Verapamil and Dofetilide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Verapamil
Dofetilide
How we grade severity & evidence
Severity levels
- Contraindicated: These should generally not be used together.
- Major: Potentially serious — often needs a change or close monitoring.
- Moderate: Can be significant — usually manageable with monitoring.
- Minor: Usually limited clinical impact.
Evidence grades
- Established: Well documented — supported by controlled studies or strong clinical data.
- Probable: Good supporting evidence, though not definitively proven.
- Suspected: Some evidence suggests this interaction, but it is not well established.
- Possible: Limited or conflicting evidence; the interaction may occur.
- Theoretical: Predicted from the drugs' pharmacology; not yet confirmed in people.
Ratings come from the documented interaction literature and are reviewed by a pharmacist. They describe the documented risk of the combination, not what will necessarily happen to you — your dose, timing, and health picture all matter.
What happens
Increased dofetilide exposure, an increased risk of QT interval prolongation, and an increased risk of torsades de pointes
Interaction Deep Dive
The concurrent administration of dofetilide and verapamil is contraindicated as it may increase dofetilide exposure1. The coadministration of dofetilide and verapamil resulted in a 42% increase in peak plasma levels of dofetilide, although the overall exposure to dofetilide was not significantly increased. Dofetilide can cause serious ventricular arrhythmias associated with QT interval prolongation, including torsades de pointes, which are directly related to the dofetilide plasma concentration. In clinical trials, the concurrent administration of verapamil and dofetilide was associated with a higher occurrence of torsades de pointes 2.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of dofetilide; additive QT interval prolongation
Literature reports
1 report — tap to read
a) The coadministration of dofetilide and verapamil resulted in a 42% increase in peak plasma levels of dofetilide, although the overall exposure to dofetilide was not significantly increased. Dofetilide can cause serious ventricular arrhythmias associated with QT interval prolongation, including torsades de pointes, which are directly related to the dofetilide plasma concentration. In clinical trials, the concurrent administration of verapamil and dofetilide was associated with a higher occurrence of torsades de pointes 21.
Common questions
Can I take Verapamil and Dofetilide together?
Increased dofetilide exposure, an increased risk of QT interval prolongation, and an increased risk of torsades de pointes Always confirm with your pharmacist or prescriber before making any change.
How serious is the Verapamil and Dofetilide interaction?
It is rated contraindicated. These should generally not be used together.
How quickly could this interaction happen?
The documented onset is "delayed". Effects tend to build up gradually over days to weeks.
How strong is the evidence for this interaction?
The evidence is graded "probable". Good supporting evidence, though not definitively proven.
From our Q&A
Real reader questions about these medications, each personally answered by our pharmacist:
Questions for your pharmacist
- Does my dose of Verapamil or Dofetilide need adjusting while I take them together?
- What symptoms should prompt me to call you or my prescriber right away?
- Does the timing of my doses matter for this combination?
- Is there a safer alternative to one of these medications for me?
References (2)
- Product Information: Dofetilide oral capsules, dofetilide oral capsules. Granules Pharmaceuticals Inc. (per DailyMed), Chantilly, VA, 2025. DailyMed
- Yamreudeewong W, DeBisschop M, Martin LG, et al: Potentially significant drug interactions of class III antiarrhythmic drugs. Drug Safety 2003; 26(6):421-438. PubMed
Keep reading about Verapamil
Keep reading about Dofetilide
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Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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