What is Gleevec (Imatinib Mesylate)?

Gleevec is a life-changing medication prescribed for the treatment of certain types of cancer, including chronic myeloid leukemia (CML) and gastrointestinal stromal tumors (GISTs). Its active ingredient, imatinib, targets specific abnormal proteins in cancer cells, inhibiting their growth and promoting remission. Gleevec has revolutionized cancer therapy, offering a highly effective and well-tolerated oral treatment option. With Gleevec, patients have experienced remarkable improvements in their prognosis and quality of life. This breakthrough medication has become a beacon of hope, providing new possibilities for long-term survival and disease management. Consult your oncologist to explore if Gleevec is the right choice for you or your loved one.


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Prescription Required.Product of Canada.Shipped from Canada.

What is Gleevec (Imatinib Mesylate)?

Gleevec (imatinib mesylate) is a protein tyrosine kinase inhibitor used for treatment in cases of chronic-phase Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) in both children and adults. It may also be utilized for those with Ph+ CML that is in the accelerated phase or in blast crisis if prior treatment with interferon-alpha has proven to be unsuccessful. Additional uses of Gleevec include treating other variations of leukemia as well as skin cancer, stomach and other digestive tumors, and bone marrow disorders.

How is Gleevec Used?

Patients taking Gleevec should consume the medication orally either once daily (for the lower doses of 400 mg or 600 mg) or twice daily for those who are required to take two doses of 400 mg to reach a total dosage of 800 mg daily. It should be taken with a meal as well as plenty of water. This medication should not be taken on an empty stomach.

Individuals who experience difficulty with swallowing the tablets have the option of dispersing the medication in a glass of apple juice or water. For those who use this method of breaking down their medication for easier consumption, the Gleevec tablets should be stirred into either the water or apple juice until fully dissolved, and the patient should immediately consume the suspension once prepared. The recommended ratio of liquid to medication is 2 oz/100 mg tablet or 7 oz/400 mg tablet.

Patients may expect a dose increase in instances of insufficient treatment results after multiple months of treatment, a reduction in results or improvement of their condition after having previously shown improvement with Gleevec, or a progression of their condition.

Patients taking a dose of 800 mg of Gleevec or more per day, depending on the severity of their condition, are often recommended to achieve this dosage using the 400 mg tablets of the medication to reduce iron exposure. Patients should not attempt to take eight of the 100 mg tablets of Gleevec to achieve the 800 mg dosage due to the coating on the tablets containing iron which may result in adverse effects from consuming too much of the mineral.


Gleevec tablets should be stored between temperatures of 68°F (20°C) to 77°F (25°C). This medication may be exposed to temperatures as low as 59°F (15°C) and as high as 86°F (30°C) in some circumstances. However, exposure to temperatures outside of the recommended range is not suggested and may impact the integrity of the medication.

Keep this medication out of the reach of pets and children at all times.

Gleevec tablets should not be crushed, and all individuals should avoid contact with any tablets that have been crushed as the medication may be dangerous when exposure occurs to one’s skin as well as the eyes, nose, or mouth. This includes breathing in any dust from crushed Gleevec tablets. Individuals that come into contact with crushed Gleevec tablets should wash the exposed areas thoroughly.


Gleevec is prescribed for a variety of conditions, including but not limited to:

  • Acute lymphoblastic disorder
  • Aggressive systemic mastocytosis
  • Chronic eosinophilic leukemia
  • Chronic myelogenous leukemia
  • Dermatofibrosarcoma protuberans
  • Hypereosinophilic syndrome
  • Leukemia
  • Multiple myeloma
  • Myelodysplastic disease
  • Myeloproliferative disorder
  • Polycythemia vera
  • Thrombocythemia

How Does Gleevec Work?

Gleevec functions as a protein tyrosine kinase inhibitor by blocking tyrosine kinase enzymes, which are responsible for cell growth, division, and communication. By inhibiting these particular enzymes, Gleevec is able to slow or halt the growth and spread of cancerous cells.

The main enzymes targeted by Gleevec include those associated with the KIT protein, SCF (stem cell factor), PDGF (platelet-derived growth factor), and BCR-ABL protein. These proteins are those most commonly associated with conditions such as acute lymphoblastic leukemia (ALL), gastrointestinal stromal tumors, chronic myelogenous leukemia (CML), and certain skin cancers.


