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.If the medication is prescribed for heart failure, assess your client’s weight, lung sounds, and for the presence of edema or dyspnea.Next, be sure to explain why the medication is prescribed and common side effects your client should watch for.

Let them know that hypotension can often occur with the first few doses, so instruct your client to make position changes slowly until they adjust to their medication.

Be sure to explain that angioedema is a less common but serious side effect that can occur within the first week of treatment, and that they should seek immediate medical attention if they notice swelling of their eyes, lips, or tongue.

Also teach your client to avoid potassium supplements and salt substitutes that contain potassium while taking an ARB; and advise them that taking NSAIDs while they are taking an ARB can reduce the antihypertensive effect of their medication.

Lastly, let your client know that they can take their medication with or without food.Now, to assist your client with blood pressure control while taking an ARB, stress the importance of lifestyle modifications that can help lower blood pressure, such as weight loss, smoking cessation, decreased alcohol intake, increased physical activity, and following a low sodium diet.

Teach your client how to take their blood pressure at home, and explain blood pressure readings that warrant the need to seek medical attention.

And finally, ensure clients understand to not abruptly stop taking their medication because of the risk of rebound hypertension.While caring for a client taking an ARB, periodically monitor their blood pressure, as well as laboratory results, including CBC, BUN, creatinine and potassium.

Evaluate for the therapeutic effect such as normalization of your client’s blood pressure and a decrease in symptoms of heart failure.Alright, as a quick recap… ARBs are medications that are typically used to treat clients with hypertension or heart failure.

ARBs work by blocking angiotensin II from binding to receptors on vascular smooth muscle, which leads to decreased vasoconstriction and decreased sodium and water retention.

Side effects include headache, dizziness, drowsiness, hypotension, tachycardia, hyperkalemia, and angioedema. ARBs are contraindicated during pregnancy and used cautiously in clients with hypotension, hypovolemia, hyperkalemia, renal or hepatic disease.

Nursing considerations for ARBs center around safe administration, as well as client education, and monitoring.