Short-course drug therapy for tuberculosis

The cost, patient compliance considerations, and toxicity of short-course chemotherapy (SCC) and conventional 18- to 24-month treatment regimens for pulmonary tuberculosis are compared; studies of the efficacy of SCC regimens are evaluated; and the future of SCC in the United States is examined. SCC is defined as treatment for nine months or less. A definite advantage of SCC over conventional therapy in terms of cost, patient compliance, or adverse effects has not been established. A series of studies conducted by the East African-British Medical Research Council documented the efficacy of various six-month, multiple-drug regimens that contain rifampin and verified the sterilizing activity of pyrazinamide during the first two months of therapy. The studies of the Hong Kong Chest Service and British Medical Research Council documented the efficacy of several intermittent drug regimens. Acceptable relapse rates were achieved with streptomycin, isoniazid, and pyrazinamide given two or three times a week for four or six months, preceded by a two-month, multiple-drug, daily regimen, and various four-drug, pyrazinamide-containing intermittent regimens. The benefit of pyrazinamide in reducing the relapse rate with SCC was confirmed by studies of the British Thoracic and Tuberculosis Association. Few studies of SCC have been conducted in the United States. Treatment practices in the United States are becoming more uniform, and SCC is being used more frequently for uncomplicated pulmonary tuberculosis. SCC will probably be used more widely in the future. Current guidelines of the Centers for Disease Control recommend treatment for nine months with isoniazid and rifampin, plus ethambutol in areas where resistance to isoniazid is common. In vitro data suggest that the addition of pyrazinamide may be more effective, but clinical experience with this drug in the United States is limited.