Flecainide and Fluoxetine Interaction
Drug interaction information between Flecainide and Fluoxetine.
Flecainide and Fluoxetine have a documented moderate interaction in FDA labeling.
FDA drug labeling documents a moderate-severity interaction between Flecainide and Fluoxetine. 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
Fluoxetine blocks the enzyme that breaks down flecainide in your body. This can cause flecainide to build up to unsafe levels in your blood.
What To Do
Use this combination with caution. Your doctor may need to monitor your heart rhythm or adjust your dosage.
FDA Label Information
Coadministration of fluoxetine with other drugs that are metabolized by CYP2D6, including certain antidepressants (e.g., TCAs), antipsychotics (e.g., phenothiazines and most atypicals), and antiarrhythmics (e.g., propafenone, flecainide, and others) should be approached with caution. Drugs with a narrow therapeutic index represent the greatest concern (e.g., flecainide, propafenone, vinblastine, and TCAs).
Flecainide Also Interacts With
- Nirmatrelvir/Ritonavir major
- Darifenacin moderate
- Propranolol minor
- Diltiazem minor
- Nifedipine minor
Fluoxetine Also Interacts With
- Aspirin major
- Warfarin major
- Olanzapine major
- Pimozide major
- Thioridazine major
Frequently Asked Questions
Can I take Flecainide and Fluoxetine together?
This is a moderate interaction. Use this combination with caution. Your doctor may need to monitor your heart rhythm or adjust your dosage.
How serious is the interaction between Flecainide and Fluoxetine?
This interaction is classified as "moderate" severity by the FDA. Moderate interactions may worsen your condition or change how your medications work.
Why do Flecainide and Fluoxetine interact?
Fluoxetine blocks the enzyme that breaks down flecainide in your body. This can cause flecainide to build up to unsafe levels in your blood.
Understanding the Flecainide and Fluoxetine Interaction
FDA-approved prescribing information for these two drugs flags their combination as a moderate-severity interaction. Flecainide belongs to the Class IC Antiarrhythmic class and Fluoxetine belongs to the Selective Serotonin Reuptake Inhibitor (SSRI) class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: Fluoxetine blocks the enzyme that breaks down flecainide in your body. 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 Fluoxetine has 68. 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: Use this combination with caution. 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 Fluoxetine 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.