Fexinidazole and Atenolol: Interaction Details
AI-assisted, pharmacist-reviewed · AI content regenerated Jul 15, 2026 · Source data updated Jul 11, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Fexinidazole
No brand names on recordAtenolol
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.
Fexinidazole is a medicine used to treat sleeping sickness, and atenolol (Tenormin) is a beta blocker that slows your heart rate to help with blood pressure or heart conditions. When taken together, both can slow the heart, and those effects may add up. This could make your heart beat too slowly, which is called bradycardia.
This concern is based on theory rather than a lot of real-world cases, so please don't panic. Signs to watch for include feeling dizzy, very tired, or lightheaded. Your care team knows how to handle this, so talk with your pharmacist or doctor before combining these two.
Effect: Additive risk of bradycardia when fexinidazole is combined with atenolol, a beta-1 selective adrenergic blocker.
- Mechanism: Possible additive negative chronotropic (PD) effect; not a metabolic/PK interaction. Neither agent's activation is at issue here.
- Direction: Enhanced heart-rate lowering.
- Evidence: Theoretical; magnitude and onset unspecified.
- Severity: Major per label guidance.
- Management: Manufacturer advises avoiding coadministration. If unavoidable, monitor heart rate and for symptomatic bradycardia (dizziness, syncope, fatigue); dose may need individualization by the care team.
What happens
Increased risk of bradycardia
Interaction Deep Dive
Do not administer fexinidazole together with beta-adrenergic blockers, because the bradycardic effects of both agents may be additive1.
Why it happens (mechanism)
Possible additive bradycardia
How to manage this interaction
What your care team may do:
- The product guidance advises avoiding this combination, so your prescriber may consider whether an alternative is appropriate.
- If both must be used, your team may monitor your heart rate more closely and watch for symptoms.
What you should do:
- Keep taking both exactly as prescribed unless your care team tells you otherwise.
- Report dizziness, lightheadedness, unusual tiredness, or a slow or fainting feeling to your pharmacist or doctor.
- Ask your pharmacist to review this combination before you start fexinidazole.
Management is individual — confirm any change with your pharmacist or prescriber.
Common questions
Can I take Fexinidazole and Atenolol together?
Taking fexinidazole with atenolol may add up to slow your heart too much, so the guidance is to avoid this combination; talk with your pharmacist or doctor, and report any dizziness or a slow heartbeat. Always confirm with your pharmacist or prescriber before making any change.
How serious is the Fexinidazole and Atenolol 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 Atenolol interaction managed?
What your care team may do: The product guidance advises avoiding this combination, so your prescriber may consider whether an alternative is appropriate. If both must be used, your team may monitor your heart rate more closely and watch for symptoms. What you should do: Keep taking both exactly as prescribed unless your care team tells you otherwise. Report dizziness, lightheadedness, unusual tir… 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 Atenolol 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 Fexinidazole
Keep reading about Atenolol
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