Felodipine is a new calcium-antagonist dihydropyridine derivative with a high degree of selectivity for smooth muscle of arteriolar resistance vessels, as opposed to cardiac cells. 2. In this double-blind, cross-over study the antihypertensive efficacy and tolerability of the new extended release (ER) formulation of felodipine 10 mg, once daily, in patients with mild essential hypertension was evaluated. After a 4-week single-blind placebo period 28 patients (15 males; mean age 48 +/- 12 years) were randomized to receive felodipine 10 mg ER once daily or placebo for 4 weeks and the alternative treatment for a further 4 weeks. Supine blood pressure and heart rate were measured in the out-patients department every 2 weeks, 22-24 h after the last drug administration. 3. Felodipine 10 mg ER induced a significant reduction in blood pressure in comparison with placebo (from 149 +/- 16/97 +/- 6 to 140 +/- 12/89 +/- 6 mm Hg). Heart rate remained unchanged. Seven patients dropped-out; five during felodipine ER administration and two during placebo. 4. A once daily dose of felodipine ER significantly reduces blood pressure in mild hypertensive patients 22-24 h after administration. It is well tolerated and the adverse events are related to its pharmacodynamic effects.
