Flecainide and Propranolol Interaction
Drug interaction information between Flecainide and Propranolol.
Flecainide and Propranolol have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Flecainide and Propranolol. Major interactions are generally avoided, moderate ones may need monitoring or a dose adjustment, and minor ones are usually low-risk. This page shows the documented mechanism and guidance. Label-documented interactions are not a complete safety review, so always confirm your own medications with a pharmacist or doctor. Educational information, not medical advice.
How They Interact
Taking these drugs together increases the amount of medicine in your blood and can further weaken the heart's ability to pump.
What To Do
Your doctor should watch your heart health closely and may need to change your medication doses.
FDA Label Information
In a study involving healthy subjects receiving flecainide acetate and propranolol concurrently, plasma flecainide levels were increased about 20% and propranolol levels were increased about 30% compared to control values. In this formal interaction study, flecainide acetate and propranolol were each found to have negative inotropic effects; when the drugs were administered together, the effects were additive. The effects of concomitant administration of flecainide acetate and propranolol on the PR interval were less than additive.
Flecainide Also Interacts With
- Nirmatrelvir/Ritonavir major
- Darifenacin moderate
- Fluoxetine moderate
- Diltiazem minor
- Nifedipine minor
Frequently Asked Questions
Can I take Flecainide and Propranolol together?
This is a minor interaction. Your doctor should watch your heart health closely and may need to change your medication doses.
How serious is the interaction between Flecainide and Propranolol?
This interaction is classified as "minor" severity by the FDA. Minor interactions are unlikely to cause significant problems but should still be mentioned to your healthcare provider.
Why do Flecainide and Propranolol interact?
Taking these drugs together increases the amount of medicine in your blood and can further weaken the heart's ability to pump.
Understanding the Flecainide and Propranolol Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Flecainide belongs to the Class IC Antiarrhythmic class and Propranolol belongs to the Non-Selective Beta-Blocker class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Taking these drugs together increases the amount of medicine in your blood and can further weaken the heart's ability to pump. Severity tiers matter: major flags generally advise avoidance, moderate flags often require monitoring or dose adjustment, and minor flags may only call for awareness.
Context around a specific patient determines real-world impact. Flecainide has 22 total documented interactions on file in this dataset, and Propranolol has 44. Each additional medication compounds the interaction surface, which is why pharmacists run full-profile checks rather than evaluating one pair at a time. FDA-derived guidance for this pair is: Your doctor should watch your heart health closely and may need to change your medication doses. Timing of doses, renal and hepatic function, age, and other concurrent prescriptions all shape whether a labeled interaction matters clinically.
An interaction flag is not a verdict. A large share of labeled interactions are managed routinely in clinical practice, the fix may be as simple as spacing doses or adding a monitoring test. Others require the prescriber to choose a different medication entirely. This page surfaces FDA-sourced labeling and openFDA data for educational purposes only; it is not medical advice and cannot account for your full clinical picture. Never start, stop, or adjust either Flecainide or Propranolol based on a web page, speak with your prescriber or pharmacist before making any change.
Sources: FDA Drug Labels (SPL) via openFDA (2026). This is for informational purposes only and is not medical advice. Always consult your healthcare provider about drug interactions.
Read our methodology - how this data is sourced, computed, and verified.