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Quick facts
- How it is given
- oral
- Type
- human prescription drug
- RxNorm ID
- 403878
We do not publish dosing. How much of this medicine to take, how often, and for how long depends on your age, weight, kidney and liver function, other conditions and other medicines. That is a decision for the person who prescribes or dispenses it. Follow the directions on your own pack and ask your pharmacist if anything is unclear.
What it is used to treat
Imatinib mesylate is a kinase inhibitor indicated for the treatment of: • Newly diagnosed adult and pediatric patients with Philadelphia chromosome positive chronic myeloid leukemia (Ph+ CML) in chronic phase ( 1.1 ) • Patients with Philadelphia chromosome positive chronic myeloid leukemia (Ph+ CML) in blast crisis (BC), accelerated phase (AP), or in chronic phase (CP) after failure of interferon-alpha therapy ( 1.2 ) • Adult patients with relapsed or refractory Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) ( 1.3 ) • Pediatric patients with newly diagnosed Philadelphia chromosome positive acute lymphoblastic leukemia (Ph+ ALL) in combination with chemotherapy ( 1.4 ) • Adult patients with myelodysplastic/myeloproliferative diseases (MDS/MPD) associated with platelet-derived growth factor receptor (PDGFR) gene re-arrangements. ( 1.5 ) • Adult patients with aggressive systemic mastocytosis (ASM) without the D816V c-Kit mutation or with c-Kit mutational status unknown ( 1.6 ) • Adult patients with hypereosinophilic syndrome (HES) and/or chronic eosinophilic leukemia (CEL) who have the FIP1L1-PDGFRα fusion kinase (mutational analysis or fluorescence in situ hybridization [FISH] demonstration of CHIC2 allele deletion) and for patients with HES and/or CEL who are FIP1L1-PDGFRα fusion kinase negative or unknown. ( 1.7 ) • Adult patients with unresectable, recurrent and/or metastatic dermatofibrosarcoma protuberans (DFSP) ( 1.8 ) • Patients with Kit (CD117) positive unresectable and/or metastatic malignant gastrointestinal stromal tumors (GIST). ( 1.9 ) • Adjuvant treatment of adult patients following resection of Kit (CD117) positive GIST. ( 1.10 ) 1.1 Newly Diagnosed Philadelphia Positive Chronic Myeloid Leukemia (Ph+ CML) Newly diagnosed adult and pediatric patients with Philadelphia chromosome positive chronic myeloid leukemia (Ph+ CML) in chronic phase. 1.2 Ph+ CML in Blast Crisis (BC), Accelerated Phase (AP) or Chronic Phase (CP) After Interferon-alpha (IFN) Therapy Patients with Philadelphia chromosome positive chronic myeloid leukemia in blast crisis, accelerated phase, or in chronic phase after failure of interferon-alpha therapy. […]
About this medicine
Imatinib is a small molecule kinase inhibitor. Imatinib mesylate film-coated tablets are supplied as 100 mg and 400 mg tablets for oral administration. Each 100 mg tablet contains 119.5 mg of imatinib mesylate equivalent to 100 mg of imatinib free base. Each 400 mg tablet contains 478 mg of imatinib mesylate equivalent to 400 mg of imatinib free base. Imatinib mesylate is designated chemically as 4-[(4-Methyl-1-piperazinyl)methyl]-N-[4-methyl-3-[[4-(3-pyridinyl)-2-pyrimidinyl]amino]-phenyl]benzamide methanesulfonate and its structural formula is: Imatinib mesylate is a white to off-white crystalline powder. Its molecular formula is C 29 H 31 N 7 O • CH 4 SO 3 and its molecular weight is 589.7 g/mol. Imatinib mesylate is freely soluble in water and freely to sparingly soluble in methanol. Inactive Ingredients: colloidal silicon dioxide (NF); crospovidone (NF); and magnesium stearate (NF). Tablet coating: ferric oxide red (NF); ferric oxide yellow (NF); hypromellose (USP); hydroxypropyl cellulose, and polyethylene glycol (NF).
