Amitriptyline and Lumefantrine: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 11, 2026 · Source data updated Jul 2, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Amitriptyline
Lumefantrine
No brand names on record
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.
Amitriptyline (Elavil) is an older antidepressant, and lumefantrine is used to treat malaria. When taken together, two things can add up. First, lumefantrine can slow down how your body breaks down amitriptyline, so more of it may build up in your blood. Second, both medicines can affect your heart's rhythm (a change on the ECG called QT prolongation).
Together this could raise the chance of an irregular heartbeat. This concern is based mostly on how the drugs work rather than lots of real-world reports, but it is still taken seriously. Please don't stop either medicine on your own. Talk with your pharmacist or doctor, who can manage this safely.
Effect: Lumefantrine (from artemether/lumefantrine) inhibits CYP2D6, reducing metabolism of amitriptyline (a CYP2D6 substrate) and increasing its exposure. Both agents independently prolong the QT interval, giving an additive proarrhythmic risk.
- Direction: Increased amitriptyline exposure; increased QT prolongation risk (neither is a prodrug).
- Severity/evidence: Major, but theoretical/mechanistic.
- Onset: Unspecified; note lumefantrine's long half-life (3 to 6 days).
- Management: Avoid coadministration where possible. If required, monitor ECG and electrolytes; remain cautious even after completing antimalarial therapy given residual lumefantrine.
What happens
Increased CYP2D6 substrates exposure and an increased risk of QT prolongation
Interaction Deep Dive
Do not give artemether/lumefantrine together with CYP2D6 substrates that lengthen the QT interval, since doing so can raise the exposure to those CYP2D6 substrates and thereby heighten the likelihood of QT interval prolongation. Should there be a medical need to use artemether/lumefantrine alongside an agent that prolongs the QT interval, perform ECG monitoring. Furthermore, because lumefantrine has a long half-life (3 to 6 days), care should be taken when giving QT-prolonging drugs even after artemether/lumefantrine treatment has finished1.
Why it happens (mechanism)
Inhibition of CYP2D6-mediated metabolism by artemether/lumefantrine; additive QT interval prolongation
How to manage this interaction
Your care team will look at whether these two can be given together, and often they will try to avoid the combination when possible.
- Keep taking both exactly as prescribed unless your doctor or pharmacist tells you otherwise.
- If both are truly needed, your team may check your heart rhythm with an ECG and monitor you more closely.
- Because lumefantrine stays in the body for a while (about 3 to 6 days), caution continues even after the malaria treatment ends.
- Tell your team about any fainting, dizziness, or fluttering/pounding heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Lumefantrine together?
Combining amitriptyline and lumefantrine can raise amitriptyline levels and add to the risk of a dangerous heart rhythm change, so this pairing is best avoided; if both are needed, your care team can monitor your ECG and manage it. Do not change either medicine on your own. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Lumefantrine 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 is the Amitriptyline and Lumefantrine interaction managed?
Your care team will look at whether these two can be given together, and often they will try to avoid the combination when possible. Keep taking both exactly as prescribed unless your doctor or pharmacist tells you otherwise. If both are truly needed, your team may check your heart rhythm with an ECG and monitor you more closely. Because lumefantrine stays in the body for a while (about 3 to 6 day… Management is individual — always follow your own care team's guidance.
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 Amitriptyline or Lumefantrine 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 Amitriptyline
Keep reading about Lumefantrine
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