Drug Interaction Report

Dofetilide and Citalopram: Interaction Details

A pharmacist-reviewed analysis of the Dofetilide and Citalopram 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

Citalopram

Celexa
+

Dofetilide

Tikosyn Tikosyn®
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

Citalopram causes dose-dependent prolongation of the QTc interval2 and dofetilide has been associated with QT prolongation 1. Although this interaction has not been evaluated, the concomitant use of citalopram with dofetilide is not recommended due to a risk of additive QT interval prolongation and torsade de pointes. If coadministration is required, do not exceed citalopram doses of 40 mg/day and monitor for ECG changes. Discontinue citalopram in patients who have persistent QTc measurements greater than 500 milliseconds 2.

Why it happens (mechanism)

Additive QT interval prolongation

Common questions

Can I take Dofetilide and Citalopram 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 Citalopram 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.

Questions for your pharmacist

  • Does my dose of Dofetilide or Citalopram 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)

  1. Product Information: TIKOSYN(R) oral capsules, dofetilide oral capsules. Pfizer,Inc, New York, NY, 2004. DailyMed
  2. Product Information: CELEXA(R) oral tablets, citalopram oral tablets. Allergan USA Inc (per FDA), Madison, NJ, 2023. DailyMed
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Citalopram

Keep reading about Citalopram

All Citalopram interactions (132)
Also serious with: Metoclopramide Injection Linezolid Injection Metoclopramide Nasal Spray Palonosetron Injection
Dofetilide

Keep reading about Dofetilide

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

Citalopram + Activated Charcoal Grapefruit Lithium St. John's Wort 5-htp Acacia Rigidula Acetyl-l-carnitine Adrafinil + 183 more
Dofetilide + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia St. John's Wort + 138 more

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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.