title: Usefulness of serum cystatin C to determine the dose of vancomycin in critically ill patients.
abstract: OBJECTIVE
  Serum creatinine (Scr) is not a reliable marker of renal function in critically ill patients because of an enhancement of protein catabolism, which makes it difficult to adjust the dosage of renally eliminated drugs such as antibiotics. This study aimed to investigate whether serum cystatin C (Scys-C) could be used as a reliable marker of renal function.
  
  
  METHODS
  We investigated whether Scys-C was a reliable marker of renal function in 56 critically ill patients. Subsequently, the usefulness of Scys-C to determine the initial loading and the maintenance dose of vancomycin was examined in 18 patients. Crea- tinine clearance (Ccr) was assessed from Scr and creatinine in urine collected over 24 h (24-h Ccr).
  
  
  RESULTS
  There was a good correlation between 24-h Ccr and 1/Scys-C (r(2) = 0.616), whereas less marked correlation was observed between 24-h Ccr and 1/Scr (r(2) = 0.221). On the other hand, vancomycin concentration was predicted from population pharmacokinetic parameters based on a two-compartment linear model. There were significant correlations between real trough concentrations of vancomycin and the values predicted from Scys-C using various equations (r(2) = 0.416-0.488), while less pronounced relationships were observed between real concentrations and the values predicted from Scr (r(2) = 0.134-0.187).
  
  
  CONCLUSIONS
  These findings suggest that Scys-C is a reliable marker reflecting renal function in critically ill patients and is applicable to determine the initial loading dose as well as the maintenance dose of vancomycin.
authors.affiliation: Department of Pharmacy, Gifu University Hospital, Gifu, Japan.
authors.forename: Akio
authors.initials: A
authors.lastname: Suzuki
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Imanishi
authors.forename: Shiho
authors.initials: S
authors.lastname: Nakano
authors.forename: Takashi
authors.initials: T
authors.lastname: Niwa
authors.forename: Tomofumi
authors.initials: T
authors.lastname: Ohmori
authors.forename: Kunihiro
authors.initials: K
authors.lastname: Shirai
authors.forename: Shozo
authors.initials: S
authors.lastname: Yoshida
authors.forename: Nobuyuki
authors.initials: N
authors.lastname: Furuta
authors.forename: Masao
authors.initials: M
authors.lastname: Takemura
authors.forename: Hiroyasu
authors.initials: H
authors.lastname: Ito
authors.forename: Ichiro
authors.initials: I
authors.lastname: Ieiri
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Seishima
authors.forename: Shinji
authors.initials: S
authors.lastname: Ogura
authors.forename: Yoshinori
authors.initials: Y
authors.lastname: Itoh
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000900:Anti-Bacterial Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D015415:Biomarkers / Q000097:blood; D003404:Creatinine / Q000097:blood / Q000378:metabolism*; D016638:Critical Illness; D055316:Cystatin C / Q000097:blood*; D004334:Drug Administration Schedule; D005260:Female; D006801:Humans; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D015203:Reproducibility of Results; D014640:Vancomycin / Q000008:administration & dosage* / Q000493:pharmacokinetics; D055815:Young Adult
chemical_list: D000900:Anti-Bacterial Agents; D015415:Biomarkers; D055316:Cystatin C; D014640:Vancomycin; D003404:Creatinine