 Welcome to Nursing School Explained. Today's video will go over angiotensin receptor blockers. In order to really understand the mechanism of action of these medications, let's go back and review the basic physiology of how our bodies usually respond when the blood pressure decreases. So the Renan angiotensin and aldosterone system, also called RAS, is very important in helping us to maintain our blood pressure. So on the normal circumstances, when the blood pressure drops, angiotensinogen combines with renan to form angiotensin I, which then, with the help of angiotensin converting enzyme or ACE, converts angiotensin II, which in turn helps us to produce aldosterone, retain more sodium and water, increase sympathetic nervous system activity, as well as constricts the blood vessels, just like the term angiotensin tells us. It makes the blood vessels more tense, therefore the blood pressure will go up. And in turn, with all these mechanisms, our blood pressure will go up. Now in patients who already have high blood pressure, they don't want this to happen because we don't want the blood pressure to be even higher. And so angiotensin receptor blockers work on angiotensin II and block the receptors at the angiotensin II site. So basically after angiotensin I, the RAS system no longer works because we have blocked those receptors and these four things cannot happen. Therefore the body is unable to increase the blood pressure even further and that's why this medication is used so many times in the treatment of hypertension. As always medications from a certain class have the same mechanism of action, side effects, nursing considerations and indications. In this case, angiotensin receptor blockers all work to block these angiotensin receptors. So the mechanism of action, they inhibit the RAS by binding to these angiotensin II receptor sites on the vascular smooth muscle as well as the adrenal glands. Therefore they are used in the treatment of hypertension. They're also used to treat diabetic neuropathy because many times patients with diabetes also have hypertension. And they are used to treat heart failure if the patient is unable to tolerate ACE inhibitors because ACE inhibitors are the first line treatment for congestive heart failure and they work a little bit different on a different part of the RAS here but sometimes patients are more likely to have side effects from ACE inhibitors. So that's when angiotensin receptor blockers help. Side effects commonly are dizziness, low blood pressure as well as rhinitis and sinusitis and then in severe cases it can lead to angioedema which we have to be very careful with because it can cause an airway obstruction so certainly we want to tell the patient that this could occur and also monitor them closely if we are there when they get their first few doses of the snow medication. ARBs are contraindicated in pregnancy and lactation because they can actually cause fetal death. And then common nursing considerations, we always want to check blood pressure and heart rate before we give any medication that affects blood pressure. We also want to check the patients for signs and symptoms of heart failure such as their daily weight intake and output as well as signs and symptoms of fluid volume excess such as peripheral edema and crackles. We want to check their labs, we want to make sure that their kidneys are functioning well because the RAS system, renin, angiotensin and aldosterone all work partly on the kidney so if the kidneys are not working properly these medications are not going to work properly. And then because again it works on the RAS system that has to do with sodium and potassium balance we also want to check their potassium and sodium levels to make sure that they are not going in the wrong direction. Many times patients who are hypertensive are recommended to adhere to a low sodium diet which then many times they are recommended to use salt substitutes instead of regular table salt but salt substitutes many times contain potassium rather than sodium and so now in patients that are on ARBs we want to make sure we check their potassium level as well as tell them to avoid these salt substitutes because they are at higher risk for electrolyte imbalances and we don't want their potassium to go up because they're taking these additional supplements or food substitutions. And then certainly as with most hypertension medications they can cause orthostatic hypotension so we want to give the patient the appropriate warning signs and what to do when they first get up. As always medications in a certain class are clumped together like I mentioned before and angiotensin receptor blockers always end in TAN as the ending so just like ACE inhibitors end in pril ARBs end in TAN and a very commonly used example is low sartan or balsartan you'll see those very commonly used in the clinical setting. Thank you very much for watching this video in the pharmacology playlist please also make sure to check the video on ACE inhibitors which are similar but not quite the same as ARBs and I'll see you soon right here on nursing school explained thanks for watching