Drug interactions
Quinidine + Rifabutin
Severity: Moderate
Quinidine and Rifabutin: 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
Rifabutin induces CYP3A4, which lowers quinidine concentrations and may lead to loss of antiarrhythmic effect. The induction effect is weaker than with rifampicin but still clinically relevant. Quinidine levels may rise again after rifabutin is stopped.
What this interaction means in plain words
Quinidine and Rifabutin 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; Rifabutin belongs to Anti Bacterial.
Why it happens
Rifabutin induces CYP3A4, increasing the metabolic clearance of quinidine.
What to do
Monitor quinidine plasma concentrations and ECG, and adjust the quinidine dose as needed. Reassess the dose when rifabutin is started or stopped, or consider an alternative antiarrhythmic.
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 Rifabutin
- Cabotegravir + Rifabutin Contraindicated
- Lorlatinib + Rifabutin Contraindicated
- Rifabutin + Voriconazole Contraindicated
- Apixaban + Rifabutin Major
- Axitinib + Rifabutin Major
- Brexpiprazole + Rifabutin Major
Frequently asked questions
Can I take Quinidine with Rifabutin?
MediHelp rates the interaction as moderate. Quinidine and Rifabutin 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. Rifabutin induces CYP3A4, which lowers quinidine concentrations and may lead to loss of antiarrhythmic effect. The induction effect is weaker than with rifampicin but still clinically relevant. Quinidine levels may rise again after rifabutin is stopped.
How serious is the interaction between Quinidine and Rifabutin?
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 plasma concentrations and ECG, and adjust the quinidine dose as needed. Reassess the dose when rifabutin is started or stopped, or consider an alternative antiarrhythmic.
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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