A double-blind randomized evaluation of converting enzyme inhibition as the first-step treatment of mild to moderate hypertension.

The new angiotensin converting enzyme inhibitor, enalapril (MK-421), was tested by a double-blind trial. Patients with uncomplicated essential hypertension were randomly allocated to one of two stepped-care treatment groups: enalapril 20 mg once-a-day, or placebo as the first step, followed when necessary by the successive addition of hydrochlorothiazide (25 and 50 mg), oxprenolol (160 and 320 mg) and dihydralazine (50 and 100 mg). Blood pressure was normalized in both groups, although the enalapril group showed lower systolic and diastolic blood pressures than the placebo group (systolic 130.5 +/- 12 versus 136.6 +/- 9 mmHg, P less than 0.01; diastolic 82.8 +/- 6 versus 87.0 +/- 5 mmHg, P less than 0.001). These results were obtained with a smaller number of tablets per day (2.6 +/- 1.8 versus 4.2 +/- 2.4 mmHg, P less than 0.0001). Plasma potassium was identical for both groups at the start of treatment. At the end of the study, it was significantly higher in the enalapril group than in the placebo group (4.1 +/- 0.3 versus 3.9 +/- 0.5 mmol/l; P less than 0.05). Spontaneous complaints were noted during the bi-weekly or monthly visit and were also expressed by patients completing a self-administered questionnaire. Differences in spontaneous complaints or in the symptoms evaluated by the questionnaire were not significant. The increase in the number of symptoms at the end of the study was greater in the placebo group than in the enalapril group, but the difference was not statistically significant.(ABSTRACT TRUNCATED AT 250 WORDS)