Drug interactions
Phenytoin + Vandetanib
Severity: Major
Phenytoin and Vandetanib: major interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Phenytoin may lower vandetanib concentrations and reduce antitumor efficacy.
What this interaction means in plain words
Phenytoin and Vandetanib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Phenytoin belongs to Central Nervous System; Vandetanib belongs to Oncology.
Why it happens
Phenytoin induces CYP3A4 metabolism of vandetanib.
What to do
Avoid potent CYP3A4 inducers with vandetanib; use a non-inducing anticonvulsant and monitor clinical response.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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Other interactions of Phenytoin
- Artemether / lumefantrine + Phenytoin Contraindicated
- Bictegravir + Phenytoin Contraindicated
- Cabotegravir + Phenytoin Contraindicated
- Doravirine + Phenytoin Contraindicated
- Elbasvir / grazoprevir + Phenytoin Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Phenytoin Contraindicated
Other interactions of Vandetanib
- Amiodarone + Vandetanib Contraindicated
- Amisulpride + Vandetanib Contraindicated
- Amitriptyline + Vandetanib Contraindicated
- Anagrelide + Vandetanib Contraindicated
- Asenapine + Vandetanib Contraindicated
- Chloroquine + Vandetanib Contraindicated
Frequently asked questions
Can I take Phenytoin with Vandetanib?
MediHelp rates the interaction as major. Phenytoin and Vandetanib can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Phenytoin may lower vandetanib concentrations and reduce antitumor efficacy.
How serious is the interaction between Phenytoin and Vandetanib?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid potent CYP3A4 inducers with vandetanib; use a non-inducing anticonvulsant and monitor clinical response.
What other medicines interact with Phenytoin?
MediHelp also lists interactions of Phenytoin with, for example, Artemether / lumefantrine, Bictegravir, Cabotegravir. The full list is on the Phenytoin page.
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