Amlodipine: a double-blind evaluation of the dose-response relationship in mild to moderate hypertension.

A multicenter, placebo-controlled trial assessed the antihypertensive efficacy and safety of different doses of amlodipine in patients with mild to moderate hypertension. Amlodipine was administered once daily in doses of 1.25-2.5 mg (low-dose group), 2.5-5.0 mg (medium-dose group), and 5.0-10.0 mg (high-dose group) during 8 weeks; doses were titrated within each group after 4 weeks of double-blind treatment if normotension or "target" blood pressures had not been achieved. After 4 weeks, supine systolic and diastolic blood pressures were significantly reduced in the medium and high-dose groups compared with placebo; standing blood pressures were significantly reduced only in the high-dose group. After 8 weeks of treatment, all blood pressures were significantly reduced except standing systolic and diastolic blood pressures in the low-dose group. There was a low incidence of side effects, which were generally mild to moderate in intensity, and there were no clinically significant effects on pulse rate, electrocardiogram, or body weight. Amlodipine produces a dose-related reduction in blood pressures with once-daily dosing, 2.5 mg being the minimum effective dose, and is well tolerated.