How it works
12.1 Mechanism of Action Imatinib mesylate is a protein-tyrosine kinase inhibitor that inhibits the BCR-ABL tyrosine kinase, the constitutive abnormal tyrosine kinase created by the Philadelphia chromosome abnormality in CML. Imatinib inhibits proliferation and induces apoptosis in BCR-ABL positive cell lines as well as fresh leukemic cells from Philadelphia chromosome positive chronic myeloid leukemia. Imatinib inhibits colony formation in assays using ex vivo peripheral blood and bone marrow samples from CML patients. In vivo , imatinib inhibits tumor growth of BCR-ABL transfected murine myeloid cells as well as BCR-ABL positive leukemia lines derived from CML patients in blast crisis. Imatinib is also an inhibitor of the receptor tyrosine kinases for platelet-derived growth factor (PDGF) and stem cell factor (SCF), c-Kit, and inhibits PDGF- and SCF-mediated cellular events. In vitro, imatinib inhibits proliferation and induces apoptosis in GIST cells, which express an activating c-Kit mutation.
Warnings and cautions
• Edema and severe fluid retention have occurred. Weigh patients regularly and manage unexpected rapid weight gain by drug interruption and diuretics. ( 5.1 , 6.1 ) • Cytopenias, particularly anemia, neutropenia, and thrombocytopenia, have occurred. Manage with dose reduction, dose interruption, or discontinuation of treatment. Perform complete blood counts weekly for the first month, biweekly for the second month, and periodically thereafter. ( 5.2 ) • Severe congestive heart failure and left ventricular dysfunction have been reported, particularly in patients with comorbidities and risk factors. Monitor and treat patients with cardiac disease or risk factors for cardiac failure. ( 5.3 ) • Severe hepatotoxicity, including fatalities may occur. Assess liver function before initiation of treatment and monthly thereafter or as clinically indicated. Monitor liver function when combined with chemotherapy known to be associated with liver dysfunction. ( 5.4 ) • Grade 3/4 hemorrhage has been reported in clinical studies in patients with newly diagnosed CML and with GIST. GI tumor sites may be the source of GI bleeds in GIST. ( 5.5 ) • Gastrointestinal (GI) perforations, some fatal, have been reported. ( 5.6 ) • Cardiogenic shock/left ventricular dysfunction has been associated with the initiation of imatinib mesylate in patients with conditions associated with high eosinophil levels (e.g., HES, MDS/MPD, and ASM). ( 5.7 ) • Bullous dermatologic reactions (e.g., erythema multiforme and Stevens-Johnson syndrome) have been reported with the use of imatinib mesylate. ( 5.8 ) • Hypothyroidism has been reported in thyroidectomy patients undergoing levothyroxine replacement. Closely monitor TSH levels in such patients. ( 5.9 ) • Fetal harm can occur when administered to a pregnant woman. Apprise women of the potential harm to the fetus, and to use effective contraception. ( 5.10 , 8.1 ) • Growth retardation occurring in children and pre-adolescents receiving imatinib mesylate has been reported. Close monitoring of growth in children under imatinib mesylate treatment is recommended. ( 5.11 , 6.2 ) • Tumor Lysis Syndrome. Close monitoring is recommended. […]
Reported side effects
