For MDR-TB patients an intensive phase of eight months is suggested by WHO, and the duration may be modified according to the patient’s response to therapy. During this intensive phase an injectable agent is used daily.
The recommended duration of treatment for MDR-TB regimens is guided by culture conversion and Xpert MTB/RIF is not an appropriate monitoring test for TB or MDR-TB patients.
Currently, WHO recommends continuing therapy for a minimum of 18 months after culture conversion and not less than 20 months total duration although extension to 24 months after culture conversion may be indicated in cases with extensive pulmonary damage.
There are new clinical trials ongoing that hope to provide evidence about the utility of shorter regimens for patients with certain types of strains
