Drug interactions
Nafcillin + Quinidine
Severity: Moderate
Nafcillin 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
Nafcillin can induce CYP3A4 and may lower quinidine concentrations, reducing therapeutic effect. The interaction is based on induction reported with other CYP3A4 substrates.
What this interaction means in plain words
Nafcillin 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.
Why it happens
Nafcillin induces CYP3A4, increasing quinidine metabolism.
What to do
Monitor quinidine levels and ECG or clinical response during and after nafcillin therapy. Adjust the quinidine dose accordingly, and expect levels to rise after nafcillin is stopped.
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
Frequently asked questions
Can I take Nafcillin with Quinidine?
MediHelp rates the interaction as moderate. Nafcillin 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. Nafcillin can induce CYP3A4 and may lower quinidine concentrations, reducing therapeutic effect. The interaction is based on induction reported with other CYP3A4 substrates.
How serious is the interaction between Nafcillin 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 or clinical response during and after nafcillin therapy. Adjust the quinidine dose accordingly, and expect levels to rise after nafcillin is stopped.
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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