title: Effect of cyclosporine on mycophenolic acid trough levels in kidney transplant recipients.
abstract: BACKGROUND
  Triple drug treatment consisting of mycophenolate mofetil (MMF), in a standard dose of 2 g daily, combined with cyclosporine (CsA) and prednisone, has become the standard immunosuppressive regimen after kidney transplantation in many centers. The need for therapeutic drug monitoring of mycophenolic acid (MPA) has not yet been established. Several drug interactions with MMF are known. We investigated the influence of CsA withdrawal on MPA trough levels in renal transplant patients.
  
  
  METHODS
  Fifty-two patients were treated with 1 g of MMF twice daily, and prednisone and CsA targeted between 125 and 175 ng/ml for 6 months after transplantation. At 6 months after transplantation, 19 patients were randomized for continuation of triple therapy (group A), 19 patients discontinued CsA (group B), and 14 patients discontinued prednisone (group C). We compared 12-hr fasted MPA trough levels at 6 and 9 months after transplantation within and between these groups.
  
  
  RESULTS
  MPA trough levels during treatment with CsA, MMF, and prednisone were significantly lower than those during treatment with MMF and prednisone only (group B); median levels were 1.87 mg/L (range: 0.56-5.27) vs. 3.16 mg/L (range: 0.32-7.78), respectively (P=0.002). MPA trough levels in groups A and C did not change between 6 and 9 months after transplantation; group A median levels were 1.87 (range: 0.31-4.32) vs. 1.53 mg/L (range: 0.36-3.70), and group C median levels were 1.62 (range: 0.69-10.34) vs. 1.79 mg/L (range: 0.54-6.00), respectively. At 9 months after transplantation, patients in whom CsA was discontinued had higher MPA trough levels as compared with patients who continued the use of triple therapy (P=0.001) or patients in whom steroids were withdrawn (P=0.014).
  
  
  CONCLUSIONS
  A significant increase of MPA trough levels was found after discontinuation of CsA (6 months after transplantation), resulting in almost a doubling of MPA trough levels at 9 months after transplantation. This resulted in increased MPA levels in patients without CsA as compared to MPA levels in patients continuing triple therapy or discontinuing prednisone.
authors.affiliation: Department of Internal Medicine I, University Hospital Rotterdam, The Netherlands. smakgregoor@inw1.azr.nl
authors.forename: P J
authors.initials: PJ
authors.lastname: Gregoor
authors.forename: R G
authors.initials: RG
authors.lastname: de Sévaux
authors.forename: R J
authors.initials: RJ
authors.lastname: Hené
authors.forename: C J
authors.initials: CJ
authors.lastname: Hesse
authors.forename: L B
authors.initials: LB
authors.lastname: Hilbrands
authors.forename: P
authors.initials: P
authors.lastname: Vos
authors.forename: T
authors.initials: T
authors.lastname: van Gelder
authors.forename: A J
authors.initials: AJ
authors.lastname: Hoitsma
authors.forename: W
authors.initials: W
authors.lastname: Weimar
mesh_terms: D016572:Cyclosporine / Q000627:therapeutic use*; D004334:Drug Administration Schedule; D016903:Drug Monitoring; D004359:Drug Therapy, Combination; D017248:Enzyme Multiplied Immunoassay Technique; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D016030:Kidney Transplantation / Q000276:immunology*; D009173:Mycophenolic Acid / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D011241:Prednisone / Q000627:therapeutic use; D013997:Time Factors
chemical_list: D007166:Immunosuppressive Agents; D016572:Cyclosporine; D009173:Mycophenolic Acid; D011241:Prednisone