Management of isoniazid mono and poly resistant tuberculosis

29 Aug 2024 14:00 14:20
Rex Room, Level 6
Mat Zuki Mat Jaeb Speaker Malaysia

Multidrug-Resistant Tuberculosis Workshop
MANAGEMENT OF ISONIAZID MONO AND POLY RESISTANT TUBERCULOSIS

Mat Zuki Mat Jaeb
Raja Perempuan Zainab II Hospital, Kota Bahru, Kelantan, Malaysia

Isoniazid-resistant TB (Hr-TB) refers to Mycobacterium tuberculosis strains with resistance to isoniazid and susceptible to rifampicin, confirmed in vitro. Polydrug-resistant refers to resistance to more than one first-line anti-TB drug, other than isoniazid and rifampicin together. 

TB strains resistant to isoniazid treated with first-line drugs reduce the effectiveness of treatment with higher failure and relapse rates. 

The basic principle of treatment success in resistant tuberculosis is early diagnosis and the establishment of a curative treatment regimen according to the patient’s DST results. Addition of levofloxacin is recommended together with rifampicin, ethambutol and pyrazinamide for six months resulted in higher success rate as compared to previous treatment regimen using rifampicin, ethambutol and pyrazinamide with or without isoniazid. For other patients, in whom Hr-TB is detected after the start of treatment with the 2HRZE/4HR regimen, the (H)REZ component drugs are continued (or pyrazinamide and ethambutol are re-introduced) and levofloxacin added. If levofloxacin cannot be used, the patient may be given 6(H)REZ as an alternative. Resistance to rifampicin must be excluded by WHO-recommended genotypic or phenotypic methods prior to treatment. 

Isoniazid resistance testing should also include information on the specific mutations associated with resistance to isoniazid (katG or inhA). Rapid molecular tests such as Xpert MTB/RIF and line probe assays (LPA) are preferred to guide patient selection for the (H)RZE-Lfx regimen. 

The clinical monitoring of patients on Hr-TB treatment follows similar principles to those that apply to other first-line TB regimens. 

Management of polydrug-resistant tuberculosis should be carried out in experienced centres. 

Referrences 

  1. Gegia, M.; Winters, N.; Benedetti, A.; van Soolingen, D.; Lancet Infect. Dis. 2017, 17, 223–234 

  2. WHO consolidated guidelines on tuberculosis. Module 4: treatment - drug-resistant tuberculosis treatment, 2022 update 

  3. Fregonese, F. et al. Lancet Respir. Med. 2018, 6, 265–275 

  4. Escalante P, Graviss EA, Griffith DE, Musser JM, Awe RJ. Chest. 2001;119(6):1730–6. 

  5. Nolan C, Goldberg S. Int J Tuberc Lung Dis. 2002;6(11):952–8.