Results at 5 years of a controlled comparison of a 6-month and a standard 18-month regimen of chemotherapy for pulmonary tuberculosis.

The relapse rate up to 5 years after the start of chemotherapy with a 6-month regimen of daily streptomycin, isoniazid, and rifampin has been compared with the rate for a standard 18-month regimen of streptomycin, thiacetazone, and isoniazid for 2 months, followed by thiacetazone and isoniazid for 16 months daily. There were 5 bacteriologic relapses in 145 patients on the 6-month regimen, 1 occurring between 3 and 5 years after admission compared with 3 in 125 patients on the 18-month regimen, 1 occurring between 3 and 5 years.