Study Objective: To evaluate the efficacy and toxicity of a 62-dose, four-drug, 6-month, and directly observed regimen for treatment of pulmonary and extrapulmonary tuberculosis.
Design: An open, nonblinded clinical trial, with intended follow-up of patients for 36 months after the completion of therapy.
Setting: A metropolitan tuberculosis clinic in a public health department.
Patients: From March 1981 through April 1989, we enrolled 160 patients with suspected or known tuberculosis; 35 of these patients were excluded from the analysis.
Interventions: Isoniazid, rifampin, pyrazinamide, and streptomycin were administered daily for 2 weeks; these drugs were then given in higher doses twice weekly for 6 weeks, followed by isoniazid and rifampin twice weekly for 18 weeks. A total of 62 doses were administered, and all therapy was directly observed by a nurse or an outreach worker.
Measurements and Main Results: Of the 125 evaluable patients, 101 (81%) had pulmonary tuberculosis, 7 (6%) had both pulmonary and extrapulmonary involvement, and 17 (13%) had extrapulmonary disease only. Seventy-one (57%) patients had a history of recent alcoholism. There were two relapses (1.6% ± 2.2%), occurring 6 and 56 months after the completion of therapy. The time at which sputum samples became culture negative in pulmonary patients ranged from 1 to 19 weeks (median, 4.6 weeks); 40% ± 9.6% of patients were culture-negative after 4 weeks of therapy, 75% ± 8.5% after 8 weeks, 94% ± 4.7% after 12 weeks, 97% ± 3.3% after 16 weeks, and 100% after 20 weeks. Adverse drug reactions included hyperuricemia (> 178 µmol/L [3 mg/dL] above normal) secondary to pyrazinamide in 80 patients (64%), twofold or greater elevations of aspartate aminotransferase in 21 patients (17%), 1.5-fold or greater elevations of alkaline phosphatase in 33 patients (27%), cutaneous abnormalities in 8 patients (6%), nausea in five patients (4%), and dizziness in 1 patient (1%).
Conclusions: This 62-dose, largely twice-weekly tuberculosis treatment regimen is efficacious and relatively nontoxic and is especially useful for patients in whom directly observed therapy is indicated.