Implementation Considerations for Shifting Between Shorter and Longer MDR-TB Regimens

Shift from Shorter to Longer Drug-resistant TB (DR-TB) Regimen

Reasons for regimen shift: Resistance, tolerability, availability and emergence of exclusion criteria.

If for any of these reasons, there is a need to change a drug in shorter regimens, then the shorter regimen cannot be modified. Instead, patients should be re-evaluated based on the reasons for the regimen shift and initiated on a full course of the longer oral Multi/ Extensively Drug-resistant TB (M/XDR-TB) regimen with necessary modifications in the regimen.

Bdq should be given for the entire 6 months duration without the loading dose in this situation.

Shift from Longer to Shorter DR-TB Regimen

Reason for regimen shift: Occurs in patients in whom resistance is not detected on baseline specimen to Isoniazid (H), i.e., both inhA and catalase-peroxidase (katG), or to Fluoroquinolone (FQ) or Pyrazinamide (Z), Clofazimine (Cfz).

Bdq can be switched, provided that the longer DR-TB treatment has not been given for more than one month.

If patients are switched in this way, the shorter oral Bdq-containing MDR/RR-TB regimen is given for the full duration, without any changes to its composition or duration. Bdq should be given for the entire 6 months duration without the loading dose.

Bdq can be reinitiated with the loading dose if the interruption (if any) is up to two months.

Points to Remember

1. For patients with a change in regimen from shorter to longer or vice-versa, in the initial months before any definitive treatment outcome applies, the outcome of only the changed regimen needs to be reported. The patient moves out of the denominator of the previous regimen.
2. In both of the above situations, the remaining drugs of the regimen stopped should be returned for reconstitution and a new box of the changed regimen should be initiated. 

Resources

• Guidelines for Programmatic Management of Drug-resistant Tuberculosis in India, 2021.

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