Amitriptyline and Fexinidazole: 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
Fexinidazole
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.
Both of your medicines can affect your heart's rhythm in the same way. Amitriptyline (Elavil), an older antidepressant, and fexinidazole, a medicine used to treat sleeping sickness, can each stretch out a part of your heartbeat called the QT interval. When taken together, that effect can add up and, in rare cases, lead to a dangerous irregular heartbeat.
This warning is based on how these drugs are expected to behave rather than reports of it happening, but because it involves the heart, doctors take it seriously. The good news is your care team can manage this by carefully spacing the two medicines apart, so please talk with your pharmacist or doctor before combining them.
Effect: Additive QT/QTcF interval prolongation with increased risk of torsades de pointes.
Mechanism: Pharmacodynamic (additive), not metabolic. Both amitriptyline (a TCA with known QT-prolonging effects) and fexinidazole independently prolong the QT interval.
- Direction: Additive PD effect; neither is a prodrug relevant here.
- Severity: Major. Evidence: Theoretical.
- Management: Avoid concomitant use. Allow washout of 5 half-lives for the QT-prolonging agent before starting fexinidazole, or 7 days after stopping fexinidazole before starting such an agent.
- Monitor: ECG/QTc, electrolytes (K+, Mg2+) if co-use is unavoidable.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Fexinidazole should not be used together with medications recognized to lengthen the QT interval. For patients who are receiving, or will require, drugs known to prolong the QTcF interval, there are two options: either delay starting fexinidazole until those drugs have cleared from the body (permitting a washout equal to 5 half-lives of the other agents), or hold off on initiating those drugs until fexinidazole has been eliminated (permitting a 7-day washout period for fexinidazole)1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
Keep taking both medicines exactly as prescribed until you have spoken with your prescriber or pharmacist. Do not stop or change either drug on your own.
Because both can prolong the QT interval, the guidance is to avoid using them at the same time. Your care team may:
- Separate the two with a washout period (about 5 half-lives after stopping the other QT-prolonging drug before starting fexinidazole, or 7 days after fexinidazole before starting such a drug).
- Consider an alternative medicine where possible.
- Monitor you more closely, which may include an ECG and checking blood electrolytes.
Ask your pharmacist to review the timing so this can be handled safely.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Amitriptyline and Fexinidazole together?
Amitriptyline and fexinidazole can both prolong the QT interval, so they should generally not be used together; talk with your doctor or pharmacist about spacing them apart or using an alternative. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Amitriptyline and Fexinidazole 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 Fexinidazole interaction managed?
Keep taking both medicines exactly as prescribed until you have spoken with your prescriber or pharmacist. Do not stop or change either drug on your own. Because both can prolong the QT interval, the guidance is to avoid using them at the same time. Your care team may: Separate the two with a washout period (about 5 half-lives after stopping the other QT-prolonging drug before starting fexinidazol… 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 Fexinidazole 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: Fexinidazole oral tablets, fexinidazole oral tablets. sanofi-aventis US LLC (per FDA), Bridgewater, NJ, 2021. DailyMed
Keep reading about Amitriptyline
Keep reading about Fexinidazole
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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.
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