title: Twelve-month evaluation of the clinical pharmacokinetics of total and free mycophenolic acid and its glucuronide metabolites in renal allograft recipients on low dose tacrolimus in combination with mycophenolate mofetil.
abstract: BACKGROUND
  The establishment of a rationale for therapeutic drug monitoring for mycophenolic acid (MPA) and outlining a therapeutic window remains a challenging task in renal transplantation. Furthermore, the pharmacokinetic characteristics of free and total MPA and its glucuronides depend directly or indirectly on graft function and the type of co-administered calcineurin-inhibitor.
  
  
  METHODS
  The authors conducted a prospective 12-month multicenter pharmacokinetic study on MPA (MPA, free MPA, free fraction MPA) and its metabolites (MPAG, Acyl-MPAG). The aim of this study was to examine the long-term pharmacokinetic characteristics of MMF when combined with tacrolimus in renal allograft recipients and to identify a possible relationship between these pharmacokinetic parameters and clinical outcome parameters.
  
  
  RESULTS
  They have demonstrated that in renal transplant recipients MPA, free MPA, Acyl-MPAG and MPAG have a particular pharmacokinetic profile when combined with tacrolimus which differs from the combination with CsA. They could not establish a relationship between pre-dose trough concentration of MPA and its metabolites and clinical efficacy endpoints and drug-related adverse events, except for anemia.
  
  
  CONCLUSIONS
  These findings suggest that trough plasma concentration monitoring of MPA and its metabolites might not provide a useful clinical tool for guiding MMF dose adjustments to avoid drug-related toxicity. More extensive pharmacokinetic measurements like area under the concentration curves might be necessary for routine therapeutic drug monitoring of MMF.
mesh_terms: D000328:Adult; D000368:Aged; D019540:Area Under Curve; D004359:Drug Therapy, Combination; D005260:Female; D005965:Glucuronates / Q000493:pharmacokinetics*; D020719:Glucuronides; D006084:Graft Rejection / Q000517:prevention & control; D006801:Humans; D007166:Immunosuppressive Agents / Q000008:administration & dosage* / Q000493:pharmacokinetics; D016030:Kidney Transplantation; D008297:Male; D008875:Middle Aged; D009173:Mycophenolic Acid / Q000008:administration & dosage* / Q000031:analogs & derivatives* / Q000493:pharmacokinetics*; D011446:Prospective Studies; D016559:Tacrolimus / Q000008:administration & dosage*; D014184:Transplantation, Homologous
chemical_list: D005965:Glucuronates; D020719:Glucuronides; D007166:Immunosuppressive Agents; C113145:mycophenolic acid glucuronide; D009173:Mycophenolic Acid; D016559:Tacrolimus