Acidosis and Hyperkalemia Caused By Losartan and Enalapril in Pediatric Kidney Transplant Recipients

Objectives: To evaluate the efficacy and safety of losartan and enalapril in pediatric kidney transplant recipients. Materials and Methods: A retrospective review was performed in 31 pediatric kidney transplant recipients who were treated with losartan (50 mg/d, oral) for 1 to 6 months because of mild hypertension and persistent proteinuria. All patients were treated concurrently with enalapril (5 or 10 mg daily, oral), and 12 patients (39%) also were treated with amlodipine (5 or 10 mg daily, oral). Demographic and clinical characteristics of the patients were reviewed. Results: Losartan use was associated with a significant decrease in mean systolic (before losartan was started, 123 +/- 14 mm Hg; before losartan was stopped, 111 +/- 10 mm Hg; P <= .001) and diastolic blood pressure (before losartan was started, 78 +/- 11 mm Hg; before losartan was stopped, 69 +/- 10 mm Hg; P <= .001) and urinary protein excretion (before losartan was started, 51 +/- 45 mg/m(2)/h; before losartan was stopped, 28 +/- 34 mg/m(2)/h; P <= .001). However, losartan therapy was associated with a significant mean increase in serum potassium level (before losartan was started, 4.0 +/- 0.4 mmol/L; before losartan was stopped, 5.7 +/- 0.5 mmol/L; P <= .001) and decrease in pH (before losartan was started, 7.35 +/- 0.0; before losartan was stopped, 7.23 +/- 0.0; P <= .001). Losartan was stopped because of hyperkalemia and acidosis earlier in patients who were on tacrolimus than cyclosporine immunosuppression (tacrolimus, 3 +/- 1 mo; cyclosporine, 4.7 +/- 0.8 mo; P <= .001). Conclusions: Losartan and enalapril may be beneficial in pediatric kidney transplant recipients by decreasing blood pressure and proteinuria, with maintenance of stable graft function, but may be associated with serious adverse events including hyperkalemia and life-threatening acidosis.