A Retrospective Analysis of Vancomycin Pharmacokinetics in Korean Neonates

Abstract

Background : Vancomycin is commonly used in neonatal intensive care units (NICU) for the treatment of gram-positive bacterial infections. The aims of this study were to determine the pharmacokinetic parameters of vancomycin in Korean neonates and to assess the percentage of neonates who reached a therapeutic level (trough concentrations of 10 to 20 mg/L) with empirical vancomycin dosing according to the Neofax􀋓. Methods : This retrospective study reviewed data from 81 neonates admitted to the NICU. The elimination rate constant (Ke), half-life (T1/2), clearance (CL), and the extrapolated trough and peak levels were calculated using first-order pharmacokinetics and a one-compartment model. Results : Only 21% of the patients achieved therapeutic trough levels (10 to 20 mg/L) with initial dosing according to the Neofax􀋓. Vancomycin clearance was significantly correlated with postmenstrual age (PMA), postnatal age (PNA), weight, and serum creatinine (SCr) level. The recommended dosing regimen in neonates 27 weeks PMA was 10~15 mg/kg q12hr. For neonates in the 27 to 30 week PMA range, the recommended regimen was 15 mg/kg q12hr or 10 mg/kg q8hr for PNA 0~14 days, 10~13 mg/kg q8hr for PNA 14 days with SCr 0.6 mg/dL, and 10~15 mg/kg q12hr for PNA 14 days with SCr 0.6 to 1.5 mg/dL. For neonates in the 30 to 37 week PMA range, the recommended regimen was 10~13 mg/kg q8hr for PNA 0~14 days, 13 mg/kg q8hr or 10 mg/kg q6hr for PNA 14 days with SCr 0.6 mg/dL, and 15 mg/kg q12hr or 10 mg/kg q8hr for PNA 14 days with SCr 0.6 to 1.5 mg/dL. For neonates in the 37 to 44 week PMA range, the recommended regimen was 10~13 mg/kg q8hr for PNA 0~7 days, 13~15 mg/kg q6hr for PNA 7 days with SCr 0.6 mg/dL, and 13 mg/kg q8hr or 10 mg/kg q6hr for PNA 7 days with SCr 0.6 to 1.5 mg/dL. Sixty-three percent (51/81) of the neonates reached a therapeutic level with the new dosing regimen. Conclusions : The Neofax􀋓 vancomycin initial dosing regimen is insufficient for Korean neonates. Further studies are needed to validate the new dosing regimen suitable for achieving target therapeutic levels in Korean neonates.