4fdc dosage
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4FDC fixed dose combination tuberculosis dosage WHO 2026
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https://tbksp.who.int/en/node/3053
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https://www.icmr.gov.in/icmrobject/uploads/STWs/1725964686_2…
Here is a complete summary of 4-FDC (Four-Drug Fixed-Dose Combination) dosing for tuberculosis treatment.
4-FDC (HRZE) - Dosage Guide
What is 4-FDC?
The 4-FDC tablet contains four first-line anti-TB drugs in one tablet:
- H - Isoniazid 75 mg
- R - Rifampicin 150 mg
- Z - Pyrazinamide 400 mg
- E - Ethambutol 275 mg
It is used during the Intensive Phase (IP) of DS-TB treatment (first 2 months / 56 doses). The continuation phase (4 months / 112 doses) uses a 3-FDC (HRE) tablet instead.
Standard regimen: 2HRZE / 4HRE
Individual Drug Target Doses
| Drug | Dose | Range |
|---|---|---|
| Isoniazid (H) | 5 mg/kg/day | 4-6 mg/kg |
| Rifampicin (R) | 10 mg/kg/day | 8-12 mg/kg |
| Pyrazinamide (Z) | 25 mg/kg/day | 20-30 mg/kg |
| Ethambutol (E) | 15 mg/kg/day | 12-18 mg/kg |
Adult 4-FDC Dosing - Number of Tablets by Weight Band
(Each tablet contains H 75mg / R 150mg / Z 400mg / E 275mg)
| Weight Band | 4-FDC Tablets (Intensive Phase) |
|---|---|
| 25 - 34 kg | 2 tablets |
| 35 - 49 kg | 3 tablets |
| 50 - 64 kg | 4 tablets |
| 65 - 75 kg | 5 tablets |
| > 75 kg | 6 tablets |
All doses are taken once daily, preferably on an empty stomach. The same number of tablets applies for the 3-FDC in the continuation phase.
If a patient's weight increases by more than 5 kg during treatment, the number of tablets should be adjusted to the new weight band.
Pediatric Dosing
Children are treated with dispersible FDC tablets (smaller strengths: RHZ 75/50/150 mg + separate Ethambutol 100 mg). Adult FDC tablets (swallowed whole) may be used for children >25 kg.
Per WHO/NTEP guidelines, pediatric drug targets are higher per kg due to faster metabolism:
| Drug | Pediatric dose |
|---|---|
| Isoniazid | 7-15 mg/kg (max 300 mg/day) |
| Rifampicin | 10-20 mg/kg (max 600 mg/day) |
| Pyrazinamide | 30-40 mg/kg (max 2000 mg/day) |
| Ethambutol | 15-25 mg/kg (max 1500 mg/day) |
Pediatric dispersible FDC (RHZ 50/75/150 mg + E 100 mg) tablet count by weight band:
| Weight Band | HRZ tablets | E tablets |
|---|---|---|
| 4-7 kg | 1 | 1 |
| 8-11 kg | 2 | 2 |
| 12-15 kg | 3 | 3 |
| 16-24 kg | 4 | 4 |
| 25-29 kg | 3 dispersible + 1 adult | 3 |
| 30-39 kg | 2 dispersible + 2 adult | 2 |
Special Situations
- CNS TB / Skeletal TB: Extend continuation phase to 24 weeks (instead of 16)
- Disseminated TB or slow response: CP may be extended on a case-by-case basis
- TB meningitis (pediatric): Regimen is 2HRZE + 10HRE
- Pyridoxine (Vitamin B6): 10 mg/day in adults; 50-100 mg/day in children (weight-based) - given to prevent isoniazid-related neuropathy
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