Drug-resistant tuberculosis treatment

1.4 Implementation considerations
Case scenarios. Implementing these recommendations requires the (H)REZ–levofloxacin regimen to 
be administered only in patients in whom resistance to isoniazid has been confirmed and resistance 
to rifampicin has been excluded. Preferably, testing for resistance to fluoroquinolones (and, if possible, 
to pyrazinamide) is also done ahead of starting treatment. It is envisaged that the treatment regimen 
for Hr-TB will apply in the following
situations:
• 
Hr-TB and rifampicin susceptibility are confirmed before TB treatment is started. Treatment with (H)
REZ–levofloxacin is started immediately. If the diagnosis is strongly presumed (e.g. close contacts of 
a confirmed Hr-TB source case) but results of DST are still pending, the regimen may be introduced. 
Should the DST results taken at the start eventually show susceptibility to isoniazid, then levofloxacin 
is stopped, and the patient continues treatment in order to complete a 2HREZ/4HR
regimen.
• 
Hr-TB is confirmed after the start of treatment with the 2HREZ/4HR regimen. This includes patients 
who had undiagnosed isoniazid resistance at the start or who developed isoniazid resistance later 
while on treatment with a first-line regimen. In such cases, rapid molecular testing for rifampicin 
resistance must be done (or repeated). Once rifampicin resistance has been excluded, a full 6-month 
course of (H)REZ–levofloxacin is given. The duration is driven by the need to give levofloxacin 
for 6 months, which usually implies that the companion first-line medicines are taken for longer 
than
this.

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WHO consolidated 
guidelines 
on
tuberculosis: 
drug-resistant tuberculosis treatment
9
If rifampicin resistance is detected, the patient needs to be started on a recommended MDR-TB 
treatment regimen, as described in subsequent sections of these
guidelines.