From the Guidelines
Gleevec (imatinib) is a tyrosine kinase inhibitor that should be taken at a standard dose of 400 mg daily to treat gastrointestinal stromal tumors (GIST), with close monitoring for side effects and treatment effectiveness, as evidenced by studies such as 1. When taking Gleevec, it is essential to watch for common side effects including nausea, vomiting, diarrhea, muscle cramps, fluid retention, and skin rashes. More serious concerns requiring immediate medical attention include unusual bleeding or bruising, severe fatigue, yellowing of skin or eyes (jaundice), dark urine, severe abdominal pain, and signs of infection like fever. Regular blood tests are crucial while on Gleevec to monitor liver function, blood counts, and treatment effectiveness, as suggested by 1. The medication works by blocking specific proteins (tyrosine kinases) that cancer cells need to grow and multiply, particularly targeting the BCR-ABL protein in CML and KIT and PDGFR in GIST, as noted in 1. Some key points to consider when taking Gleevec include:
- Taking the medication with food and water to reduce stomach irritation
- Avoiding grapefruit products and St. John's Wort as they can interact with the medication
- Informing healthcare providers about all medications being taken to prevent potentially dangerous drug interactions
- Continuing treatment until disease progression or unacceptable toxicity, as recommended in 1
- Monitoring imatinib plasma levels, which may be useful in cases of suspected poor compliance or unexpected toxicities, as suggested by 1.
From the FDA Drug Label
Imatinib mesylate can cause fetal harm when administered to a pregnant woman. Bullous dermatologic reactions, including erythema multiforme and Stevens-Johnson syndrome, have been reported with use of imatinib mesylate. Clinical cases of hypothyroidism have been reported in thyroidectomy patients undergoing levothyroxine replacement during treatment with imatinib mesylate tablets. Growth retardation has been reported in children and pre-adolescents receiving imatinib mesylate tablets. Cases of Tumor Lysis Syndrome (TLS), including fatal cases, have been reported in patients with CML, GIST, ALL, and eosinophilic leukemia receiving imatinib mesylate tablets. A decline in renal function may occur in patients receiving imatinib mesylate tablets. Motor vehicle accidents have been reported in patients receiving imatinib mesylate tablets.
Gleevec (Imatinib) is a medication used to treat certain types of cancer, including:
- Chronic Myeloid Leukemia (CML)
- Gastrointestinal Stromal Tumors (GIST)
- Acute Lymphoblastic Leukemia (ALL)
- Eosinophilic leukemia
Key things to watch out for:
- Pregnancy and breastfeeding: Imatinib can cause fetal harm and should be avoided during pregnancy and breastfeeding.
- Dermatologic reactions: Bullous dermatologic reactions, including erythema multiforme and Stevens-Johnson syndrome, have been reported.
- Hypothyroidism: Clinical cases of hypothyroidism have been reported in thyroidectomy patients undergoing levothyroxine replacement.
- Growth retardation: Growth retardation has been reported in children and pre-adolescents receiving imatinib.
- Tumor Lysis Syndrome: Cases of TLS, including fatal cases, have been reported.
- Renal toxicity: A decline in renal function may occur.
- Driving and operating machinery: Patients may experience side effects, such as dizziness, blurred vision, or somnolence, and should exercise caution when driving or operating machinery 2.
From the Research
What is Gleevec
- Gleevec, also known as imatinib, is a tyrosine kinase inhibitor used as first-line treatment in Philadelphia chromosome-positive chronic myeloid leukemia (Ph+ CML) and metastatic or unresectable gastrointestinal stromal tumors (GIST) 3.
- It targets constitutively activated tyrosine kinases, such as BCR-ABL, c-KIT, and PDGFR, and has substantially changed the clinical management of both diseases 4.
Efficacy and Safety
- Imatinib has proven efficacy in improving treatment response and survival in patients with Ph+ CML and GIST 5.
- The introduction of imatinib has profoundly improved the prognosis of both entities, while being surprisingly well tolerated 4.
- Treatment with imatinib is generally well tolerated, and the risk for severe adverse effects is low, generally occurring during the early phase of treatment and correlating with imatinib dose, phase of disease, and patient's characteristics 6.
Adverse Effects and Monitoring
- Common adverse effects of imatinib include musculoskeletal and joint pain, muscle cramps, oedema, and gastrointestinal symptoms, which are generally grade I or II toxicities and occur during the early phase of treatment 4.
- Therapeutic drug monitoring (TDM) for imatinib has been suggested to improve efficacy, assess compliance, and evaluate drug-drug interactions 5.
- TDM may provide additional information on efficacy, compliance, and safety than clinical evaluation alone, particularly in patients with suboptimal response to treatment, treatment failure, rare adverse events, drug interactions, or suspected nonadherence 5.
Adherence to Therapy
- Adherence to imatinib therapy is crucial to maximize benefits from therapy and improve clinical outcomes 7.
- Despite the survival benefit and favorable toxicity profile of imatinib, adherence to imatinib remains poor, and improving adherence depends on open communication and comprehensive patient education 7.