Drug interactions
Exemestane + Phenytoin
Severity: Moderate
Exemestane and Phenytoin: moderate 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 exemestane exposure and may reduce estrogen suppression in breast cancer treatment.
What this interaction means in plain words
Exemestane and Phenytoin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Exemestane belongs to Oncology; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, increasing exemestane metabolism.
What to do
Increase exemestane to 50 mg daily after a meal when given with a potent CYP3A4 inducer, and return to 25 mg after phenytoin is stopped.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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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 Exemestane
Frequently asked questions
Can I take Exemestane with Phenytoin?
MediHelp rates the interaction as moderate. Exemestane and Phenytoin can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Phenytoin lowers exemestane exposure and may reduce estrogen suppression in breast cancer treatment.
How serious is the interaction between Exemestane and Phenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Increase exemestane to 50 mg daily after a meal when given with a potent CYP3A4 inducer, and return to 25 mg after phenytoin is stopped.
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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