LONG-TERM ANTIHYPERTENSIVE EFFECTS WITH CHRONIC ADMINISTRATION OF ISRADIPINE CONTROLLED-RELEASE

Isradipine controlled release (ISR-CR) is a reformulated long-acting d ihydropyridine calcium channel blocker. Its long-term antihypertensive effects and safety were tested in a 52-week open-label extension of t wo previous short-term (6 weeks), double-blind, placebo-controlled stu dies in patients with mild-to-moderate hypertension (sitting diastolic blood pressure 100 to 115 mm Hg). Of those who completed the two doub le-blind studies, 115 elected to enter the 52-week open-label trial. O f these, 79 (69%) were from a double-blind study in which the patients received fixed doses of isradipine (5, 10, 15, or 20 mg/d), and the r esults of this study have been published. The other 36 patients (31%) were from another double-blind study of g-weeks' duration, in which pa tients received variable dose titration of isradipine (5, 10, or 15 mg /d), and these results have not been published. In the present study, ISR-CR was administered in single daily doses of 5 to 20 mg depending on blood pressure control. Of the 115 patients, 88 received monotherap y with ISR-CR and 27 received ISR-CR plus hydrochlorothiazide (12.5 to 50 mg/d). A total of 65 of the 88 patients on monotherapy (74%) and 2 0 of the 27 patients on combination therapy (74%) completed the 52-wee k study. Both drug regimens statistically significantly reduced sittin g systolic blood pressure (16.1 +/- 12.8 mm Hg) and diastolic blood pr essure (17.3 +/- 13.0 mm Hg) 22 to 26 hours after drug administration and had no effect on heart rate. ISR-CR did not cause any adverse clin ical or metabolic effects, and was well tolerated. The results of this study indicate that ISR-CR is a once-daily (24-hour) long-acting effe ctive drug that provides sustained long-term antihypertensive efficacy and tolerability.