Imatin

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Medically reviewed

Rosario Oropesa

Last updated on 22/12/2025

This page provides general, reference-level information compiled from official medical sources. It is not a substitute for professional medical advice, diagnosis, or treatment. For decisions about your health, please consult a qualified healthcare professional.

Overview of Imatin

Property Description
Active Ingredient Imatinib mesylate
Form Oral tablet or solution
Pharmacological Class Tyrosine Kinase Inhibitor (TKI), Antineoplastic agent
Common Use Managing abnormal cell growth
Origin Synthetic, small molecule inhibitor

Defining Imatin: Composition and Type

Imatin is a prescription-only medication whose active pharmaceutical ingredient is Imatinib mesylate, a synthesized small molecule compound. It is primarily classified as an antineoplastic agent within the broader field of oncology. The drug is a single-ingredient product typically provided for the oral route of administration in the form of a tablet or an oral solution. As a version of the originator compound, Imatin possesses high oral bioavailability, which is recognized for facilitating long-term patient adherence.


What Type of Therapy is Imatin?

Imatin is specifically categorized as a Protein Kinase Inhibitor, functioning as a Tyrosine Kinase Inhibitor (TKI). This classification signifies that Imatinib is a form of targeted therapy, a departure from older, conventional cytotoxic chemotherapy agents. The development of imatinib is characterized as establishing the therapeutic category known as targeted therapy. This advanced therapeutic approach uses the synthetic compound, a 2-phenylamino-pyrimidine derivative, to focus its action on underlying molecular causes, distinguishing it from general cell-killing treatments.


The General Purpose of Imatinib

The general purpose of Imatinib is to help manage medical conditions driven by the abnormal, uncontrolled growth of specific cells. It achieves this by performing a signal transduction inhibition, which means it blocks hyperactive growth signals within cells that tell them to multiply. Imatinib is designed to neutralize specific malignant proteins, such as the BCR-ABL fusion protein, along with other related signaling proteins like c-Kit (KIT) and the Platelet-Derived Growth Factor Receptor (PDGFR). It acts as a selective inhibitor of these various protein tyrosine kinases. By disrupting these continuous growth messages, Imatinib leads to the selective self-destruction (apoptosis) of the unhealthy cells.

Regulatory References

  1. About the National Cancer Institute
  2. Definition of targeted therapy

What side effects are possible with Imatin?

The official safety profile for Imatin (Imatinib mesylate) is structured by regulatory authorities to communicate the documented risks associated with its use, classifying them by frequency and the body system affected.

Frequency-Classified Adverse Reactions

The most frequently reported adverse reactions, classified as Very Common (occurring in ge 10% of patients) in regulatory documents, include fluid retention (edema), gastrointestinal disturbances (nausea, vomiting, diarrhea), muscle cramps, musculoskeletal pain, rash, fatigue, and myelosuppression (neutropenia, anemia, thrombocytopenia).

Reactions categorized as Common (occurring in ge 1% to <10% of patients) may include headache, dizziness, insomnia, fever, chills, and weight gain.


System-Organ-Class and Serious Risks

Adverse reactions are formally grouped into categories such as Blood and Lymphatic System Disorders (cytopenias), Gastrointestinal Disorders (abdominal pain, hemorrhage, and rare reports of perforation), Cardiac Disorders (severe congestive heart failure and left ventricular dysfunction), and Hepatobiliary Disorders (potential for severe hepatotoxicity, including fatal cases).

Serious adverse reactions officially highlighted include severe fluid retention, severe cardiac dysfunction, and bullous dermatologic reactions such as Stevens-Johnson syndrome.


Population and Duration Safety Statements

Safety notes for specific patient groups are documented in the labeling. Reports of growth retardation exist for pediatric patients, and the potential for fetal harm is noted regarding pregnancy. Older adults may be more likely to experience serious effects, such as fluid retention. Regulatory documents also note that cytopenias most often appear within the first few months of treatment, and long-term use requires consideration of potential liver, kidney, and cardiac toxicity.

Overdose and Emergency Response

Overdose Manifestations and Severe Outcomes

The official regulatory profile for Imatin (Imatinib mesylate) overdose details specific manifestations documented following high-dose exposure. Reported presentations include severe gastrointestinal effects such as nausea, vomiting, diarrhea, and abdominal pain, along with systemic effects like severe fatigue, headache, muscle cramps, and swelling.

The most severe, life-threatening outcomes are associated with acute, very high single-dose ingestions (e.g., ge 6,400 mg). These severe outcomes encompass hematological toxicity (myelosuppression, including severe leukopenia and thrombocytopenia) and hepatic toxicity (elevated liver transaminases and bilirubin).

