Pharmacology, part 5: Cardiovascular Medications - Hypertension & the RAAS system

by Cathy Parkes April 30, 2020

Full Transcript

Alright. So starting in this video, we are going to be talking about cardiovascular medications. There are a lot to know in this category, but we're going to break it off into chunks to help make it more manageable. If you are following along with cards, I'm on card 11, and we're going to start off with medications that are used for hypertension or angina.

So before we get into our first batch of medications, let's do a review of the renin-angiotensin-aldosterone system or RAAS system. So renin is released by the kidneys in response to a decrease in renal blood flow or low blood pressure. Then, renin activates angiotensinogen into angiotensin I. Then, ACE, which is angiotensin converting enzyme, converts angiotensin I into angiotensin II. And then, angiotensin II does a number of things. The first thing it does is it causes vasoconstriction of the blood vessels. It also causes water and sodium to be reabsorbed at the kidneys. And then, finally, it causes the release of aldosterone from the adrenal cortex, which, in turn, also causes reabsorption of water and sodium at the kidneys so these medications that I'm about to go over, they will act on different parts of this renin-angiotensin-aldosterone system.

So the first medication we're going to talk about that is used to treat hypertension is a direct renin inhibitor, and the medication that's important to know in this class is aliskiren, and it's used to treat hypertension. It acts by inhibiting renin, which is at the top of our RAAS system, which prevents angiotensinogen from being activated into angiotensin I. So the way I remember this medication-- if you look at the word aliskiren, it kind of looks like Alice and Karen. So Alice and Karen gang up on Angie, right, so Angie being angiotensinogen, to stop it. So side effects with aliskiren include hypotension as well as angioedema and GI upset. This medication also carries a black box warning because of fetal toxicity. It's going to be really important to monitor the patient's blood pressure during therapy. And, again, like I shared in my introduction video to this whole series, for a lot of these medications, you could kind of figure out what one of the key side effects is going to be just by its mode of action so this medication is used to treat hypertension, so if it does its job too well, we're going to end up with hypotension, which is a side effect for this medication.

Now, let's talk about ACE inhibitors. ACE inhibitors include medications such as captopril and lisinopril. They will all end in that -pril, which kind of looks like thrill, so if you're playing cards and you draw an ace, then you get a thrill. So that kind of helps you to remember that medications that end in that -pril are ACE inhibitors. So ACE inhibitors can be used for hypertension as well as heart failure, a myocardial infarction, and diabetic nephropathy. They work by blocking the conversion of angiotensin I into angiotensin II, which results in vasodilation. They do have some key side effects. So hypotension is going to be a key side effect. Again, if our medication is doing its job too well-- it's being used for hypertension. If it works too well, we're going to end up with hypotension. So hypotension is a key side effect. Other really important side effects to know include angioedema, cough, and elevated potassium. So those all start with A, C, E. So A for angioedema C for cough, and E for elevated potassium. And so that's how you can remember those key side effects in addition to hypotension.

Other side effects. This drug is toxic for fetuses, so it does carry a black box warning, and you would not want to use this during pregnancy. And then it's important to monitor blood pressure during therapy, and you want to teach your patient to change positions slowly because of that hypotension side effect. So when a patient has hypotension, and if they get up too quickly, they may be going right back down. So you want them to kind of sit up on the side of the bed and dangle their feet for a little while before just popping out of bed. So hopefully, that's helpful.

Now, let's talk about angiotensin II receptor blockers. So medications that fall within this class include losartan and valsartan. These medications will all end in that -sartan, which kind of looks like Satan, and if you saw Satan, it would probably make your blood pressure drop, make you feel dizzy, and make your stomach hurt, which are key side effects with this class of medication. So angiotensin II blockers are used to treat hypertension as well as diabetic nephropathy. They work by blocking the effects of angiotensin II which results in vasodilation. So key side effects, you can probably guess what one of them's going to be. It's hypotension. In addition, it's dizziness and GI upset. It also carries a black box warning because of fetal toxicity. And again, when your patient is on this medication, you're going to want to monitor their blood pressure carefully. And also, teach them to change their positions slowly because of that hypotension.

Okay. So the last medication that works within that RAAS system is an aldosterone antagonist. So the medication in this class that I would be familiar with is eplerenone. And it is used for hypertension as well as heart failure after an MI. It works by blocking mineral corticoid receptors which inhibits the effect of aldosterone and results in reabsorption of sodium and water. So the way I remember this medication is that eplerenone does an epic job of blocking aldosterone. So the E-P at the beginning of eplerenone kind of reminds me of epic. And again, the end of it is that -one. So eplerenone does an epic job of blocking aldosterone. Side effects include hyperkalemia, very important side effect to know with this medication, as well as dizziness. So when a patient is taking this medication, you want to make sure you're monitoring their blood pressure during therapy. But also monitoring their potassium levels because of that side effect of hyperkalemia.

Alright. In my next video, we're going to talk about more medications that are used to treat hypertension. If you found this video helpful, be sure to like, leave your comment, and share a link with your classmates or friends in nursing school!

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