The effectiveness of a 9-month regimen of isoniazid alone versus 3- and 4-month regimens of isoniazid plus rifampin for treatment of latent tuberculosis infection in children: results of an 11-year randomized study.

BACKGROUND A 9-month course of isoniazid monotherapy is currently recommended for the treatment of latent tuberculosis infection (LTBI) and has been shown to be effective in both children and adults. Reduced compliance with this regimen has forced physicians to explore shorter regimens. The aim of this study was to compare 3- and 4-month combination regimens of isoniazid plus rifampin with a 9-month regimen of isoniazid monotherapy for the treatment of LTBI in children. METHODS This prospective, randomized, controlled study was conducted over an 11-year period (1995-2005). In period 1 (1995-1998), 232 patients received isoniazid therapy for 9 months (group A), and 238 patients received isoniazid and rifampin for 4 months (group B). In period 2 (1999-2002), 236 patients were treated with isoniazid and rifampin for 4 months (group C), and 220 patients received the same regimen for 3 months (group D). All patients were observed for > or = 3 years. RESULTS Overall compliance with treatment was good, but patients who received isoniazid monotherapy were less compliant than were those who received short-course combination therapy (P=.011, for group A vs. group B; P=.510, for group C vs. group D). No patient in any group developed clinical disease during the follow-up period. New radiographic findings suggestive of possible active disease were more common in patients who received isoniazid monotherapy (24%) than in those treated with shorter regimens (11.8%, 13.6%, and 11% for groups B, C, and D, respectively; P=.001 for group A vs. group B; P=.418 for group C vs. group D). Serious drug-related adverse effects were not detected. CONCLUSIONS Short-course treatment with isoniazid and rifampin for 3-4 months is safe and seems to be superior to a 9-month course of isoniazid monotherapy.