Drug interactions
Bosentan + Valproic acid
Severity: Moderate
Bosentan and Valproic acid: 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
Valproate may weakly inhibit CYP2C9, the main enzyme metabolizing bosentan, potentially raising bosentan exposure. Both drugs can cause liver enzyme elevations, so hepatotoxicity may be additive. The pharmacokinetic effect is probably small.
What this interaction means in plain words
Bosentan and Valproic acid 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; Valproic acid belongs to Central Nervous System.
Why it happens
Valproate inhibits CYP2C9, reducing bosentan clearance, and both drugs have hepatotoxic potential.
What to do
Monitor liver function tests at least monthly, as already required for bosentan, with closer attention during combined use. Reduce or stop therapy if transaminases rise significantly.
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 Valproic acid
- Ertapenem + Valproic acid Contraindicated
- Imipenem / cilastatin / relebactam + Valproic acid Contraindicated
- Imipenem / cilastatin + Valproic acid Contraindicated
- Meropenem / vaborbactam + Valproic acid Contraindicated
- Meropenem + Valproic acid Contraindicated
- Calcium / magnesium / potassium / sodium oxybates + Valproic acid Major
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 Valproic acid?
MediHelp rates the interaction as moderate. Bosentan and Valproic acid 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. Valproate may weakly inhibit CYP2C9, the main enzyme metabolizing bosentan, potentially raising bosentan exposure. Both drugs can cause liver enzyme elevations, so hepatotoxicity may be additive. The pharmacokinetic effect is probably small.
How serious is the interaction between Bosentan and Valproic acid?
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 liver function tests at least monthly, as already required for bosentan, with closer attention during combined use. Reduce or stop therapy if transaminases rise significantly.
What other medicines interact with Valproic acid?
MediHelp also lists interactions of Valproic acid with, for example, Ertapenem, Imipenem / cilastatin / relebactam, Imipenem / cilastatin. The full list is on the Valproic acid page.
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