Multidrug-resistant tuberculosis: An update on the best regimens

Multidrug-resistant tuberculosis is defined as tuberculosis caused by strains that have documented in vitro resistance to isoniazid and rifampin. Treatment involves a regimen consisting of at least 4 or 5 drugs to which the infecting strain has documented susceptibility. These agents may include ethambutol, pyrazinamide, streptomycin, a fluoroquinolone, ethionamide, prothionamide, cycloserine, and para-amino salicylic acid. In addition, an injectable agent, such as kanamycin, amikacin, or capreomycin, should be used until negative sputum cultures have been documented for at least 6 months. If the patient has severe parenchymal damage, high-grade resistance, or clinically advanced disease, also. consider clofazimine, amoxicillin/clavulanate, or clarithromycin, although there is little evidence supporting their efficacy in this setting. Routine monitoring includes monthly sputum smear and culture testing, monthly assessment of renal function and electrolyte levels, and liver function tests every 3 to 6 months.