The renin‐angiotensin system during converting enzyme inhibition with captopril in patients with severe treatment‐resistant hypertension

Abstract

The effect of captopril on blood pressure (BP) and various components of the renin-angiotensin system was assessed in ten severely hypertensive patients. Captopril acutely reduced the BP with a maximum decrease of 23% at 90-120 min. Maintenance treatment with captopril alone could not control the BP in any of the patients. Addition of hydrochlorothiazide markedly reduced the BP, while supplementation with propranolol caused no consistent changes. Three patients attained a supine diastolic blood pressure (SDBP) less than or equal to 90 mmHg. Only two patients had a fall in SDBP less than 10 mmHg. One patient stopped because of taste disturbances. Monitoring the renin-angiotensin system showed suppressed plasma concentrations of angiotensin II and increased levels of angiotensin I and renin, indicating the inhibition of converting enzyme activity. Plasma concentration of renin substrate decreased significantly. This observation has important implications for the methodology of renin assays. Captopril is an effective alternative in the treatment of hypertensive patients not readily controlled with conventional therapy.

Converting Enzyme Inhibition in Mild and Moderate Essential Hypertension. II

“…A similar experience has been reported in hypertensive and normotensive subjects (19). In agreement with our previous experience (20) and that of other investigators (2, 5), no correlations could be demonstrated between the long-term blood pressure reduction and pre-captopril PA11 levels. However, the thiazide-treated patients in group B had higher PA11 levels and a subsequent larger fall in blood pressure during captopril treatment than the untreated patients in group A.…”

Converting Enzyme Inhibition in Mild and Moderate Essential Hypertension: I. Acute Effects on Blood Pressure, the Renin‐Angiotensin System and Blood Bradykinin after a Single Dose of Captopril

“…

Converting enzyme inhibition in mild and moderate essential hypertension. I. Acta Med Scand 1985; 218: 435-42.some authors to be proportional to the prevailing plasma concentrations of angiotensin I1 (4-7), whereas others have failed to find such a relationship (8,9). Maintenance therapy often leads to further reductions in blood pressure which in some studies have been shown to be correlated to the pretreatment levels of angiotensin I1 or renin (10-12), but not in others (7,9,(13)(14)(15).

…”

“…I. Acta Med Scand 1985; 218: 435-42.some authors to be proportional to the prevailing plasma concentrations of angiotensin I1 (4-7), whereas others have failed to find such a relationship (8,9). Maintenance therapy often leads to further reductions in blood pressure which in some studies have been shown to be correlated to the pretreatment levels of angiotensin I1 or renin (10-12), but not in others (7,9,(13)(14)(15). The evidence for involvement of bradykinin in the hypotensive action Abbreviations: ACE = angiotensin converting enzyme, PRC = plasma concentration of renin, PRSC = plasma concentration of renin substrate, PA1 = plasma concentration of angiotensin I, PA11 = plasma concentration of angiotensin 11, BBK = blood concentration of bradykinin, DBP = diastolic blood pressure, MAP = mean arterial pressure, HR = heart rate.…”