title: The effect of ACE inhibitor and angiotensin II receptor antagonist therapy on serum uric acid levels and potassium homeostasis in hypertensive renal transplant recipients treated with CsA.
abstract: BACKGROUND
  The angiotensin II (AT II) type I receptor antagonist losartan has been reported to increase urinary uric acid and potassium excretion. These effects might be beneficial in cyclosporin (CsA)-treated renal transplant recipients, who frequently suffer from hyperuricaemia and hyperkalaemia.
  
  
  METHODS
  In this prospective, open, randomized, two-way cross-over study we included 13 hypertensive CsA-treated patients after renal transplantation and administered either the angiotensin-converting enzyme (ACE) inhibitors enalapril or losartan. Laboratory parameters, 24-h urinary protein excretion, and mean 24-h arterial blood pressure (MAP) were checked after 3 weeks treatment with enalapril, after a wash-out period of 2 weeks, and before and after a 3-week treatment course with losartan.
  
  
  RESULTS
  Both drugs slightly reduced MAP (losartan from 97+/-6 to 94+/-9 and enalapril to 93+/-8 mmHg). Serum potassium levels significantly increased during enalapril therapy (from 4.3+/-0.5 to 4.8+/-0.4 mmol/l, P<0.05), as did, although not significantly, uric acid concentrations (from 7.8+/-1.9 to 8.2+/-1.8 mg/dl, P=0.5). Losartan, on the contrary, only mildly affected serum potassium (4.3+/-0.5 vs 4.5+/-0.5 mmol/l, P=0.25) and serum uric acid decreased (from 7.8+/-2.4 to 7.3+/-1.8 mg/dl, P=0.6). Serum aldosterone and urinary aldosterone excretion were significantly reduced only during ACE inhibitor treatment, which might explain the variable effects on potassium homeostasis.
  
  
  CONCLUSIONS
  Losartan may be a useful agent to reduce blood pressure and serum uric acid levels in renal transplant recipients treated with CSA: Furthermore, in this high-risk population, the effects on serum potassium levels are less marked with losartan than with enalapril.
authors.affiliation: Division of Nephrology and Dialysis, Department of Medicine III, University of Vienna, Währinger Gürtel 18-20, A-1090 Vienna, Austria.
authors.forename: A
authors.initials: A
authors.lastname: Schmidt
authors.forename: U
authors.initials: U
authors.lastname: Gruber
authors.forename: G
authors.initials: G
authors.lastname: Böhmig
authors.forename: E
authors.initials: E
authors.lastname: Köller
authors.forename: G
authors.initials: G
authors.lastname: Mayer
mesh_terms: D000368:Aged; D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000627:therapeutic use*; D000959:Antihypertensive Agents / Q000627:therapeutic use; D001794:Blood Pressure / Q000187:drug effects; D018592:Cross-Over Studies; D016572:Cyclosporine / Q000627:therapeutic use*; D004656:Enalapril / Q000627:therapeutic use; D005260:Female; D006706:Homeostasis / Q000187:drug effects; D006801:Humans; D006973:Hypertension / Q000188:drug therapy*; D007166:Immunosuppressive Agents / Q000627:therapeutic use*; D016030:Kidney Transplantation; D019808:Losartan / Q000627:therapeutic use; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000097:blood*; D011446:Prospective Studies; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D014527:Uric Acid / Q000097:blood*
chemical_list: D057911:Angiotensin Receptor Antagonists; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D007166:Immunosuppressive Agents; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D014527:Uric Acid; D004656:Enalapril; D016572:Cyclosporine; D019808:Losartan; D011188:Potassium