Infectious Disease
RCT
● RCT
Potential drug interactions did not affect rifampin TB prevention completion or adverse events
The international journal of tuberculosis and lung disease : the official journal of the International Union against Tuberculosis and Lung Disease
Published March 30, 2026
Fregonese F, White J, Lim R K, Bedingfield N, Cook V J, Gafar F, Gibson D, Menzies D, Fisher D
PubMed ↗
DOI ↗
This secondary analysis of the 2R² randomized clinical trial examined 1368 participants receiving rifampin tuberculosis preventive treatment (TPT), with 282 participants (21%) taking medications with potential rifampin drug-drug interactions (DDI). The study compared TPT completion and safety outcomes between participants with potential DDI and those without.
For TPT completion, there was no significant difference between groups (risk difference 0.04, 95% CI: -0.02 to 0.09). Adverse events also showed no difference (risk difference 0.02, 95% CI: -0.01 to 0.06). However, participants with potential DDI had significantly more unscheduled follow-up visits (12% vs 5%, p=0.0001).
Safety data showed no increased risk of adverse events in the DDI group. Key limitations include this being a secondary analysis with observational comparisons within an RCT, and the data are from an abstract only, limiting detail availability. The analysis cannot establish causality for DDI effects, generalize beyond the study population, or assess specific drug interactions.
For practice, these findings suggest rifampin TPT can be used in patients taking medications with potential DDI without impacting completion rates or adverse events, but clinicians should anticipate additional follow-up visits. Given the observational nature and limited data source, these results should be interpreted cautiously.
If you need to take medicine to prevent tuberculosis, but you're already on other medications, you might worry about dangerous interactions or whether you'll be able to finish the treatment. A fresh look at data from a large trial offers some reassurance. The study focused on over 1,300 people taking rifampin to prevent TB. About one in five were also on other medications flagged as having a potential interaction with rifampin. The analysis found no difference between groups in who completed the full prevention course or who reported side effects. However, people taking those other medications were more than twice as likely to need two or more unscheduled doctor visits. It's important to remember this was a secondary look at existing trial data, not a study designed from the start to answer this question. The full details are only available in an abstract, so we're missing some context. While this is encouraging news for using rifampin safely with other common drugs, it clearly shows that closer monitoring and more follow-up appointments are a practical reality for these patients.
What this means for you: TB prevention with rifampin works with other meds, but expect more doctor visits.
View Original Abstract ↓
<sec><title>BACKGROUND</title>Rifamycin TB preventive treatment (TPT) is critical to TB elimination. However, clinicians may be reluctant to recommend it over concerns related to drug-drug interactions (DDI). In this secondary analysis of data from the 2R² randomised clinical trial (comparing standard dose rifampin to high-dose rifampin for TPT), we investigate if participants taking medications with potential rifampin DDI had similar TPT completion, safety, and follow-up visits compared to those without.</sec><sec><title>METHODS</title>Data on concomitant medications, adverse events, treatment completion, and follow-up visits were compared between participants with and without potential rifampin DDI. Analyses were conducted with R, reporting risk difference (RD) using g-computation with logistic regression.</sec><sec><title>RESULTS</title>282 of 1,368 participants (21%) were taking essential medications with potential rifampin DDI. There was no RD in TPT completion (RD 0.04 [95% confidence interval (CI): -0.02; 0.09]) or adverse events (RD 0.02 [95% CI: -0.01; 0.06]) between participants with and without these medications. Individuals talking medications with potential DDI had a higher percentage of two or more unscheduled visits (12%) compared to those not taking them (5%) ( = 0.0001).</sec><sec><title>CONCLUSION</title>In participants taking medications with potential rifampin DDI, rifampin TPT can be used safely without impacting completion rates. However, additional follow-up visits should be anticipated.</sec>.
