Treatment of Isoniazid-Resistant TB in Pediatric Patients

Core Treatment Regimen

• The American Thoracic Society (ATS) recommends a 6-month regimen of rifampin, pyrazinamide, and a later-generation fluoroquinolone (levofloxacin or moxifloxacin) for pediatric patients with isoniazid-resistant tuberculosis who cannot receive ethambutol 1
• The ATS/CDC/ERS/IDSA guidelines suggest that rifampin, pyrazinamide, and a later-generation fluoroquinolone should be given daily for a total duration of 6 months 1

Duration Modifications Based on Disease Severity

• For limited disease, the ATS guidelines recommend that pyrazinamide duration can be shortened to 2 months in selected situations, while rifampin and fluoroquinolone should be continued for the full 6 months 1
• For extensive disease or tuberculous meningitis, the ATS guidelines recommend maintaining all three drugs for the full 6-month duration, and consider adding a fourth drug from Group 4 agents 2, 3, 4

Alternative Fourth Drug Options

• The ATS guidelines suggest using injectable aminoglycosides, such as amikacin, as an alternative to ethambutol in pediatric patients with isoniazid-resistant tuberculosis 4
• The ATS guidelines also recommend using oral second-line agents, such as ethionamide/prothionamide, cycloserine, or terizidone, as alternative options 5

Critical Monitoring and Supportive Care

• The ATS guidelines recommend giving prophylactic pyridoxine 10 mg/day to all pediatric patients on fluoroquinolones or second-line agents, with higher doses needed if cycloserine or high-dose isoniazid analogs are used 2, 3, 4
• The ATS guidelines also suggest assessing and addressing malnutrition, which is common in pediatric DR-TB, and considering multivitamin supplements for all pediatric patients with DR-TB 2, 3, 4

Important Caveats and Pitfalls

• The ATS guidelines emphasize the importance of avoiding common errors, such as using ethambutol despite a documented allergy, using older fluoroquinolones, and assuming all isoniazid resistance is the same 2, 3, 4, 5
• The ATS guidelines also recommend consulting with a TB expert for all drug-resistant cases, and accessing experts through CDC TB Centers of Excellence or local health department TB Control Programs 1