Serum potassium concentrations in cyclosporine- and azathioprine-treated renal transplant patients.

Hyperkalemia was commonly observed in successful renal transplant patients treated with cyclosporine and prednisone. At 1, 3 and 6 months after transplantation, 13 of 50, 9 of 50, and 5 of 50 patients, respectively, had serum concentrations of potassium greater than 5 mEq/1. This contrasts with the finding of hyperkalemia in only 1 of 13 comparable patients treated with azathioprine and prednisone. Mean serum concentrations of potassium at these dates were significantly higher in cyclosporine-treated patients than azathioprine-treated patients. The 2 patient groups had similar mean serum concentrations of chloride, bicarbonate and creatinine, and mean creatinine clearances at 1 and 3 months. Exposure to diuretic agents and antihypertensive agents was similar in the 2 groups. Serum concentrations of electrolytes and renal function data in hyperkalemic and normokalemic transplant patients receiving cyclosporine were similar. These observations suggest an association between cyclosporine administration and hyperkalemia in renal transplant recipients.