Home Drug Guide Imatinib Mesylate

Drug Guide

Generic Name

Imatinib Mesylate

Brand Names Gleevec, Imkeldi

Classification

Therapeutic: Antineoplastic agent

Pharmacological: Tyrosine kinase inhibitor

FDA Approved Indications

  • Chronic myeloid leukemia (CML)
  • Gastrointestinal stromal tumors (GIST)
  • Certain other malignancies such as Philadelphia chromosome-positive ALL and other rare malignancies

Mechanism of Action

Imatinib inhibits specific tyrosine kinases including BCR-ABL, c-KIT, and PDGF receptor tyrosine kinases, thereby blocking tumor cell proliferation and inducing apoptosis.

Dosage and Administration

Adult: Typically 400 mg once daily; dosage varies based on indication and response.

Pediatric: Dosing based on body surface area, usually 260 mg/m² daily for CML and GIST.

Geriatric: Adjustments based on renal and hepatic function; close monitoring recommended.

Renal Impairment: For mild to moderate impairment, no initial dose adjustment needed; severe impairment requires caution.

Hepatic Impairment: Use cautiously; dosage adjustments may be necessary based on hepatic function.

Pharmacokinetics

Absorption: Well absorbed orally, peak plasma levels in 1-4 hours.

Distribution: High protein binding (~95%), primarily to albumin.

Metabolism: Hepatic via CYP3A4, CYP3A5, and CYP2C8.

Excretion: Eliminated primarily in feces; small amounts in urine.

Half Life: Approximately 18 hours.

Contraindications

  • Hypersensitivity to imatinib or its components.

Precautions

  • Use with caution in patients with hepatic or renal impairment; monitor blood counts; risk of fluid retention, hepatotoxicity, and cardiac failure.

Adverse Reactions - Common

  • Edema (Common)
  • Nausea (Common)
  • Muscle cramps (Common)
  • Skin rash (Common)
  • Vomiting (Common)

Adverse Reactions - Serious

  • Myelosuppression (neutropenia, thrombocytopenia, anemia) (Serious)
  • Hepatotoxicity (Serious)
  • Heart failure, cardiomyopathy (Serious)
  • Severe skin reactions (Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis) (Serious)

Drug-Drug Interactions

  • CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin), CYP3A4 inducers (e.g., rifampin), other QT prolonging agents.

Drug-Food Interactions

N/A

Drug-Herb Interactions

N/A

Nursing Implications

Assessment: Monitor complete blood counts, liver function tests, and cardiac function. Assess for signs of fluid retention and skin reactions.

Diagnoses:

  • Risk for infection due to myelosuppression
  • Impaired skin integrity
  • Risk of bleeding

Implementation: Administer medication as prescribed; monitor for adverse effects; instruct patient to report signs of hepatotoxicity or cardiac symptoms.

Evaluation: Evaluate blood counts periodically, assess for adverse reactions, and ensure therapeutic response.

Patient/Family Teaching

  • Take medication exactly as prescribed, with or without food.
  • Report any symptoms of swelling, jaundice, rash, or cardiac symptoms.
  • Avoid pregnancy due to teratogenic effects; use effective contraception.
  • Inform about possible side effects and when to seek medical attention.

Special Considerations

Black Box Warnings:

  • Potential for severe hepatotoxicity, QT prolongation, and tumor lysis syndrome.

Genetic Factors: Genetic variations in CYP3A4 may affect drug metabolism.

Lab Test Interference: May cause elevations in liver enzymes, and interference with blood counts.

Overdose Management

Signs/Symptoms: Severe nausea, vomiting, diarrhea, hypotension, and hepatotoxicity.

Treatment: Supportive care, gastric lavage, activated charcoal, and monitoring in a medical facility.

Storage and Handling

Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F).

Stability: Stable for the shelf life as per manufacturer instructions.

🛡️ 5 Critical Medication Safety Tips for Nurses

1

Triple-Check High-Risk Medications

Always have another nurse verify insulin, heparin, warfarin, and chemotherapy drugs. These "high-alert" medications cause the most serious errors. Check concentration, dose calculation, and pump settings twice.

2

Know Look-Alike, Sound-Alike Drugs

Common mix-ups: hydromorphone/morphine, Celebrex/Celexa, Zyprexa/Zyrtec. Always use BOTH generic and brand names, read labels twice, and use barcode scanning when available. One wrong letter can be fatal.

3

Assess Before AND After Giving Meds

Check vitals before cardiac meds, pain levels before analgesics, and blood glucose before insulin. Always reassess within 30 minutes to evaluate effectiveness and watch for adverse reactions.

4

Watch for Drug Interactions

Common dangerous combinations: warfarin + aspirin (bleeding), ACE inhibitors + potassium (hyperkalemia), digoxin + diuretics (toxicity). Always check drug interactions before administering new medications.

5

Educate Your Patients

Teach patients medication names, purposes, major side effects, and what to report. Informed patients catch errors and improve compliance. Always encourage questions - an educated patient is a safer patient.

⚡ Remember: When in doubt, don't give it out! It's always safer to double-check than regret later.

⚠️ Medical Disclaimer

This drug guide is for educational purposes only and is NOT intended for clinical use. Always consult current prescribing information, healthcare providers, and institutional protocols before administering any medication. Do not use this information for patient care decisions.