Drug interactions
Flecainide + Venlafaxine
Severity: Moderate
Flecainide and Venlafaxine: 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
Venlafaxine is a weak CYP2D6 inhibitor and a CYP2D6 substrate and can cause QT prolongation and blood pressure rises, mainly at higher doses. With flecainide, there may be modestly higher flecainide exposure and additive proarrhythmic risk.
What this interaction means in plain words
Flecainide and Venlafaxine 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.
Flecainide belongs to Cardiovascular; Venlafaxine belongs to Central Nervous System.
Why it happens
Weak CYP2D6 inhibition by venlafaxine plus additive effects on cardiac conduction and repolarization.
What to do
Monitor ECG and blood pressure, especially during dose titration of venlafaxine. Consider flecainide level monitoring if conduction intervals increase.
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 Flecainide
- Flecainide + Nirmatrelvir Contraindicated
- Flecainide + Nirmatrelvir / ritonavir Contraindicated
- Flecainide + Pimozide Contraindicated
- Flecainide + Ritonavir Contraindicated
- Flecainide + Thioridazine Contraindicated
- Flecainide + Tipranavir Contraindicated
Other interactions of Venlafaxine
- Isocarboxazid + Venlafaxine Contraindicated
- Methylene blue + Venlafaxine Contraindicated
- Phenelzine + Venlafaxine Contraindicated
- Procarbazine + Venlafaxine Contraindicated
- Rasagiline + Venlafaxine Contraindicated
- Safinamide + Venlafaxine Contraindicated
Frequently asked questions
Can I take Flecainide with Venlafaxine?
MediHelp rates the interaction as moderate. Flecainide and Venlafaxine 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. Venlafaxine is a weak CYP2D6 inhibitor and a CYP2D6 substrate and can cause QT prolongation and blood pressure rises, mainly at higher doses. With flecainide, there may be modestly higher flecainide exposure and additive proarrhythmic risk.
How serious is the interaction between Flecainide and Venlafaxine?
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 ECG and blood pressure, especially during dose titration of venlafaxine. Consider flecainide level monitoring if conduction intervals increase.
What other medicines interact with Flecainide?
MediHelp also lists interactions of Flecainide with, for example, Nirmatrelvir, Nirmatrelvir / ritonavir, Pimozide. The full list is on the Flecainide page.
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