4.2.3 Angiotensin II Receptor Blockers (ARBs)
Angiotensin II Receptor Blockers (ARBs)
From Pharmacology for Nurses, OpenStax Chapter 18
Learning Objectives
By the end of this section, you should be able to:
- 18.3.1 Identify the characteristics of the angiotensin II receptor blocker drugs used to treat hypertension.
- 18.3.2 Explain the indications, actions, adverse reactions, and interactions of the angiotensin II receptor blocker drugs used to treat hypertension.
- 18.3.3 Describe nursing implications of angiotensin II receptor blocker drugs used to treat hypertension.
- 18.3.4 Explain the client education related to angiotensin II receptor blocker drugs used to treat hypertension.
Introduction and Use
Angiotensin II receptor blockers (ARBs) are a classification of drug that binds to and inhibits angiotensin II type I receptors. Renin secretion catalyzes the conversion of angiotensinogen to angiotensin in the liver where it is then converted to angiotensin II by the angiotensin-converting enzyme.
ARBs resemble ACE inhibitors in how they affect blood pressure and the cardiovascular system. However, there are three notable differences: ARBs are less likely than ACE inhibitors to cause a chronic cough (Carter, 2022); the risk of angioedema is decreased with ARBs as compared with ACE inhibitors; and ARBs have been shown to be effective in the treatment of chronic kidney disease and heart failure.
Table 18.5 lists common ARBs and typical routes and dosing for adult clients.
| Drug | Routes and Dosage Ranges |
|---|---|
| Candesartan (Atacand) | 16 mg orally daily; maximum dose 32 mg daily in 1–2 divided doses. |
| Losartan (Cozaar) | 25–100 mg orally daily in 1–2 divided doses. |
| Telmisartan (Micardis) | 40 mg orally daily initially; maximum dose 80 mg daily. |
| Valsartan (Diovan) | 80–320 mg orally once daily. |
Adverse Effects and Contraindications
Adverse effects of ARBs include dizziness, muscle cramps, weakness, heartburn, diarrhea, leg swelling, headaches, and weight loss. Serious adverse effects include angioedema, hypotension, hepatic impairment, and hyperkalemia.
Special Considerations
ARBs
The renin-angiotensin system has been associated with increased risk of mood disorders. The use of ARBs may be associated with an increased risk of suicide compared with other antihypertensive therapies (Sanches & Teixeira, 2021). Hypertensive clients with low renin (sometimes seen more often in Black clients) demonstrate a lower response to ARB monotherapy. Concomitant therapy may be required to increase response to antihypertensive therapies. Older adults (65 years and older) and clients with hepatic impairment should start on a low initial dose because ARBs are metabolized by the liver.
(Source: Colvin et al., 2020)
ARBs should not be taken during pregnancy. Clients with hepatic impairment should use ARBs cautiously. Clients with a previous hypersensitivity reaction or angioedema to an ARB should not be prescribed this classification of drug. Clients with a history of mood disturbances or who are at risk for mood disturbances should be monitored closely for suicidal ideation.
Safety Alert
ARBs
ARBs can have teratogenic effects (causing harm to the embryo or fetus), so clients should avoid being pregnant while taking an ARB.
Table 18.6 is a drug prototype table for ARBs featuring valsartan. It lists drug class, mechanism of action, adult dosage, indications, therapeutic effects, drug and food interactions, adverse effects, and contraindications.
| Drug Class Angiotensin II receptor blocker (ARB)Mechanism of Action Blocks the binding of angiotensin II to the angiotensin I receptor, thereby decreasing vasoconstriction and lowering blood pressure |
Drug Dosage 80–320 mg orally daily. |
| Indications To control hypertension In the treatment of heart failureTherapeutic Effects Lowers blood pressure Increases blood supply and oxygen to the heart |
Drug Interactions Aliskiren Spironolactone Triamterene Amiloride NSAIDs, including selective COX-2 inhibitors ACE inhibitors Lithium Potassium supplements Salt substitutesFood Interactions Alcohol Tobacco |
| Adverse Effects Hematuria Dizziness Syncope Increased thirst Decreased urinary output Irregular heartbeat Angioedema Hyperkalemia Orthostatic hypotension |
Contraindications Hypersensitivity Concomitant use with aliskiren in clients with diabetes mellitus PregnancyCaution: Hepatic impairment Renal impairment Hypotension Hypovolemia Hyperkalemia Breastfeeding |
Nursing Implications
The nurse should do the following for clients who are taking ARBs:
- Monitor the client’s blood pressure as prescribed.
- Monitor the client for interactions because many medications and herbal supplements interact with ARBs.
- Monitor the client for adverse effects, including electrolyte imbalances and alterations in liver and renal function.
- Provide client teaching regarding the drug and when to call the health care provider. See below for client teaching guidelines.
Client Teaching Guidelines
The client taking an ARB should:
- Avoid foods high in potassium and salt substitutes (because these are high in potassium).
- Report side effects such as low blood pressure, cough, heart palpitations, fever, chills, sore throat, swelling of lips or face, shortness of breath, or difficulty breathing to the health care provider.
- Notify their health care provider if they experience abdominal pain, joint or muscle aches, muscle weakness, change in the amount of urine produced, or trouble breathing.
- Notify their health care provider if pregnant, planning on getting pregnant, or breastfeeding before starting an ARB.
FDA Black Box Warning
ARBs
ARBs have the potential to harm or even kill a fetus if a client takes these drugs while pregnant.
Next- 4.2.4 Beta-Adrenergic Blockers
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