Pharmacokinetics Of Netilmicin In The Newborns With Gestational Ages Greater-Than-34 Weeks

Background. - Neonatal bacterial infections are potentially lethal. The infant must be started on an antibiotic regimen to cover the organisms most frequently implicated. Since the introduction of gentamicin therapy for neonatal infections, attention has focused on aminoglycoside pharmacokinetics in these very young patients. Patients and methods. - The pharmacokinetics parameters of netilmicin during its first administration were analysed in 22 newborn infants with a gestational age over 34 weeks, aged 1 to 3 days, in whom a maternofetal infection was suspected. Netilmicin was given intravenously at a dose of 6 mg/kg/day in two daily injections for 35 minutes. Blood concentrations of netilmicin were measured from samples taken 5, 15, 30, 60 minutes and 2 1/2, 5 1/5 and 11 1/2 hours after injection. The patients were also given cefotaxime plus ampicillin. Results. - The kinetics were bicompartimental: prematurity, proven infections and other perinatal factors influenced the pharmacologic parameters and it was not possible to define a predictive formula for antibiotic administration. Conclusion. - The blood levels of netilmicin must be monitored even in infants who were not born prematurely. Because of the large distribution volume and the long half-life, we propose a dose of 6-7.5 mg/kg given once daily.