Drug interactions
Bosentan + Phenytoin
Severity: Moderate
Bosentan 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 CYP3A4 and CYP2C9 and can lower bosentan concentrations, reducing its effect on pulmonary hypertension. Bosentan is itself an inducer and may lower phenytoin levels.
What this interaction means in plain words
Bosentan 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.
Bosentan belongs to Miscellaneous; Phenytoin belongs to Central Nervous System.
Why it happens
Mutual enzyme induction involving CYP3A4 and CYP2C9.
What to do
Monitor clinical response to bosentan and serum phenytoin concentrations, adjusting doses as needed. Watch for liver enzyme elevations.
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 Bosentan
- Bosentan + Cyclosporin Contraindicated
- Bosentan + Glibenclamide Contraindicated
- Bosentan + Glyburide-metformin Contraindicated
- Bosentan + Lonafarnib Contraindicated
- Bosentan + Sparsentan Contraindicated
- Artemether / lumefantrine + Bosentan Major
Frequently asked questions
Can I take Bosentan with Phenytoin?
MediHelp rates the interaction as moderate. Bosentan 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 CYP3A4 and CYP2C9 and can lower bosentan concentrations, reducing its effect on pulmonary hypertension. Bosentan is itself an inducer and may lower phenytoin levels.
How serious is the interaction between Bosentan 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 clinical response to bosentan and serum phenytoin concentrations, adjusting doses as needed. Watch for liver enzyme elevations.
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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