Fexinidazole and Buprenorphine: 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
Buprenorphine
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 buprenorphine (a pain and opioid-dependence medicine) and fexinidazole (used for sleeping sickness) can each affect your heart's electrical rhythm in a way called QT prolongation. When two medicines that do this are taken together, the effect can add up, which in rare cases can lead to an abnormal heartbeat.
This warning is based on how the drugs work rather than lots of real-world reports, so try not to worry. The important thing is that your care team knows about it. They can decide on the safest timing, watch your heart rhythm, or choose a different plan. Please don't stop either medicine on your own, just talk with your pharmacist or doctor first.
Effect: Additive risk of QTc prolongation with concomitant buprenorphine and fexinidazole. Both agents independently prolong the QT interval; the mechanism is pharmacodynamic (additive), not a CYP-mediated PK change. Neither is a relevant prodrug here.
- Severity: Major. Evidence: Theoretical. Onset: Unspecified.
- Management: Avoid concomitant use. If unavoidable, separate with a washout: do not start fexinidazole until the other QT-prolonging drug is cleared (5 half-lives), or do not start the other drug until fexinidazole is cleared (allow 7 days).
- Consider ECG and electrolyte (K+, Mg2+) monitoring; correct imbalances before/during therapy.
What happens
An increased risk of QT interval prolongation
Interaction Deep Dive
Fexinidazole should not be used together with agents recognized to extend the QT interval. When a patient is receiving, or must receive, medications known to prolong the QTcF interval, one of two approaches should be followed: postpone fexinidazole until those agents have cleared the body (permitting a washout equal to 5 half-lives of the other drugs), or refrain from starting those agents until fexinidazole has cleared the body (permitting a 7 day washout for fexinidazole)1.
Why it happens (mechanism)
Additive QT interval prolongation
How to manage this interaction
The general guidance is to avoid taking these two together when possible, because both can affect heart rhythm.
- Keep taking your medicines as prescribed and do not stop either one on your own.
- Tell your pharmacist and prescriber that you take (or may need) both, so they can plan the safest timing. A washout may be used, allowing one drug to clear before starting the other (for fexinidazole this is about 7 days).
- Your team may check an ECG and blood levels of potassium and magnesium.
- Report any fainting, palpitations, or irregular heartbeat right away.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Fexinidazole and Buprenorphine together?
Buprenorphine and fexinidazole can each prolong the QT interval, so combining them may add up and raise heart-rhythm risk; ideally they are not used together, and your care team can manage timing and monitoring if both are needed. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fexinidazole and Buprenorphine 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 Fexinidazole and Buprenorphine interaction managed?
The general guidance is to avoid taking these two together when possible, because both can affect heart rhythm. Keep taking your medicines as prescribed and do not stop either one on your own. Tell your pharmacist and prescriber that you take (or may need) both, so they can plan the safest timing. A washout may be used, allowing one drug to clear before starting the other (for fexinidazole this is… 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.
Questions for your pharmacist
- Does my dose of Fexinidazole or Buprenorphine 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 Buprenorphine
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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