Abstract
Gentamicin toxicity and efficacy studies have indicated desired peak and trough serum concentrations of 4-12 mcg/ml and less than 2 mcg/ml, respectively. Choosing an appropriate dose and dosage interval for premature infants is complicated by decreasing glomerular function with decreasing gestational age. We tested a regimen in which 24 infants less than 7 days of age,who were born between 26 and 36 weeks of gestation, received 2.5 mg/kg of gentamicin intravascularly every 18 hours. Trough serum gentamicin concentrations exceeded 2 mcg/ml in 33%; peak serum concentrations exceeded 12 mcg/ml in none but were less than 4 mcg/ml in 12.5%. Regression analysis of the data revealed inverse linear correlations between peak and trough serum gentamicin concentrations and gestational age (p<0.01 and p<0.05, respectively). Using these relationships a mathematical model was derived for calculating optimal gentamicin dose and dosage interval based on gestational age (G, in weeks):
Initial dose (mg/kg) ė 4.2 + 0.038 G
Subsequent doses (mg/kg) ė 3.4 + 0.031 G
Dosage interval (hours) ė 50 − 0.76 G
This regimen is designed to yield peak and trough serum concentrations of 8 mcg/ml and 1.5 mcg/ml, respectively. We conclude that the observed variations in gentamicin serum concentrations in premature neonates warrants the use of dosage regimens based on estimated gestational age. Additional clinical experience is needed to confirm the validity of these dosage recommendations.
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Lugo, E., Smith, F. & Rawlings, J. GENTAMICIN IN PREMATURE NEONATES: A DOSAGE REGIMEN BASED ON MATURITY. Pediatr Res 18 (Suppl 4), 333 (1984). https://doi.org/10.1203/00006450-198404001-01439
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DOI: https://doi.org/10.1203/00006450-198404001-01439