Drug interactions
Bosentan + Erythromycin stearate
Severity: Major
Bosentan and Erythromycin stearate: 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
Erythromycin inhibits CYP3A4 and can raise bosentan exposure considerably, increasing the risk of dose-related hepatotoxicity, headache, hypotension and fluid retention. Bosentan is a modest CYP3A4 inducer and may slightly lower erythromycin levels, but the dominant concern is increased bosentan exposure.
What this interaction means in plain words
Bosentan and Erythromycin stearate 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
Erythromycin inhibits CYP3A4-mediated bosentan metabolism, while bosentan weakly induces CYP3A4 and may reduce erythromycin concentrations.
What to do
Prefer a non-macrolide antibiotic such as a non-CYP3A4-inhibiting alternative. If combined, monitor liver enzymes, blood pressure and signs of bosentan toxicity, and consider the antibiotic response.
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 Erythromycin stearate?
MediHelp rates the interaction as major. Bosentan and Erythromycin stearate 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. Erythromycin inhibits CYP3A4 and can raise bosentan exposure considerably, increasing the risk of dose-related hepatotoxicity, headache, hypotension and fluid retention. Bosentan is a modest CYP3A4 inducer and may slightly lower erythromycin levels, but the dominant concern is increased bosentan exposure.
How serious is the interaction between Bosentan and Erythromycin stearate?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Prefer a non-macrolide antibiotic such as a non-CYP3A4-inhibiting alternative. If combined, monitor liver enzymes, blood pressure and signs of bosentan toxicity, and consider the antibiotic response.
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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