title: New concepts in cyclosporine pharmacokinetic and dynamic monitoring: the impact of concomitant immunosuppression on target C2 concentrations.
abstract: BACKGROUND
  There is a correlation between cyclosporine (CsA) pharmacokinetics (PK) and pharmacodynamics (PD), especially 2 hours after drug administration.
  
  
  OBJECTIVE
  To evaluate the relationship between CsA PK and PD profiles in two groups of stable renal transplant patients treated with CsA alone or CsA plus mycophenolate mofetil (CsA+MMF), so as to define the best target for C2 and clarify the impact of concomitant immunosuppression.
  
  
  METHODS
  Thirty-eight stable renal transplant recipients were treated with CsA (n=20) or CsA+MMF (n=18). Twelve nontreated normal healthy controls (NHC) were also included. Calcineurin activity (CNa), IL-2 production, and CsA levels were measured at 0 and 2 hours postdose.
  
  
  RESULTS
  There were no significant differences in median CsA C2 values and CNa between the CsA alone and the CsA+MMF groups (388 microg/L and 497.5 microg/L and CNa 2h; 3.92% alkaline phosphatase [AP]; 3.94% AP, respectively). In vitro production of IL-2 was significantly lower in the CsA+MMF group than in the CsA group (median IL-2 2h: 280.52 ng/L, 169.48 ng/L, P<.001). The correlations (r) between C2 and CNa 2h were: CsA r=0.74; CsA+MMF r=0.84 (P<.001 in both cases).
  
  
  CONCLUSIONS
  In stable renal transplant patients, median CsA C2 values below 500 microg/L were associated with inhibition of CNa and IL-2 synthesis. CNa and IL-2 production may be good biological markers of CsA immunosuppression. The measurement of CNa depends mainly on CsA concentration, whereas in vitro IL-2 production reflects the effect of both CsA and MMF. Further studies are necessary to define the optimal C2 target concentration and the possible impact of concomitant immunosuppression.
authors.affiliation: Department of Servei de Farmacologia y Toxicologia, IDIBAPS, Hospital Clinic, Universitat de Barcelona, Barcelona, Spain. mbrunet@clinic.ub.es
authors.forename: M
authors.initials: M
authors.lastname: Brunet
authors.forename: O
authors.initials: O
authors.lastname: Millán
authors.forename: O
authors.initials: O
authors.lastname: Jiménez
authors.forename: J M
authors.initials: JM
authors.lastname: Campistol
authors.forename: E
authors.initials: E
authors.lastname: Vidal
authors.forename: I
authors.initials: I
authors.lastname: Rojo
authors.forename: F
authors.initials: F
authors.lastname: Oppenheimer
authors.forename: V
authors.initials: V
authors.lastname: Fortuna
authors.forename: J
authors.initials: J
authors.lastname: Martorell
mesh_terms: D065095:Calcineurin Inhibitors; D016572:Cyclosporine / Q000097:blood / Q000493:pharmacokinetics* / Q000627:therapeutic use*; D004347:Drug Interactions; D004359:Drug Therapy, Combination; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000276:immunology* / Q000502:physiology; D008657:Metabolic Clearance Rate; D009173:Mycophenolic Acid / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D012016:Reference Values; D013997:Time Factors
chemical_list: D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D009173:Mycophenolic Acid