Comparison of once daily endralazine with placebo in the treatment of hypertension uncontrolled by a beta-blocker and diuretic.

We report the first placebo controlled parallel group study of once daily endralazine (5-20 mg) in hypertension uncontrolled by a beta-blocker plus a diuretic. Following a 4-week run-in period 22 patients with a sitting mean arterial pressure (MAP) greater than 110 mm Hg were entered into the study and received either endralazine 5 mg or placebo. Blood pressure was measured 2 h and 24 h after dosing and the drug dose doubled at 2 and 4 weeks if the 24-h MAP remained greater than 110 mg Hg. The final blood pressure assessment was made after 6 weeks treatment in the 19 patients who completed the study. Three patients withdrew from the study because of side effects. The hypotensive effect (sitting) was in excess of placebo at 2 h by 15.8 mm Hg systolic (NS), 15.4 mm Hg diastolic (p less than 0.01), 15.5 mm Hg MAP (p less than 0.02) and at 24 hours by 7.7 mm Hg systolic (NS), 8.9 mm Hg diastolic (p less than 0.02) and 11.1 mm Hg MAP (p less than 0.02). This study suggests that endralazine should be prescribed twice daily.