Flecainide and Diltiazem Interaction
Drug interaction information between Flecainide and Diltiazem.
Flecainide and Diltiazem have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Flecainide and Diltiazem. 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
There is not enough medical information available to know how these two drugs interact when used together.
What To Do
Doctors generally do not recommend taking these two drugs at the same time because the risks are not yet clear.
FDA Label Information
There has been too little experience with the coadministration of flecainide acetate with nifedipine or diltiazem to recommend concomitant use.
Flecainide Also Interacts With
- Nirmatrelvir/Ritonavir major
- Darifenacin moderate
- Fluoxetine moderate
- Propranolol minor
- Nifedipine minor
Diltiazem Also Interacts With
- Ezetimibe major
- Ezetimibe/Simvastatin major
- Simvastatin major
- Theophylline major
- Rifampin moderate
Frequently Asked Questions
Can I take Flecainide and Diltiazem together?
This is a minor interaction. Doctors generally do not recommend taking these two drugs at the same time because the risks are not yet clear.
How serious is the interaction between Flecainide and Diltiazem?
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 Diltiazem interact?
There is not enough medical information available to know how these two drugs interact when used together.
Understanding the Flecainide and Diltiazem 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 Diltiazem belongs to the Calcium Channel Blocker class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: There is not enough medical information available to know how these two drugs interact when used together. 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 Diltiazem has 46. 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: Doctors generally do not recommend taking these two drugs at the same time because the risks are not yet clear. 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 Diltiazem 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.