Drug-resistant tuberculosis

• Mycobacterium tuberculosis infection that is resistant to both first-line drugs, isoniazid and rifampin

Classification

• Multidrug resistant tuberculosis (MDR-TB): resistance to isoniazid and rifampicin
• Extensively drug-resistant tuberculosis (XDR-TB): resistance to at least isoniazid and rifampicin, and to any fluoroquinolone, and to any of the three second-line injectables
• Totally drug-resistant tuberculosis (TDR-TB): not well-defined

Management

• 8 months of an intensive four-drug regimen that includes any four drugs to which it is susceptible, in order of preference:
  • Any first-line agents to which it is still susceptible
  • A fluoroquinolone (except ciprofloxacin)
  • An injectable: kanamycin, or other parenteral agent
  • Other second-line agents, starting with ethionamide
• Followed by 12 months of a less intensive regimen (at least three effective drugs), for a total of at least 20 months