title: Pharmacokinetic Profile of Twice- and Once-daily Tacrolimus in Pediatric Kidney Transplant Recipients.
abstract: BACKGROUND
  The aim of this study was to assess the differences in pharmacokinetic (PK) profiles after the 1:1 ratio-based conversion from a twice-daily to a once-daily tacrolimus formulation (TD-TAC and OD-TAC, respectively) in pediatric recipients of kidney transplants.
  
  
  METHODS
  TD-TAC was initially administered to 29 pediatric patients who underwent kidney transplantations between April 2010 and September 2015 and were then subsequently switched to OD-TAC. The switch dose ratio was 1:1, and the 24-hour complete PK parameter assessment was performed before and after the regimen was changed from TD-TAC to OD-TAC.
  
  
  RESULTS
  The mean total daily dose at baseline was 5.5 ± 2.9 mg (0.18 ± 0.10 mg/kg body weight). Consecutive PK studies revealed no significant difference in the mean time to achieve maximum concentrations and the area under the concentration-time curve from 0 to 24 hours (AUC0-24) of both drug formulations. However, the mean trough concentration (Cmin) and the maximum concentration of OD-TAC were 22% and 6% lower and higher, respectively, than those of TD-TAC. Therefore, a better correlation was observed between the AUC0-24and Cminof OD-TAC than between those of TD-TAC.
  
  
  CONCLUSIONS
  After the change from TD-TAC to OD-TAC, the AUC0-24values were equivalent despite a 22% reduction in Cmin. Cminmay therefore be an excellent predictor in the therapeutic drug monitoring of OD-TAC because of its superior correlation with AUC0-24.
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan; Department of Pediatric Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Takahashi
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan; Department of Pediatric Nephrology, Toho University Faculty of Medicine, Tokyo, Japan. Electronic address: shishido@med.toho-u.ac.jp.
authors.forename: S
authors.initials: S
authors.lastname: Shishido
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hyodo
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yonekura
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nihei
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Itabashi
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Muramatsu
authors.affiliation: Department of Pediatric Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Hamasaki
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: T
authors.initials: T
authors.lastname: Kawamura
authors.affiliation: Department of Nephrology, Toho University Faculty of Medicine, Tokyo, Japan.
authors.forename: A
authors.initials: A
authors.lastname: Aikawa
mesh_terms: D000293:Adolescent; D019540:Area Under Curve; D002648:Child; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D016903:Drug Monitoring; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage / Q000493:pharmacokinetics*; D016030:Kidney Transplantation; D008297:Male; D016559:Tacrolimus / Q000008:administration & dosage / Q000493:pharmacokinetics*; D013997:Time Factors
chemical_list: D007166:Immunosuppressive Agents; D016559:Tacrolimus