6.2.3 Duration of the regimen

The total length of a long treatment regimen is 18 to 20 months.

Three evidence-based recommendations guide the duration of the longer MDR-TB regimens:


The all-oral longer MDR-TB regimens have no intensive phase. The duration of use of different medicines will depend on their clinical indication, patient tolerability (e.g. linezolid used for as long as no serious adverse event emerges) and individual treatment response (e.g. culture negativity), until completion of the expected total duration of treatment or time after culture conversion.

Although the total length of treatment is expected to be about 18–20 months in most patients, it may be modified based on the patient’s clinical situation and response to treatment.

The evidence assessed using the IPD11 demonstrated that there was a marginally increased risk of treatment failure or relapse when the duration of MDR-TB treatment was 20–22 months (compared with 17.5–20.0 months), and 18–20 months was determined to be an optimal treatment duration to maximize treatment success (1). In practice, NTPs may choose a fixed duration (e.g. 18 months) for implementation purposes.

11 Data used for analysis to support these recommendations were from patients who did not receive two or more Group A medicines. However, a small proportion of patients included in the analysis were on all-oral regimens, and in these patients the same optimal treatment duration was observed using identical parameters.

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