title: Two controlled studies of the efficacy of isoniazid alone in preventing relapse in patients with bacteriologically quiescent pulmonary tuberculosis at the end of one year of chemotherapy.
abstract: An earlier report showed that, in patients with bacteriologically quiescent pulmonary tuberculosis at the end of 1 year of chemotherapy, isoniazid alone in a single daily dose of 150-200 mg, given as maintenance therapy in the second year, did not markedly prevent relapse over a 4-year period of follow-up in patients who had had residual cavitation (the "open-negative" syndrome) at 1 year, but was highly effective in patients who had not. As a result of these findings, two controlled studies, reported here, were undertaken.The first study was undertaken in patients with bacteriologically quiescent disease and residual cavitation at 1 year, and investigated the value of isoniazid in a higher daily dose (400 mg) throughout the second year; this is known to be the optimum therapeutic dose when isoniazid is prescribed alone for 1 year in the initial treatment of the disease. The second study was carried out in patients with bacteriologically quiescent disease and no residual cavitation at 1 year, and sought to determine the value of a shorter duration (6 months) of chemotherapy in the second year with a daily dose of 300 mg of isoniazid. Neither of the two isoniazid regimens was highly satisfactory, although both appeared to have had some effect in preventing relapse during the 4-year period of follow-up.
mesh_terms: D002986:Clinical Trials as Topic; D005500:Follow-Up Studies; D006801:Humans; D007194:India; D007538:Isoniazid / Q000008:administration & dosage* / Q000627:therapeutic use; D012008:Recurrence; D014397:Tuberculosis, Pulmonary / Q000188:drug therapy* / Q000517:prevention & control
chemical_list: D007538:Isoniazid