Drug interactions
Flecainide + Ranolazine
Severity: Major
Flecainide and Ranolazine: major interaction.
Last updated Sources: UK SmPC
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
Ranolazine weakly inhibits CYP2D6 and may raise flecainide levels, while both agents affect cardiac conduction and repolarization. Flecainide toxicity can cause conduction block and proarrhythmia, especially in structural heart disease.
What this interaction means in plain words
Flecainide 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.
Flecainide belongs to Cardiovascular; Ranolazine belongs to Cardiovascular.
Why it happens
CYP2D6 inhibition by ranolazine raises flecainide exposure, combined with additive effects on cardiac conduction and QT interval.
What to do
Monitor ECG for PR, QRS and QT changes and consider checking flecainide plasma levels. Lower the flecainide dose if conduction prolongation occurs.
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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References
Other interactions of Ranolazine
- Adagrasib + Ranolazine Contraindicated
- Amobarbital + Ranolazine Contraindicated
- Apalutamide + Ranolazine Contraindicated
- Butabarbital + Ranolazine Contraindicated
- Carbamazepine + Ranolazine Contraindicated
- Clarithromycin + Ranolazine Contraindicated
Other interactions of Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Frequently asked questions
Can I take Flecainide with Ranolazine?
MediHelp rates the interaction as major. Flecainide 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. Ranolazine weakly inhibits CYP2D6 and may raise flecainide levels, while both agents affect cardiac conduction and repolarization. Flecainide toxicity can cause conduction block and proarrhythmia, especially in structural heart disease.
How serious is the interaction between Flecainide 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: Monitor ECG for PR, QRS and QT changes and consider checking flecainide plasma levels. Lower the flecainide dose if conduction prolongation occurs.
What other medicines interact with Ranolazine?
MediHelp also lists interactions of Ranolazine with, for example, Adagrasib, Amobarbital, Apalutamide. The full list is on the Ranolazine page.
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