Potassium-sparing Diuretics (Nursing)

00:00 Now we've laid out this nephron again for you here and I really love what we did for you in this drawing because now hopefully it makes more sense that you fall from the glomerulus all the way down for you to where urine is excreted. I want to talk about a different type of diuretic now, the potassium-sparing diuretics. These are the guys at the very end, right? They have 1-5% of sodium we lose here. So this just causes the mildest increase in urine output. These are not the killer kind of diuretics. It's not often used in monotherapy. Now, take a minute and just underline the first part of the word that says "mono" that just means one. So when you see the term in pharmacology monotherapy, that means by itself. So just write by itself, makes me think of a song that I will spare you from singing right now, but we don't often use potassium-sparing diuretics all by themselves because they're kind of puny. You don't get much of an effect from them. Now we can use it with loop diuretics if we're losing a lot of potassium. So that's kind of cool. I know it sounds weird like what you're on one diuretic and put them on the other diuretic.

01:11 Well the reason we would use the potassium-sparing diuretic with the furosemide is because we want to make sure we try to help keep that potassium level up. So the healthcare provider may decide for this particular patient. They could benefit from a potassium-sparing diuretic being added. Now there are 2 types of potassium-sparing diuretics. One is aldosterone antagonist. Remember, aldosterone is a hormone. Right? It's a hormone that tells my body to hang on to sodium. And when my body hangs on to or reabsorb sodium, what follows? Right, water. So when I've got aldosterone antagonist, that was our drugs that will block that action. So these types of potassium-sparing diuretics will block the action of aldosterone, meaning I will get rid of sodium and I'll hang on to potassium which is why they're called potassium-sparing diuretics. The other type of potassium-sparing diuretic is a non-aldosterone antagonist. Okay, I'll give it to you here. The names are not that clever. Right? The people that named these 2 types of diuretics really couldn't ever work for some type of nail polish or lipstick naming company but they get the job done. Aldosterone antagonist or non-aldosterone antagonist. An example of an aldosterone antagonist is spironolactone. An example of a non-aldosterone antagonist is triamterene and amiloride. Okay, that's another tongue twister but you've got these 2 groups. So let's go back over this. We've got potassium-sparing diuretics. Think about what you know about potassium-sparing diuretics without looking at your notes. Okay, hopefully you're thinking about "Okay, no potassium-sparing diuretics, glomerulus there at the end, they're the weakest of what we have, we don't use them by themselves, and they're going to help potassium levels go up and that's why we call them potassium-sparing diuretics. Brilliant. You're right with us. Now, as we're studying and talking to pharmacology, that's what we want you to do. Pause, give your brain a break, and see what you can recall. You can't just wrap your lips around a fire hydrant. Right? When you want to drink of water. You take a sip and then you take a break. Same thing with pharmacology information. You take a little bit of information, stop, pause, recall what you know about it and then move on to the next topic. So let's take a look at an aldosterone blocker, spironolactone.

03:49 It's still a potassium-sparing diuretic but it blocks the action of aldosterone in the distal nephron. Okay, so hang with me here, I promise this is really straightforward. Spironolactone is an aldosterone blocker. Okay, so we're looking in the distal nephron, look at aldosterone, it will increase the sodium and therefore decrease potassium. That's what aldosterone does in my body. Now, spironolactone is an aldosterone blocker so it's going to block this action in my body. So, hang with me. Remember we're looking at the nephron. What aldosterone normally does in my kidney in that nephron is it tells my body to hang on to sodium, that's why the up arrow was by sodium. When my body hangs on to sodium, the sodium level goes up and when my body increases sodium it naturally gets rid of potassium. Now when we give a drug like spironolactone, it's going to block that action.

04:49 Spironolactone will tell my body "Hey, I'm gonna block that action so my body gets rid of sodium and therefore hangs on to more potassium." Okay, so you're tracking with me. Spironolactone is a blocker. It blocks the action of aldosterone. Aldosterone normally tells my body "hang on to sodium" so you'll end up getting rid of potassium but spironolactone blocks that action. So instead my body gets rid of sodium, that's why you have a down arrow, and your potassium level will therefore go up. So that's why spironolactone is considered a potassium-sparing diuretic. Mechanism of action? It blocks aldosterone in the distal nephron. Okay, so take a minute and write any notes down that you need to add to that slide to make sure that's clear to you, but the up arrow means your serum sodium levels are going to go up, your down arrow means your potassium levels are going to go down with aldosterone and we're talking about blood levels.