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

Resistance To	Drug to Stop	Drug to Add	Regimen	Total Duration
INH	INH	FQN	6 months RMP+EMB+PZA+FQN	6 months from date FQN started
INH	INH	FQN	2 months RMP+EMB+PZA+FQN then 4 months RMP+EMB+FQN	6 months from date FQN started
RMP	RMP	FQN	2 months daily INH+EMB+PZA+FQN then 10-16 months INH+EMB+FQN	18 months from date FQN started
RMP	RMP	None	2 months INH+EMB+PZA, then 16 months INH+EMB	18 months from date FQN started
EMB	EMB	None	2 months INH+RMP+PZA, then 4 months INH+RMP	6 months from start of therapy
PZA	PZA	None	2 months INH+RMP+EMB, then 7 months INH+RMP	9 months from start of therapy
INH+EMB	INH+EMB	FQN	6 months daily RMP+PZA+FQN	6 months from date FQN started
INH+PZA	INH+PZA	FQN	9 months RMP+EMB+FQN	9 months from date FQN started
INH+EMB+PZA	INH+EMB+PZA	FQN+injectable	2 months TMP+FQN+injectable, then 7 months RMP+FQN	9 months from date FQN started