Gleevec is available in two different strengths:

  • 100 mg tablets (film-coated)
  • 400 mg tablets (film-coated)

Most individuals of adult age with CML in its chronic phase are prescribed a dosage of 400 mg per day, whereas patients with CML in blast crisis or its accelerated phase will often be required to take 600 mg per day. Adults using Gleevec for the treatment of Ph+ ALL that is refractory or in relapse will generally be prescribed a daily dose of 600 mg.

Adult patients who are prescribed Gleevec for myelodysplastic or myeloproliferative disorders are most commonly prescribed a dose of 400 mg per day for treatment.

The recommended daily dose of Gleevec for adult patients with hypereosinophilic syndrome or chronic eosinophilic leukemia is 400 mg per day. Those with FIP1L1-PDGFR? fusion kinase will typically start treatment with Gleevec at a lower dose of 100 mg per day that may be increased as needed.

Patients with aggressive systemic mastocytosis will typically be prescribed a dose of 400 mg per day for both those who have not had a sufficient response to prior therapy options as well as those without the D816V c-Kit mutation. A daily dose of 100 mg per day is recommended for those who have ASM that is linked to eosinophilia or that have hematological conditions associated with the fusion kinase FIP1L1-PDGFR?. These individuals may also have their dosage increased to 400 mg per day if they show sufficient tolerance to Gleevec in regard to adverse reactions along with the need for a higher dose of the medication to achieve a positive response.

Adult patients with dermatofibrosarcoma protuberans most commonly are treated with a daily dose of 800 mg of Gleevec per day.

Patients with gastrointestinal stromal tumors are typically prescribed a daily dose of 400 mg of Gleevec when the condition is adjuvant. When metastatic or unresectable, the prescribed dosage of Gleevec may vary between 400 mg per day up to 800 mg per day (taken as a twice-daily dose of the 400 mg tablets) when required based on the progression of the disease as well as a decent tolerance for any adverse side effects.

Pediatric patients with a new diagnosis of Ph+ CML should not exceed 600 mg of Gleevec per day. The recommended dosage for this age group is 340 mg/m2/day, and it may be administered once per day in a single dose or split into two doses taken once in the morning and once in the evening.


Individuals who have overdosed on Gleevec or suspect they may have taken too much of the medication should seek emergency medical attention immediately or call their local Poison Control Center.

A single dose of 8 g to 10 g of Gleevec has been reported to result in gastrointestinal pain and vomiting.

A patient who ingested a single dose of 6,400 mg experienced abdominal pain, facial swelling, a decrease in neutrophil count, nausea, pyrexia, vomiting, and an increase in transaminases.

Prolonged overdosage of Gleevec (such as 1,800 mg to 3,200 mg of Gleevec ingested for a period of six days) has been shown to result in gastrointestinal pain, an increase in bilirubin, an increase in CPK, myalgia, and weakness.

A duration of one to ten days with ingestion of overdose levels of 1,200 mg to 1,600 mg of Gleevec has been shown to result in symptoms such as abdominal pain, a decrease in appetite, fatigue, edema, headache, muscle spasms, diarrhea, nausea, swelling, vomiting, pancytopenia, and thrombocytopenia.

Side Effects

The most common side effects of taking Gleevec are as follows:

  • abdominal pain
  • blurred vision
  • diarrhea
  • dizziness
  • fatigue or unusual tiredness
  • fluid retention
  • gas
  • hair loss
  • joint pain
  • muscle pain
  • nausea
  • rash
  • sinus pain
  • stuffy nose
  • vomiting

Some of the eye-related side effects associated with Gleevec use include the following:

  • bleeding in the eye
  • cataract development
  • eye irritation
  • dryness of the eyes
  • blurry vision
  • glaucoma
  • infections (e.g., pink eye)
  • a red spot developing on the sclera

Please contact your doctor for further information if you experience any of the following additional side effects and have any concerns, as the following symptoms are considered serious and may impact treatment with this medication:

