DOSAGE & ADMINISTRATION Pyrazinamide should always be administered with other effective antituberculous drugs. It is administered for the initial 2 months of a 6-month or longer treatment regimen for drug-susceptible patients. Patients who are known or suspected to have drug-resistant disease should be treated with regimens individualized to their situation. Pyrazinamide frequently will be an important component of such therapy. Patients with concomitant HIV infection may require longer courses of therapy. Physicians treating such patients should be alert to any revised recommendations from CDC for this group of patients. Usual dose: Pyrazinamide is administered orally, 15 to 30 mg/kg once daily. Older regimens employed 3 or 4 divided doses daily, but most current recommendations are for once a day. Three grams per day should not be exceeded. The CDC recommendations do not exceed 2 g per day when given as a daily regimen (see table). Alternatively, a twice weekly dosing regimen (50 to 75 mg/kg twice weekly based on lean body weight) has been developed to promote patient compliance with a regimen on an outpatient basis. In studies evaluation the twice weekly regimen, doses of pyrazinamide in excess of 3 g twice weekly have been administered. This exceeds the recommended maximum 3 g/daily dose. However, an increased incidence of adverse reactions has not been reported. This table is taken from the CDC-American Thoracic Society joint recommendations. 4 Recommended Drugs for the Initial Treatment of Tuberculosis in Children and Adults Daily Dose * Drug Children Adults Isoniazid 10 to 20 mg/kg PO or IM 5 mg/kg PO or IM Rifampin 10 to 20 mg/kg PO 10 mg/kg PO Pyrazinamide 15 to 30 mg/kg PO 15 to 30 mg/kg PO Streptomycin 20 to 40 mg/kg IM 15 mg/kg † IM Ethambutol 15 to 25 mg/kg PO 15 to 25 mg/kg PO Doses based on weight should be adjusted as weight changes. In persons older than 60 yr of age the daily dose of streptomycin should be limited to 10 mg/kg with a maximal dose of 750 mg. Maximal Daily Dose in Children and Adults Drug Isoniazid 300 mg Rifampin 600 mg Pyrazinamide 2 g Streptomycin 1 g * Ethambutol 2.5 g In persons older than 60 yr of age the daily dose of streptomycin should be limited to 10 mg/kg with a maximal dose of 750 mg. Twice Weekly Dose Drug Children Adults Isoniazid 20 to 40 mg/kg Max. 900 mg 15 mg/kg Max. 900 mg Rifampin 10 to 20 mg/kg Max. 600 mg 10 mg/kg Max. 600 mg Pyrazinamide 50 to 70 mg/kg 50 to 70 mg/kg Streptomycin 25 to 30 mg/kg IM 25 to 30 mg/kg IM Ethambutol 50 mg/kg 50 mg/kg Definition of abbreviations: PO = per-orally; IM = intramuscularly.