CURRENT APPROACHES TO CONTROL OF ISONIAZID-RESISTANT TUBERCULOSIS

Abstract

Isoniazid (H; INH) is an important first-line drug for the treatment of active tuberculosis (TB) and latent TB infection because of its potent early bactericidal activity against Мycobacterium tuberculosis. Currently, TB resistant to INH, alone or in combination with other drugs, is the most common type of drug-resistant TB. Epidemiology of INH-resistant TB, the molecular mechanisms of drug resistance, current methods for diagnosis and therapeutic regimens of this TB form are presented. Studies in the last years have shown that resistance to INH reduces the probability of treatment success and increases the risk of acquiring resistance to other impor­tant first-line drugs. Based on the most recent meta-analyses, the last WHO recommendations for treatment of INH-resistant TB are to include rifampicin (RIF), ethambutol, pyrazinamide and levofloxacin for 6 months, and not to add streptomycin or other injectable agents to the drug regimen. The guideline emphasizes the importance of excluding resistance to RIF before starting the regimen for INH-resistant TB because of the risk for development of multidrug-resistant TB during the treatment course. The WHO recommendations are based on observational studies, not randomized controlled trials, and are thus conditional and based on low certainty in the estimates of effect. There­fore, further work is needed to optimize the treatment and control of INH-resistant TB.