Drug Interaction Report

Ondansetron and Bedaquiline: Interaction Details

A pharmacist-reviewed analysis of the Ondansetron and Bedaquiline interaction: the documented clinical effects, severity rating, onset, mechanism, and management considerations, with cited references throughout.

AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature

Ondansetron

No brand names on record
+

Bedaquiline

Sirturo Sirturo®
Dr. Brian Staiger, PharmD, BCPS
Medically reviewed by
Dr. Brian Staiger, PharmD, BCPS
Updated Aug 8, 2026
Editorial policy · Data sources
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Interaction severity
Major
Potentially serious — often needs a change or close monitoring.
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.

Of 84 documented Ondansetron interactions, 81 are rated major — including this one.
Worried about symptoms right now? Contact your pharmacist or prescriber, or call Poison Control at 1-800-222-1222 (US). Call 911 for an emergency.
Onset
unspecified
Evidence
probable
Severity
Major

What happens

Increased risk of QT interval prolongation

Interaction Deep Dive

Bedaquiline is associated with QT-interval prolongation. Concomitant use of bedaquiline with other drugs that prolong the QT interval may result in additive prolonging effects on the QT interval. Monitor ECG before initiation of treatment, 2 weeks after initiation and during treatment. Obtain electrolytes at baseline and during treatment and correct electrolytes. Discontinue bedaquiline if there is evidence of serious ventricular arrhythmia or QTc interval greater than 500 ms1.

Why it happens (mechanism)

Additive QT interval prolongation

Literature reports

1 report — tap to read

a) In a study, where bedaquiline was administered with the QTc prolonging drugs clofazimine and levoFLOXacin, 5% of patients in the 40-week bedaquiline treatment group experienced a QTc 500 ms or greater and 43% of patients experienced an increase in QTc 60 ms or greater over baseline. Of the clofazimine-and levoFLOXacin-treated patients in the 40-week control arm, 7% of patients experienced a QTc 500 ms or greater and 39% experienced an increase in QTc 60 ms or greater over baseline 1.

Common questions

Can I take Ondansetron and Bedaquiline together?

Increased risk of QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.

How serious is the Ondansetron and Bedaquiline 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 "probable". Good supporting evidence, though not definitively proven.

From our Q&A

Real reader questions about these medications, each personally answered by our pharmacist:

Questions for your pharmacist

  • Does my dose of Ondansetron or Bedaquiline 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)

  1. Product Information: SIRTURO(R) oral tablets, bedaquiline oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2024. DailyMed
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Ondansetron

Keep reading about Ondansetron

All Ondansetron interactions (84)
Also serious with: Ketoconazole Topical Palonosetron Injection Capmatinib Morphine Injection
Bedaquiline

Keep reading about Bedaquiline

All Bedaquiline interactions (320) Bedaquiline drug information
Also serious with: Fluconazole Ketoconazole Mesoridazine Levoketoconazole
Beyond drug–drug

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:

Ondansetron + Activated Charcoal Grapefruit Lithium St. John's Wort 1,3-dmaa 5-htp Acacia Rigidula Acetyl-l-carnitine + 187 more
Bedaquiline + Activated Charcoal American Hellebore Arsenic Cesium Ephedra Grapefruit Sida Cordifolia St. John's Wort + 138 more

major · moderate · minor — check everything you take with our drug–supplement interaction checker.

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This information is for education, not a substitute for professional medical advice. Do not start, stop, or change any medication without talking to your pharmacist or prescriber.