Short- and long-term efficacy of nifedipine in hypertensive patients with impaired renal function, with special reference to influencing factors.

Both the antihypertensive efficacy and side effects of nifedipine were investigated in hypertensive patients with impaired renal function (n = 44) in short-term (7 days) and long-term (6 months) therapeutic trials. Comparable hypotensive effects were obtained in both the short- and long-term studies (from 184 +/- 4.6/108 +/- 2.8 to 166 +/- 4.6/97 +/- 3.2 mmHg, and from 178 +/- 4.2/108 +/- 2.1 to 157 +/- 4.4/95 +/- 2.4 mmHg, respectively). In the short-term study (n = 20), the antihypertensive effect was significantly related to the pretreatment blood pressure (r = 0.51) and inversely related to the plasma renin activity (PRA) (r = -0.61; p less than 0.05). However, it was not related to age or reciprocal value of the pretreatment serum creatinine. In the long-term study (n = 24), blood-pressure-lowering effects of nifedipine were found to depend on the reciprocal value of the serum creatinine but not on PRA. The blood urea nitrogen and creatinine were not changed significantly during the observation period. Side effects occurred in 8 of the 44 patients, but severe side effects necessitating termination of administration were observed in only 2 patients. These results indicate that nifedipine is effective in both the short- and long-term treatment of hypertensives patients with impaired renal function. Impaired renal function is a key factor in the hypotensive effects of nifedipine in long-term therapy.