Drug interactions
Ospemifene + Phenytoin
Severity: Moderate
Ospemifene 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 induces several CYP enzymes that metabolize ospemifene, which is likely to lower its exposure and reduce efficacy. Ospemifene is highly protein bound and could also displace phenytoin, though this is of uncertain relevance.
What this interaction means in plain words
Ospemifene 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.
Ospemifene belongs to Endocrine; Phenytoin belongs to Central Nervous System.
Why it happens
Phenytoin induces CYP3A4, CYP2C9 and CYP2C19, increasing ospemifene clearance.
What to do
Monitor for reduced symptom relief with ospemifene and consider an alternative therapy. Check phenytoin levels if toxicity is suspected.
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 Ospemifene
- Bazedoxifene-conjugated estrogens + Ospemifene Contraindicated
- Estradiol + Ospemifene Contraindicated
- Clomiphene + Ospemifene Major
- Fluconazole + Ospemifene Major
- Ketoconazole + Ospemifene Major
- Ospemifene + Raloxifene Major
Frequently asked questions
Can I take Ospemifene with Phenytoin?
MediHelp rates the interaction as moderate. Ospemifene 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 induces several CYP enzymes that metabolize ospemifene, which is likely to lower its exposure and reduce efficacy. Ospemifene is highly protein bound and could also displace phenytoin, though this is of uncertain relevance.
How serious is the interaction between Ospemifene 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: Monitor for reduced symptom relief with ospemifene and consider an alternative therapy. Check phenytoin levels if toxicity is suspected.
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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