A placebo-controlled dose-response study of felodipine extended release in hypertensive patients.

This placebo-controlled study assessed antihypertensive effect and tolerability of two dose levels of an extended release (ER) formulation of felodipine (Plendil), given once daily to patients in primary health care. The patients had mild to moderate hypertension and were randomized to receive felodipine ER (FER) 20 mg (n = 50), FER 10 mg (n = 50), or placebo (n = 51) in a 4-week, double-blind, parallel-group multicenter study. After 4 weeks, the 24-h reduction in supine diastolic BP (DBP) was greater (p less than 0.01) in both FER groups (7 +/- 6 and 8 +/- 5 mm Hg) than in the placebo group (4 +/- 6 mm Hg). The 24-h reduction in supine systolic BP (SBP) was greater (p less than 0.01) in the FER 20-mg group (14 +/- 11 mm Hg), but not in the FER 10-mg group, than in the placebo group (8 +/- 11 mm Hg). No significant difference in blood pressure (BP) was found between FER 10 and 20 mg. Heart rate (HR) did not differ between any of the groups, nor did body weight or routine laboratory parameters. During felodipine treatment, 17 patients (12 receiving FER 20 mg) were withdrawn mostly because of vasodilatory side effects such as headache and ankle edema. We conclude that FER 10 mg and 20 mg once daily had an antihypertensive 24-h effect and that FER 10 mg may be more suitable as initial dose.