The following serious adverse reactions are described elsewhere in the labeling: Fluid Retention and Edema [see Warnings and Precautions ( 5.1 )] Hematologic Toxicity [see Warnings and Precautions ( 5.2 )] Congestive Heart Failure and Left Ventricular Dysfunction [see Warnings and Precautions ( 5.3 )] Hepatotoxicity [see Warnings and Precautions ( 5.4 )] Hemorrhage [see Warnings and Precautions ( 5.5 )] Gastrointestinal Disorders [see Warnings and Precautions ( 5.6 )] Hypereosinophilic Cardiac Toxicity [see Warnings and Precautions ( 5.7 )] Dermatologic Toxicities [see Warnings and Precautions ( 5.8 )] Hypothyroidism [see Warnings and Precautions ( 5.9 )] Growth Retardation in Children and Adolescents [see Warnings and Precautions ( 5.11 )] Tumor Lysis Syndrome [see Warnings and Precautions ( 5.12 )] Impairments Related to Driving and Using Machinery [see Warnings and Precautions ( 5.13 )] Renal Toxicity [see Warnings and Precautions ( 5.1 4 ) ] The most frequently reported adverse reactions (greater than or equal to 30%) were edema, nausea, vomiting, muscle cramps, musculoskeletal pain, diarrhea, rash, fatigue and abdominal pain. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Apotex Corp. at 1-800-706-5575 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Chronic Myeloid Leukemia The majority of imatinib mesylate-treated patients experienced adverse reactions at some time. Imatinib was discontinued due to drug-related adverse reactions in 2.4% of patients receiving imatinib mesylate in the randomized trial of newly diagnosed patients with Ph+ CML in chronic phase comparing imatinib mesylate versus IFN+Ara-C, and in 12.5% of patients receiving imatinib mesylate in the randomized trial of newly diagnosed patients with Ph+ CML in chronic phase comparing imatinib mesylate and nilotinib. […]
Interactions with other medicines
CYP3A4 inducers may decrease imatinib mesylate C max and area under curve (AUC). ( 2.12 , 7.1 , 12.3 ) CYP3A4 inhibitors may increase imatinib mesylate C max and AUC. ( 7.2 , 12.3 ) Imatinib mesylate is an inhibitor of CYP3A4 and CYP2D6 which may increase the C max and AUC of other drugs. ( 7.3 , 7.4 , 12.3 ) Patients who require anticoagulation should receive low-molecular weight or standard heparin and not warfarin. ( 7.3 ) Imatinib mesylate tablets delay the clearance of methotrexate when methotrexate is used at high doses (> 500 mg/m 2 ). ( 7.5 ) 7.1 Agents Inducing CYP3A Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inducers may reduce total exposure of imatinib; consider alternative agents [see Clinical Pharmacology ( 12.3 )] . 7.2 Agents Inhibiting CYP3A Metabolism Concomitant administration of imatinib mesylate tablets and strong CYP3A4 inhibitors may result in a significant imatinib exposure increase. Grapefruit juice may also increase plasma concentrations of imatinib; avoid grapefruit juice [see Clinical Pharmacology ( 12.3 )] . 7.3 Interactions With Drugs Metabolized by CYP3A4 Imatinib mesylate will increase plasma concentration of CYP3A4 metabolized drugs (e.g., triazolo-benzodiazepines, dihydropyridine calcium channel blockers, certain HMG-CoA reductase inhibitors, etc.). Use caution when administering imatinib mesylate tablets with CYP3A4 substrates that have a narrow therapeutic window. Because warfarin is metabolized by CYP2C9 and CYP3A4, use low-molecular weight or standard heparin instead of warfarin in patients who require anticoagulation [see Clinical Pharmacology ( 12.3 )] . 7.4 Interactions With Drugs Metabolized by CYP2D6 Use caution when administering imatinib mesylate with CYP2D6 substrates that have a narrow therapeutic window. 7.5 Interactions With Methotrexate Imatinib mesylate tablets delay the clearance of methotrexate and result in sustained methotrexate concentrations when methotrexate is used at high doses (>500 mg/m 2 ). Refer to the prescribing information for methotrexate injection for recommendations on management of methotrexate concentrations.
