EVENING VS MORNING ISRADIPINE SUSTAINED-RELEASE IN ESSENTIAL-HYPERTENSION - A DOUBLE-BLIND-STUDY WITH 24-H AMBULATORY MONITORING

A randomized, double-blind, placebo controlled study evaluated the effects on 24 h ambulatory blood pressure (ABP) of isradipine sustained release (I-SRO) administered once daily, in the morning (AM) or in the evening (PM). Eighteen uncomplicated essential hypertensives (10 men, mean age 55 +/- 6 years) with casual sitting DBP 96-110 mm Hg received, according to a triple-way crossover design, I-SRO 5 mg AM, or 5 mg PM, or placebo for 4 weeks. A 24 h ABP monitoring (Spacelabs 90207) was carried out at the end of each treatment. Twenty-four hour BP was 145.3/89.8 mm Hg after randomized placebo. AM and PM I-SRO significantly reduced 24 h BP, by 13.7/8.7 and 12.9/8.2 mm Hg respectively. Daytime (07.00 h-23.00 h) BP significantly decreased by 15.0/9.7 mm Hg with AM and 13.2/8.7 mm Hg with PM regimen; night-time BP (23.00 h-07.00 h) significantly decreased by 11.6/7.1 and 12.3/7.4 mm Hg, respectively. Nocturnal nadir BP values were 132.6/78.1 after randomized placebo, 120.9/71.4 after AM I-SRO and 121.0/72.4 mm Hg after PM I-SRO. Morning peak BP values were 154.6/96.9,139.5/87.6 and 137.5/85.5 mm Hg, respectively. Mean BP values in the early morning hours (i.e. between 03.00 h and 08.00 h) were significantly decreased by 12.1/7.3 mm Hg after AM and 14.3/7.9 mm Hg after PM intake. No significant differences were detected in the BP lowering effect of the two I-SRO regimens. In hypertensive patients, isradipine sustained release 5 mg once daily given in the morning or in the evening is effective in reducing the 24 h blood pressure profile, irrespective of the time of administration.