Required Emergency Actions and Management

Management is defined as symptomatic and supportive. Regulatory documents require close monitoring of both hematological function and hepatic function. There is no specific antidote known, and Imatinib is not significantly dialyzed by hemodialysis.

Immediate medical attention is officially required for acute neurological crises. Individuals must contact emergency services immediately if they have collapsed, are experiencing a seizure, have trouble breathing, or cannot be awakened. The Poison Help line should be contacted for all other suspected overdose cases.

Therapeutic Uses of Imatin

Quick Facts: Therapeutic Domains

  • Chronic Myeloid Leukemia (CML): Addresses newly diagnosed and previously treated Philadelphia chromosome positive (Ph+) CML.
  • Gastrointestinal Stromal Tumors (GIST): Used for advanced GIST that cannot be removed surgically and as an adjuvant treatment after tumor resection.
  • Acute Lymphoblastic Leukemia (ALL): Utilized for Ph+ ALL in specific adult and pediatric settings.
  • Rare Cancers and Blood Disorders: Supports management of several myelodysplastic/myeloproliferative diseases, advanced hypereosinophilic syndrome (HES), chronic eosinophilic leukemia (CEL), aggressive systemic mastocytosis, and unresectable dermatofibrosarcoma protuberans (DFSP).

Imatin is a prescribed agent intended to manage the symptoms and progression of several specific cancers and blood cell conditions. Its usage is primarily anchored in the treatment of Philadelphia chromosome positive (Ph+) Chronic Myeloid Leukemia (CML), which constitutes a core indication. The medication is administered to newly diagnosed adult and pediatric patients with Ph+ CML in the chronic phase, as well as those in advanced stages or who have experienced insufficient response to prior treatments.

Furthermore, Imatin is utilized to support the care of adults with advanced or metastatic Kit (CD117)-positive Gastrointestinal Stromal Tumors (GIST). For patients who have undergone complete surgical removal of GIST, the drug is also utilized as an adjuvant therapy. Additional indications include the management of Ph+ Acute Lymphoblastic Leukemia (ALL) and specific myelodysplastic/myeloproliferative diseases, advanced hypereosinophilic syndrome (HES), and dermatofibrosarcoma protuberans (DFSP) in certain contexts. All therapeutic decisions should be guided by a qualified healthcare professional.

Eligibility and Restrictions for Use

Eligibility Map: Who Can and Cannot Use Imatinib — Official Regulatory Information

The eligibility for using Imatinib is strictly defined by government regulatory documents, which establish clear restrictions for certain populations and conditions.

Category Eligibility Rule Regulatory Status
Populations for whom use is allowed Adults and pediatric patients (generally mathbfge 1 year of age) with specific labeled indications (e.g., Ph+ CML, Kit+ GIST) Established
Populations for whom use is contraindicated Patients with known hypersensitivity to Imatinib or to any of the product's excipients Contraindicated
Pregnancy and lactation eligibility Pregnancy: Not recommended. Lactation/Breastfeeding: Contraindicated Not Recommended / Contraindicated

Age- and Condition-Specific Eligibility

Safety and effectiveness are established in pediatric patients mathbfge 1 year of age for its main indications, but use in infants under 1 year is not established. Older adults (mathbfge 65) generally require no specific dose adjustment based on age alone.

Patients with hepatic impairment (mild, moderate, or severe) or severe renal impairment may be eligible but are categorized as conditional use, requiring close monitoring due to limited data or the potential for increased drug exposure. Additionally, individuals with pre-existing cardiac disease or risk factors for cardiac failure require close supervision, as specified in regulatory warnings.

What should I know about interactions with other medicines?

Imatinib is metabolized primarily by the Cytochrome P450 3A4 (CYP3A4) enzyme, which is the main basis for its potential drug interactions. It is also an inhibitor of CYP3A4, as well as CYP2D6 and potentially other enzymes.

Interacting Medicines and Products

Interaction Mechanism Interacting Category / Examples Outcome / Restriction
Metabolism decreased (Imatinib levels rise) Strong CYP3A4 Inhibitors (e.g., ketoconazole, clarithromycin, grapefruit juice) Use Caution. May increase Imatinib's plasma concentrations and toxicity. Avoid grapefruit juice.
Metabolism increased (Imatinib levels fall) Strong CYP3A4 Inducers (e.g., rifampin, phenytoin, carbamazepine, St. John's wort) Avoid Combination. Can significantly decrease Imatinib's concentration and efficacy. Dose adjustment (increase) is required if unavoidable.
Substrate levels increased (Risk of toxicity) CYP3A4 Substrates with Narrow Therapeutic Window (e.g., simvastatin, cyclosporine, pimozide, warfarin) Use Caution. Imatinib increases the plasma concentration of these co-administered drugs. Warfarin should generally be replaced by low-molecular-weight or standard heparin due to a significant risk of increased bleeding.
Other Specific Interactions Levothyroxine Monitor TSH closely in thyroidectomy patients receiving replacement therapy, as hypothyroidism has been reported.

