Effective dose range of enalapril in mild to moderate essential hypertension

The dose-response relationship of enalapril was evaluated in a double-blind, balanced, two-period, incomplete-block study in 91 patients with mild to moderate essential hypertension. Patients were randomly assigned to two of six treatments: placebo, 2.5, 5, 10, 20 and 40 mg/day of enalapril maleate. There were two 3-week treatment periods, each preceded by a 4-week, single-blind placebo washout. Each dose of enalapril produced significant decreases in standing and supine systolic and diastolic blood pressure after 2 and 3 weeks of treatment. There were no significant changes on placebo. There was a significant linear dose response relationship for both mean blood pressure and mean change from baseline in blood pressure (P less than 0.01 for systolic and mean arterial pressure, and P less than 0.05 for diastolic pressure). Enalapril was associated with an increasing dose-response relationship across the 2.5-40 mg/day range. The 2.5 mg/dose is effective in some patients; however, doses greater than or equal to 10 mg/day may be necessary to achieve satisfactory blood pressure control.