10.4 Duration of MDR-TB regimens

10.4.1 Intensive phase

Duration of intensive phase is guided by culture. The injectable agent should be continued for at least 8 months1 and at least 4 months after the patient becomes culture negative – which ever is longer.

The use of an individualized approach which reviews the cultures, smears, X-rays and the patient’s clinical status may also aid in deciding whether or not to continue an injectable agent longer than the above recommendation, particularly in the case of patients for whom the susceptibility pattern is unknown, effectiveness is questionable for an agent(s) or extensive or bilateral pulmonary disease is present.

A change to intermittent therapy with the injectable agent (3 times weekly) is done when signs of toxicity are noticed. Three times a week therapy is recommended in patients after 6 months of an injectable agent and who have had culture conversion, as toxicity becomes a greater risk to patients with longer periods of the injectable agent.

10.4.2 Length of treatment

The duration of treatment is guided by culture. It is recommended continuing therapy for a minimum of 20 months1 and at least 18 months after the patient becomes culture negative.

Extension of therapy to 24 months may be indicated in chronic cases with extensive pulmonary damage.