Drug interactions
Quinidine + Ranolazine
Severity: Major
Quinidine and Ranolazine: 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
Both drugs prolong the QT interval, and quinidine inhibits P-glycoprotein, which can raise ranolazine levels. The combination increases the risk of torsades de pointes.
What this interaction means in plain words
Quinidine and Ranolazine 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.
Quinidine belongs to Anti Parasitic; Ranolazine belongs to Cardiovascular.
Why it happens
Additive QT prolongation and P-glycoprotein inhibition increasing ranolazine exposure.
What to do
Avoid the combination if possible. If used, monitor ECG and reduce the ranolazine dose per labeling.
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
Other interactions of Ranolazine
- Adagrasib + Ranolazine Contraindicated
- Amobarbital + Ranolazine Contraindicated
- Apalutamide + Ranolazine Contraindicated
- Butabarbital + Ranolazine Contraindicated
- Carbamazepine + Ranolazine Contraindicated
- Clarithromycin + Ranolazine Contraindicated
Frequently asked questions
Can I take Quinidine with Ranolazine?
MediHelp rates the interaction as major. Quinidine and Ranolazine 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. Both drugs prolong the QT interval, and quinidine inhibits P-glycoprotein, which can raise ranolazine levels. The combination increases the risk of torsades de pointes.
How serious is the interaction between Quinidine and Ranolazine?
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 used, monitor ECG and reduce the ranolazine dose per labeling.
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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