Use of 4-mg/kg/24-hour empiric aminoglycoside dosing in preoperative neonates with congenital heart disease.

BACKGROUND: Empiric dosing of gentamicin has not been evaluated in critically ill neonates with unrepaired congenital heart disease (CHD). Many factors may alter gentamicin pharmacokinetics in this patient population and there are few data describing gentamicin dosing regimens in this patient population.
OBJECTIVE: To determine whether an empiric gentamicin dosing regimen for neonates achieves acceptable serum trough concentrations in neonatal patients with unrepaired CHD receiving alprostadil.
METHODS: Term neonates with unrepaired CHD who received gentamicin for empiric treatment of sepsis were identified over a 3-year period. Patients were included if they received gentamicin 4 mg/kg/dose every 24 hours, were receiving alprostadil for maintenance of a patent ductus arteriosus, and had at least one gentamicin serum trough concentration determined. Patients were evaluated to determine whether they achieved a serum trough concentration of <1 mg/L, and differences in patient characteristics were noted for those who achieved an appropriate trough concentration and those who did not.
RESULTS: Twenty-eight patients met study criteria, and 22% of patients had a trough gentamicin concentration of <1 mg/L at a mean (SD) time of 23.6 (0.3) hours after a dose. Few statistically significant differences in patient characteristics were noted for those who achieved an appropriate serum trough concentration and those who did not, and included Apgar scores at 1 minute and later day of life at admission.
CONCLUSIONS: Current empiric gentamicin dosing regimens may not be appropriate for critically ill neonates with unrepaired CHD. Routine serum concentration monitoring may be warranted in this population.