Drug interactions
Phenytoin + Selexipag
Severity: Moderate
Phenytoin and Selexipag: 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 can lower exposure to selexipag and its active metabolite, possibly reducing efficacy in pulmonary arterial hypertension.
What this interaction means in plain words
Phenytoin and Selexipag 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 belongs to Central Nervous System; Selexipag belongs to Cardiovascular.
Why it happens
Enzyme induction by phenytoin, including CYP2C8, increases the metabolism of selexipag and its active metabolite.
What to do
Monitor clinical response and increase the selexipag dose as tolerated, up to double. Reduce the dose again when 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 Selexipag
- Gemfibrozil + Selexipag Contraindicated
- Abiraterone + Selexipag Moderate
- Apalutamide + Selexipag Moderate
- Carbamazepine + Selexipag Moderate
- Clopidogrel + Selexipag Moderate
- Cyclosporin + Selexipag Moderate
Frequently asked questions
Can I take Phenytoin with Selexipag?
MediHelp rates the interaction as moderate. Phenytoin and Selexipag 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 can lower exposure to selexipag and its active metabolite, possibly reducing efficacy in pulmonary arterial hypertension.
How serious is the interaction between Phenytoin and Selexipag?
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 clinical response and increase the selexipag dose as tolerated, up to double. Reduce the dose again when 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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