Abstract

This chapter covers the strategies recommended to build an effective regimen for drug resistant tuberculosis. Treatment outcomes for multidrug resistant tuberculosis (MDR-TB) and beyond show a progressively lower cure rate as the resistance pattern became more complex. Basically all treatment recommendations for drug-resistant tuberculosis are based on expert opinion, with just a few available clinical trials. Rifampin is the most important drug in the first line regimen; if the strain is resistant is considered as pre-MDR TB and the patient must be treated for at least 18 months. There are two types of MDR-TB patients: patients who have never been treated for tuberculosis in the past and that were infected with an already resistant strain and patients previously treated for tuberculosis. The latter are much more frequent and more difficult to treat. To design a regimen for MDR-TB the following order is recommended: include ethambutol and/or pyrazinamide (WHO recommends the use of pyrazinamide regardless of the results of the drug susceptibility testing); however this drugs should not be counted as effective drugs. As a second step, a second line injectable (amikacin, kanamycin or capreomycin) will be included. Then add a fluoroquinolone (levofloxacin or moxifloxacin). Finally to complete the regimen add as many drugs from Group 4 (ethionamide, cycloserine and PAS) as needed. If necessary, include drugs from group 5. The first choice will be linezolid.