title: Increase in renal vascular resistance after intake of cyclosporin A and tacrolimus and reversal by nitroglycerin spray: a study in patients with stable renal allograft function.
abstract: OBJECTIVE
  Acute effects of drug administration on renal arterial resistance index (RI) are still discussed controversially. In our study we investigated the immediate effects of cyclosporin A (CyA) and tacrolimus (FK-506) on renal arterial resistance indices in patients with stable graft function after renal transplantation. Additionally we studied the effects of nitroglycerin spray on resistance indices.
  
  
  METHODS
  RI was measured by color Doppler sonography at baseline, at 1 and 2 hours after intake of medication and 30 minutes after administration of nitroglycerin spray which followed the 2-hour measurement. 34 renal transplant recipients were examined. 16 patients received CyA, 18 patients received FK-506. Whole blood levels of calcineurin inhibitors were taken at each time point. Arterial blood pressure and heart rate were measured to assess possible systemic hemodynamic effects.
  
  
  RESULTS
  Mean RI values increased significantly in both groups 1 hour after calcineurin inhibitor intake and remained still significantly elevated after 2 hours. There was no significant increase of mean arterial blood pressure nor was there any correlation between whole blood levels of calcineurin inhibitors and mean RI. 30 minutes after administration of nitroglycerin spray, mean RI values decreased significantly to a level even below baseline. Mean arterial blood pressure also decreased after administration of nitroglycerin.
  
  
  CONCLUSIONS
  Renal RI values are markedly influenced by a recent intake of calcineurin inhibitors and vasoactive substances such as nitrates. This demonstrates the necessity of keeping standardized conditions when using RI as a tool in followup investigations after renal transplantation.
authors.affiliation: Clinic and Policlinic for Internal Medicine II - Nephrology, University of Regensburg, Regensburg, Germany. christian.weingart@klinik.uni-regensburg.de
authors.forename: C
authors.initials: C
authors.lastname: Weingart
authors.forename: T
authors.initials: T
authors.lastname: Leingärtner
authors.forename: T
authors.initials: T
authors.lastname: Bergler
authors.forename: B
authors.initials: B
authors.lastname: Krüger
authors.forename: C
authors.initials: C
authors.lastname: Böger
authors.forename: M
authors.initials: M
authors.lastname: Mack
authors.forename: B
authors.initials: B
authors.lastname: Banas
authors.forename: B K
authors.initials: BK
authors.lastname: Krämer
mesh_terms: D000328:Adult; D065095:Calcineurin Inhibitors; D016572:Cyclosporine / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007166:Immunosuppressive Agents / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D007668:Kidney / Q000187:drug effects / Q000502:physiology; D016030:Kidney Transplantation / Q000502:physiology; D008297:Male; D008875:Middle Aged; D005996:Nitroglycerin / Q000627:therapeutic use*; D012077:Renal Artery / Q000187:drug effects / Q000502:physiology; D016559:Tacrolimus / Q000097:blood / Q000493:pharmacokinetics / Q000627:therapeutic use*; D014655:Vascular Resistance / Q000187:drug effects; D014665:Vasodilator Agents / Q000627:therapeutic use
chemical_list: D065095:Calcineurin Inhibitors; D007166:Immunosuppressive Agents; D014665:Vasodilator Agents; D016572:Cyclosporine; D005996:Nitroglycerin; D016559:Tacrolimus