Drug interactions
Cabozantinib + Phenytoin
Severity: Major
Cabozantinib and Phenytoin: 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 lowers cabozantinib exposure through CYP3A4 induction, which may reduce anticancer efficacy.
What this interaction means in plain words
Cabozantinib and Phenytoin 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.
Cabozantinib belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
Induction of CYP3A4 by phenytoin increases cabozantinib clearance.
What to do
Avoid the combination where possible and use a non-inducing antiepileptic. If unavoidable, raise the cabozantinib dose per product labeling and return to the usual dose a few days after stopping phenytoin.
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 Cabozantinib
Frequently asked questions
Can I take Cabozantinib with Phenytoin?
MediHelp rates the interaction as major. Cabozantinib and Phenytoin 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 lowers cabozantinib exposure through CYP3A4 induction, which may reduce anticancer efficacy.
How serious is the interaction between Cabozantinib and Phenytoin?
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 the combination where possible and use a non-inducing antiepileptic. If unavoidable, raise the cabozantinib dose per product labeling and return to the usual dose a few days after stopping phenytoin.
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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