Comparative effects of enalapril and nifedipine on renal hemodynamics in hypertensive renal allograft recipients.

The comparative effects of enalapril (E) and nifedipine (N) on renal hemodynamics were assessed in twenty-two moderately hypertensive, cadaveric renal transplant patients who were maintaining stable renal function. Fourteen patients were on cyclosporin (CSA) and eight were receiving azathioprine with prednisolone (AZA). In each patient effective renal plasma flow (ERPF) was determined four times, first baseline, second with E, third as another baseline after a washout period, and fourth with N; and renal vascular resistance (RVR) was derived in each. ERPF and RVR were significantly compromised in the CSA group (202 +/- 55 ml/min and 65 +/- 18 mmHg/ml/min) compared to the AZA group (302 +/- 99 and 43 +/- 15 respectively). During E therapy, RVR further increased in the CSA group to 82 +/- 37 while it decreased in the AZA group to 31 +/- 7 (both changes were significant when compared to their respective baseline values). N, on the other hand, only significantly lowered RVR in the AZA group. Furthermore, two patients, one from each group, developed acute reversible renal failure shortly after E therapy. However, both agents were effective in lowering blood pressure to a comparable degree in both groups. In conclusion, our data showed a somewhat less favourable renal hemodynamic response to short-term enalapril therapy in hypertensive renal transplant patients maintained on CSA. However, the significance of such hemodynamic changes for long-term renal function remains uncertain.