Drug interactions
Bosentan + Saquinavir
Severity: Major
Bosentan and Saquinavir: major interaction.
Last updated Sources: US FDA label
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
Boosted saquinavir (with ritonavir) greatly increases bosentan exposure, raising the risk of hepatotoxicity and hypotension. Bosentan may also lower saquinavir concentrations, potentially compromising antiviral control.
What this interaction means in plain words
Bosentan and Saquinavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Saquinavir/ritonavir inhibits CYP3A4 and OATP, reducing bosentan clearance, while bosentan induces CYP3A4 and lowers saquinavir levels.
What to do
If starting a boosted protease inhibitor in a patient on bosentan, stop bosentan at least 36 hours beforehand and resume after about 10 days at 62.5 mg once daily or every other day. Monitor liver enzymes, blood pressure and HIV viral load.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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References
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 Saquinavir?
MediHelp rates the interaction as major. Bosentan and Saquinavir can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Boosted saquinavir (with ritonavir) greatly increases bosentan exposure, raising the risk of hepatotoxicity and hypotension. Bosentan may also lower saquinavir concentrations, potentially compromising antiviral control.
How serious is the interaction between Bosentan and Saquinavir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: If starting a boosted protease inhibitor in a patient on bosentan, stop bosentan at least 36 hours beforehand and resume after about 10 days at 62.5 mg once daily or every other day. Monitor liver enzymes, blood pressure and HIV viral load.
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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