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Angiotensin II receptor blockers (ARBs): Nursing Pharmacology

Notes

Notes

ANGIOTENSIN II RECEPTOR BLOCKERS (ARBs)
DRUG NAME
-sartan: i.e., valsartan (Diovan); losartan (Cozaar); candesartan (Atacand); irbesartan (Avapro)
CLASS
Angiotensin II receptor blockers (ARBs)
MECHANISM OF ACTION
Prevent angiotensin II from binding to angiotensin II receptors on blood vessels and adrenal glands; decrease aldosterone secretion
INDICATIONS
  • Hypertension
  • Heart failure
ROUTE(S) OF ADMINISTRATION
PO
SIDE EFFECTS
  • Headache
  • Dizziness
  • Drowsiness
  • Angioedema
  • Hypotension
  • Hypoglycemia
  • Hyperkalemia
CONTRAINDICATIONS AND CAUTIONS
  • Boxed warning: pregnancy
  • Hypotension
  • Hypovolemia
  • Hyperkalemia
  • Renal or hepatic disease
NURSING CONSIDERATIONS
Assessment and monitoring
  • Vital signs, ECG, CBC, urinalysis, sodium, potassium, creatinine, and BUN, negative pregnancy test
  • For heart failure: weight, edema, lung sounds, dyspnea
  • Monitor for side effects; have 1:1000 epinephrine available for angioedema

Client education
  • Purpose of medication
  • Side effects
    • Change position slowly to avoid orthostatic hypotension
    • Avoid potassium supplements, salt substitutes, NSAIDs
    • Angioedema
  • Do not stop abruptly
  • Lifestyle modifications
  • Blood pressure self-monitoring
Transcript

Angiotensin II receptor blockers or ARBs for short, are a group of medications that help decrease blood pressure and are typically used to treat hypertension or high blood pressure, and heart failure.

Now, ARBs usually end in “-sartan,” like candesartan, valsartan, irbesartan and losartan, and are taken orally.

Alright, ARBs work by binding to angiotensin II receptors on vascular smooth muscles and the adrenal glands, which prevents angiotensin II from binding.

Normally, when angiotensin II binds to these receptors on blood vessels, it causes them to constrict, which increases the blood pressure.

On the other hand, in the adrenal glands, angiotensin II stimulates the release of aldosterone, which increases reabsorption of sodium and water in the kidneys.

This results in increased blood volume, which also increases blood pressure. Once ARBs are administered, angiotensin II can’t bind to angiotensin II receptors, which decreases vasoconstriction, as well as aldosterone release by the adrenals.

This causes natriuresis, or excretion of sodium along with water by the kidneys. In this way, ARBs effectively lower the blood pressure.

However, ARBs can also cause some side effects. The most common ones are mild and nonspecific and include headache, dizziness, and drowsiness.

ARBs have also rarely been associated with the development of angioedema, which is a fluid accumulation and swelling of the eyes, lips, tongue, pharynx, and glottis, and can be life threatening.

Other side effects include hypotension, tachycardia, and hypoglycemia. Finally, ARBs decrease potassium excretion in the urine, and this could lead to hyperkalemia, so it’s important for clients who are taking ARBs to avoid taking potassium supplements and salt substitutes that contain potassium.

As far as contraindications go, as a boxed warning, ARBs and other medications with a similar mechanism of action are contraindicated during pregnancy, since they may cause fetal injury.

Finally, ARBs should be used with caution in clients with hypotension, hypovolemia, and hyperkalemia, as well as renal or hepatic disease.

Alright, if your client is prescribed an ARB, perform a baseline assessment, including vital signs, ECG, CBC, urinalysis, sodium, potassium, creatinine, and BUN.

For female clients of childbearing age, obtain a negative pregnancy test, and advise them to let their healthcare provider know if they plan to become pregnant.

Sources
  1. "Focus on Nursing Pharmacology" LWW (2019)
  2. "Pharmacology" Elsevier Health Sciences (2014)
  3. "Mosby's 2021 Nursing Drug Reference" Mosby (2020)
  4. "Saunders Comprehensive Review for the NCLEX-RN Examination" Saunders (2016)
  5. "Lewis's Medical-Surgical Nursing" Mosby (2019)