Drug interactions
Flecainide + Peginterferon alfa 2b
Severity: Moderate
Flecainide and Peginterferon alfa 2b: 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
Peginterferon alfa 2b may alter CYP2D6 activity and so change flecainide exposure in an unpredictable way. Because flecainide has a narrow therapeutic index and proarrhythmic risk, even modest changes matter.
What this interaction means in plain words
Flecainide and Peginterferon alfa 2b 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; Peginterferon alfa 2b belongs to Anti Virals.
Why it happens
Possible interferon modulation of CYP2D6, a main flecainide clearance pathway; not firmly established.
What to do
Monitor ECG (QRS and PR intervals) and consider flecainide plasma levels when interferon is started or stopped. Adjust the dose as needed.
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 Peginterferon alfa 2b
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 Peginterferon alfa 2b?
MediHelp rates the interaction as moderate. Flecainide and Peginterferon alfa 2b 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. Peginterferon alfa 2b may alter CYP2D6 activity and so change flecainide exposure in an unpredictable way. Because flecainide has a narrow therapeutic index and proarrhythmic risk, even modest changes matter.
How serious is the interaction between Flecainide and Peginterferon alfa 2b?
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 (QRS and PR intervals) and consider flecainide plasma levels when interferon is started or stopped. Adjust the dose as needed.
What other medicines interact with Peginterferon alfa 2b?
MediHelp also lists interactions of Peginterferon alfa 2b with, for example, Aldesleukin, Deferiprone, Pexidartinib. The full list is on the Peginterferon alfa 2b page.
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