Effects of sustained-release diltiazem on blood pressure and serum lipids: a multicenter, randomized, placebo-controlled study.

A randomized, double-blind dose-response study on the antihypertensive action of sustained-release diltiazem was performed in four parallel groups. The aim of the trial was to evaluate the antihypertensive efficacy of sustained-release diltiazem and its dose-dependent clinical and biological tolerance. The four homogeneous groups consisted of 25 patients each who had presented with mild to moderate hypertension (diastolic blood pressure of 95-115 mm Hg) in the supine position. The study protocol comprised three successive periods: a placebo period lasting 14 days to verify the persistence of arterial hypertension under placebo; a first therapeutic period during which each of the 25 patients of the four groups received a single daily dose every morning at 9 a.m. of a capsule containing 0.240, 300, or 360 mg of sustained-release diltiazem over a period of 28 days; and a second therapeutic period during which the patients of the four groups received 240, 300, 360, and 300 mg, respectively. All other antihypertensive treatment had been suspended at least 15 days before the initial period under placebo. The results were evaluated with respect to clinical parameters such as systolic blood pressure, diastolic blood pressure, and heart rate, which were measured at 9 a.m. 24 h after the last administration of the drug on days 14, 28, and 56. The plasma serum levels of diltiazem were measured on days 28 and 56, the biological parameters, including measurements of hepatic and renal function as well as lipid and glucose levels, on days 14 and 56, and electrocardiography was performed on days 14, 28, and 56.(ABSTRACT TRUNCATED AT 250 WORDS)