Improved adherence and less toxicity with rifampin vs isoniazid for treatment of latent tuberculosis: a retrospective study

BACKGROUND: Treatment of latent tuberculosis infection (LTBI) is an important aspect of tuberculosis control in the United States, but the effectiveness of this strategy is compromised by poor adherence to the recommended 9-month isoniazid regimen. In this study, we compared treatment completion and clinically recognized adverse drug reactions in patients prescribed 9 months of isoniazid therapy or 4 months of rifampin therapy for LTBI. METHODS: Retrospective chart review of patients who received LTBI treatment at a public health clinic. RESULTS: A total of 770 patients were prescribed 9 months of isoniazid therapy, and 1379 patients were prescribed 4 months of rifampin therapy. The percentages of patients who completed 80% or more of their prescribed treatment were 52.6% and 71.6% in the isoniazid and rifampin groups, respectively (P<.001). In multivariate logistic regression analysis, treatment regimen was independently associated with treatment completion (adjusted odds ratio for treatment completion, 2.88 for rifampin group vs isoniazid group; 95% confidence interval, 2.27-3.66). Clinically recognized adverse reactions resulting in permanent treatment discontinuation occurred in 4.6% and 1.9% of patients in the isoniazid and rifampin groups, respectively (P<.001). Clinically recognized hepatotoxicity was more common in the isoniazid group (1.8%) than in the rifampin group (0.08%, P<.001). CONCLUSIONS: Compared with a 9-month isoniazid regimen, a 4-month rifampin regimen was associated with a higher percentage of patients completing treatment and a lower percentage of patients with clinically recognized adverse reactions. Additional studies are warranted to determine efficacy and effectiveness of rifampin therapy for LTBI.