ARBs and ACE inhibitors NCLEX review for nursing students!
Angiotensin II receptors blockers (ARBs) and ACE inhibitors (angiotensin-converting enzyme) are cardiac medications that help manage blood pressure.
ACE Inhibitors and ARBs Lecture
Angiotensin II Receptor Blockers vs. ACE Inhibitors
To help you from confusing these medications, remember this about the generic name:
- ACE Inhibitors will end with “pril”…example: Lisinopril
- ARBs will end with “sartan”…example: Losartan
Both of these mediations affect the renin-angiotensin-aldosterone system (RAAS) BUT in DIFFERENT ways. However, they both achieve the SAME results.
What is RAAS? This system manages the blood pressure, especially when it drops too low. Here is a quick review on how the renin-angiotensin-aldosterone system works:
Blood pressure drops -> Kidneys release Renin -> this activates Angiotensinogen in the Liver -> it turns into Angiotensin I -> ACE (angiotensin-converting enzyme) converts it to -> Angiotensin II -> this active vasoconstrictor will act on receptors, specifically Angiotensin II receptor Type I -> constrict vessels and triggers the adrenal cortex to release aldosterone to help increase blood volume (kidneys will keep sodium and water but excrete potassium)
How do these medications work to affect RAAS?
Both of these medications target Angiotensin II so it won’t be able to act as a vasoconstrictor, but in different ways.
- ACE Inhibitors inhibit ACE from converting angiotensin I to angiotensin II….so no angiotensin II.
- Angiotensin II receptor blockers (ARBs) inactivate the receptors that readily accept angiotensin II called Angiotensin II Receptors Type 1…..so angiotensin II can’t bind to it receptors to do its job.
What effects do these medication cause?
They both will lead to vasodilation of vessels, which will decrease the systemic vascular resistance and blood pressure. In addition, it will decrease the release of aldosterone, which will cause the kidneys to excrete sodium and water but keep potassium…..watch for hyperkalemia with these medications.
What are these medications used for?
They both treat the same conditions like:
- Heart failure
- Post myocardial infarction
- Diabetic Nephropathy in Type 2 Diabetics (helps slow down the progression of the disease): these medications will decrease the blood pressure, which will help decrease the amount of protein in the urine…hence slowing down the progression of renal disease associated to diabetes.
One of the main concepts you need to take away from these two medications is that ACE Inhibitors can cause a dry, nagging cough in SOME patients along with angioedema (this is deep swelling of the tissues and is a medical emergency). These side effects are less likely with ARBs. In fact, some patients who do experience the cough while taking an ACE Inhibitor may be switched to an ARB to help alleviate it.
WHY a cough with ACE Inhibitors and not ARBs? ACE is a substance that not only converts Angiotensin I to Angiotensin II, but it breakdowns and inactivates an inflammatory substance called bradykinin. However, if ACE is inhibited it can’t do this and bradykinin will increase and it can lead to a dry, nagging cough in SOME patients. This doesn’t occur with ARBs because ACE will not be inhibited.
Nursing Considerations and Patient Education
- Monitor potassium levels for hyperkalemia (normal potassium is 3.5-5 mEq/L)
- Educate to avoid salt substitutes with potassium and eating an excessive intake of foods high in potassium like potatoes, avocadoes, bananas etc.
- Monitor renal function (elevated BUN and Creatinine, less than 30 cc/hr urinary output, swelling)
- Patients who are at risk for renal failure are those who are dependent on the RAAS to maintain cardiac output….example: patients with severe heart failure
- Monitor liver function
- Assess for hypotension (SBP less than 90) and educate the patient to monitor their blood pressure at home (daily) and to record the measurements to show the physician during follow-up appointments.
- Stress the importance of lifestyle changes because antihypertensive meds do NOT cure high pressure….needs to eat healthy, exercise, and quit smoking.
- Preventing rebound hypertension (blood pressure becomes extremely elevated and it is hard to bring down)….teach the patient to NEVER abruptly quit taking the medication because it can lead to this condition.
Angiotensin-Converting Enzyme Inhibitor (ACE inhibitor) Drugs. Retrieved from https://www.fda.gov/drugs/postmarket-drug-safety-information-patients-and-providers/angiotensin-converting-enzyme-inhibitor-ace-inhibitor-drugs
Food and Drug Administration. Angiotensin II receptor blocker: diovan (valsartan) tablet [Ebook]. Retrieved from https://www.fda.gov