Gentamicin Pharmacokinetics and Optimal Dosage in Infant Patients: A Case Report and Literature Review

Abstract

Gentamicin is an aminoglycoside antibiotic that is mostly used for the pediatric population. While the pediatric population is classified into neonates, infants, children, and adolescents based on developmental or maturational changes, infants are often overlooked in research. Three infant cases receiving gentamicin are presented to illustrate the pharmacokinetics and optimum dosage of gentamicin. Three infant patients received gentamicin (5.6–7.5 mg/kg/day) for urinary tract infections (UTIs) or bacteremia caused by Enterobacter aerogenes. The trough (Cmin) and peak (Cpeak) concentrations of gentamicin were 0.2–1.8 and 8.9 mg/L, respectively. The Cmin of a patient receiving gentamicin at 9.0 mg/kg/day was 3.3 mg/L, and the patient showed a decrease in urinary volume. The other two patients fully recovered from the infection and did not experience any adverse events. Additionally, we reviewed three studies regarding infant patients receiving gentamicin. The studies used gentamicin therapy for Gram-negative pathogen infections and UTIs caused by Escherichia coli and Enterococcus faecalis. The Cmin and Cpeak of patients receiving gentamicin at 2.2–7.5 mg/kg/day were 0.58–2.15 mg/kg and 4.67–8.88 mg/L, respectively. All patients were cured without any adverse events. Gentamicin dosages below 7.5 mg/kg/day may be effective and safe for use in infant patients. However, the optimal dosing regimen of gentamicin in infant patients is controversial, and limited data are available.

Pragmatic physiologically-based pharmacokinetic modeling to support clinical implementation of optimized gentamicin dosing in term neonates and infants: proof-of-concept

“…Especially in preterm neonates, several popPK models have been developed, and also term neonates in their first week of life were extensively studied (19). Older neonates and young infants, however, are less studied, despite reported large dose ranges of 4.5-7.5 mg/kg every 24 h (19,20). This variation in dosing partially reflects the wide variability in pharmacokinetics (PK), as body composition and organ maturation change tremendously during neonatal and infant periods (21).…”