: i-MA-tin-ib
Classification: Tyrosine Kinase Inhibitor
About Imatinib (Gleevec®)
A kinase is an enzyme that helps a cell grow. There are different types of kinases. Each type affects a different phase of cell growth. Kinase inhibitors slow down the growth of cancer cells.
How to Take This Medication
This medication comes as a tablet you take by mouth. Your dose will depend on your diagnosis. Take each dose with a glass of water and a meal. Imatinib may be dissolved in water or apple juice if you have trouble swallowing the tablets. Use approximately 50ml of liquid for a 100mg tablet and 200ml for a 400mg tablet, and drink immediately after the tablet disintegrates completely. Take this medication at around the same time(s) every day.
It is important to be sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed.
Certain medications/foods/supplements are broken down by the same enzymes as imatinib. This can cause the blood levels of these medications, or the blood levels of imatinib, to be higher or lower than expected. These include: grapefruit, grapefruit juice, acetaminophen (Tylenol), warfarin (Coumadin), several cholesterol medications, certain antibiotics, St. John’s wort, and some anti-seizure medications. Be sure to tell your healthcare provider about all medications and supplements you take.
Storage and Handling
Store your medication in the original container with the label. If you want to use a pillbox, talk to your pharmacist. Keep it in a dry place at room temperature unless your provider or pharmacist tells you otherwise. Keep containers out of reach of children and pets.
If a caregiver prepares your dose for you, they should consider wearing gloves or pour the pills directly from their container into the cap, a small cup, or directly into your hand. They should avoid touching the pills. They should always wash their hands before and after giving you the medication. Pregnant or nursing people should not prepare the dose for you. Ask your provider where to return any unused medication for disposal. Do not flush down the toilet or throw in the trash.
Insurance Information
This medication may be covered by your prescription plan. If you qualify, you may be able to get financial help through patient assistance programs (PAP). Co-pay cards may also be available to lower your out-of-pocket cost if you have commercial (not Medicare/Medicaid/Tricare) insurance. Your pharmacist, social worker, or navigator can help find resources for financial support.
Possible Side Effects
These are some of the most common or most serious side effects of this medication. Talk with your provider about the side effects you are having and how they can be managed.
Nausea and/or Vomiting
Talk to your providers if you have nausea and/or vomiting. They can prescribe medications to help you. Making changes to your diet can also help. Avoid things that make your symptoms worse, like heavy or greasy/fatty foods and spicy or acidic foods, like tomatoes, lemons, and oranges. Try saltines or ginger ale to help your symptoms.
Call your providers if you cannot keep fluids down for more than 12 hours or if you feel lightheaded or dizzy.
Diarrhea
Diarrhea is when you pass three or more stools in a day. Your providers can suggest medications to relieve diarrhea. Do not take any medications to manage your diarrhea without talking to your provider first, as your stool may need to be tested. To manage it, try eating foods that are low in fiber and bland, like white rice and boiled or baked chicken. Try not to eat raw fruits, vegetables, whole grain breads, cereals, and seeds. Soluble fiber is a type of fiber found in some foods that helps absorb (soak up) fluid. Foods high in soluble fiber are applesauce, bananas (ripe), canned fruit, oranges, boiled potatoes, white rice, foods made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Stay hydrated by drinking 8 to 10 glasses of non-alcoholic, non-caffeinated fluid each day.
Rash
Some people may get a rash, scaly skin, or red, itchy bumps from this medication. Tell your provider if you notice any of these changes in your skin, since it could be a reaction. Your provider may suggest:
- Using an alcohol-free moisturizer on your skin and lips, and do not use moisturizers with perfumes or scents.
- Keep the area clean to avoid infection, especially if it cracks or bleeds.
- Using a topical medication (applied to the skin) if the itching bothers you.
Be sure to talk with your provider about how to care for your skin.
Low White Blood Cell Count (Leukopenia or Neutropenia)
White blood cells (WBC) help your body fight infection. While you are having treatment for cancer, your WBC count can drop, putting you at a higher risk of an infection. Tell your provider right away if you have a fever (temperature greater than 100.4°F or 38°C), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.
Tips for preventing infection:
- Hand washing: both yours and your visitors is the best way to prevent the spread of infection.
- Avoid large crowds and people who are sick (those who have a cold, fever, or cough, or live with someone with these symptoms).
- When working outside, wear clothes that protect you, like long pants and gloves.
- Do not handle pet waste.
- Keep all cuts and scratches clean.
- Shower or bathe daily.
- Brush your teeth at least twice a day.
- Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
- Ask your providers before scheduling dental appointments or procedures.
- Ask your providers before you or someone you live with has any vaccines.
Low Red Blood Cell Count (Anemia)
Anemia is when your red blood cell count is lower than normal. Red blood cells carry oxygen to the tissues in your body. When your red cell count is low, you may feel tired or weak. Tell your providers if you have shortness of breath, trouble breathing, or pain in your chest. If your count gets too low, you may receive a blood transfusion.
