title: Comparison of pharmacokinetic variables for creatinine and iohexol in dogs with various degrees of renal function.
abstract: OBJECTIVE
  To compare pharmacokinetics and clearances of creatinine and iohexol as estimates of glomerular filtration rate (GFR) in dogs with various degrees of renal function.
  
  
  METHODS
  50 Great Anglo-Francais Tricolor Hounds with various degrees of renal function.
  
  
  METHODS
  Boluses of iohexol (40 mg/kg) and creatinine (647 mg/kg) were injected IV. Blood samples were collected before administration and 5 and 10 minutes and 1, 2, 4, 6, and 8 hours after administration. Plasma creatinine and iohexol concentrations were assayed via an enzymatic method and high-performance liquid chromatography, respectively. A noncompartmental approach was used for pharmacokinetic analysis. Pharmacokinetic variables were compared via a Bland-Altman plot and an ANOVA.
  
  
  RESULTS
  Compared with results for creatinine, iohexol had a significantly higher mean ± SD plasma clearance (3.4 ± 0.8 mL/min/kg vs 3.0 ± 0.7 mL/min/kg) and a significantly lower mean volume of distribution at steady state (250 ± 37 mL/kg vs 539 ± 73 mL/kg), mean residence time (80 ± 31 minutes vs 195 ± 73 minutes), and mean elimination half-life (74 ± 20 minutes vs 173 ± 53 minutes). Despite discrepancies between clearances, especially for high values, the difference was < 0.6 mL/min/kg for 34 (68%) dogs. Three dogs with a low GFR (< 2 mL/min/kg) were classified similarly by both methods.
  
  
  CONCLUSIONS
  Plasma iohexol and creatinine clearances can be used interchangeably for screening patients suspected of having chronic kidney disease (ie, low GFR), but large differences may exist for dogs with a GFR within or above the reference range.
authors.affiliation: Unité de recherche clinique, Institut national polytechnique de Toulouse, Université de Toulouse, F-31076 Toulouse, France.
authors.forename: Cécile M
authors.initials: CM
authors.lastname: Collignon
authors.forename: Reidun
authors.initials: R
authors.lastname: Heiene
authors.forename: Yann
authors.initials: Y
authors.lastname: Queau
authors.forename: Brice S
authors.initials: BS
authors.lastname: Reynolds
authors.forename: Amanda J
authors.initials: AJ
authors.lastname: Craig
authors.forename: Didier
authors.initials: D
authors.lastname: Concordet
authors.forename: Nathaniel X
authors.initials: NX
authors.lastname: Harran
authors.forename: Unni
authors.initials: U
authors.lastname: Risøen
authors.forename: David
authors.initials: D
authors.lastname: Balouka
authors.forename: Mathieu R
authors.initials: MR
authors.lastname: Faucher
authors.forename: Knut A
authors.initials: KA
authors.lastname: Eliassen
authors.forename: Vincent
authors.initials: V
authors.lastname: Biourge
authors.forename: Hervé P
authors.initials: HP
authors.lastname: Lefebvre
mesh_terms: D000818:Animals; D003287:Contrast Media / Q000493:pharmacokinetics*; D003404:Creatinine / Q000097:blood / Q000493:pharmacokinetics*; D004283:Dog Diseases / Q000378:metabolism*; D004285:Dogs; D005260:Female; D005919:Glomerular Filtration Rate; D007472:Iohexol / Q000493:pharmacokinetics*; D007674:Kidney Diseases / Q000378:metabolism / Q000473:pathology / Q000662:veterinary*; D008297:Male
chemical_list: D003287:Contrast Media; D007472:Iohexol; D003404:Creatinine