Drug interactions
Flecainide + Valbenazine
Severity: Moderate
Flecainide and Valbenazine: 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
Valbenazine can prolong the QT interval at higher exposures and flecainide has proarrhythmic effects, so the combination may increase risk of ventricular arrhythmia. Risk rises with heart disease or electrolyte abnormalities.
What this interaction means in plain words
Flecainide and Valbenazine 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; Valbenazine belongs to Central Nervous System.
Why it happens
Additive effects on cardiac repolarization and conduction.
What to do
Obtain baseline ECG and monitor QTc and QRS, and correct potassium and magnesium. Use caution especially in patients with congenital long QT or CYP2D6 poor metabolizer status.
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 Valbenazine
- Deutetrabenazine + Valbenazine Contraindicated
- Tranylcypromine + Valbenazine Contraindicated
- Amiodarone + Valbenazine Major
- Amisulpride + Valbenazine Major
- Apalutamide + Valbenazine Major
- Carbamazepine + Valbenazine Major
Frequently asked questions
Can I take Flecainide with Valbenazine?
MediHelp rates the interaction as moderate. Flecainide and Valbenazine 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. Valbenazine can prolong the QT interval at higher exposures and flecainide has proarrhythmic effects, so the combination may increase risk of ventricular arrhythmia. Risk rises with heart disease or electrolyte abnormalities.
How serious is the interaction between Flecainide and Valbenazine?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Obtain baseline ECG and monitor QTc and QRS, and correct potassium and magnesium. Use caution especially in patients with congenital long QT or CYP2D6 poor metabolizer status.
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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