Drug interactions
Bosentan + Sulfamethoxazole
Severity: Moderate
Bosentan and Sulfamethoxazole: 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
Sulfamethoxazole inhibits CYP2C9 and may increase bosentan concentrations. This could raise the risk of dose-related liver injury and other adverse effects, though the effect is generally modest.
What this interaction means in plain words
Bosentan and Sulfamethoxazole 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.
Why it happens
Sulfamethoxazole inhibits CYP2C9, reducing bosentan metabolism.
What to do
Monitor liver aminotransferases and for signs of bosentan toxicity such as hypotension and edema during co-therapy. Consider an alternative antibiotic if abnormalities develop.
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 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 Sulfamethoxazole?
MediHelp rates the interaction as moderate. Bosentan and Sulfamethoxazole 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. Sulfamethoxazole inhibits CYP2C9 and may increase bosentan concentrations. This could raise the risk of dose-related liver injury and other adverse effects, though the effect is generally modest.
How serious is the interaction between Bosentan and Sulfamethoxazole?
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 aminotransferases and for signs of bosentan toxicity such as hypotension and edema during co-therapy. Consider an alternative antibiotic if abnormalities develop.
What other medicines interact with Bosentan?
MediHelp also lists interactions of Bosentan with, for example, Cyclosporin, Glibenclamide, Glyburide-metformin. The full list is on the Bosentan page.
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