Hidoc Bulletin

Tuberculosis needs to be properly treated in order to avoid fatal outcomes. The most important part of the treatment is to understand the type of TB as in case of drug resistant TB, the treatment approaches need to be different. For instance, rifampicin-resistant TB (RR-TB) strains may or may not be resistant to isoniazid or other medicines of the first-line group or second-line group (e.g. XDR-TB). Thus, it is mandatory to perform drug-susceptibility testing (DST) to determine the susceptibility or resistance of the strain. Line probe assays can help in determining the resistance to second-line anti-TB drugs. According to the guidelines of WHO, second-line TB drugs can be used to treat drug-resistant TB and it can also be administered in children. For the treatment of RR-TB and MDR-TB, streptomycin may be used as an alternative when other second-line drugs like aminoglycosides or capreomycin are not used.

Treating Multidrug-Resistant TB:

The guidelines of the World Health Organization (WHO) has provided a detailed account regarding the management of drug-resistant TB. It suggests that the treatment requires longer duration in the case of MDR-TB and it is absolutely necessary to monitor the patient during the treatment. Most importantly, a delay in starting antiretroviral therapy can cause negative results. The 2022 guidelines of WHO in treating MDR-TB focused on the observational studies and evidence based approaches. Bedaquiline and linezolid can be used along with other anti-TB drugs for longer duration TB therapy. Specific recommendations are provided for patients with surgeries and pediatric patients.

In the case of a shorter MDR-TB regimen i.e. treatment lasting for 9-12 months bedaquiline, pretomanid and linezolid drugs can be used as per the observational studies. Patients who have not received any treatment with second-line drugs and the criteria of resistance to fluoroquinolones and second-line injectable agents are excluded can be subjected to a shorter MDR-TB regimen.

Compared to the shorter MDR-TB regimen the longer MDR-TB regimens Lasts for 18 months or more and it needs to be standardized with the minimum number of second-line TB medicines which can be effective based on patient history or drug-resistance patterns. The treatment recommendations include:

● Use of at least 5 effective TB medicines including pyrazinamide and four core second-line TB medicines during the intensive phase.

● Among the 5 medicines, one should be from Group A, one from Group B, at least two from Group C2. Further one from Group D2 and another from Group D3 can also be added to prepare an effective dose of TB medicines.

● High-dose isoniazid and/or ethambutol may be added to strengthen the regimen ● Patients with absence of niazid resistance need to be treated with a recommended MDR-TB regimen.

● Rifabutin can be used as a substitute for rifampin in rifampin-resistant TB

● Considering the duration of treatment- In case of treatment during intensive phase (IP) an initial 6 months of treatment is required and in continuation phase (CP) a period of 18 months is required for treatment.