Pharmacokinetics and dosing of arbekacin in preterm and term newborn infants.
BACKGROUND
The objective of the present study was to determine pharmacokinetic variables and to characterize a new initial dosing regimen of arbekacin (ABK) for preterm and term newborn infants.


METHODS
Subjects were 40 infants treated with ABK in a tertiary care neonatal unit over a period of 18 months. At birth, the infants were 23 5/7-40 0/7 weeks and weighed 530-3428 g. Serum ABK concentration was measured at two points in a course of treatment. Data were analyzed by a one-compartment model to obtain volume of distribution (Vd) and clearance (CL) of ABK. These variables were correlated with the patients' demographic and laboratory data. The new initial dosing regimen was determined based on these data.


RESULTS
Sixty pairs of blood samples were taken from the infants. They were divided into three groups: preterm early (PE), gestational age (GA) < 37 weeks and postnatal age (PNA) < 28 days; preterm late (PL), GA < 37 weeks and PNA >or= 28 days; and term (T), GA >or= 37 weeks and PNA < 28 days. The Vd was 0.50 +/- 0.02, 0.48 +/- 0.04, and 0.43 +/- 0.03 L/kg, and CL was 0.59 +/- 0.04, 1.12 +/- 0.10, and 0.78 +/- 0.09 mL/min per kg (mean +/- SEM) in PE, PL, and T, respectively. The new dosing regimen is 5 mg/kg every 48 h, 5 mg/kg every 24 h, and 4 mg/kg every 24 h for PE, PL, and T, respectively.


CONCLUSIONS
With the new dosing regimen, more infants achieved serum ABK levels within the optimal range than the conventional one.
Suzuki
Keiji
K
Division of Neonatology, Perinatal Center, St Marianna University School of Medicine, Yokohama City Seibu Hospital, Yokohama, Japan. dks@med.monash.edu.au
Tanikawa
Kouji
K
Matsuzaki
Takashi
T
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000097:blood / Q000493:pharmacokinetics*; D003982:Dibekacin / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics*; D005839:Gentamicins; D005865:Gestational Age; D006801:Humans; D007230:Infant, Low Birth Weight; D007231:Infant, Newborn; D007234:Infant, Premature
D000617:Aminoglycosides; D000900:Anti-Bacterial Agents; D005839:Gentamicins; D003982:Dibekacin; C031986:arbekacin