Drug interactions
Eplerenone + Fosphenytoin
Severity: Moderate
Eplerenone and Fosphenytoin: 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
Fosphenytoin is converted to phenytoin, a strong CYP3A4 inducer. Eplerenone exposure may fall markedly, reducing its therapeutic effect.
What this interaction means in plain words
Eplerenone and Fosphenytoin 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.
Eplerenone belongs to Cardiovascular; Fosphenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, accelerating eplerenone metabolism.
What to do
Monitor blood pressure and heart failure status, and increase the eplerenone dose if response is lost. Consider another antihypertensive if control remains inadequate.
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 Eplerenone
- Amiloride + Eplerenone Contraindicated
- Atazanavir + Eplerenone Contraindicated
- Clarithromycin + Eplerenone Contraindicated
- Cobicistat + Eplerenone Contraindicated
- Elvitegravir / cobicistat / emtricitabine / tenofovir df + Eplerenone Contraindicated
- Ensitrelvir + Eplerenone Contraindicated
Other interactions of Fosphenytoin
- Dronedarone + Fosphenytoin Contraindicated
- Fosphenytoin + Ledipasvir-sofosbuvir Contraindicated
- Fosphenytoin + Lorlatinib Contraindicated
- Fosphenytoin + Lurasidone Contraindicated
- Fosphenytoin + Ranolazine Contraindicated
- Fosphenytoin + Sofosbuvir-velpatasvir-voxilaprevir Contraindicated
Frequently asked questions
Can I take Eplerenone with Fosphenytoin?
MediHelp rates the interaction as moderate. Eplerenone and Fosphenytoin 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. Fosphenytoin is converted to phenytoin, a strong CYP3A4 inducer. Eplerenone exposure may fall markedly, reducing its therapeutic effect.
How serious is the interaction between Eplerenone and Fosphenytoin?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor blood pressure and heart failure status, and increase the eplerenone dose if response is lost. Consider another antihypertensive if control remains inadequate.
What other medicines interact with Eplerenone?
MediHelp also lists interactions of Eplerenone with, for example, Amiloride, Atazanavir, Clarithromycin. The full list is on the Eplerenone page.
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