Mexiletine and Propafenone Interaction
Drug interaction information between Mexiletine and Propafenone.
Mexiletine and Propafenone have a documented minor interaction in FDA labeling.
FDA drug labeling documents a minor-severity interaction between Mexiletine and Propafenone. 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
These two drugs do not appear to interfere with how the body processes either medication. They also do not cause extra changes to the heart's electrical activity when used together.
What To Do
No specific dose changes are usually needed for this combination. Your doctor will monitor your heart health as they normally would.
FDA Label Information
In another formal study (n = 8 extensive and n = 7 poor metabolizers of CYP2D6), coadministration of propafenone did not alter the kinetics of mexiletine in the poor CYP2D6 metabolizer group. In this crossover steady state study, the pharmacokinetics of propafenone were unaffected in either phenotype by the coadministration of mexiletine. Addition of mexiletine to propafenone did not lead to further electrocardiographic parameters changes of QRS, QT c , RR, and PR intervals than propafenone alone.
Mexiletine Also Interacts With
- Lidocaine Topical moderate
- Propranolol minor
- Digoxin minor
- Theophylline minor
- Cimetidine minor
Propafenone Also Interacts With
- Nirmatrelvir/Ritonavir major
- Amiodarone moderate
- Fluoxetine moderate
- Nebivolol moderate
- Ketoconazole minor
Frequently Asked Questions
Can I take Mexiletine and Propafenone together?
This is a minor interaction. No specific dose changes are usually needed for this combination. Your doctor will monitor your heart health as they normally would.
How serious is the interaction between Mexiletine and Propafenone?
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 Mexiletine and Propafenone interact?
These two drugs do not appear to interfere with how the body processes either medication. They also do not cause extra changes to the heart's electrical activity when used together.
Understanding the Mexiletine and Propafenone Interaction
FDA-approved prescribing information for these two drugs flags their combination as a minor-severity interaction. Mexiletine belongs to the Class IB Antiarrhythmic class and Propafenone belongs to the Class IC Antiarrhythmic class - two categories that can collide when co-prescribed. The mechanism described in FDA labeling is: These two drugs do not appear to interfere with how the body processes either medication. 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. Mexiletine has 14 total documented interactions on file in this dataset, and Propafenone has 26. 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: No specific dose changes are usually needed for this combination. 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 Mexiletine or Propafenone 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.