Evaluation of Gentamicin Dosage Regimen and Route of Administration Based on Achieved Serum Concentrations in Neonates

Abstract

Purpose Combination antibiotics consisting beta-lactam and aminoglycoside are commonly utilized in the treatment of neonatal septicaemia. The aims of this study were (1) to determine safety and efficacy of the revised gentamicin dosage regimen and (2) to compare intravascular (IV) versus intramuscular (IM) route of gentamicin administration, in term of attaining peak and trough serum concentration targets. Methods This was a retrospective study from 2012 to 2017. All neonates who received gentamicin with therapeutic drug monitoring performed were included in this study. Data for all eligible neonates were collected from electronic medical records and included demographics, serum creatinine levels, the complete gentamicin dosing and concentration history. Results A total of 737 neonates who received the correct institutional gentamicin dosage regimen (± 5% of the intended dose) were included in this study. There were 635 trough concentrations (within 30 minutes prior to subsequent dose) and 430 peak concentrations (60 to 90 minutes post administration) included in the comparison of IV and IM route of administration. With the revised dosage regimen, 91% of peak and 98% of trough concentrations were found within therapeutic range. There was no difference in terms of proportion of trough concentrations within therapeutic range for IV as compared to IM (97.8 vs 98.6%, p = 0.556) while IM resulted in a higher proportion of peak concentrations within therapeutic range (86.1 vs 97.0%, p < 0.001). Conclusions The current institutional gentamicin dosage regimen is safe and effective in attaining therapeutic targets. Intramuscular injection can be an alternative route of administration for gentamicin in neonates.