  • bloody or black stools
  • dark-colored urine
  • easy bleeding or bruising
  • extreme fatigue
  • fluid-filled blisters
  • flu-like symptoms that are severe
  • gastrointestinal bleeding
  • headaches that are notably severe
  • jaundice (yellowing of the eyes or skin)
  • rapid heart rate
  • rashes with severe blistering
  • severe rashes on the skin
  • shortness of breath
  • swelling around the eyes
  • swelling of the lower legs
  • symptoms of impaired immunity
  • unusual or sudden weight gain
  • vomit that resembles coffee grounds
  • weakness

If you experience any of the following symptoms of an allergic reaction, stop taking Gleevec immediately and seek out emergency medical care:

  • swelling of the tongue, mouth, lips, or throat
  • difficulty breathing
  • swelling under the skin of the hands, feet, or eyelids
  • itching
  • rash
  • skin flushing

Due to some of the potential side effects of taking Gleevec, patients are advised to avoid exposure to individuals who have infections or are otherwise sick, avoid any activities that may have an increased risk of causing injury or bleeding, and exercise caution when operating a motor vehicle or any other equipment before knowing how Gleevec will impair their ability to concentrate and perform such tasks.

Patients are also advised to exercise caution when using marijuana or consuming alcohol due to the dizziness and drowsiness that already occurs with Gleevec. The use of alcohol while taking this medication should be limited, and patients should discuss any prior or ongoing cannabis or alcohol use when being prescribed Gleevec.

Warnings & Precautions

Gleevec has been associated with a number of significant health conditions resulting from both short-term as well as long-term use of the medication. Please discuss all preexisting health conditions and your medical history with your prescribing physician before beginning treatment with this medication.


Although pediatric use of Gleevec has been approved, this medication has been reported to cause growth retardation in pediatric patients. The growth and development of pediatric patients should be monitored for the duration of their treatment with Gleevec.

Fluid Retention and Swelling

Gleevec has been closely associated with symptoms of severe swelling and fluid retention in patients using the medication for treatment. Any unusual or sudden weight gain while taking this medication should be reported to the patient’s doctor immediately. Treatment for excessive fluid retention or swelling may be treated with diuretics or by temporarily stopping treatment with Gleevec until the symptoms become manageable.

Gastrointestinal Perforations

One significant risk of using Gleevec for treatment is the occurrence of small tears or holes presenting in the intestines and walls of patients’ stomachs. Patients who may be at risk for this issue are strongly recommended to contact their prescribing physician if they suspect such a condition may be occurring. In some cases, this development has proven to be fatal, so patients should communicate any concerns with their doctor.


Gleevec has been closely associated with significant liver damage as well as fatal cases of liver failure resulting in liver transplants. This has occurred in patients using the medication for both short-term use and long-term use. Patients using Gleevec for treatment will have their liver function checked before starting treatment with Gleevec as well as for the duration of treatment if problems begin to arise regarding the function of their liver.

Heart Conditions

Gleevec has been reported to result in some patients experiencing left ventricular dysfunction as well as severe congestive heart failure. If an individual taking this medication has preexisting heart conditions or a medical history that includes heart disease or other associated risks, they will require monitoring for these conditions throughout the duration of their treatment with Gleevec.


Patients taking Gleevec alongside the use of levothyroxine for thyroid conditions have been reported to experience hypothyroidism. Individuals taking Gleevec should have their thyroid levels monitored throughout the duration of treatment.


Cytopenias have been reported in patients using Gleevec for treatment. Patients that develop severe cytopenias may have their use of Gleevec discontinued. Patients taking this medication will have their blood tested weekly, bi-weekly, and then periodically throughout the duration of their treatment.


This medication has been detected in the breast milk of lactating patients when using Gleevec for treatment. Due to the health risks this poses for any infant that is breastfed by the patient or receiving milk from the patient using Gleevec, it is strongly advised that such patients either avoid breastfeeding or delay breastfeeding until at least one month after their last dose of the medication. Up to 10% of the dose taken by the breastfeeding patient has been shown to be passed to the infant receiving the breastmilk while the patient has used the medication.


Gleevec is a category D medication regarding pregnancy, meaning that it has been shown to result in adverse effects on infants impacted by a patient having used this medication during pregnancy. Due to the significant health risks this medication poses for unborn babies, patients requiring the use of Gleevec are advised to weigh the risks to the pregnant patient’s health against the potential complications the medication may cause in pregnancy as well as to the developing child.

Patients using Gleevec that are capable of becoming pregnant are strongly advised to use suitable contraception during treatment to avoid pregnancy and any complications.

