Antihypertensive effect of enalapril as first-step treatment of mild and moderate uncomplicated essential hypertension. Evaluation by two methods of blood pressure measurement

Abstract

The new angiotensin converting enzyme inhibitor enalapril (MK-421), was given in a single daily dose of 20 mg to 53 patients with uncomplicated essential hypertension. Its effects were compared with those of a placebo given to 47 patients on a double-blind randomized basis. The blood pressure was measured in all patients by a physician, using a mercury sphygmomanometer, and by an automatic device in the absence of the physician. After 15 days of treatment, enalapril induced a significant reduction in systolic blood pressure (161.4 +/- 13 versus 145.1 +/- 15, p less than 0.001) and in diastolic blood pressure (103.3 +/- 6 versus 92.9 +/- 8, p less than 0.001) measured by the physician. The magnitude of the fall in blood pressure was identical after 30 days of active treatment. The reduction in blood pressure induced by enalapril was similarly detected by both methods of measurement, despite the fact that blood pressure values were higher when measured by the physician. A placebo effect was observed with the physician's values that was not present with the automatically recorded values. A very significant correlation between blood pressure values obtained by these two methods was observed. However, among nine of 53 patients treated with enalapril, a difference in the decrease of blood pressure of 10 mm Hg or more was noted between the two methods of measurement. The decrease in blood pressure occurred with no change noted in the pulse rate or orthostatic hypotension. Plasma renin activity increased after treatment. No changes were observed in creatinine clearance and plasma electrolyte levels.