Antihypertensive and metabolic effects of a new converting enzyme inhibitor, enalapril

Thirty-one men with mild, uncomplicated essential hypertension were studied for 18 wk in a double-blind, placebo-controlled, randomized clinical trial. Those whose supine diastolic pressure was 90 to 104 mm Hg after 4 wk of placebo were randomly assigned to three groups. Group I (11 subjects) initially received one 10-mg enalapril capsule in the morning and one placebo capsule in the evening. Group II (10 subjects) received one 5-mg enalapril capsule twice daily. Group III (10 subjects) received one placebo capsule twice daily. Drug dosages were doubled and then quadrupled in all groups at wk 8 and 12. Metabolic, ophthalmologic, and audiometric studies were done on all subjects at wk 2, 4, 8, 12, and 16. Enalapril lowered diastolic pressure in the supine and upright positions in single and divided doses. Its antihypertensive effect was dose dependent, and it was greater in white patients than in black patients. The drug was well tolerated by all subjects and did not cause clinical or metabolic complications. It is concluded that enalapril is effective in lowering the arterial pressure in single and divided daily doses; its effect is dose dependent and is greater on the diastolic arterial pressure than on the systolic pressure; and it is well tolerated.