Drug interactions
Fosaprepitant + Quinidine
Severity: Moderate
Fosaprepitant 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
Aprepitant, the active metabolite of fosaprepitant, moderately inhibits CYP3A4 and may raise quinidine levels. Quinidine has a narrow therapeutic index and the increase could heighten QT prolongation risk. With single-dose fosaprepitant the effect is typically short-lived.
What this interaction means in plain words
Fosaprepitant 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.
Fosaprepitant belongs to Gastrointestinal Tract; Quinidine belongs to Anti Parasitic.
Why it happens
Aprepitant inhibits CYP3A4 (and transiently induces other CYPs), altering quinidine clearance.
What to do
Monitor ECG/QTc and signs of quinidine toxicity for several days after fosaprepitant. Consider reducing the quinidine dose if levels rise.
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 Fosaprepitant
- Flibanserin + Fosaprepitant Contraindicated
- Fosaprepitant + Pimozide Contraindicated
- Alprazolam + Fosaprepitant Moderate
- Amiodarone + Fosaprepitant Moderate
- Amobarbital + Fosaprepitant Moderate
- Apalutamide + Fosaprepitant Moderate
Frequently asked questions
Can I take Fosaprepitant with Quinidine?
MediHelp rates the interaction as moderate. Fosaprepitant 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. Aprepitant, the active metabolite of fosaprepitant, moderately inhibits CYP3A4 and may raise quinidine levels. Quinidine has a narrow therapeutic index and the increase could heighten QT prolongation risk. With single-dose fosaprepitant the effect is typically short-lived.
How serious is the interaction between Fosaprepitant 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 ECG/QTc and signs of quinidine toxicity for several days after fosaprepitant. Consider reducing the quinidine dose if levels rise.
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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