title: Gentamicin and tobramycin pharmacokinetics in pediatric bone marrow transplant patients.
abstract: OBJECTIVE
  To describe the pharmacokinetic parameters of gentamicin and tobramycin in pediatric bone marrow transplant patients.
  
  
  METHODS
  Retrospective medical record review.
  
  
  METHODS
  Pediatric bone marrow transplant unit in a university teaching hospital.
  
  
  METHODS
  Pharmacokinetic parameters (apparent volume of distribution [Vd] in L/kg, half-life [t1/2] in h, elimination rate constant [ke] in h-1, clearance [Cl] in mL/min/1.73 m2 and mL/min/kg) calculated from serum concentrations.
  
  
  METHODS
  Thirty-three patients aged 15 years or less who underwent bone marrow transplant and received gentamicin or tobramycin.
  
  
  RESULTS
  Mean pharmacokinetic parameters were Vd 0.32 +/- 0.07 L/kg, t1/2 2.32 +/- 0.65 h, Cl 1.71 +/- 0.53 mL/min/kg, and Cl 86.2 +/- 24.5 mL/min/1.73 m2. Factors such as disease state, type of marrow graft, gender, or exposure to cyclosporine had no significant effect on pharmacokinetic parameters. Linear regression indicated a weak relationship between serum creatinine (SCr) and Cl in mL/min/kg (r = 0.59), but no relationship was found between SCr and Cl in mL/min/1.73 m2, between age and apparent Vd, or between SCr and apparent Vd. Models for estimating Cl and Ke developed by multiple regression were somewhat predictive (r = 0.7). Required calculated maintenance dosages to obtain therapeutic concentrations were 8, 7, and 6 mg/kg/d in children 6 or younger, 7-12, and 13-15 years, respectively.
  
  
  CONCLUSIONS
  The mean Cl and apparent Vd for all ages are similar to those reported in pediatric oncology patients who had not undergone marrow transplantation. Children 6 years or younger had lower than expected Cls and larger apparent Vds than did the older children. Dosages estimated to be necessary to achieve therapeutic concentrations were 6-8 mg/kg/d.
authors.affiliation: Blood and Marrow Stem Cell Transplantation Program, College of Pharmacy, University of Michigan, Ann Arbor 48109, USA.
authors.forename: P A
authors.initials: PA
authors.lastname: Jacobson
authors.forename: N J
authors.initials: NJ
authors.lastname: West
authors.forename: J
authors.initials: J
authors.lastname: Price
authors.forename: R J
authors.initials: RJ
authors.lastname: Hutchinson
mesh_terms: D000293:Adolescent; D000900:Anti-Bacterial Agents / Q000097:blood / Q000493:pharmacokinetics*; D016026:Bone Marrow Transplantation; D002648:Child; D002675:Child, Preschool; D005260:Female; D005839:Gentamicins / Q000097:blood / Q000493:pharmacokinetics*; D006207:Half-Life; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012189:Retrospective Studies; D014031:Tobramycin / Q000097:blood / Q000493:pharmacokinetics*
chemical_list: D000900:Anti-Bacterial Agents; D005839:Gentamicins; D014031:Tobramycin