Drug interactions
Erythromycin base + Tolvaptan
Severity: Major
Erythromycin base and Tolvaptan: 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 is a moderate CYP3A4 inhibitor and increases tolvaptan exposure. This raises the risk of excessive aquaresis, dehydration and overly rapid rise in serum sodium.
What this interaction means in plain words
Erythromycin base and Tolvaptan 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, decreasing the metabolism of tolvaptan.
What to do
Use a reduced tolvaptan dose according to labeling or choose a non-interacting antibiotic. Monitor serum sodium and volume status closely.
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 Tolvaptan
- Atazanavir + Tolvaptan Contraindicated
- Ceritinib + Tolvaptan Contraindicated
- Cobicistat + Tolvaptan Contraindicated
- Conivaptan + Tolvaptan Contraindicated
- Darunavir + Tolvaptan Contraindicated
- Idelalisib + Tolvaptan Contraindicated
Frequently asked questions
Can I take Erythromycin base with Tolvaptan?
MediHelp rates the interaction as major. Erythromycin base and Tolvaptan 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 is a moderate CYP3A4 inhibitor and increases tolvaptan exposure. This raises the risk of excessive aquaresis, dehydration and overly rapid rise in serum sodium.
How serious is the interaction between Erythromycin base and Tolvaptan?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Use a reduced tolvaptan dose according to labeling or choose a non-interacting antibiotic. Monitor serum sodium and volume status closely.
What other medicines interact with Tolvaptan?
MediHelp also lists interactions of Tolvaptan with, for example, Atazanavir, Ceritinib, Cobicistat. The full list is on the Tolvaptan page.
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