Multidrug Resistance 

Treatment of MDRTB is  based on limited data; patients should be referred, if possible, to clinicians who have experience in treating such cases. MDRTB (resistant at least to isoniazid and rifampin) should be treated with > 4 drugs to which the organism is susceptible. Three drugs are usually given by mouth, the fourth by injection. When MDRTB is likely, or in patients with a history of previous treatment for TB, some clinicians start with combinations of 5, 6 or 7 drugs before laboratory susceptibility data are available.

Typically, empiric therapy for suspected MDRTB includes isoniazid, rifampin, ethambutol, pyrazinamide, an aminoglycoside (streptomycin, kanamycin or amikacin) or capreomycin, a fluoroquinolone (usually levofloxacin, moxifloxacin or gatifloxacin), and either cycloserine, ethion amide or aminosalicylic acid (PAS).