Drug interactions
Finerenone + Phenytoin
Severity: Major
Finerenone and Phenytoin: major interaction.
Last updated Sources: UK SmPC
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 is a strong CYP3A4 inducer and can markedly lower finerenone exposure. This is likely to blunt its renal and cardiovascular protective effect. Finerenone labeling advises against use with strong CYP3A4 inducers.
What this interaction means in plain words
Finerenone 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.
Finerenone belongs to Cardiovascular; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, increasing the metabolic clearance of finerenone.
What to do
Avoid the combination and choose a non-inducing antiseizure drug where possible. If it cannot be avoided, monitor potassium, eGFR and blood pressure for loss of effect.
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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References
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 Finerenone
- Carbamazepine + Finerenone Contraindicated
- Clarithromycin + Finerenone Contraindicated
- Ensitrelvir + Finerenone Contraindicated
- Finerenone + Itraconazole Contraindicated
- Finerenone + Ketoconazole Contraindicated
- Finerenone + Posaconazole Contraindicated
Frequently asked questions
Can I take Finerenone with Phenytoin?
MediHelp rates the interaction as major. Finerenone 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 is a strong CYP3A4 inducer and can markedly lower finerenone exposure. This is likely to blunt its renal and cardiovascular protective effect. Finerenone labeling advises against use with strong CYP3A4 inducers.
How serious is the interaction between Finerenone 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 and choose a non-inducing antiseizure drug where possible. If it cannot be avoided, monitor potassium, eGFR and blood pressure for loss of effect.
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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