Bedaquiline and Phenobarbital: Interaction Details
AI-assisted, pharmacist-reviewed · Source data updated Aug 8, 2026 · Sources: FDA labeling, DDInter 2.0, cited literature
Phenobarbital
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
An increased risk of QT interval prolongation, reduced bedaquiline exposure and reduced efficacy of bedaquiline
Interaction Deep Dive
Avoid the concomitant use of bedaquiline (a CYP3A4 substrate) with PHENobarbital CYP3A4 inducer), used systemically, may decrease bedaquiline exposure1. The efficacy of bedaquiline may also be reduced. Also, concomitant use of PHENobarbital with other products that prolong the QTc interval may result in a greater increase in the QTc interval and adverse reactions associated with QTc interval prolongation. If concomitant use of bedaquiline and PHENobarbital cannot be avoided, monitor patients for increased risk of QTc interval prolongation, closely monitor neonates and consider increasing the dosage of the bedaquiline accordingly 2. 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 ms 1.
Why it happens (mechanism)
Additive QT interval prolongation; induction of CYP3A4-mediated metabolism of bedaquiline
Literature reports
1 report — tap to read
a) During drug interaction studies in healthy volunteers, coadministration of a single dose of bedaquiline 400 mg and efavirenz 600 mg/day for 27 days resulted in a 20% decrease in bedaquiline AUC. Alteration in the Cmax of bedaquiline were not reported. Increases in both AUC and Cmax were reported in the primary metabolite of bedaquiline (70% and 80%, respectively) 1.
Common questions
Can I take Bedaquiline and Phenobarbital together?
An increased risk of QT interval prolongation, reduced bedaquiline exposure and reduced efficacy of bedaquiline Always confirm with your pharmacist or prescriber before making any change.
How serious is the Bedaquiline and Phenobarbital 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.
Questions for your pharmacist
- Does my dose of Bedaquiline or Phenobarbital 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)
- Product Information: SIRTURO(R) oral tablets, bedaquiline oral tablets. Janssen Products, LP (per FDA), Horsham, PA, 2024. DailyMed
- Product Information: SEZABY(TM) intravenous injection, phenobarbital sodium intravenous injection. Sun Pharmaceutical Industries Inc (per manufacturer), Cranbury, NJ, 2022. DailyMed
Keep reading about Phenobarbital
Keep reading about Bedaquiline
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