Table 1.

Short-course tuberculosis (TB) treatment regimens, according to patient category, as recommended by the World Health Organization (WHO).

TB diagnostic category	Condition	Treatment regimensa
		Intensive phase	Continuation phase
I	New smear-positive pulmonary disease; new smear-     negative pulmonary disease with extensive lung     involvement; concomitant HIV disease or severe     forms of extrapulmonary diseaseb	Preferred: 2HRZE;c optional:     2(HRZE)3 or 2HRZEd	Preferred: 4HR, 4(HR)3;     optional: 4(HR)3 or 6HEe
II	Previously treated sputum smear–positive pulmonary     TB: (1) relapse or (2) treatment after default	Preferred: 2HRZES/1HRZE;f     optional: 2(HRZES)3/1HRZE3	Preferred: 5HRE;f optional:     5(HRE)3
	Treatment failure of category Ig in a setting with (1)     adequate program performance or (2) representative     data showing high rates of MDR-TB and/or capacity for     DST of cases and availability of category IV regimens	Specially designed standardized     or individualized regimens     often needed	Specially designed standardized     or individualized regimens     often needed
	In setting where representative DRS data show low rates     of MDR-TB or individualized DST shows drug-susceptible     disease or in setting of (1) poor program performance     and (2) absence of representative DRS data and     insufficient resources to implement category     IV treatment	Preferred: 2HRZES/1HRZE;     optional: 2(HRZES)3, 1(HRZE)3	Preferred: 5HRE;f     optional: 5(HRE)3
III	New smear-negative pulmonary TB (other than in category     I), less-severe form of extrapulmonary TB	Preferred: 2HRZE;h optional:     2(HRZE)3 or 2HRZE	Preferred: 4HR, 4(HR)3;     optional: 4(HR)3 or 6HE
IV	Chronic, still smear positive after supervised retreatment;     proven or suspected MDR-TB casesi	Specially designed standardized     or individual regimens	Specially designed standardized     or individual regimens

NOTE. Adapted from the WHO [5]. DRS, drug resistance surveillance; DST, drug susceptibility testing; MDR-TB, multidrug-resistant TB.

^aE, ethambutol; H, isoniazid; R, rifampin; S, streptomycin; Z, pyrazinamide. Nos. preceding regimens denote length of treatment (in months). Subscripts following regimens denote frequency of administration (days per week); when no subscripts are given, the regimen is daily. Direct observation of drug intake is always required during the initial phase of the treatment and is strongly recommended when R is used in the continuation phase and required when treatment is given intermittently. Fixed-dose combinations are highly recommended for use in both the intensive and the continuation phases of treatment.

^bSevere forms of extrapulmonary TB are listed in [5].

^cS may be used instead of E. In tuberculous meningitis, E should be replaced by S.

^dIntermittent initial-phase therapy is not recommended when the continuation phase of H and E is used.

^eThis regimen may be considered in a situation in which the preferred regimen cannot be used as recommended. However, it is associated with a higher rate of treatment failure and relapse, compared with the 4HR continuation phase.

^fDaily treatment is preferred. However, 3-times-weekly treatment in both phases is an acceptable option.

^gPatients with treatment failure may be at increased risk for developing MDR-TB, particularly if R was used in the continuation phase. DST is recommended in these cases, if available. Patients with treatment failure with known or suspected MDR-TB must be treated with a category IV regimen.

^hE in the initial phase may be omitted for patients with limited, noncavity, smear-negative TB who are known to be HIV negative, for patients with less severe forms of extrapulmonary TB, and for young children with primary TB.

ⁱDST is recommended for patients who are contacts of patients with MDR-TB.