Drug interactions
Bosentan + Nirmatrelvir
Severity: Major
Bosentan and Nirmatrelvir: 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
Nirmatrelvir is given with ritonavir, which strongly inhibits CYP3A4 and raises bosentan concentrations. This can cause hepatotoxicity, hypotension and fluid retention.
What this interaction means in plain words
Bosentan and Nirmatrelvir 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.
Bosentan belongs to Miscellaneous; Nirmatrelvir belongs to Anti Virals.
Why it happens
Ritonavir-boosted nirmatrelvir inhibits CYP3A4 and hepatic uptake of bosentan, increasing its exposure.
What to do
Stop bosentan at least 36 hours before starting nirmatrelvir/ritonavir and resume it about 10 days after starting. Monitor for hypotension and liver toxicity.
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
Other interactions of Nirmatrelvir
- Alfuzosin + Nirmatrelvir Contraindicated
- Amiodarone + Nirmatrelvir Contraindicated
- Apalutamide + Nirmatrelvir Contraindicated
- Carbamazepine + Nirmatrelvir Contraindicated
- Colchicine + Nirmatrelvir Contraindicated
- Dronedarone + Nirmatrelvir Contraindicated
Frequently asked questions
Can I take Bosentan with Nirmatrelvir?
MediHelp rates the interaction as major. Bosentan and Nirmatrelvir 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. Nirmatrelvir is given with ritonavir, which strongly inhibits CYP3A4 and raises bosentan concentrations. This can cause hepatotoxicity, hypotension and fluid retention.
How serious is the interaction between Bosentan and Nirmatrelvir?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Stop bosentan at least 36 hours before starting nirmatrelvir/ritonavir and resume it about 10 days after starting. Monitor for hypotension and liver toxicity.
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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