Additional Medical Conditions

If you have any of the following medical conditions, exercise caution when taking Gleevec and discuss your medical history with your doctor before beginning this medication:

  • diabetes
  • heart disease
  • hypertension
  • irregular heartbeat
  • liver disease or impairment
  • kidney disease or impairment
  • previous history of heart attack
  • thyroid conditions

Individuals taking Gleevec should also inform their physician they are taking the medication before receiving any vaccinations or immunizations. Patients using Gleevec should also try to avoid exposure to those who have recently received any live vaccines.

Additionally, geriatric patients using Gleevec are more at risk for experiencing adverse side effects such as swelling and fluid retention.

Drug Interactions

Speak to your doctor about any medications or herbal supplements you are currently taking before beginning treatment with Gleevec. Discuss any concerns you may have with your doctor or a trusted pharmacist. Do not take any medications, including over-the-counter medications or herbal supplements, without first consulting your physician if you are currently taking Gleevec.

Drugs That May Interact with Gleevec

The following medications have been shown to interact with Gleevec, whether impairing the effectiveness of those medications or impairing the efficacy of Gleevec itself. Exercise caution and inform your prescribing physician or pharmacist if you are currently taking or may need to take one of the following drugs during the time in which you are being treated with Gleevec:

  • acetaminophen
  • amlodipine (Norvasc, Caduet)
  • anticoagulants (blood thinners)
  • antifungals
  • anxiety medications
  • atorvastatin (Lipitor)
  • birth control implants
  • birth control injections
  • birth control patches
  • birth control pills
  • birth control rings
  • calcium channel blockers
  • carbamazepine (Tegretol)
  • certain antibiotics
  • cholesterol-lowering medications (statins)
  • clarithromycin (Biaxin)
  • cyclosporine (Neoral, Sandimmune)
  • dexamethasone
  • diltiazem (Cardizem, Tiazac)
  • erythromycin (E-Mycin, Erythrocin)
  • felodipine (Plendil)
  • hormonal contraceptives
  • isradipine (Dynacirc)
  • itraconazole (Sporanox)
  • ketoconazole (Nizoral)
  • lovastatin (Mevacor)
  • nicardipine (Cardene)
  • nifedipine (Adalat, Procardia)
  • nimodipine (Nimotop)
  • nisoldipine (Sular)
  • phenobarbital
  • phenytoin (Dilantin)
  • pimozide (Orap)
  • rifampin (Rifadin, Rifamate)
  • sedatives
  • seizure medications
  • simvastatin (Zocor)
  • sleeping pills
  • tranquilizers
  • verapamil (Calan, Covera, Isoptin, Verelan)
  • warfarin (Coumadin)

Drugs That Should Not Be Used with Gleevec

The following should never be used alongside Gleevec:

  • anti-diarrhea medications

Other Drugs That May Interact with Gleevec

The following medications are also indicated to potentially cause interactions when used while taking Gleevec:

  • grapefruit juice
  • Hypericum perforatum
  • iron supplements
  • John’s wort

Alternative Medications

For patients who are unable to take Gleevec or experiencing significant adverse side effects, alternative medications may be used to treat some of the associated conditions for which this medication is commonly prescribed.

For the treatment of Ph+ CML, alternatives to Gleevec include:

  • Bosulif (bosutinib)
  • Cerubidine (daunorubicin)
  • cytarabine
  • Iclusig (ponatinib)
  • Intron A (interferon-alpha)
  • Sprycel (dasatinib)
  • Synribo (omacetaxine)
  • Tasigna (nilotinib)

For the treatment of GIST (gastrointestinal stromal tumors) and other conditions treated by Gleevec, some of the alternatives include:

  • Nexavar (sorafenib)
  • Sprycel (dasatinib)
  • Stivarga (regorafenib)
  • Sutent (sunitinib)
  • Tasigna (nilotinib)
  • Votrient (pazopanib)

Frequently Asked Questions

Individuals that are pregnant are strongly advised to avoid using Gleevec for treatment during pregnancy due to the proven risks to the unborn baby. Patients that are currently pregnant or planning to become pregnant should discuss the benefits and risks of using Gleevec for treatment during pregnancy with their doctor.

