Active tuberculosis in individuals infected with human immunodeficiency virus after isoniazid prophylaxis

A review was conducted in Haiti to determine the timing and outcome of acti ve tuberculosis (TB) in human immunodeficiency virus (HIV)-positive patient s who had previously received isoniazid (INH) prophylaxis. Of 1005 HIV-sero positive patients who completed INH prophylaxis, 14 (1.4%) subsequently had active TB diagnosed. The median interval between discontinuation of INH pr ophylaxis and TB diagnosis was 8 months for 6 patients receiving 6 months o f INH, 22 months for 5 patients receiving 12-24 months of INH, and 40 month s for 3 patients receiving 24-36 months of INH (P=.026). There is a postpro phylaxis effect on INH that is dependent upon the duration of therapy.