Drug interactions
Bosentan + Fostemsavir
Severity: Moderate
Bosentan and Fostemsavir: 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
Strong CYP3A4 inducers markedly reduce temsavir concentrations, while bosentan is a moderate inducer and may also lower exposure, threatening HIV suppression.
What this interaction means in plain words
Bosentan and Fostemsavir 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; Fostemsavir belongs to Anti Virals.
Why it happens
CYP3A4 induction by bosentan increases temsavir clearance.
What to do
Monitor HIV viral load for loss of response, or consider an alternative to bosentan; strong inducers are contraindicated but bosentan is moderate.
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
Other interactions of Fostemsavir
- Apalutamide + Fostemsavir Contraindicated
- Carbamazepine + Fostemsavir Contraindicated
- Enzalutamide + Fostemsavir Contraindicated
- Fostemsavir + Mitotane Contraindicated
- Fostemsavir + Phenytoin Contraindicated
- Fostemsavir + Rifampicin Contraindicated
Frequently asked questions
Can I take Bosentan with Fostemsavir?
MediHelp rates the interaction as moderate. Bosentan and Fostemsavir 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. Strong CYP3A4 inducers markedly reduce temsavir concentrations, while bosentan is a moderate inducer and may also lower exposure, threatening HIV suppression.
How serious is the interaction between Bosentan and Fostemsavir?
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 HIV viral load for loss of response, or consider an alternative to bosentan; strong inducers are contraindicated but bosentan is moderate.
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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