Serum concentration-effect relationship of (+/-)-nicardipine and nifedipine in elderly hypertensive patients.

The concentration-effect relationships of (+/-)-nicardipine and nifedipine have been investigated in hypertensive geriatric patients. Following a parallel group, randomised, double blind trial design, they received either slow release nifedipine 20 mg b.d. (n = 9) or slow release (+/-)-nicardipine 50 mg b.d. (n = 10) for 7 days. On Days 1 and 7 serum (+/-)-nicardipine and nifedipine, blood pressure and heart rate were measured 6 and 12 h after drug administration. (+/-)-Nicardipine showed significant cumulation (ca 2 x) without a corresponding decrease in blood pressure or increase in heart rate. Concentration-effect plots indicated that (+/-)-nicardipine was more potent than nifedipine but that it showed apparently comparable efficacy in reducing the blood pressure. Compared to young healthy volunteers, both drugs had a more pronounced effect in elderly patients.