What is the recommended dosage of gentamicin (an aminoglycoside antibiotic) for newborns?

From the Guidelines

The recommended dosage of gentamicin for newborns is 5 mg/kg/dose IV q48 h for those with a gestational age of less than 30 weeks and postnatal age of less than 14 days, as stated in the most recent guidelines 1. This dosage may vary based on the gestational age and postnatal age of the newborn.

• For neonates with a gestational age of less than 30 weeks and postnatal age of more than 14 days, the recommended dosage is 5 mg/kg/dose IV q24 h.
• For those with a gestational age of 30-34 weeks and postnatal age of less than 14 days, the dosage is 5 mg/kg/dose IV q36 h.
• For neonates with a gestational age of more than 34 weeks, the recommended dosage is 5 mg/kg/dose IV q24 h. It is essential to adjust the dosing based on gestational age, postnatal age, and renal function, and to monitor therapeutic drug levels to minimize toxicity.
• Peak levels should be drawn 30 minutes after infusion completion, and trough levels should be obtained just before the next dose.
• Target peak concentrations should be 6-10 mcg/mL, and trough levels should be less than 2 mcg/mL. Gentamicin should be administered as a slow intravenous infusion over 30 minutes, and close monitoring of renal function is necessary during treatment due to the risk of nephrotoxicity and ototoxicity. Treatment duration typically ranges from 5-10 days, depending on the infection being treated, with reassessment after 48-72 hours based on clinical response and culture results. The guidelines from 1 provide the most up-to-date recommendations for gentamicin dosing in newborns, and should be consulted for specific guidance on dosing and administration.

From the FDA Drug Label

Infants and Neonates 7.5 mg/kg/day (2.5 mg/kg administered every eight hours). Premature or Full-Term Neonates One Week of Age or Less 5 mg/kg/day (2. 5 mg/kg administered every 12 hours).

The recommended dosage of gentamicin for newborns is 7.5 mg/kg/day (2.5 mg/kg administered every eight hours) for infants and neonates, and 5 mg/kg/day (2.5 mg/kg administered every 12 hours) for premature or full-term neonates one week of age or less 2.

From the Research

Gentamicin Newborn Dosage

The recommended dosage of gentamicin for newborns varies based on factors such as birth weight, gestational age, and postnatal age.

• The dosage of gentamicin for newborns can range from 2.5-5 mg/kg/day, depending on the specific circumstances of the patient 3, 4, 5.
• For immature babies with birth weights below 1500 g, the daily dose should not exceed 3 mg/kg, while term babies, especially during the second week of life, should be treated with a daily gentamicin dose of near 4 mg/kg/day 3.
• A once-daily dosing regimen of gentamicin in preterm and term newborns is safe and effective, with a reduced risk of serum drug concentrations falling outside the therapeutic range 4.
• Gentamicin serum levels should be monitored to ensure that trough levels are below 2 mg/l and peak levels are between 4 mg/l and 12 mg/l 3, 5.
• The optimal dosing regimen of gentamicin in newborns is still a matter of debate, and current guidelines may not always achieve effective peak concentrations or safe trough concentrations 6.

Factors Affecting Dosage

Several factors can affect the dosage of gentamicin in newborns, including:

• Birth weight: Newborns with lower birth weights may require lower doses of gentamicin 3, 5.
• Gestational age: Premature newborns may require lower doses of gentamicin due to their immature renal function 5.
• Postnatal age: The dosage of gentamicin may need to be adjusted based on the newborn's postnatal age 4, 5.
• Renal function: Newborns with impaired renal function may require lower doses of gentamicin or more frequent monitoring of serum levels 5.

Monitoring and Adjustment

• Gentamicin serum levels should be monitored regularly to ensure that the dosage is effective and safe 3, 4, 5.
• The dosage of gentamicin may need to be adjusted based on the results of serum level monitoring 3, 4, 5.
• Therapeutic drug monitoring is advised to maintain adequate serum concentrations, especially for treatment beyond 3 days 6.