The standardized treatment regimens for the different categories of TB cases, and dosage schedules (number of tablets) in relation to body weight, are presented in Tables 3, 4 and 5.
Table 1: The recommended dosage of essential first-line anti-TB drugs
Drug
(abbreviation) |
Mode of action |
Recommended dose (dose range) in mg/kg body weight |
| |
|
Daily |
Intermittent 3 times per week |
rifampicin (R) |
bactericidal |
10 (8-12) |
10 (8-12) |
isoniazid (H) |
bactericidal |
5 (4-6) |
10 (8-12) |
pyrazinamide (Z) |
bactericidal |
25 (20-30) |
35 (30-40) |
streptomycin (S) |
bactericidal |
15 (12-18) |
15 (12-18) |
ethambutol (E) |
bacteriostatic |
15 (15-20) |
30 (25-35) |
Although used in some programmes, WHO does not recommend the use of thioacetazone (T) because of the risk of severe toxicity, particularly in HIV infected individuals. In general, thioacetazone should be replaced by ethambutol.
Table 2:Fixed-dose combinations from the WHO Model List of Essential Medicines (revised April 2002)
Drug |
Dose form |
Strength for Daily use |
Strength for intermittent use 3 times per week |
rifampicin + isoniazid [RH] |
Tablet |
150 mg + 75 mg
300 mg + 150 mg |
150 mg + 150 mg |
| |
Tablet or pack of granules* |
60 mg + 30 mg |
60 mg + 60 mg |
ethambutol + isoniazid [EH] |
Tablet |
400 mg + 150 mg |
- |
isoniazid + thioacetazone [HT]** |
Tablet |
100 mg + 50 mg
300 mg + 150 mg |
-
- |
rifampicin + isoniazid + pyrazinamide [RHZ] |
Tablet
Tablet or pack of granules* |
150 mg + 75 mg + 400 mg
60 mg + 30 mg + 150 mg |
150 mg + 150 mg + 500 mg - |
rifampicin + isoniazid + pyrazinamide + ethambutol [RHZE] |
Tablet |
150 mg + 75 mg
+ 400 mg + 275 mg |
-
- |
* For paediatric use
** Although used in some programmes, WHO does not recommend the use of thioacetazone (T) because of the risk of severe toxicity, particularly in HIV infected individuals. In general, thioacetazone should be replaced by ethambutol.
Table 3: Recommended treatment regimens for each treatment category
Tuberculosis diagnostic category |
Tuberculosis patients |
Tuberculosis treatment regimens |
| |
|
Initial phase (daily or 3 times per week*) |
Continuation phase (daily or 3 times per week*) |
I |
New smear-positive patients; new smear-negative PTB with extensive parenchymal involvement; severe concomitant HIV disease or severe forms of extrapulmonary TB |
2 RHZE** |
4 RH*** |
II |
Previously treated sputum smear-positive PTB:
- relapse;
- treatment after interruption;
- treatment failure† |
2 RHZES/1 RHZE |
5 RHE |
III |
New smear-negative PTB (other than in Category 1) and less severe forms of extrapulmonary TB. |
2 RHZE†† |
4 RH*** |
* Direct observation of treatment intake is required for the initial phase in smear positive cases, and always when treatment includes rifampicin.
** Streptomycin may be used instead of ethambutol.
*** 4RH may be replaced by 6 EH daily when supervision of treatment is not possible. However, preliminary data from a recent clinical trial have shown that 6EH is much less effective than 4RH in terms of cure, with higher failure and relapse rates.
In meningitis: 2 RHZS/4 RH or 2 RHZS/4 (RH)3, replacing ethambutol with streptomycin.
† Whenever possible, drug sensitivity testing is recommended before prescribing category II treatment in failure cases. In patients with proven MDR-TB, it is recommended to use category IV regimens which are not described in this Guide (please refer to guidelines for management of failure and chronic cases in MDR-TB).
†† Ethambutol may be omitted for patients with non-cavitary, smear-negative pulmonary TB who are known to be HIV-negative, patients who are known to be infected with fully drug-susceptible bacilli. Young children with primary TB should be given 3 drugs combination only (without ethambutol).
R - rifampicin; H - isoniazid; Z - pyrazinamide; E - ethambutol; S - streptomycin; PTB - pulmonary tuberculosis.
Note: Standard code for TB treatment regimens. Each anti-TB drug has an abbreviation (shown in the Tables above). Aregimen consists of 2 phases. The number before a phase is the duration of that phase in months. Anumber in subscript (e.g. 3) after a letter is the number of doses of that drug per week. If there is no number in subscript after a letter, then treatment with that drug is daily. For example: 2 RHZE/4 (RH)3. The duration of the initial phase is 2 months and drug treatment is daily, with rifampicin (R), isoniazid (H), pyrazinamide (Z) and ethambutol (E). The continuation phase is 4 (RH)3. The duration is 4 months, with rifampicin (R) and isoniazid (H) three times per week.
Table 4: Dosage schedules for adults: number of 4-, 3- and 2-drug FDC tablets
Patient body weight (kg) |
Initial phase |
Continuation phase |
| |
2 months |
4 months |
or 6 months* |
| |
Daily |
or Daily |
or 3 times per week |
Daily |
or 3 times per week |
Daily |
| |
RHZE**
150 mg+75 mg+400 mg+275 mg |
RHZ
150 mg + 75 mg + 400 mg |
RHZ
150 mg +150 mg + 500 mg |
RH
150 mg + 75 mg + |
RH
150 mg + 150 mg |
EH
400 mg +150 mg |
30-39 |
2 |
2 |
2 |
2 |
2 |
1.5 |
40-54 |
3 |
3 |
3 |
3 |
3 |
2 |
55-70 |
4 |
4 |
4 |
4 |
4 |
3 |
71 and more |
5 |
5 |
5 |
5 |
5 |
3 |
R - rifampicin; H - isoniazid; Z - pyrazinamide; E - ethambutol
* 4RH may be replaced by 6 EH daily when supervision of treatment is not possible. However, preliminary data from a recent clinical trial have shown that 6EH is much less effective than 4RH in terms of cure, with higher failure and relapse rates.
** Maximum recommended daily dose of rifampicin in FDCs is 750 mg.
Table 5:Dosage schedules for smear-negative children: number of 3- and 2-drug FDC tablets
Patient body weight (kg) |
Initial phase |
Continuation phase |
| |
2 months |
4 months |
| |
Daily |
or Daily |
or 3 times per week |
| |
RHZ
60 mg+30 mg+150 mg |
RH
60 mg+30 mg |
RH
60 mg+60 mg |
<7 |
1 |
1 |
1 |
8-9 |
1.5 |
1.5 |
1.5 |
10-14 |
2 |
2 |
2 |
15-19 |
3 |
3 |
3 |
20-24 |
4 |
4 |
4 |
25-29 |
5 |
5 |
5 |
R - rifampicin; H - isoniazid; Z - pyrazinamide
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