Drug interactions
Quinidine + Rifampin
Severity: Major
Quinidine and Rifampin: major 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
Rifampin strongly induces CYP3A4 and substantially reduces quinidine concentrations. Loss of antiarrhythmic effect has been reported and arrhythmias may recur.
What this interaction means in plain words
Quinidine and Rifampin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for.
Why it happens
Rifampin induces CYP3A4 and increases the hepatic clearance of quinidine.
What to do
Avoid the combination if possible. If both are required, monitor quinidine levels and ECG and increase the quinidine dose, then reduce it again after rifampin is stopped.
What to ask your pharmacist
- Does the benefit of taking both outweigh the risk in my case?
- Do I need any blood test, ECG or other check while on both?
- What early warning signs should I watch for, and what should I do if they appear?
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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 Quinidine with Rifampin?
MediHelp rates the interaction as major. Quinidine and Rifampin can interact in a way that may be serious. Using them together is sometimes necessary, but it needs a deliberate decision by the prescriber, a plan for monitoring, and clear advice on the warning signs to watch for. Rifampin strongly induces CYP3A4 and substantially reduces quinidine concentrations. Loss of antiarrhythmic effect has been reported and arrhythmias may recur.
How serious is the interaction between Quinidine and Rifampin?
MediHelp rates it major, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid the combination if possible. If both are required, monitor quinidine levels and ECG and increase the quinidine dose, then reduce it again after rifampin 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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