Use in specific groups
8.1 Pregnancy Risk Summary Imatinib mesylate tablets can cause fetal harm when administered to a pregnant woman based on human and animal data. There are no clinical studies regarding use of imatinib mesylate tablets in pregnant women. There have been postmarket reports of spontaneous abortions and congenital anomalies from women who have been exposed to imatinib mesylate tablets during pregnancy. Reproductive studies in rats have demonstrated that imatinib mesylate induced teratogenicity and increased incidence of congenital abnormalities following prenatal exposure to imatinib mesylate at doses equal to the highest recommended human dose of 800 mg/day based on BSA. Advise women to avoid pregnancy when taking imatinib mesylate tablets. If this drug is used during pregnancy, or if the patient becomes pregnant while taking this drug, apprise the patient of the potential hazard to the fetus. The background risk of major birth defects and miscarriage for the indicated population is not known; however, in the U.S. general population, the estimated background risk of major birth defects of clinically recognized pregnancies is 2% to 4% and of miscarriage is 15% to 20%. Data Animal Data In embryo-fetal development studies in rats and rabbits, pregnant animals received oral doses of imatinib mesylate up to 100 mg/kg/day and 60 mg/kg/day, respectively, during the period of organogenesis. In rats, imatinib mesylate was teratogenic at 100 mg/kg/day (approximately equal to the maximum human dose of 800 mg/day based on BSA), the number of fetuses with encephalocoele and exencephaly was higher than historical control values and these findings were associated with missing or underdeveloped cranial bones. Lower mean fetal body weights were associated with retarded skeletal ossifications. In rabbits, at doses 1.5 times higher than the maximum human dose of 800 mg/day based on BSA, no effects on the reproductive parameters with respect to implantation sites, number of live fetuses, sex ratio or fetal weight were observed. The examinations of the fetuses did not reveal any drug related morphological changes. […]
If too much is taken
Experience with doses greater than 800 mg is limited. Isolated cases of imatinib mesylate overdose have been reported. In the event of overdosage, observe the patient and give appropriate supportive treatment. Adult Overdose 1,200 to 1,600 mg (duration varying between 1 to 10 days) : Nausea, vomiting, diarrhea, rash erythema, edema, swelling, fatigue, muscle spasms, thrombocytopenia, pancytopenia, abdominal pain, headache, decreased appetite. 1,800 to 3,200 mg (as high as 3,200 mg daily for 6 days) : Weakness, myalgia, increased CPK, increased bilirubin, GI pain. 6,400 mg (single dose) : One case in the literature reported one patient who experienced nausea, vomiting, abdominal pain, pyrexia, facial swelling, neutrophil count decreased, increase transaminases. 8 to 10 g (single dose): Vomiting and GI pain have been reported. A patient with myeloid blast crisis experienced Grade 1 elevations of serum creatinine, Grade 2 ascites and elevated liver transaminase levels, and Grade 3 elevations of bilirubin after inadvertently taking 1,200 mg of imatinib mesylate (imatinib as free base) daily for 6 days. Therapy was temporarily interrupted and complete reversal of all abnormalities occurred within 1 week. Treatment was resumed at a dose of 400 mg daily (imatinib as free base) without recurrence of adverse reactions. Another patient developed severe muscle cramps after taking 1,600 mg of imatinib mesylate (imatinib as free base) daily for 6 days. Complete resolution of muscle cramps occurred following interruption of therapy and treatment was subsequently resumed. Another patient that was prescribed 400 mg daily (imatinib as free base), took 800 mg of imatinib mesylate (imatinib as free base) on Day 1 and 1,200 mg (imatinib as free base) on Day 2. Therapy was interrupted, no adverse reactions occurred and the patient resumed therapy. Pediatric Overdose One 3 year old male exposed to a single dose of 400 mg experienced vomiting, diarrhea, and anorexia and another 3 year old male exposed to a single dose of 980 mg experienced decreased white blood cell (WBC) count and diarrhea.
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This page is built from the openFDA record of the U.S. Food and Drug Administration's approved labelling for this product, effective 28 July 2026. Label text has been shortened and reformatted for readability; safety wording has not been altered in meaning. FDA labelling describes products approved in the United States — brand names, strengths, formulations and approved uses may differ in your country. Always read the leaflet that comes with your own pack. PocketsInfo is not affiliated with, and is not endorsed by, the FDA. Retrieved 2026-07-30.