Under NTEP guidelines, which of the following is the correct first-line anti-TB drug regimen for a newly diagnosed case of drug-susceptible pulmonary tuberculosis?

Explanation

## First-Line Anti-TB Drug Regimen (HRZE) **Key Point:** The NTEP standard first-line regimen for drug-susceptible TB is **HRZE**—Isoniazid, Rifampicin, Pyrazinamide, and Ethambutol. ### Components of HRZE Regimen | Drug | Mechanism | Role in Regimen | |------|-----------|------------------| | **H**isoniazid | Inhibits mycolic acid synthesis | Bactericidal; backbone drug | | **R**ifampicin | Inhibits RNA polymerase | Bactericidal; backbone drug | | **Z**pyrazinamide | Prodrug (converted to pyrazinoic acid) | Bactericidal; penetrates caseous lesions | | **E**thambutol | Inhibits arabinosyl transferase | Bacteriostatic; prevents resistance | **High-Yield:** The HRZE regimen is used in the **intensive phase (2 months)** of TB treatment. Streptomycin is no longer part of the standard first-line regimen in NTEP (it was used historically but has been replaced by pyrazinamide due to better efficacy and safety profile). **Mnemonic:** **HRZE** — Remember "**H**ard **R**ock **Z**one **E**xplosion" or simply "**H**isoniazid, **R**ifampicin, **Z**pyrazinamide, **E**thambutol." **Clinical Pearl:** Pyrazinamide is crucial for shortening TB treatment from 9 months to 6 months; it is the only drug that can sterilize caseous lesions and dormant bacilli. [cite:Park 26e Ch TB Control; NTEP Guidelines]