Drug interactions
Erythromycin + Tolvaptan
Severity: Major
Erythromycin 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 increases tolvaptan exposure substantially. This can cause excessively rapid aquaresis, dehydration, hypernatremia and overly rapid correction of serum sodium.
What this interaction means in plain words
Erythromycin 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 belongs to Anti Bacterial; Tolvaptan belongs to Endocrine.
Why it happens
Erythromycin inhibits CYP3A4, which is the main metabolic pathway of tolvaptan.
What to do
Avoid with moderate CYP3A4 inhibitors where possible, or use a reduced tolvaptan dose per labeling. 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 Erythromycin
- Conivaptan + Erythromycin Contraindicated
- Dihydroergotamine intranasal + Erythromycin Contraindicated
- Dihydroergotamine + Erythromycin Contraindicated
- Domperidone + Erythromycin Contraindicated
- Dronedarone + Erythromycin Contraindicated
- Droperidol + Erythromycin Contraindicated
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 with Tolvaptan?
MediHelp rates the interaction as major. Erythromycin 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 increases tolvaptan exposure substantially. This can cause excessively rapid aquaresis, dehydration, hypernatremia and overly rapid correction of serum sodium.
How serious is the interaction between Erythromycin 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: Avoid with moderate CYP3A4 inhibitors where possible, or use a reduced tolvaptan dose per labeling. Monitor serum sodium and volume status closely.
What other medicines interact with Erythromycin?
MediHelp also lists interactions of Erythromycin with, for example, Conivaptan, Dihydroergotamine intranasal, Dihydroergotamine. The full list is on the Erythromycin page.
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