Vandetanib Tablets: Safe Dosing, Side Effects & Precautions
Comprehensive guide to Vandetanib (Caprelsa) for treating aggressive medullary thyroid cancer in adults and children over 5 years.
Vandetanib, sold under the brand name Caprelsa, is a prescription medication specifically indicated for treating aggressive and symptomatic medullary thyroid cancer (MTC) in patients with unresectable locally advanced or metastatic disease. Approved for use in adults, children, and adolescents aged 5 years and older, it functions as a protein tyrosine kinase inhibitor that targets key receptors driving cancer cell growth and vascularization.
About Vandetanib Tablets
Vandetanib belongs to the class of antineoplastic agents known as tyrosine kinase inhibitors. It works by blocking enzymes called tyrosine kinases associated with vascular endothelial growth factor (VEGF), epidermal growth factor (EGF), and RET receptors on cancer cells. These receptors promote cell division, tumor growth, and the formation of new blood vessels (angiogenesis) that nourish the tumor. By inhibiting VEGF receptors, Vandetanib reduces blood supply to cancer cells; blocking EGF halts growth signals; and targeting RET is particularly effective against MTC cells, which often harbor RET mutations.
Medullary thyroid cancer originates from the C-cells of the thyroid gland and accounts for about 5% of thyroid cancers. It is often aggressive when locally advanced or metastatic, and surgery is not always feasible. Vandetanib offers a targeted oral therapy option, improving progression-free survival in clinical studies, though it is reserved for symptomatic or progressive cases due to significant risks.
Caprelsa is available only through a restricted program: the CAPRELSA REMS (Risk Evaluation and Mitigation Strategy) in the US, and similar oversight in Europe, ensuring prescribers are certified and patients are monitored for cardiac risks.
Before Taking Vandetanib Tablets
Consult your doctor if you have any allergies to Vandetanib or its ingredients. Inform your healthcare provider about all medications, supplements, and herbal products, as Vandetanib interacts with many drugs, particularly those prolonging the QT interval (e.g., anti-arrhythmics like amiodarone, disopyramide).
Pregnancy and Contraception: Vandetanib can harm the unborn baby. Women of childbearing potential must use effective contraception during treatment and for at least 4 months after the last dose. Men should use contraception during treatment and for 4 months post-treatment. Pregnancy testing is required before starting.
- Do not use if pregnant or breastfeeding.
- Discuss family planning with your doctor.
Medical History: Not suitable for patients with congenital long QT syndrome, uncorrected electrolyte imbalances, or recent myocardial infarction. Use caution in renal or hepatic impairment.
How to Take Vandetanib Tablets
The recommended dose is 300 mg orally once daily, with or without food, until disease progression or unacceptable toxicity. Tablets are 100 mg (yellow) or 300 mg (red), film-coated, and must be swallowed whole—do not chew, crush, or dissolve.
Dose Adjustments:
- QT Prolongation: If QTc exceeds 500 ms, interrupt and reduce to 200 mg upon normalization. Further reductions to 100 mg if recurrent.
- Toxicity (CTCAE Grade 3+): Withhold until Grade 1 or resolved, then resume at 200 mg; recurrent issues reduce to 100 mg.
- Moderate Renal Impairment (CrCl 30-50 mL/min): Start at 200 mg daily.
- Severe Renal Impairment (CrCl <30 mL/min): Not recommended.
- Hepatic Impairment: Not recommended for moderate/severe cases.
| Condition | Starting Dose | Notes |
|---|---|---|
| Normal Renal Function | 300 mg daily | Monitor ECG, electrolytes at baseline, 2-4 weeks, then periodically |
| Moderate Renal Impairment | 200 mg daily | Frequent QT monitoring |
| Severe Renal Impairment | Not recommended | Insufficient data |
| Hepatic Impairment (Moderate/Severe) | Not recommended | Limited safety data |
Miss a dose? Take as soon as remembered unless close to next dose; do not double up. Store at room temperature, away from moisture.
Possible Side Effects of Vandetanib
Common side effects (≥20%) include diarrhea, rash, nausea, fatigue, and hypertension. Serious risks include QT prolongation/Torsades de pointes (monitor ECG), which occurs in up to 69% of patients >450 ms.
Common Side Effects:
- Diarrhea (manage with loperamide)
- Rash/Photosensitivity (use sunscreen)
- Hypertension (monitor BP)
- Fatigue, nausea, headache
- Decreased appetite, vomiting
Serious Side Effects (Seek Immediate Help):
- QT Prolongation: Fast/irregular heartbeat, dizziness, fainting.
- Interstitial Lung Disease: New cough, shortness of breath.
- Reversible Posterior Leukoencephalopathy Syndrome (RPLS): Headache, seizure, confusion, vision changes.
- Impaired Wound Healing: Withhold before/after surgery.
- Stevens-Johnson Syndrome, hemorrhage, stroke symptoms.
Lab abnormalities: Hypocalcemia, hypokalemia, elevated liver enzymes—correct electrolytes before and during treatment.
How to Cope with Side Effects of Vandetanib
Diarrhea: Stay hydrated, use anti-diarrheals as prescribed; dose reduce if severe.
Rash: Moisturize, avoid sun; topical steroids if needed.
Hypertension: Antihypertensives; monitor weekly initially.
Fatigue: Rest, light exercise, balanced diet.
Report persistent or worsening symptoms. Regular monitoring includes ECG (baseline, 2-4 weeks, then monthly), blood tests for electrolytes, renal/liver function, and thyroid.
Precautions While Taking Vandetanib
Under REMS, only certified prescribers can prescribe. Patients receive an alert card for risks like QT prolongation.
- Avoid grapefruit juice (increases exposure).
- Monitor for infections (neutropenia risk).
- Use sunscreen (photosensitivity).
- Drive cautiously if dizziness occurs.
Stopping or Switching from Vandetanib
Do not stop without doctor advice. Taper if needed for toxicity; restart possible after resolution. Upon discontinuation, monitor QT for 1 month due to long half-life (~19 days).
Expiry, Credit, and Product Feedback
Check expiry on packaging. Report issues via MHRA Yellow Card (UK) or FDA MedWatch (US). For credits/recalls, contact manufacturer.
Frequently Asked Questions (FAQs)
Q: Who can take Caprelsa?
A: Adults and children ≥5 years with aggressive, symptomatic unresectable or metastatic MTC. Consider RET status.
Q: What is the main risk of Vandetanib?
A: QT prolongation and Torsades de pointes—requires ECG monitoring and REMS.
Q: Can I take it with food?
A: Yes, with or without food.
Q: Is Vandetanib safe in pregnancy?
A: No—use contraception; category D.
Q: How long until side effects improve?
A: Varies; many resolve with dose adjustment or supportive care.
References
- Caprelsa | European Medicines Agency (EMA) — EMA. 2023-12-05. https://www.ema.europa.eu/en/medicines/human/EPAR/caprelsa
- CAPRELSA® (vandetanib) tablets label — FDA. 2025-05-01. https://www.accessdata.fda.gov/drugsatfda_docs/label/2025/022405s023lbl.pdf
- CAPRELSA® REMS Program — Genentech. Accessed 2026. https://www.caprelsarems.com
- Vandetanib (Caprelsa®) — OncoLink/University of Pennsylvania. Accessed 2026. https://www.oncolink.org/cancer-treatment/oncolink-rx/vandetanib-caprelsa-R
- Vandetanib (oral route) – Mayo Clinic — Mayo Clinic. Accessed 2026. https://www.mayoclinic.org/drugs-supplements/vandetanib-oral-route/description/drg-20074848
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