Which drug is used for latent TB infection prophylaxis?

Which drug is used for latent TB infection prophylaxis?

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

Answer: (B)

Preventing disease progression in latent TB infection relies on giving a drug that effectively targets dormant bacilli and lowers the risk of reactivation. Isoniazid has long been used for this purpose. It is given to people with a positive TB test who are at risk of developing active TB (for example, close contacts or individuals with immunocompromise) to substantially reduce the chance of reactivation. Mechanistically, isoniazid is a prodrug that, once activated by the mycobacterial enzyme KatG, inhibits the synthesis of mycolic acids in the bacterial cell wall. This disruption weakens the bacilli and helps prevent their growth as they attempt to reactivate, which is why it’s the standard choice for latent TB prophylaxis. The typical course is several months of daily isoniazid, though shorter regimens using other drugs exist in some guidelines.

Preventing disease progression in latent TB infection relies on giving a drug that effectively targets dormant bacilli and lowers the risk of reactivation. Isoniazid has long been used for this purpose. It is given to people with a positive TB test who are at risk of developing active TB (for example, close contacts or individuals with immunocompromise) to substantially reduce the chance of reactivation.

Mechanistically, isoniazid is a prodrug that, once activated by the mycobacterial enzyme KatG, inhibits the synthesis of mycolic acids in the bacterial cell wall. This disruption weakens the bacilli and helps prevent their growth as they attempt to reactivate, which is why it’s the standard choice for latent TB prophylaxis. The typical course is several months of daily isoniazid, though shorter regimens using other drugs exist in some guidelines.