Which medication can be used for latent tuberculosis infection treatment?

• A. Isoniazid
• B. Rifampin
• C. Ethambutol
• D. Pyrazinamide

Answer: (A)

Treating latent TB infection aims to eradicate dormant bacilli and prevent progression to active disease. Isoniazid is the classic choice because it has proven efficacy as a single-agent regimen for LTBI, significantly reducing the risk of reactivation when taken for several months. It works by inhibiting the synthesis of mycolic acids in the mycobacterial cell wall, helping suppress bacteria that are not actively dividing. The usual approach is several months of isoniazid therapy with monitoring for liver toxicity and drug interactions, and adherence is crucial for effectiveness. Some guidelines allow a shorter course with rifampin for those who cannot take isoniazid, but isoniazid monotherapy remains the most widely taught LTBI regimen. The other drugs listed are primarily used for active TB or in multi-drug regimens, not as standard LTBI therapy.