Drug interactions
Ivacaftor + Quinidine
Severity: Moderate
Ivacaftor and Quinidine: 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
Ivacaftor and its metabolite inhibit P-glycoprotein and may increase exposure to quinidine, a P-gp substrate with a narrow therapeutic index. Higher levels could cause QT prolongation and other toxicity.
What this interaction means in plain words
Ivacaftor and Quinidine 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.
Ivacaftor belongs to Miscellaneous; Quinidine belongs to Anti Parasitic.
Why it happens
Ivacaftor inhibits P-glycoprotein efflux of quinidine.
What to do
Monitor quinidine levels and ECG, and reduce the quinidine dose if toxicity develops.
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 Ivacaftor
- Ensitrelvir + Ivacaftor Contraindicated
- Apalutamide + Ivacaftor Major
- Carbamazepine + Ivacaftor Major
- Clarithromycin + Ivacaftor Major
- Efavirenz + Ivacaftor Major
- Enzalutamide + Ivacaftor Major
Frequently asked questions
Can I take Ivacaftor with Quinidine?
MediHelp rates the interaction as moderate. Ivacaftor and Quinidine 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. Ivacaftor and its metabolite inhibit P-glycoprotein and may increase exposure to quinidine, a P-gp substrate with a narrow therapeutic index. Higher levels could cause QT prolongation and other toxicity.
How serious is the interaction between Ivacaftor and Quinidine?
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 quinidine levels and ECG, and reduce the quinidine dose if toxicity develops.
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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