Antihypertensive Effect of the Oral Angiotensin I-Converting Enzyme Inhibitor in Long-Term Treatment of Hypertensive Patients

Abstract

Antihypertensive effect of an orally active angiotensin I-converting enzyme inhibitor, SQ 14225 (Captopril), was assessed in 18 hypertensive patients, of whom 13 had essential hypertension, 2 had malignant hypertension, 2 had hypertension associated with chronic renal failure, and 1 had renovascular hypertension. Blood pressure decreased markedly not only in patients with high renin levels but also in those with low renin levels. Nevertheless, the magnitude of blood pressure reduction was correlated with the pre-treatment plasma renin activity (r=-0.64, p<0.01 systolic, r=-0.60, p<0.05 diastolic). There was a significant correlation between the fall in mean blood pressure and the decrease in plasma aldosterone concentration 3 weeks after treatment (r=0.64, p<0.05). The serum potassium elevated from 4.2±0.4 to 4.8±0.9mEq/L (p<0.05), and the change correlated inversely with the reduction of plasma aldosterone concentration (r=-0.71, p<0.02), while serum sodium slightly decreased from 140±2 to 138±3mEq/L. There was neither finding of orthostatic hypotension nor escape from the antihypertensive effect. These results indicate that chronic inhibition of angiotensin I-converting enzyme with an orally active compound offers an effective and well-tolerated approach to treatment of hypertension