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Gentamicin Dosing in Neonates with Normal Renal Function: Trough and Peak Levels
Kristin O'Connor1, Mark W Davies2,3, Pieter Koorts1
1Grantley Stable Neonatal Unit, Department of Neonatology, Royal Brisbane and Women's Hospital, Herston, Brisbane, QLD, 4029, Australia.
Insights
Increasing gentamicin dosage to 3.5 mg/kg improved therapeutic peak concentrations in neonates. The new regimen achieved optimal gentamicin levels in 98% of infants, ensuring better treatment outcomes.
Area of Science:
- Neonatal pharmacology
- Pediatric infectious diseases
- Antibiotic pharmacokinetics
Background:
- Gentamicin is a critical antibiotic for neonatal infections, necessitating careful therapeutic drug monitoring.
- Current dosing regimens may not consistently achieve target serum concentrations, impacting treatment efficacy and safety.
Purpose of the Study:
- To evaluate the effectiveness of a revised gentamicin dosing regimen in neonates.
- To determine the incidence of subtherapeutic peak and toxic trough gentamicin concentrations.
- To optimize gentamicin dosing for improved therapeutic outcomes in neonates.
Main Methods:
- A prospective cohort study involving neonates with normal renal function receiving gentamicin.
- Comparison of two gentamicin IV dosing regimens: 2.5 mg/kg vs. 3.5 mg/kg, with adjusted intervals based on gestational age.
- Assessment of serum gentamicin trough (≥ 2 mg/l) and peak (5-12 mg/l) concentrations.
Main Results:
- The initial 2.5 mg/kg regimen showed suboptimal peak concentrations in 23% of neonates < 30 weeks GA and 13% of those ≥ 30 weeks GA.
- The revised 3.5 mg/kg regimen achieved therapeutic peak concentrations in 98% of neonates.
- The 3.5 mg/kg regimen resulted in non-toxic trough concentrations in 86% of neonates.
Conclusions:
- The initial gentamicin regimen of 2.5 mg/kg was inadequate for achieving therapeutic peak levels in neonates.
- Increasing gentamicin dosage to 3.5 mg/kg significantly improved the achievement of therapeutic peak concentrations.
- The adjusted 3.5 mg/kg regimen demonstrated a favorable safety profile with predominantly non-toxic trough concentrations.
Abstract:
BACKGROUND AND OBJECTIVE: Gentamicin is commonly used in neonates, and it requires drug concentration monitoring. The objective of this study was to determine the extent of high trough (≥ 2 mg/l) and therapeutic peak serum gentamicin concentrations (5-12 mg/l) using our current gentamicin regimen and to adjust the dosing regimen accordingly and reassess.
Methods:
This was a prospective cohort study of neonates, with normal renal function, who were prescribed gentamicin. Group 1: March 2014-July 2017-gentamicin intravenous (IV) 2.5 mg/kg given every 36 h if < 30 weeks gestational age (GA) and every 24 h if ≥ 30 weeks GA; Group 2: August 2019-February 2020-gentamicin IV 3.5 mg/kg given every 36 h if < 30 weeks GA and every 24 h if ≥ 30 weeks GA. We assessed the number of neonates with aberrant trough and peak serum gentamicin concentrations.
Results:
Forty-eight neonates < 30 weeks GA and 34 ≥ 30 weeks GA were given 2.5 mg/kg gentamicin. Eleven (23%) neonates < 30 weeks GA and four (13%) ≥ 30 weeks GA had subtherapeutic peak concentrations (< 5 mg/l); none had supratherapeutic (> 12 mg/l) or toxic trough concentrations (≥ 2 mg/l). Forty-four neonates < 30 weeks GA and 54 ≥ 30 weeks GA were given 3.5 mg/kg gentamicin. Eighty-four (86%) had non-toxic trough concentrations (< 2 mg/l). One (1%) < 30 weeks GA neonate had subtherapeutic (< 5 mg/l) and one (1%) neonate ≥ 30 weeks GA had supratherapeutic (> 12 mg/l) peak concentrations.
Conclusions:
Gentamicin regimen of 2.5 mg/kg given every 36 h for neonates < 30 weeks GA and every 24 h for neonates ≥ 30 weeks GA was suboptimal at achieving therapeutic gentamicin peak. Increasing the dosage to 3.5 mg/kg achieved therapeutic peak concentrations in 98% and non-toxic trough concentrations in 86% of all neonates (prior to dose interval adjustment).
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