Close monitoring is required when Imatinib is combined with any medication or product that may affect the CYP3A4 or CYP2D6 enzyme systems.

Mechanism of Action

Inhibiting Tyrosine Kinase Activity

Imatin functions as a targeted inhibitor that acts primarily by binding to the ATP-binding pocket of specific tyrosine kinases, most notably the BCR-ABL fusion protein . This competitive binding blocks the enzyme's ability to transfer a phosphate group, effectively inhibiting its signal transduction activity within the cell. The drug also demonstrates inhibitory activity against other related tyrosine kinases, including the c-KIT and Platelet-Derived Growth Factor Receptor (PDGFR), thereby modulating pathways activated by external growth factors.

Modulating Cellular Signaling and Population

By disrupting the constant proliferative signals transmitted by the inhibited enzymes, Imatin causes the cells dependent on this signaling to cease proliferation. The disruption of these internal survival pathways subsequently triggers programmed cell death (apoptosis) in the dependent cell populations. This physiological process leads directly to a decrease in the cell count of those specific cells in the body, which modulates the overall cellular population dynamics.

Dosage and Administration Information

How Imatin is Used: Official Administration Guidelines

Imatin (imatinib mesylate) is a medicine administered strictly via the oral route as tablets or an oral solution. Standardized instructions regarding dosage, timing, and patient-specific adjustments are established to ensure appropriate use.


Dosing and Schedule Structure

Parameter Official Instruction (Adults)
Starting Dose (Standard) 400 mg daily for CML Chronic Phase, GIST, and MDS/MPD. 600 mg daily for CML Accelerated/Blast Crisis and Ph+ ALL.
Maximum Starting Dose 800 mg daily (for DFSP), administered as two 400 mg doses.
Dose Frequency Generally once daily (QD). The 800 mg dose must be split and taken twice daily (BID).
Duration Pattern Treatment is often long-term (continued until disease progression). Adjuvant GIST therapy is recommended for three years.

Administration Requirements and Adjustments

  1. Timing and Intake: Imatin must be taken with a meal and a large glass of water.
  2. Preparation: For patients unable to swallow the tablets, they may be dispersed in water or apple juice and stirred until completely dissolved for immediate oral administration.
  3. Missed Dose: If a daily dose is missed, it should be taken as soon as it is remembered, unless it is close to the next scheduled dose, in which case the missed dose is skipped. Guidelines indicate not to double the dose to compensate.
  4. Special Populations: The dosage for pediatric patients is calculated based on Body Surface Area (BSA) (340 mg/m^2/ day, max 600 mg daily). A dose reduction of 25% (e.g., 400 mg reduced to 300 mg) is required for patients with severe hepatic impairment.

Recent Clinical Evidence

Research Evidence / Overview of Studies for Imatin

This overview describes the research landscape for Imatin, focusing on the types of studies conducted and the specific disease measurements used by researchers. This information provides context but does not offer personal medical advice or predict individual outcomes.


Evidence for use in Chronic Myeloid Leukemia (CML)

The research landscape for Imatin in CML consists of a large body of evidence, including foundational, multi-center Randomized Controlled Trials (RCTs) and extensive long-term observational cohort studies tracking patients over a decade. Researchers primarily studied newly diagnosed adults in the chronic phase, with trials designed to compare Imatin against specific alternative treatments. Studies monitored key outcomes such as hematologic and cytogenetic responses, and molecular responses (measuring the BCR-ABL transcript). Research reports that achieving these biomarker changes early was observed to be related to specific long-term survival patterns in the cohorts studied. Research remains limited regarding a clear advantage for higher starting doses when compared against standard doses in newly diagnosed patients.


Evidence for use in Gastrointestinal Stromal Tumors (GIST)

The research for GIST includes Phase III randomized trials for both advanced, unresectable tumors and for the adjuvant setting (treatment following surgical removal). These trials were designed to evaluate the drug's effect by measuring tumor shrinkage (Objective Response Rate) and tracking Progression-Free Survival (PFS). Adjuvant studies described a difference in the measured time until disease recurrence between the treatment and placebo groups. Research highlights that outcomes relate to the underlying genetic profile of the tumor, but limited information is available regarding the optimal duration of adjuvant therapy beyond three years.


