ACE Inhibitors

(angiotensin-converting enzyme inhibitors)

ACE inhibitors act by suppressing the renin-angiotensin-aldosterone system. In the kidneys, Renin is synthesized producing Angiotensin I; this in turn is converted by the enzyme ACE to Angiotensin II. This very potent vasoconstrictor, Angiotensin II, stimulates secretion of aldosterone which results in sodium and fluid retention.

ACE inhibitors prevent Angiotensin I from converting to Angiotensin II, resulting in decreased peripheral and pulmonary vascular resistance, and decreased blood pressure. ACE inhibitors can improve diastolic function of the heart, which aids in the relief of congestive heart failure by reducing the work load of the heart.

Although ACE inhibitors may improve renal function, caution should be used in preexisting renal disease. ACE inhibitors are excreted in feces, urine, and breast milk.