11.2 Standard treatment regimen

Box 11.1 – Standard regimen composition for Hr-TB

Although there is no evidence about the effect of taking isoniazid despite resistance to this drug, the fixed-dose combination (HRZE) is used for the patient’s convenience because no fixed-dose combination (RZE) is currently available.

The combination (HRZE) is administered at the same dose as for the intensive phase of drug-susceptible TB (DS-TB) treatment.

In children < 23 kg, ethambutol should be given with the fixed-dose-combination (HRZ). See Appendix 13.

Levofloxacin is preferred over moxifloxacin in the standard Hr-TB regimen (better safety profile). In addition, rifampicin reduces the plasma concentration of moxifloxacin [1] Citation 1. Naidoo A, Naidoo K, McIlleron H, Essack S, Padayatchi N. A Review of Moxifloxacin for the Treatment of Drug-Susceptible Tuberculosis. J Clin Pharmacol. 2017 Nov;57(11):1369-1386.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5663285/pdf/nihms879749.pdf .

Treatment prolongation may be considered on a case-by-case basis for patients with lung cavities or with sputum smear still positive after the end of Month 2. However, before prolonging the treatment, the emergence of resistances to rifampicin, fluoroquinolones (and, if possible, pyrazinamide) should be ruled out.

If isoniazid resistance is detected after the patient started a DS-TB treatment, perform a new rapid molecular test (RMT) to rule out the emergence of resistance to rifampicin. Once susceptibility to rifampicin is confirmed, change to a full 6-month standard Hr-TB regimen.