Nurses Compass
Drug Guide
Vandetanib
Classification
Therapeutic: Antineoplastic agent (Thyroid cancer)
Pharmacological: Selective inhibitor of VEGFR, EGFR, and RET tyrosine kinases
FDA Approved Indications
- Medullary thyroid carcinoma (MTC) in patients with unresectable locally advanced or metastatic disease
Mechanism of Action
Vandetanib inhibits the activity of multiple receptor tyrosine kinases, including VEGFR, EGFR, and RET, which are involved in tumor growth and angiogenesis, thereby reducing tumor progression.
Dosage and Administration
Adult: Typically 300 mg orally once daily. Dose adjustments may be needed based on tolerability and side effects.
Pediatric: Not approved for pediatric use.
Geriatric: Use with caution; no specific dose adjustment based on age alone, but monitor closely.
Renal Impairment: No specific adjustment recommended; however, severity of impairment may require dose modifications.
Hepatic Impairment: Use with caution; in severe hepatic impairment, dose adjustment is recommended.
Pharmacokinetics
Absorption: Well absorbed orally.
Distribution: Extensive protein binding (~95%).
Metabolism: Hepatic via CYP3A4 and conjugation pathways.
Excretion: Primarily fecal, minor renal excretion.
Half Life: 40 to 45 days, allowing once-daily dosing.
Contraindications
- Hypersensitivity to vandetanib or any component of the formulation.
Precautions
- QT prolongation risk, cardiac arrhythmias, arterial thrombosis, bleeding, gastrointestinal perforation, interstitial lung disease, hepatotoxicity, skin reactions, and interactions with drugs prolonging QT interval. Regular monitoring of cardiac function and electrolytes is recommended. Use in pregnancy and breastfeeding is contraindicated.
Adverse Reactions - Common
- Diarrhea (Common)
- QT prolongation (Common)
- rash (Common)
- Hypertension (Common)
Adverse Reactions - Serious
- QT prolongation leading to Torsades de Pointes (Serious but less common)
- Interstitial lung disease/pneumonitis (Rare)
- Hepatotoxicity (Rare)
- Cardiac failure, arrhythmias (Rare)
Drug-Drug Interactions
- Other QT-prolonging drugs (e.g., amiodarone, sotalol)
- CYP3A4 inhibitors or inducers
Drug-Food Interactions
N/ADrug-Herb Interactions
N/ANursing Implications
Assessment: Monitor ECG for QT prolongation, electrolytes, blood pressure, liver function tests, and pulmonary symptoms.
Diagnoses:
- Risk for cardiac arrhythmias due to QT prolongation
- Risk for bleeding
- Impaired skin integrity
Implementation: Administer as prescribed; monitor labs and vital signs regularly; educate patient on symptoms of adverse effects.
Evaluation: Assess for signs of adverse reactions, effectiveness of therapy, and patient adherence.
Patient/Family Teaching
- Report symptoms like irregular heartbeat, chest pain, shortness of breath, or severe diarrhea.
- Attend regular lab and ECG appointments.
- Avoid other medications that prolong QT interval without physician approval.
- Use effective contraception during treatment and for at least 4 months after discontinuation.
Special Considerations
Black Box Warnings:
- QT prolongation and sudden death
Genetic Factors: Patients with inherited long QT syndrome should not use vandetanib.
Lab Test Interference: May cause elevated liver enzymes and electrolyte disturbances.
Overdose Management
Signs/Symptoms: Severe diarrhea, hypotension, arrhythmias, bleeding.
Treatment: Supportive care; observe cardiac and respiratory function; correct electrolytes; ensure adequate hydration.
Storage and Handling
Storage: Store at room temperature, 20°C to 25°C (68°F to 77°F).
Stability: Stable through expiration date when stored properly.