A 6-year-old child from rural India presents with a 3-month history of persistent cough, low-grade fever, and weight loss. Chest X-ray shows hilar lymphadenopathy with a cavitary lesion in the right upper lobe. Sputum smear microscopy is positive for acid-fast bacilli. What is the drug of choice for the intensive phase of treatment in this child?

## First-Line TB Treatment in Children **Key Point:** The intensive phase of pediatric TB treatment uses a 4-drug regimen (HRZE) for 2 months, followed by a continuation phase of 2 drugs (HR) for 4 months in drug-susceptible TB. ### Intensive Phase (2 months) The standard regimen is: - **H** — Isoniazid - **R** — Rifampicin - **Z** — Pyrazinamide - **E** — Ethambutol **High-Yield:** This 4-drug combination is recommended by WHO, RNTCP (India), and AAP for all children with TB, regardless of disease severity or site of TB. ### Why All 4 Drugs? 1. **Rapid bactericidal action** — Isoniazid and Rifampicin are the most potent 2. **Prevention of drug resistance** — Pyrazinamide and Ethambutol reduce the risk of monoresistance 3. **Shorter total duration** — 6 months total (vs. 9 months with 2 drugs alone) ### Continuation Phase (4 months) After intensive phase completion: - **H** — Isoniazid - **R** — Rifampicin **Clinical Pearl:** In children with TB meningitis or severe disseminated TB, some guidelines recommend extending the intensive phase to 3 months, but the 4-drug combination remains the same. **Mnemonic:** **HRZE** = **H**ard **R**iddance **Z**aps **E**very TB bacillus (intensive phase) | Regimen | Intensive Phase | Continuation Phase | Total Duration | |---------|-----------------|-------------------|----------------| | Standard (Drug-susceptible) | HRZE × 2 months | HR × 4 months | 6 months | | TB meningitis | HRZE × 3 months | HR × 3 months | 6 months | | MDR-TB | Longer, complex regimen | — | 20+ months | **Warning:** Do NOT use 2-drug regimens (HR only) in the intensive phase for children — this increases relapse and drug resistance rates.