Dofetilide and Tafenoquine: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Dofetilide
Tafenoquine
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 plasma concentrations of OCT2 and MATE substrates
Interaction Deep Dive
Avoid concomitant use of tafenoquine with organic cation transporter-2 (OCT2) or multidrug and toxin extrusion (MATE) substrates. If concomitant use cannot be avoided, monitor closely and consider dose reduction of OCT2 and MATE substrates1.
Why it happens (mechanism)
Inhibition of OCT2- and MATE-mediated drug transport by tafenoquine
Common questions
Can I take Dofetilide and Tafenoquine together?
Increased plasma concentrations of OCT2 and MATE substrates Always confirm with your pharmacist or prescriber before making any change.
How serious is the Dofetilide and Tafenoquine 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 Tafenoquine 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 (1)
- Product Information: KRINTAFEL oral tablets, tafenoquine oral tablets. GlaxoSmithKline (per FDA), Research Triangle Park, NC, 2018. DailyMed
Keep reading about Dofetilide
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
Check another combination
Our instant two-drug interaction checker is almost here.
Still have questions about this combination?
Every question gets a real answer from a licensed pharmacist — free, and usually within a day.
Ask the pharmacist