Evidence for Rare Indications and Research Gaps

For less common conditions like Philadelphia chromosome-positive Acute Lymphoblastic Leukemia (Ph+ ALL) and certain myeloproliferative disorders, evidence is often based on smaller Phase II studies or case series. These studies explored molecular changes and hematologic responses associated with the confirmed presence of a specific molecular target. Due to the rarity of these conditions, sample sizes were modest, and comparative evidence is lacking.

Research has also explored outcomes in children and adolescents, but studies for very specific subgroups (such as pregnant patients or those with certain pre-existing conditions) remains limited. The research overall highlights what is known, and what is still uncertain, requiring continued investigation.

Frequently Asked Questions (FAQ)

Common questions about Imatin (FAQ)


Q: What is the primary condition this medicine is approved to treat?

According to official regulatory documents, Imatin is approved for the treatment of chronic hepatitis B virus (HBV) infection. Specifically, it is indicated for adults with compensated liver disease. In certain regions, it is also approved for use in specific groups of children and adolescents.


Q: Can I stop taking this medication once my symptoms improve?

Regulatory warnings indicate that stopping treatment for HBV may lead to a severe acute exacerbation of hepatitis B, which is a potentially serious flare-up of the infection. Regulatory warnings state that monitoring by a healthcare provider is recommended for several months following discontinuation to assess liver function.


Q: What are the most common side effects of this medication?

Based on clinical trial data published in the official product information, the most common side effects reported were headache and nausea. The full range of possible adverse reactions is listed in the official regulatory documents, but not everyone experiences them.


Q: Is this medicine safe to take if I am co-infected with HIV?

Official information advises that prior to initiating treatment, patients should be tested for HIV-1 infection. Taking this medicine alone is not recommended for treating HIV-1, as this may lead to the HIV virus developing resistance to the drug. A healthcare provider is responsible for determining the appropriate combination therapy if a patient has both HBV and HIV.


Q: Does this medication affect my kidneys or bones?

Regulatory documents include warnings that kidney problems (renal impairment) have been reported in some patients taking this class of medication, and kidney function should be monitored before and during treatment. Additionally, reductions in bone mineral density (BMD), particularly in certain pediatric patients, have been observed.


Q: What should I do if I miss a dose or vomit after taking it?

Official product information specifies that: If a dose is forgotten, it may be taken as soon as possible, unless it is already more than 18 hours past the usual dose time, in which case the missed dose should be skipped. If vomiting occurs within 1 hour of taking the medicine, another tablet may be taken; if vomiting occurs later than 1 hour, no additional tablet is generally needed.


Q: Can I take this medicine with other drugs, like common pain relievers?

Official product information contains a list of important drug interactions. Coadministration with certain medicines is not recommended because it can change how the body processes Imatin or increase the risk of adverse reactions, especially kidney-related issues. It is important for a patient to disclose all medicines, including over-the-counter pain relievers and supplements, to their healthcare provider before beginning treatment.


Q: Can children under 6 years old use this medicine?

According to the official prescribing information, the safety and effectiveness of Imatin have not been established in children who are younger than 6 years of age or who weigh less than 25 kilograms. Regulatory information specifies the age and weight groups where efficacy and safety data for pediatric use are available.


Q: Can this be taken by people with severe liver problems?

The official documents state that no dose adjustment is required for patients with mild liver impairment (Child-Pugh A). However, this medicine is not recommended for use in patients who have decompensated (severe) hepatic impairment (Child-Pugh B or C).


Q: Should I take this medicine with or without food?

Regulatory information specifies that the recommended way to take this medicine is once daily with food. This is a factor that can influence how the medicine is absorbed by the body.


How should Imatin be stored and disposed of?

Storage and Disposal Requirements for Imatinib Mesylate

Imatinib mesylate tablets must be stored at Controlled Room Temperature, defined as 20 C to 25 C (68 F to 77 F), with brief excursions permitted up to 30 C. Storage must be in a tight container and the product must be protected from moisture and excessive heat. To prevent accidental ingestion, the medication must be kept out of reach of children.

Handling and Disposal

Tablets should not be crushed. If powder from a broken tablet contacts skin or mucous membranes, the area must be washed thoroughly. Unused or expired Imatinib is considered a hazardous drug and must not be disposed of in household trash or down the toilet/sink. All disposal must comply with local pharmaceutical waste regulations.

Attention! Always consult to a doctor or pharmacist before using pills or medicines.

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