Angiotensin II receptor blockers (ARBs): Nursing pharmacology

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.