Lumefantrine and Flecainide: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Lumefantrine
No brand names on recordFlecainide
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 CYP2D6 substrates exposure and an increased risk of QT prolongation
Interaction Deep Dive
Avoid coadministration of artemether/lumefantrine and CYP2D6 substrates that prolong QT interval as it may increase CYP2D6 substrates exposure which may increase the risk of QT interval prolongation. If concomitant administration of artemether/lumefantrine and QT prolonging agent is medically required, monitor the ECG. Additionally, caution is advised when administering drugs that prolong the QT interval after completing artemether/lumefantrine therapy due to the long half-life of lumefantrine (3 to 6 days)1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism by artemether/lumefantrine; additive QT interval prolongation
Common questions
Can I take Lumefantrine and Flecainide together?
Increased CYP2D6 substrates exposure and an increased risk of QT prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Lumefantrine and Flecainide 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 Lumefantrine or Flecainide 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: COARTEM® oral tablets, artemether lumefantrine oral tablets. Novartis Pharmaceuticals Corporation (per DailyMed), East Hanover, NJ, 2025. DailyMed
Keep reading about Lumefantrine
Keep reading about Flecainide
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