Farmacocinética de ceftazidima en neonatos / Pharmacokinetics of ceftazidime in newborn infants

RESUMO

A pharmacokinetic study of ceftazidime was performed in newborn children. Six premature infants with a body weight up to 2000 g and with symptoms of pneumonia (Table 1) were treated with ceftazidime (50 mg/kg body weight) by endovenous route. Plasma concentrations of the antibiotic (Fig. 1) were determined by HPLC. A kinetic behavior was described through a compartment model independent analysis. The calculated parameters were as follows half-life (T1/2z = 4.05 +/- 0.81 h) apparent volume of distribution (Vz = 686.0 +/- 258.6 ml/kg), elimination rate constant (lambda z = 0.18 +/- 0.04h-1), area under curve (AUC = 464.4 +/- 139.1 mu gh/ml, mean residence time (MRT = 5.2 +/- 1.3 h), and total clearance (CI = 114.9 +/- 30.0 ml/h. kg) (Table 2). Good correlation was observed (r = 0.83, p < 0.05 between lambda z = and Vz). The loading and maintenance doses calculated for enterobacteria and P. aeruginosa were 15 and 13 mg/kg i.v. respectively each 12 h.