To evaluate the pharmacokinetics and pharmacodynamic indices of pyrazinamide at doses of 15 and 25 mg kg−1 in children suffering from tuberculosis.METHODS
Twenty children with tuberculosis received pyrazinamide at a single dose of 25 mg kg−1 (group I) and 15 mg kg−1 (group II). Serial blood samples were collected and the drug concentrations were analyzed spectrophotometrically. The pharmacokinetic parameters were calculated and the duration of time for which pyrazinamide concentrations in serum remained above the pyrazinamide inhibitory concentrations of 20 μg ml−1 and 25 μg ml−1 was studied.RESULTS
The mean peak serum concentration was 42.4 ± 3.3 μg ml−1 (95% CI ± 6.5) and 38.6 ± 3.9 μg ml−1 (95% CI ± 7.7) in groups I and II, respectively. The elimination half-life was 9.3 ± 1.3 h and 10.5 ± 2.3 h (P = 0.6) and clearance was 0.06 ± 0.01 l h−1 kg−1 and 0.04 ± 0.01 l h−1 kg−1 (P = 0.08) in groups I and II, respectively. Pharmacokinetic parameters and PKPD indices were comparable with both the doses.CONCLUSIONS
The study indicates that comparable serum concentrations of pyrazinamide are attained with 25 mg kg−1 and 15 mg kg−1 doses in children. The elimination half-life was longer and volume of distribution greater in children than in the adult population.