18.2: Angiotensin-Converting Enzyme (ACE) Inhibitors
By the end of this section, you should be able to:
- 18.2.1 Identify the characteristics of the angiotensin-converting enzyme inhibitor drugs used to treat hypertension.
- 18.2.2 Explain the indications, actions, adverse reactions, and interactions of the angiotensin-converting enzyme inhibitor drugs used to treat hypertension.
- 18.2.3 Describe nursing implications of angiotensin-converting enzyme inhibitor drugs used to treat hypertension.
- 18.2.4 Explain the client education related to angiotensin-converting enzyme inhibitor drugs used to treat hypertension.
Introduction and Use
Angiotensin-converting enzyme (ACE) inhibitors are a classification of drugs that block the body’s production of angiotensin II. Angiotensin II induces oxidative stress and inflammation of cardiac tissue, which contributes to adverse remodeling processes. Angiotensin II also causes vasoconstriction and inhibits the reuptake of norepinephrine, stimulating catecholamine release. The release of catecholamine decreases urinary excretion of sodium and water, which then causes the release of aldosterone. Aldosterone stimulates the hypertrophy of the vascular smooth muscles, causing thickening of the vascular smooth muscle wall and restricting blood flow. ACE inhibitors (see Figure 18.5) are used to treat hypertension and cardiovascular diseases by reducing the release of aldosterone as part of the first line of treatment for clients who have hypertension (Goyal et al., 2022).
Adverse Effects and Contraindications
ACE inhibitors are relatively safe to use and have a low incidence of serious adverse effects. Adverse effects include angioedema, nonproductive cough, neutropenia (low neutrophils in the blood), agranulocytosis (low granulocytes in the blood), proteinuria (protein in the urine), and rash. Clients may develop an ACE inhibitor–associated cough (a persistent, dry, itchy cough), hyperkalemia (elevated potassium level in the blood), or hypotension (Jun et al., 2021).
ACE inhibitors should not be taken during pregnancy. Clients with renal impairment should use them cautiously. Clients with a previous hypersensitivity reaction to an ACE inhibitor should not be prescribed this classification of drug.
Table 18.4 is a drug prototype table for ACE inhibitors featuring enalapril. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
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Drug Class
Angiotensin-converting enzyme (ACE) inhibitor Mechanism of Action Inhibits the enzyme that converts angiotensin I to angiotensin II and thereby suppresses the renin-angiotensin-aldosterone system |
Drug Dosage
5–40 mg administered in 1–2 daily doses. Initial dose: 5 mg orally once daily; maximum dose: 40 mg/day. May divide dose and administer twice daily. |
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Indications
To control hypertension In the treatment of heart failure Treatment of acute myocardial infarction Therapeutic Effects Lowers blood pressure Increases blood supply and oxygen to the heart |
Drug Interactions
Aliskiren Sacubitril/valsartan Nonsteroidal anti-inflammatory drugs (NSAIDs) including selective cyclooxygenase-2 (COX-2) inhibitors Potassium-sparing diuretics Lithium Temsirolimus Sirolimus Everolimus Food Interactions No significant interactions |
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Adverse Effects
Angioedema Fatigue Orthostatic hypotension Asthenia Diarrhea Nausea/vomiting Headache Dizziness/vertigo Hyperkalemia Cough Rash Abdominal pain Angina |
Contraindications
Hypersensitivity A history of angioedema related to previous treatment with an angiotensin-converting enzyme inhibitor or hereditary or idiopathic angioedema Pregnancy Caution: Aortic stenosis Diabetes Syncope Orthostatic hypotension Impaired renal function Breastfeeding |
Nursing Implications
The nurse should do the following for clients who are taking ACE inhibitors:
- Assess the client’s blood pressure and pulse on an ongoing basis with initial dosing and intermittently during drug therapy.
- Monitor serum potassium levels for hyperkalemia.
- Assess and monitor the client for adverse effects, drug and food interactions, and contraindications.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Safety Alert
ACE Inhibitors
Taking ACE inhibitors with potassium-containing salt substitutes or consuming large amounts of high potassium foods increases the risk of hyperkalemia. Having a blood potassium level above 6.0 mmol/L is considered a medical emergency and can result in cardiac arrest.
Client Teaching Guidelines
The client taking an ACE inhibitor should:
- Avoid foods high in potassium and salt substitutes (because these are high in potassium) due to the aldosterone release.
- Report side effects such as low blood pressure, cough, heart palpitations, nausea, vomiting, fever, chills, sore throat, swelling of the eyes and lips, or difficulty breathing to their health care provider.
- Notify their health care provider if pregnant, planning on getting pregnant, or breastfeeding before starting an ACE inhibitor.
- Report symptoms such as chest pain, slurred speech, hemiparesis, and difficulty speaking or walking to their health care provider immediately because these may be symptoms of a heart attack or stroke.
- Be aware that a persistent cough may develop when taking ACE inhibitors.
FDA Black Box Warning
ACE Inhibitors
The use of ACE inhibitors during the second and third trimesters of pregnancy has been associated with fetal and neonatal injury, including hypotension, neonatal skull hypoplasia, anuria, reversible or irreversible renal failure, and death.