TB Treatment Regimens - Park's Textbook of Preventive and Social Medicine

1. Drug-Sensitive TB (DS-TB) - Standard Regimen (NTEP 2019)

The thrice-weekly intermittent regimen has been replaced by a daily fixed-dose combination (FDC) regimen under NTEP.

Regimen

Type of TB Case	Intensive Phase (IP)	Continuation Phase (CP)
New and previously treated cases (H and R sensitive / unknown)	2 HRZE (8 weeks, 56 doses)	4 HRE (16 weeks, 112 doses)

IP: Isoniazid (H) + Rifampicin (R) + Pyrazinamide (Z) + Ethambutol (E) - daily, under DOT
CP: Isoniazid + Rifampicin + Ethambutol - daily
Extension of CP by 12-24 weeks is allowed in CNS TB, skeletal TB, and disseminated TB

Adult Daily Dose Schedule (FDC by Weight Band)

Weight	IP tablets (HRZE 75/150/400/275)	CP tablets (HRE 75/150/275)
25-34 kg	2	2
35-49 kg	3	3
50-64 kg	4	4
65-75 kg	5	5
≥75 kg	6	6

First-Line Drug Dosages

Drug	Adults	Children	Max in children
Isoniazid (H)	10 mg/kg/day (7-15)	5 mg/kg/day (4-6)	300 mg
Rifampicin (R)	15 mg/kg/day (10-20)	10 mg/kg/day (8-12)	600 mg
Pyrazinamide (Z)	35 mg/kg/day (30-40)	25 mg/kg/day (20-30)	2000 mg
Ethambutol (E)	20 mg/kg/day (15-25)	15 mg/kg/day (12-15)	1500 mg
Streptomycin (S)*	20 mg/kg/day	15 mg/kg/day	1000 mg

Streptomycin is used only in TB meningitis or as a substitute if a first-line drug is stopped due to adverse drug reaction (ADR)

2. Paediatric TB

Children up to 18 years and <39 kg use paediatric weight bands; those >39 kg use adult weight bands
IP: Dispersible FDC - Rifampicin 75 mg + INH 50 mg + Pyrazinamide 150 mg + Ethambutol 100 mg (separate)
CP: Dispersible FDC - Rifampicin 75 mg + INH 50 mg + Ethambutol 100 mg (separate)

Weight	IP: HRZ (tabs)	IP: E (tabs)	CP: HR (tabs)	CP: E (tabs)
4-7 kg	1	1	1	1
8-11 kg	2	2	2	2
12-15 kg	3	3	3	3
16-24 kg	4	4	4	4

3. Drug-Resistant TB (DR-TB) Regimens (PMDT Guidelines 2019)

Under NTEP, three standard DR-TB regimens are used:

Standard DR-TB Regimens

Regimen	Intensive Phase	Continuation Phase
1. All oral H mono/poly DR-TB regimen (R sensitive, H resistant)	(6) Lfx R E Z	-
2. Shorter MDR-TB regimen	(4-6) Mfx^h Km/Am* Eto Cfz Z H^h E	5 Mfx^h Cfz Z E
3. All oral longer MDR-TB regimen	(18-20) Bdq(6) Lfx Lzd Cfz Cs*	-

H mono/poly DR-TB: 6 months total with Levofloxacin + R + E + Z
Shorter MDR-TB: 4-6 month IP + 5 month CP = ~9-11 months total
Longer MDR-TB: 18-20 months all-oral, includes Bedaquiline for 6 months

Grouping of Medicines for Longer MDR-TB Regimens (WHO/NTEP)

Group	Medicines
Group A (include all 3)	Levofloxacin (Lfx) OR Moxifloxacin (Mfx); Bedaquiline (Bdq); Linezolid (Lzd)
Group B (add one or both)	Clofazimine (Cfz); Cycloserine (Cs) OR Terizidone (Trd)
Group C (complete regimen if A/B unavailable)	Ethambutol (E); Delamanid (Dlm); Pyrazinamide (Z); Imipenem-cilastatin/Meropenem; Amikacin (Am) or Streptomycin (S); Ethionamide (Eto)/Prothionamide (Pto); PAS

Key shift (WHO 2019): Fully oral regimens are now the priority for most MDR-TB patients. Injectable agents are no longer among priority medicines for longer MDR-TB regimens.

4. Latent TB Infection (LTBI) Treatment

Three currently recommended regimens:

Isoniazid daily or twice weekly for 9 months
Isoniazid + Rifapentine once weekly for 12 weeks
Rifampicin (or Rifabutin) daily for 4 months (DOTS mandatory)

WHO also recommends: 3 or 4 months of INH + Rifampicin daily, or 6 months of INH daily.

Summary of Key Principles from Park's

DOTS (Directly Observed Treatment, Short Course) remains the cornerstone of TB control globally
Short-course chemotherapy (6 months) replaced the old 18-month regimen since the 1970s (Wallace Fox's work)
Steroids are adjunctive therapy in TB pericarditis and TB meningitis (initial high dose tapered over 6-8 weeks)
All TB patients must be offered HIV testing

- Park's Textbook of Preventive and Social Medicine, Chapter on Tuberculosis (NTEP/PMDT 2019 guidelines)

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