Drug Interaction Report

Sultopride and Dofetilide: Interaction Details

A pharmacist-reviewed analysis of the Sultopride and Dofetilide interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Dofetilide

Tikosyn Tikosyn®
+

Sultopride

No brand names on record
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 44 documented Sultopride interactions, 44 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
rapid
Evidence
theoretical
Severity
Major

What happens

An increased risk of QT interval prolongation, and an increased risk of torsades de pointes

Interaction Deep Dive

Concomitant use of dofetilide with other drugs that prolong QT interval, such as sultopride has not been studied, and its not recommended as it may increase QT interval prolongation1. Class III antiarrhythmics have been shown to prolong the QT interval, which may result in ventricular tachycardia, ventricular fibrillation, and torsades de pointes 3.

Why it happens (mechanism)

Additive QT interval prolongation

Literature reports

1 report — tap to read

a) Class III antiarrhythmics have been shown to prolong the QT interval, which may result in ventricular tachycardia, ventricular fibrillation, and torsades de pointes. Several antipsychotic agents have also demonstrated QT prolongation including sultopride 3. Concomitant use of Class III antiarrhythmic agents such as dofetilide and sultopride may have additive effects on the QT interval and is not recommended 2.

Common questions

Can I take Sultopride and Dofetilide together?

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 Sultopride and Dofetilide interaction?

It is rated major. Potentially serious — often needs a change or close monitoring.

How quickly could this interaction happen?

The documented onset is "rapid". Effects can appear quickly, often within about 24 hours of combining the drugs.

How strong is the evidence for this interaction?

The evidence is graded "theoretical". Predicted from the drugs' pharmacology; not yet confirmed in people.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Sultopride 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 (3)

  1. Product Information: Dofetilide oral capsules, dofetilide oral capsules. Granules Pharmaceuticals Inc. (per DailyMed), Chantilly, VA, 2025. DailyMed
  2. 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
  3. Lande G, Drouin E, Gauthier C, et al: Arrhythmogenic effects of sultopride chlorhydrate: clinical and cellular electrophysiological correlation. Ann Fr Anesth Reanim 1992; 11:629-635.
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Dofetilide

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All Dofetilide interactions (454) Dofetilide drug information
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Sultopride

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All Sultopride interactions (44)
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Beyond drug–drug

These medications also interact with supplements

Prescription drugs aren't the whole picture — herbal and dietary supplements can interact with them too. From the evidence-graded Natural Medicines database:

Dofetilide + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia St. John's Wort + 138 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.