Evaluation of gentamicin pharmacokinetics and dosing protocols in 195 neonates

John E. Murphy, Mauricio L. Austin, Reginald F. Frye

Research output: Contribution to journalArticle

30 Scopus citations

Abstract

Gentamicin pharmacokinetics and dosing protocols in neonates were studied. Demographic and pharmacokinetic data on 202 neonates treated with gentamicin at a 500-bed medical center were collected over a three-year period. Administered doses, gentamicin concentration measurements, and recorded times were used to calculate each patient's clearance, volume of distribution, elimination rate constant, and half-life. The performance of 15 dosing protocols, inducing 6 previously published ones and 9 developed on the basis of the study, was evaluated using the pharmacokinetic data. Of the 202 patients, 195 were included in the analysis. The mean ± S.D. clearance, volume of distribution, elimination rate constant, and half-life were 0.047 ± 0.015 L/hr/kg, 0.45 ± 0.11 L/kg, 0.107 ± 0.032 L/hr, and 7.19 ± 2.64 hours, respectively. Weight, urine output, gestational age, and postconceptional age (PCA) had the highest correlation with the pharmacokinetic values. Blood urea nitrogen concentration (BUN) and Apgar score were poor predictors of the pharmacokinetic values. There were no significant differences among patient subsets based on race and BUN, but subset analysis based on PCA did indicate significant differences. In simulations, the protocols based on the study patients tended to perform better than the literature protocols, with all but three achieving therapeutic goals in 75% or more of the neonates. Of the published protocols, Murphy and Carter's produced the greatest percentage of neonates with peaks from 5 to 10 mg/L and troughs of <2 mg/L. The devised protocols tended to perform poorly in producing troughs between 1 and 2 mg/L, yet performed comparatively well in providing therapeutic peaks from 5 to 10 mg/L.

Original languageEnglish (US)
Pages (from-to)2280-2288
Number of pages9
JournalAmerican Journal of Health-System Pharmacy
Volume55
Issue number21
StatePublished - Nov 1 1998

Keywords

  • Age
  • Aminoglycosides
  • Blood levels
  • Dosage schedules
  • Drugs, body distribution
  • Excretion
  • Gentamicin
  • Half- life
  • Pediatrics
  • Pharmacokinetics
  • Protocols
  • Weight

ASJC Scopus subject areas

  • Pharmacology
  • Health Policy

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