Pharmacokinetic and therapeutic monitoring of gentamicin serum concentration in neonates

: Pharmacokinetic analysis of gentamicin in 355 neonates hospitalized in the Clinical Dept. of Neonatology of the National Institute of Mother and Child in Warsaw was performed. The patients' group consisted of 119 premature and 236 full-term neonates, who were receiving gentamicin i.v. in the mean doses 4.461 +/- 0.921 ing/kg and 4.706 +/- 0.676 mg/kg, respectively. With use of the non-compartmental method, the following pharmacokinetic parameters were measured: biological half-life (t 0.5), elimination rate constant (k el), area under the curve (AUC), volume of distribution (V d) and total clearance (C T). Results differ considerably in term and preterm neonates and amount to: 11.25+/- 3.40 h-1, 0.0673 +/- 0.02 h-1, 233.7+/- 95.44 ug h/ml, 1.22 +/- 0.79 l/kg, 0.086 +/- 0.077 l/h/kg - for premature neonates versus 8.19 +/- 2.58 h, 0.089 +/- 0.02 h-1, 157.5 +/- 60.2 ug h/ml, 0.637 +/- 0.316 l/kg, 0.060 +/- 0.042 l/h/kg for full- term neonates. The analysis of pharmacokinetic parameters suggests that these findings may be already used as a preliminary basis of gentamicin population pharmacokinetics in both groups of neonates. The obtained results confirm that monitoring of gentamicin serum concentration helps to improve the treatment of neonates with this antibiotic. It was also found that the use of the dosing schedule of gentamicin with the dose intervals 36 or 48 h should guarantee adequate Cmax and Cmin without the need of routine monitoring of each patient in the premature neonate group.