Mechanism of action
Angiotensin converting enzyme inhibitors are a class of oral medications that act primarily through blockade of the angiotensin converting enzyme.
This enzyme converts angiotensin I to angiotensin II. Angiotensin II causes vasoconstriction increasing afterload, thus increasing systemic blood pressure. Angiotensin contributes to the production of aldosterone, which normally acts to retain sodium and water.
ACE inhibitors are used to treat hypertension, systolic congestive heart failure and as nephroprotection in diabetic nephropathy. They are also used during acute myocardial infarction and left ventricular systolic dysfunction without heart failure.
- A non-productive cough is common with ACE inhibitors and is due to increased bradykinin in the lungs. This cough does not occur with angiotensin receptor blockers (ARBs).
- Angioedema is a life-threatening reaction relatively common with ACE inhibitors.
- A rash is common with ACE inhibitors.
- Hypotension can occur with ACE inhibitors, causing dizziness and weakness.
- Hyperkalemia can occur due to the aldosterone inhibition.
- Renal failure can occur due to efferent arteriolar vasodilation.
ACE inhibitors can dramatically decrease renal function when bilateral renal artery stenosis is present.
The dose of ACE inhibitors needs to be slowly up-titrated to a goal dose in patients with systolic congestive heart failure.
The only IV ACE inhibitor is enalapril and it is not commonly used in this manner.