Drug Interaction Report

Flecainide and Pazopanib: Interaction Details

A pharmacist-reviewed analysis of the Flecainide and Pazopanib 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

Flecainide

Tambocor®
+

Pazopanib

Votrient Votrient®
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 300 documented Flecainide interactions, 270 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

Increased flecainide exposure and increased risk of QT-interval prolongation

Interaction Deep Dive

Both flecainide, a CYP2D6 substrate1 with a narrow therapeutic index, and pazopanib, a weak CYP2D6 inhibitor, have been associated with QT-interval prolongation. Due to the potential for increased flecainide exposure and additive effects on the QT interval, concurrent use of flecainide with pazopanib is not recommended2. If concomitant use is required, close monitoring of cardiac function is warranted.

Why it happens (mechanism)

Inhibition of CYP2D6-mediated metabolism of flecainide by pazopanib; additive effects on QT interval

Common questions

Can I take Flecainide and Pazopanib together?

Increased flecainide exposure and increased risk of QT-interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Flecainide and Pazopanib 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 Flecainide or Pazopanib 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: FLECAINIDE ACETATE oral tablets, flecanide acetate oral tablets. Roxane Laboratories (per DailyMed), Columbus, OH, 2012. DailyMed
  2. Product Information: VOTRIENT(R) oral tablets, pazopanib oral tablets. GlaxoSmithKline (per FDA), Research Triangle Park, NC, 2013. DailyMed
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Flecainide

Keep reading about Flecainide

All Flecainide interactions (300) Flecainide drug information
Also serious with: Nirmatrelvir Mesoridazine Pimozide Mavorixafor
Pazopanib

Keep reading about Pazopanib

All Pazopanib interactions (91) Pazopanib drug information
Also serious with: Ketoconazole Topical Granisetron Transdermal Patch Histrelin Implant 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:

Flecainide + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia 1,3-dmaa + 78 more
Pazopanib + Activated Charcoal American Hellebore Arsenic Asarabacca Beer Cesium Danshen Ephedra + 341 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.