Source: DGNews  |  Posted 8 years ago

By Jill Stein

NEW YORK, NY -- May 20, 2003 -- Sustained-release isradipine (SR-I) 10 mg may provide better 24-hour control of blood pressure than does sustained-release amlodipine 10 mg, as evidenced by significantly better sustained decreases in systolic blood pressure.

Michael Ganz, MD, of the Clinical Research Center of Cleveland, Cleveland, Ohio, reported new study results on May 16th at the 18th Annual Scientific Meeting of the American Society of Hypertension.

Dihydropyridine calcium channel blockers have been widely used for many years to treat mild to moderate hypertension, Dr. Ganz pointed out. Numerous clinical trials have also shown their efficacy in improving related outcomes such as: fatal and nonfatal myocardial infarction, heart failure, and stroke.

Despite the similarities between these agents, however, recent evidence suggests that not all dihydropyridine calcium channel blockers are equivalent in terms of blood pressure control or incidence of treatment-emergent side effects, such as pedal edema. In particular, sustained-release isradipine has previously been shown to produce lower rates of edema than amlodipine, an intrinsically long-acting dihydropyridine calcium channel blocker.

The present study was undertaken to determine whether substituting sustained-release isradipine for amlodipine improves the antihypertensive response in subjects currently being treated with amlodipine, and to compare the tolerability, particularly of edema, between sustained-release isradipine and sustained-release amlodipine.

One hundred and fourteen patients with mild to moderate hypertension, who had been treated with sustained-release amlodipine (5 or 10 mg qd) for at least 4 months, were eligible for enrollment. The only major exclusion criteria were evidence of coronary heart disease, or congestive heart failure.

Seated cuff blood pressure was measured after a 20-minute period of quiet rest. Blood pressure measurements were made at trough 3 times during the 6-month run-in period, and again 2 weeks before drug substitution. The average of these 4 measurements was used as the baseline blood pressure.

At the end of the run-in period, subjects who were currently treated with amlodipine 5 mg/d were switched to sustained- release isradipine 5 mg/d, and those currently treated with amlodipine 10 mg/d were switched to sustained- release isradipine 10 mg/d. Adjuvant antihypertensive therapy was permitted, provided the drugs and their doses remained stable.

Blood pressure was measured at 2-week intervals during the sustained