Low Platelet Count (Thrombocytopenia)
Platelets are blood cells that help your blood clot. Thrombocytopenia is when your platelet count is lower than normal, and you are at a higher risk of bleeding. Tell your providers if you have any bruising or bleeding, including nose bleeds, bleeding gums, or blood in your urine or stool. If your count gets too low, you may receive platelets from a donor.
- Do not use a razor (an electric razor is fine).
- Do not do activities that can cause injury or bleeding.
- Talk to your provider before taking any non-steroidal, anti-inflammatory medications (NSAIDs) like Motrin/Advil (ibuprofen), Aleve (naproxen), Celebrex (celecoxib), and others. These can raise the risk of bleeding.
- Use a soft-bristle toothbrush to brush your teeth. Ask your provider about flossing or using toothpicks.
Fatigue
Fatigue can cause exhaustion, feeling worn out and that your body is "heavy" and hard to move, or being unable to focus. It is common when you have cancer, and it is not the same as feeling tired. You may need to adjust your schedule to manage fatigue. Plan times to rest during the day and save your energy for more important activities. Exercise can help lessen fatigue. Talk to your providers about ways to deal with this side effect.
Edema
Some patients experience swelling around the eyes or in the legs or feet due to fluid retention in the tissues. Fluid can also build up in the lungs or heart. Notify your healthcare team if you develop swelling, have unexpected weight gain, chest pain, or shortness of breath. Your doctor may prescribe a diuretic (medication that causes you to produce more urine) to help get rid of some of the excess fluid.
Muscle Cramps
Some patients develop mild muscle aches, cramps, spasms, or pain in their legs or feet while taking the medication. These aches and cramps can usually be managed with calcium and magnesium supplements or mild pain medications, such as ibuprofen. Let your provider know if you have muscle cramps.
Muscle or Joint Pain/Aches and Headache
You may have joint or muscle pain/aches and headaches while taking this medication. Your provider can recommend medications and other ways to help relieve your pain.
Driving or Operating Machinery
Some patients may experience dizziness, sleepiness, or blurred vision while taking this medication. You should use caution when driving or operating machinery until you know how this medication will affect you.
Reproductive Concerns
There is a higher risk of health problems for your baby if you are pregnant, become pregnant, or get someone pregnant while on this medication. To lower the risk of birth defects, you should use birth control (contraception) to avoid pregnancy. Talk with your provider about what kind of birth control is safest for you and your partner.
If you can become pregnant, you will need to use effective birth control during treatment and for 2 weeks after the last dose of this medication, even if your menstrual cycle has stopped or changed. You should not breastfeed during treatment and for 1 month after the last dose of this medication.
Important but Less Common Side Effects
Liver Toxicity
This medication can cause liver toxicity, or liver problems, which your provider may monitor for with blood tests called liver function tests. Symptoms may be:
- Yellowing of your skin or eyes.
- Dark or brown urine.
- Pain in your abdomen (belly).
Tell your provider if you have any of these symptoms.
Skin Reactions
This medication can cause severe skin reactions. Notify your provider if you develop sores or ulcers on your skin, lips, or in your mouth, or if you develop a rash, blisters, or peeling skin.
Thyroid Problems
Your thyroid is a gland that makes hormones. This medication can cause hypothyroidism (when your thyroid does not work as well as it should). Your provider will do blood tests to check your thyroid and treat this side effect if you have it. Symptoms of hypothyroidism include:
- Feeling cold.
- Weight gain.
- Feeling anxious.
- Changes in your voice.
- Muscle cramps.
Talk to your provider about any symptoms you are having.
Heart Problems
This medication can cause or worsen pre-existing heart problems, like congestive heart failure, restrictive cardiomyopathy, decreased heart function, and heart attack. Symptoms may be:
- Sudden weight gain.
- Swelling in your ankles or legs.
- Chest pain or pressure.
- Pain in your left arm, back, or jaw.
- Sweating.
- Shortness of breath.
- Clammy skin.
- Nausea.
- Dizziness or lightheadedness.
If you have any of these symptoms, call 911.
Gastrointestinal (GI) Bleed & Tear
This medication can cause bleeding or a tear in the wall of your gastrointestinal (GI) system. Signs of these problems are:
- Bright red blood in your stool or black stools.
- Coughing up blood.
- Vomiting blood or vomit that looks like coffee grounds.
- Fever.
- Severe pain in your abdomen (belly) or new abdominal swelling.
If you have any of these symptoms, call 911.
Tumor Lysis Syndrome
Tumor Lysis Syndrome (TLS) is a side effect that happens when tumor cells die too quickly, and their waste overwhelms the body. You may be given a medication (allopurinol) and IV fluids to help prevent this. TLS can affect your kidney function. Your provider will monitor your kidney function with blood work. Symptoms may be:
- Nausea.
- Vomiting.
- Diarrhea.
- Lethargy (feeling tired, drowsy, sluggish).
- Little or no urine output.
Tell your provider right away if you have any of these symptoms.
Kidney Problems
This medication can cause kidney problems, like an increased creatinine level. Your provider may monitor for kidney problems with blood tests. Symptoms may be:
- Less urine output than normal.
- Blood in the urine.
- Swelling in the ankles.
- Loss of appetite.
Tell your provider if you have any of these symptoms.