Weight-Based Dosing for the 4-Month Tuberculosis Regimen
The 4-month rifapentine-moxifloxacin regimen uses fixed dosing for most medications (rifapentine 1200 mg, moxifloxacin 400 mg, isoniazid 300 mg daily) in patients ≥40 kg, with only pyrazinamide requiring weight-based adjustment: 1000 mg for 40-<55 kg, 1500 mg for 55-75 kg, and 2000 mg for >75 kg 1.
Dosing Algorithm
The regimen consists of two phases for patients aged ≥12 years with body weight ≥40 kg 1:
Intensive Phase (8 weeks, 56 doses)
- Rifapentine: 1200 mg daily (all patients ≥40 kg)
- Moxifloxacin: 400 mg daily (all patients ≥40 kg)
- Isoniazid: 300 mg daily (all patients ≥40 kg)
- Pyrazinamide (weight-based):
- 40 to <55 kg: 1000 mg daily
- 55 to 75 kg: 1500 mg daily
75 kg: 2000 mg daily
Continuation Phase (9 weeks, 63 doses)
- Rifapentine: 1200 mg daily
- Moxifloxacin: 400 mg daily
- Isoniazid: 300 mg daily
- Pyrazinamide is discontinued after intensive phase
Total treatment duration: 17 weeks (119 total doses) 1
Key Administration Details
All medications should be administered with food, and pyridoxine (vitamin B6) 25-50 mg daily must be given with isoniazid to all patients 1. The regimen demonstrated noninferiority to the standard 6-month regimen in the pivotal trial, with 11.6% unfavorable outcomes versus 9.6% in controls (difference 2.0 percentage points, 95% CI -1.1 to 5.1) 2.
Critical Caveats
This dosing applies only to patients ≥40 kg body weight—the regimen was not studied in patients <40 kg 1. The guideline specifically recommends this regimen for patients aged ≥12 years, which inherently assumes adequate body weight 1.
Unlike traditional TB regimens that use mg/kg dosing across all weight ranges, this simplified approach uses predominantly fixed dosing, making it operationally easier to implement but requiring strict adherence to the weight cutoff 1. Pyrazinamide is the only medication requiring weight-band adjustment, which translates to approximately 18-36 mg/kg depending on body weight—higher per-kilogram doses in lighter patients and lower in heavier patients.