Patients taking Gleevec should not consume grapefruit or grapefruit juice when taking Gleevec for treatment as it is known to impact the levels of medication present within the body.

Gleevec should not be used by those who are breastfeeding due to the presence of the medication detected in the breastmilk of those taking the medication. The presence of Gleevec in breastmilk poses a significant health risk to infants. Patients should postpone breastfeeding for at least one month after their last dose of Gleevec to avoid any risks associated with infant consumption of the trace amounts of the medication passed through the patient’s breastmilk.

If a patient has accidentally missed a dose of their medication, they should typically take it as soon as they remember to do so. However, if it is less than 12 hours until your next dose, disregard the missed dose and simply take the next upcoming dose as scheduled.

Yes. A generic form of Gleevec is available for patients who have been prescribed this medication.

Gleevec is approved for use in pediatric patients, but its safety and efficacy have not been determined in those below the age of one year. Aside from the common side effects presented in all patients taking Gleevec, the most common concern of Gleevec use in pediatric patients is impaired growth.

Most individuals that have taken Gleevec for treatment have experienced improvement in their condition within the first two months. Others may take up to six months to notice significant results based on the severity of their condition as well as any other factors, such as age, other comorbid conditions, and the rate of disease progression.

The efficacy and side effects of the generic form of Gleevec are primarily the exact same as those of the name-brand form of Gleevec since the generic variation of the medication is simply a copy of the active ingredients present in Gleevec. There should be very little to no noticeable difference between the two in most circumstances.

Gleevec effectively targets cancer cells within the body, but it is also capable of reducing a patient’s level of white blood cells. When an individual experiences a reduction in white blood cells, this causes the body to be less capable of fighting off infections. Due to this weakening of a patient’s immune system, individuals taking Gleevec are advised to avoid exposure to those who are sick, have any active infections, or have just received a live vaccine.

Many of the adverse side effects of taking Gleevec resolve within a short period of time. However, Gleevec does come with the potential long-term risks of certain blood disorders as well as heart failure. Please discuss any concerns you may have about the long-term implications of Gleevec with your prescribing physician.

Gleevec is considered a targeted treatment. Due to the way in which this medication functions in response to the presence of cancerous cells, it is more often referred to as a “cancer growth inhibitor” since it does not perform in the same manner as chemotherapy drugs.

Individuals taking Gleevec for the treatment of gastrointestinal stromal tumors are recommended to avoid certain beverages and foods (such as coffee) that may aggravate their symptoms and any side effects that may be attributed to Gleevec.

The coating of Gleevec tablets contains iron. Due to the amount contained in the coating of each tablet, a patient that attempts to take eight of the 100 mg tablets would ingest too much iron and likely experience adverse effects. Taking two of the 400 mg tablets to achieve your prescribed dosage of 800 mg of Gleevec per day allows you to safely consume the medicine without significantly impacting your body’s iron levels.

The active ingredient in Gleevec is imatinib mesylate. The inactive ingredients also included in this medication are as follows: colloidal silicon dioxide, microcrystalline cellulose, magnesium stearate, crospovidone, and hydroxypropyl methylcellulose. The coating of the tablets includes the following additional ingredients: talc, polyethylene glycol, hydroxypropyl methylcellulose, ferric oxide yellow, and ferric oxide red.

No. Gleevec has been detected in the breast milk of those lactating while using the medication. It is strongly recommended that patients desiring to breastfeed either not use this medication or avoid breastfeeding while taking Gleevec to avoid the potential health risks to the breastfed infant.

In studies performed on rats, fertility was not impacted by Gleevec in males or females. A human study regarding Gleevec and infertility has not been performed.

Gleevec has been prescribed for the treatment of newly diagnosed Ph+ ALL and chronic phase Ph+ CML in pediatric patients and has been proven to be safe and effective. However, there is no information regarding the safety and efficacy of Gleevec in patients under the age of one year old.

A study was conducted that showed certain symptoms associated with withdrawal from Gleevec after stopping treatment, among these being itching and bone pain. Additionally, a patient that stops taking the medication before cessation has been recommended by their doctor will have their cancer symptoms and symptoms of any other conditions being treated by Gleevec worsen in intensity. This medication should not be abruptly stopped without a patient first consulting their prescribing physician regarding the best way to stop the medication or switch to one that may be more suitable.