Imastop 100 Tablet contains Imatinib mesylate 100 mg, a selective tyrosine kinase inhibitor used primarily in the treatment of chronic myeloid leukemia (CML), gastrointestinal stromal tumors (GIST), and other malignancies characterized by specific genetic mutations. Imatinib mesylate exerts its therapeutic effect by inhibiting the BCR-ABL tyrosine kinase enzyme, which is produced by the Philadelphia chromosome abnormality in CML, thereby preventing the proliferation of malignant cells. Additionally, it targets other tyrosine kinases such as c-KIT and PDGF receptors involved in tumor growth. Imastop 100 is indicated for adult patients diagnosed with Philadelphia chromosome-positive CML in chronic, accelerated, or blast phases, as well as for patients with unresectable and/or metastatic malignant GIST. The recommended dosage and duration of treatment depend on the specific condition and patient response, and therapy should be initiated under specialist supervision. Common adverse effects include nausea, edema, muscle cramps, rash, and hematologic toxicity, necessitating regular monitoring of blood counts and liver function tests during treatment. Imastop 100 should be used with caution in patients with hepatic impairment and potential drug interactions should be assessed prior to initiation. This medication is a cornerstone in targeted cancer therapy, significantly improving survival and quality of life in affected patients.