Drug interactions
Cimetidine + Conivaptan
Severity: Moderate
Cimetidine and Conivaptan: moderate interaction.
Last updated
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
Conivaptan is a CYP3A4 substrate and a CYP3A4 inhibitor. Cimetidine may raise conivaptan levels slightly, increasing the risk of overly rapid sodium correction and infusion-site reactions.
What this interaction means in plain words
Cimetidine and Conivaptan can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Cimetidine weakly inhibits CYP3A4 metabolism of conivaptan.
What to do
Monitor serum sodium frequently and adjust the infusion to avoid overly rapid correction.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Cimetidine
- Cimetidine + Dofetilide Contraindicated
- Cimetidine + Fezolinetant Contraindicated
- Alfentanil + Cimetidine Major
- Atazanavir + Cimetidine Major
- Carmustine + Cimetidine Major
- Cimetidine + Citalopram Major
Frequently asked questions
Can I take Cimetidine with Conivaptan?
MediHelp rates the interaction as moderate. Cimetidine and Conivaptan can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Conivaptan is a CYP3A4 substrate and a CYP3A4 inhibitor. Cimetidine may raise conivaptan levels slightly, increasing the risk of overly rapid sodium correction and infusion-site reactions.
How serious is the interaction between Cimetidine and Conivaptan?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor serum sodium frequently and adjust the infusion to avoid overly rapid correction.
What other medicines interact with Cimetidine?
MediHelp also lists interactions of Cimetidine with, for example, Dofetilide, Fezolinetant, Alfentanil. The full list is on the Cimetidine page.
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