title: Reduced elimination of cyclosporine A in elderly (>65 years) kidney transplant recipients.
abstract: BACKGROUND
  Physiologic functions that may affect pharmacokinetics of drugs are altered in elderly patients. The current study was performed to elucidate the effect of age on cyclosporine A (CsA) pharmacokinetics in renal transplant recipients.
  
  
  METHODS
  Twenty-five renal transplant recipients on CsA treatment were included in the study. CsA doses were adjusted by C2 monitoring. The patients were divided into two groups based on age; elderly: more than 65 years (n=11, mean 73 years) and younger: 18 to 64 years (n=14, mean 43 years). A full 12-hr pharmacokinetic profile was performed during stable phase. CsA whole blood and intracellular T-lymphocytes concentrations (first 6 hr) were measured. Genotyping of the CYP3A5*1/*3 and ABCB1 (C1236T, G2677T, C3435T) polymorphisms and quantification of whole blood mRNA ABCB1 expression were performed in all patients.
  
  
  RESULTS
  Elderly patients achieved target C2 levels with lower CsA doses than the younger patients (4.3+/-0.8 vs. 6.1+/-2.1 mg/day/kg, P=0.025) because of lower clearance of CsA (22.7+/-5.1 vs. 30.5+/-11.1 L/hr, P=0.031). Elderly patients also showed 44% higher intracellular-to-whole blood CsA ratio than younger patients (P=0.02). Neither the CYP3A5*1, the ABCB1 genotypes nor mRNA ABCB1 expression revealed any significant influence on CsA pharmacokinetics.
  
  
  CONCLUSIONS
  The clearance of CsA decreased with increasing age. In addition, elderly patients had a significant larger proportion of the whole blood CsA concentration located at the site of action (within T lymphocytes). This indicates that in elderly recipients it might be safe to aim for an even lower whole blood target levels than current guidelines propose.
authors.affiliation: Department of Pharmaceutical Biosciences, School of Pharmacy, University of Oslo, Oslo, Norway. pal.falck@farmasi.uio.no
authors.forename: Pål
authors.initials: P
authors.lastname: Falck
authors.forename: Anders
authors.initials: A
authors.lastname: Asberg
authors.forename: Karen-Therese
authors.initials: KT
authors.lastname: Byberg
authors.forename: Sara
authors.initials: S
authors.lastname: Bremer
authors.forename: Stein
authors.initials: S
authors.lastname: Bergan
authors.forename: Jan L E
authors.initials: JL
authors.lastname: Reubsaet
authors.forename: Karsten
authors.initials: K
authors.lastname: Midtvedt
mesh_terms: D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1 / Q000235:genetics; D000293:Adolescent; D000328:Adult; D000368:Aged; D001189:Aryl Hydrocarbon Hydroxylases / Q000235:genetics; D016572:Cyclosporine / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D065637:Cytochrome P-450 CYP2A6; D004334:Drug Administration Schedule; D005786:Gene Expression Regulation; D005838:Genotype; D006801:Humans; D007166:Immunosuppressive Agents / Q000009:adverse effects / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use; D016030:Kidney Transplantation / Q000276:immunology* / Q000502:physiology; D008657:Metabolic Clearance Rate; D008875:Middle Aged; D010865:Pilot Projects; D011446:Prospective Studies; D013601:T-Lymphocytes / Q000276:immunology; D055815:Young Adult
chemical_list: C513055:ABCB1 protein, human; D018435:ATP Binding Cassette Transporter, Subfamily B; D020168:ATP Binding Cassette Transporter, Subfamily B, Member 1; D007166:Immunosuppressive Agents; D016572:Cyclosporine; D001189:Aryl Hydrocarbon Hydroxylases; D065637:Cytochrome P-450 CYP2A6