Prediction of the Distribution Volumes of Cefazolin and Tobramycin in Obese Children Based on Physiological Pharmacokinetic Concepts

Rie Koshida, Emi Nakashima, Noboru Taniguchi, Akira Tsuji, Leslie Z. Benet, Fujio Ichimura

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


So as to estimate the appropriate dose of antibacterial drugs in obese children, prediction of the volume of distribution in these children was attempted based on physiological pharmacokinetic concepts which had been constructed from results in normal-weight children. Serum concentration–time data after intravenous drip infusions of tobramycin and cefazolin were analyzed using noncompartmental analysis of obese children in whom the degree of obesity ranged from 30 to 80%. Volume of distribution at steady state (Vss) per total body weight of tobramycin was significantly less than that for normal-weight children (P < 0.05), whereas the value of cefazolin was almost equal to that for normal-weight children. The equation to express the difference of Vss between cefazolin and tobramycin obtained in normal-weight children failed in obese children, suggesting that there is a large decrease in the extracellular space in obese children exceeding the interindividual variations in normal-weight children. The Vss value (liter) for tobramycin was predicted by using the equation 0.261 · {ideal body weight (kg) + 0.4 · [total body weight (kg) – ideal body weight (kg)]}. The Vss value of cefazolin was predicted to be 0.3 · (predicted Vss of tobramycin) + 0.052 · total body weight (kg). A good correlation between the predicted and the observed Vss values was obtained.

Original languageEnglish
Pages (from-to)486-491
Number of pages6
JournalPharmaceutical Research: An Official Journal of the American Association of Pharmaceutical Scientists
Issue number6
Publication statusPublished - 1989 Jun
Externally publishedYes


  • cefazolin
  • intravenous administration
  • obese children
  • pharmacokinetics
  • tobramycin
  • volume of distribution

ASJC Scopus subject areas

  • Biotechnology
  • Molecular Medicine
  • Pharmacology
  • Pharmaceutical Science
  • Organic Chemistry
  • Pharmacology (medical)


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