Drug Interaction Report

Dofetilide and Zuclopenthixol: Interaction Details

A pharmacist-reviewed analysis of the Dofetilide and Zuclopenthixol 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®
+

Zuclopenthixol

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 454 documented Dofetilide interactions, 288 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
unspecified
Evidence
theoretical
Severity
Major

What happens

An increased risk of QT interval prolongation

Interaction Deep Dive

Avoid the concomitant use of zuclopenthixol and other drugs known to significantly increase the QT interval. Additionally, drugs known to cause electrolyte disturbances (eg, hypokalemia) or drugs known to increase the plasma concentration of zuclopenthixol should be used cautiously. Cases of QT prolongation, ventricular arrhythmias and fibrillation, ventricular tachycardia, torsade de pointes, and sudden death have been reported with zuclopenthixol123.

Why it happens (mechanism)

Additive QT interval prolongation

Literature reports

1 report — tap to read

a) Cases of QT prolongation, ventricular arrhythmias and fibrillation, ventricular tachycardia, torsade de pointes, and sudden death have been reported with zuclopenthixol 123.

Common questions

Can I take Dofetilide and Zuclopenthixol together?

An increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Dofetilide and Zuclopenthixol interaction?

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

How quickly could this interaction happen?

The documented onset is "unspecified". The timing of this interaction is not well characterized.

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 Dofetilide or Zuclopenthixol 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: CLOPIXOL-ACUPHASE(R) intramuscular injection, zuclopenthixol acetate intramuscular injection. Lundbeck Canada Inc (per Health Canada), Montreal, QC, Canada, 2014.
  2. Product Information: Clopixol oral tablets, zuclopenthixol dihydrochloride oral tablets. Lundbeck Limited (per MHRA), 2015.
  3. Product Information: Clopixol-Acuphase intramuscular injection solution, zuclopenthixol acetate intramuscular injection solution. Lundbeck Limited (per MHRA), Milton Keynes, United Kingdom, 2015.
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Dofetilide

Keep reading about Dofetilide

All Dofetilide interactions (454) Dofetilide drug information
Also serious with: Bictegravir Cimetidine Saquinavir Cisapride
Zuclopenthixol

Keep reading about Zuclopenthixol

All Zuclopenthixol interactions (68)
Also serious with: Metoclopramide Injection Metoclopramide Nasal Spray Ofloxacin Otic Oxaliplatin Injection
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.