Ketoconazole and Bedaquiline: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Ketoconazole
Bedaquiline
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.
What happens
Increased bedaquiline exposure and an increased risk for QT interval prolongation
Interaction Deep Dive
Coadministration of ketoconazole together with a CYP3A4 substrate known to prolong the QT interval, such as bedaquiline is contraindicated, as it may result in increased bedaquiline exposure, increasing the risk for QT prolongation and life-threatening ventricular tachyarrhythmias including torsades de pointes2. If coadministered, monitor ECG before initiation of treatment, 2 weeks after initiation and during treatment. Closely monitor patient safety (eg, liver function) when bedaquiline is coadministered with CYP3A4 inhibitors. Obtain electrolytes at baseline and during treatment and correct electrolytes. Discontinue all QT prolonging agents if the patient develops clinically significant arrhythmias or a QTcF interval of greater than 500 msec (confirmed on repeat ECG) 1.
Why it happens (mechanism)
Inhibition of CYP3A4-mediated metabolism of bedaquiline; additive QT interval prolongation
Literature reports
2 reports — tap to read
a) In a pharmacokinetic study in healthy subjects, the bedaquiline AUC at 24 hours, Cmax, and minimum concentration were increased by 22% (90% CI, 12% to 32%), 9% (90% CI, -2% to 21%), and 33% (90% CI, 24% to 43%), respectively, during coadministration of bedaquiline 400 mg/day for 14 days and ketoconazole 400 mg/day for 4 days 1.
b) 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 Ketoconazole and Bedaquiline together?
Increased bedaquiline exposure and an increased risk for QT interval prolongation Always confirm with your pharmacist or prescriber before making any change.
How serious is the Ketoconazole and Bedaquiline interaction?
It is rated contraindicated. These should generally not be used together.
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.
Questions for your pharmacist
- Does my dose of Ketoconazole 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 (2)
Keep reading about Ketoconazole
Keep reading about Bedaquiline
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:
major · moderate · minor — check everything you take with our drug–supplement interaction checker.
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