American Board of Internal Medicine (ABIM) Certification Practice Exam

What is the recommended treatment for patients with latent TB suspected to be resistant to isoniazid?

1. Three months of rifampin

2. Four months of daily rifampin

3. Six months of isoniazid and rifampin

4. Two months of streptomycin

The correct answer is: Four months of daily rifampin

For patients with latent tuberculosis (TB) who are suspected to be resistant to isoniazid, the recommended treatment is four months of daily rifampin. This approach is supported by guidelines due to the effectiveness of rifampin in treating latent TB while addressing the potential for isoniazid resistance. Isoniazid is commonly used in the treatment of latent TB infection (LTBI), but if resistance is suspected, reliance on isoniazid could lead to treatment failure or the progression of the disease. Rifampin offers a preferable alternative; it not only has good efficacy against TB but also works quickly, allowing for a shorter treatment duration compared to some other regimens. Four months of rifampin is effective, generally well-tolerated, and allows for better compliance compared to longer regimens. This guideline takes into account the need to ensure both safety and effectiveness, emphasizing the importance of promptly addressing latent TB in individuals suspected of having drug resistance. Using rifampin monotherapy is also less likely to lead to further resistance compared to using a suboptimal regimen. In summary, the recommendation for four months of daily rifampin is based on its efficacy in treating latent TB, especially in cases where isoniazid