Antihypertensive efficacy of a slow release nifedipine tablet formulation given once daily in patients with mild to moderate hypertension. A placebo-controlled, double-blind parallel-group trial.

In a double-blind, randomized parallel-group, multi-center study the antihypertensive efficacy of a slow release tablet containing 60 mg nifedipine (Aprical long, CAS 21829-25-4) has been investigated. After two-weeks wash-out of previous antihypertensive medication and a two-weeks placebo run-in period, 88 patients of both gender with a diastolic blood pressure between 95 and 115 mmHg received either nifedipine or placebo for 8 weeks. Blood pressure was measured at the end of the dose interval at rest by a semi-automatic, auscultatory device. Control measurements were recorded using a standard cuff sphygmomanometer. Primary efficacy criterion was the drop in diastolic blood pressure (DBP, measured semi-automatically) after 8 weeks therapy. 88 patients were randomized to nifedipine or placebo. 86 patients completed the protocol (42 nifedipine, 44 placebo). However, only in 73 patients BP measurements were recorded appropriately with the semi-automatic device (36 nifedipine, 37 placebo). In the nifedipine group, blood pressure fell from 152 (+/- 18)/102 (+/- 6) mmHg to 139 (+/- 16)/91 (+/- 10) mmHg. Blood pressure under placebo was determined to 149 (+/- 20)/102 (+/- 8) mmHg before treatment and 146 (+/- 18)/100 (+/- 10) mmHg at the end of the study. Heart rate was not affected under both treatments. The 90% confidence interval of the difference between the mean fall in DBP ranged from 5.0 to 12.5 mmHg, the point estimator was 8.8 mmHg. At the end of the study, 21 of 36 patients under nifedipine and 10 of 37 patients under placebo had a DBP below 90 mmHg and/or a decrease in DBP > 10 mmHg.(ABSTRACT TRUNCATED AT 250 WORDS)