Enalapril versus captopril: a double-blind multicentre comparison in essential hypertension

A collective, multicentre (Ljubljana, Split, Zagreb) comparison of the antihypertensive effects between two angiotensin converting enzyme inhibitors (ACEI) captopril and enalapril was made in 69 hypertensives of both sexes, having a diastolic blood pressure (DBP), following two weeks on a placebo, of between 110 and 130 mm Hg (14.7 and 17.3 kPa). There were 35 patients on enalapril (20-40 mg), and 34 on captopril (50-100 mg). Both drugs under study decreased significantly the mean DBP already after the first week of ACEI treatment (p less than 0.001). By the end of the trial (9th week) captopril had decreased the DBP in the supine position from the initial 180.3 +/- 15.3/117.7 +/- 6.4 mm Hg to 151.6 +/- 11.1/96.8 +/- 7.2 mm Hg. Enalapril had lowered the DBP more efficiently: from 182.7 +/- 16.7/118.7 +/- 7.7 to 145.6 +/- 12.8/92.2 +/- 6.4 mm Hg (p less than 0.05). The average reduction in mean DBP was 16.9% on captopril, and 20.9% on enalapril. Low dose ACEI monotherapy (i.e. 50 mg and 20 mg) achieved DBP normalization in 11.8% on captopril and in 26.4% on enalapril (p less than 0.01). There were no significant heart rate changes. The laboratory results did not change appreciably and there were no relevant side-effects, although particular attention was paid to the expected adverse reactions, such as cough, ageusia or proteinuria. It is concluded that the ACEIs under study showed comparable effectiveness within the used dose range, enalapril being more potent, longer acting, and possibly safer.