Biochem/Physiol Actions | Benazepril Hydrochloride is the hydrochloride salt of benazepril, a carboxyl-containing angiotensin converting enzyme (ACE) inhibitor with antihypertensive activity. As a prodrug, benazepril is metabolized to its active form benazeprilat. Benazeprilat competitively binds to and inhibits ACE, thereby blocking the conversion of angiotensin I to angiotensin II. This prevents the potent vasoconstrictive actions of angiotensin II, resulting in vasodilation. Benazeprilat also decreases angiotensin II-induced aldosterone secretion by the adrenal cortex, which leads to an increase in sodium excretion and subsequently increases water outflow. Renal and hemodynamic effects of diet alone and of single oral doses of the nonsulphydryl angiotensin converting enzyme (ACE) inhibitor, benazepril (10 mg), were investigated in eight healthy volunteers under stable conditions of high salt intake (300 mmol NaCl/day) and low salt intake (10 mmol NaCl/day), in a double blind, placebo controlled study. There were no changes in blood pressure between the two dietary extremes either during the run-in period or once sodium balance had been achieved ...Glomerular filtration rates were found to be similar irrespective of the state of salt balance. Both plasma urate concentration and plasma renin activity were significantly elevated in the low salt compared to high salt state. Benazepril caused a greater fall in blood pressure in the sodium depleted state. Significant increases in the mean renal plasma flow, in the order of 15-20%, were seen over 6 h postbenazepril when compared with placebo response, regardless of the level of salt intake. Glomerular filtration rate over the same period remained unaltered. Benazepril doubled the urinary excretion of sodium over the first 4 hours after dosing whilst on the low salt diet; the equivalent increase during salt loading was approximately 20%. These results suggest that benazepril may exert direct effects on renal tubular function additional to those achieved through ACE blockade. |
Application | 1. Angiotensin-Converting Enzyme Inhibitors A class of drugs whose main indications are the treatment of hypertension and heart failure. They exert their hemodynamic effect mainly by inhibiting the renin-angiotensin system. They also modulate sympathetic nervous system activity and increase prostaglandin synthesis. They cause mainly vasodilation and mild natriuresis without affecting heart rate and contractility. 2. Antihypertensive Agents Drugs used in the treatment of acute or chronic vascular HYPERTENSION regardless of pharmacological mechanism. Among the antihypertensive agents are DIURETICS; |
