Multi-kinase inhibitor (RET, EGFR, VEGFR) Pregnancy: Based on its mechanism of action and findings in animals, CAPRELSA can cause fetal harm when administered to a pregnant woman. There are no available human data in pregnant women to inform a drug-associated risk. Vandetanib was embryotoxic, fetotoxic and induced fetal malformations in rats at exposures less than or equal to those expected at the recommended human dose of 300 mg/day. Advise patients of the potential risk to a fetus and advise women of reproductive potential to use effective contraception.

Vandetanib (Specialist drug)

Brand names: Caprelsa

Vandetanib is an oral tyrosine kinase inhibitor used in the treatment of aggressive and symptomatic medullary thyroid cancer that is unresectable or metastatic.

Auto-extracted from the source labelling — not yet independently clinician-verified. These values were distilled from the UK SPC (or the US label where noted) but have not had a clinician sign-off. Confirm against the current SmPC before prescribing.

Adult dose

Dose: 300 mg

Route: Oral — may be taken with or without food; do not crush the tablets. Tablets can be dispersed in 2 ounces of water by stirring for approximately 10 minutes (they will not completely dissolve) and swallowed immediately, with any remaining residue mixed with a further 4 ounces of water and swallowed; the dispersion can also be administered through nasogastric or gastrostomy tubes. Do not use other liquids for dispersion.

Frequency: Once daily until disease progression or unacceptable toxicity occurs

No UK SPC (eMC) record was fetched — this draft is distilled from the US prescribing information for CAPRELSA (label date 2026-04-23) and must be verified against the UK SPC. Indication in the fetched label is medullary thyroid cancer (MTC). MISSED DOSE: do not take a missed dose within 12 hours of the next dose. DOSE MODIFICATION: the 300 mg daily dose can be reduced to 200 mg (two 100 mg tablets) and then to 100 mg for CTCAE Grade 3 or greater toxicities. Interrupt for QTcF greater than 500 ms and resume at a reduced dose when the QTcF returns to less than 450 ms; interrupt for CTCAE Grade 3 or greater toxicity and resume at a reduced dose when the toxicity resolves or improves to Grade 1. For recurrent toxicities reduce to 100 mg after resolution or improvement to Grade 1, if continued treatment is warranted. Adverse events including QT prolongation should be monitored closely as they may not resolve fully until approximately three plasma half-lives of the drug have elapsed. HEPATIC: not recommended for use in patients with moderate or severe hepatic impairment. PAEDIATRIC: safety and efficacy in paediatric patients have not been established — verify any under-18 use against a children's formulary. Boxed warning: QT prolongation, torsades de pointes and sudden death — monitor ECGs and serum potassium, calcium, magnesium and TSH. Withhold for at least 1 month prior to elective surgery and for at least 2 weeks after major surgery until adequate wound healing; withhold for 1 month prior to scheduled dental surgery (osteonecrosis risk).

Dose adjustments

Renal

Reduce the starting dose to 200 mg in patients with moderate renal impairment (creatinine clearance ≥30 to <50 mL/min).

Dose auto-extracted from US FDA prescribing information (openFDA / DailyMed) — cross-check; US labelling may differ from UK — not yet clinician-verified. Always confirm against the product SmPC and your local formulary before prescribing.

Contraindications

Congenital long QT syndrome (US label §4 and boxed warning)

Side effects

Diarrhoea/colitis (most common, >20%)
Rash and acneiform dermatitis
Hypertension
Nausea, decreased appetite and abdominal pain
Headache and upper respiratory tract infections; labelled serious reactions include QT prolongation and torsades de pointes, severe skin reactions (toxic epidermal necrolysis and Stevens-Johnson syndrome, some fatal), interstitial lung disease, ischaemic cerebrovascular events, haemorrhage, heart failure, reversible posterior leukoencephalopathy syndrome, renal failure, hypothyroidism and osteonecrosis

Interactions

Strong CYP3A4 inducers (e.g. rifampicin) — decrease vandetanib plasma concentrations; avoid concomitant use
St John's wort — avoid, as it can decrease vandetanib exposure unpredictably
Agents that prolong the QT interval — avoid concomitant use
Drugs transported by OCT2 (e.g. metformin) — vandetanib increases their plasma concentrations; use caution and monitor closely for toxicity
Digoxin — vandetanib increases digoxin plasma concentrations; use caution and monitor closely for toxicity

Clinical monograph

How it works

It inhibits multiple receptor tyrosine kinases including RET, vascular endothelial growth factor receptor (VEGFR) and epidermal growth factor receptor (EGFR), thereby blocking tumour cell proliferation and angiogenesis.

Prescribing in practice

It prolongs the QT interval and has been associated with torsades de pointes and sudden death; correct electrolytes and review concomitant QT-prolonging or interacting drugs before and during treatment.
It is a specialist oncology medicine initiated and supervised by clinicians experienced in cancer therapy.
Dose and continuation depend on tolerability, organ function and ECG findings as set out in the SPC.

Monitoring

Monitor ECG (QT interval), serum electrolytes including potassium, calcium and magnesium, thyroid-stimulating hormone, blood pressure and renal and hepatic function periodically.

Counselling the patient

Use effective sun protection as photosensitivity and severe skin reactions can occur.
Report fainting, palpitations, severe diarrhoea or new breathlessness promptly.
Do not start any new medicine, including over-the-counter products, without checking for interactions.

Evidence & guidelines

Use is informed by the ZETA trial and aligned with MHRA-approved labelling for medullary thyroid cancer.

Reference: SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. The structured dose values shown have been reviewed by a clinician. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways