Drug interactions
Quinidine + Tolvaptan
Severity: Moderate
Quinidine and Tolvaptan: 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
Quinidine may raise tolvaptan exposure by inhibiting P-gp, which could cause excessive aquaresis, dehydration, hypernatremia or rapid sodium correction. The effect is predicted rather than well quantified.
What this interaction means in plain words
Quinidine and Tolvaptan 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.
Quinidine belongs to Anti Parasitic; Tolvaptan belongs to Endocrine.
Why it happens
Quinidine inhibits P-gp efflux of tolvaptan, increasing its exposure.
What to do
Monitor serum sodium and fluid status closely, and consider reducing the tolvaptan dose. Avoid overly rapid sodium 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 Quinidine
- Adagrasib + Quinidine Contraindicated
- Arsenic trioxide + Quinidine Contraindicated
- Artemether / lumefantrine + Quinidine Contraindicated
- Chloroquine + Quinidine Contraindicated
- Dofetilide + Quinidine Contraindicated
- Dronedarone + Quinidine 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 Quinidine with Tolvaptan?
MediHelp rates the interaction as moderate. Quinidine and Tolvaptan 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. Quinidine may raise tolvaptan exposure by inhibiting P-gp, which could cause excessive aquaresis, dehydration, hypernatremia or rapid sodium correction. The effect is predicted rather than well quantified.
How serious is the interaction between Quinidine and Tolvaptan?
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 and fluid status closely, and consider reducing the tolvaptan dose. Avoid overly rapid sodium correction.
What other medicines interact with Quinidine?
MediHelp also lists interactions of Quinidine with, for example, Adagrasib, Arsenic trioxide, Artemether / lumefantrine. The full list is on the Quinidine page.
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