Jan 7, 2018
This one-day, two hour seven lecture series provides a basic understanding of how to recognize common drug names, understand the basic classifications, and quickly memorize them for exams. The print, e-book, and audiobooks these lectures are based on, Memorizing Pharmacology: A Relaxed Approach, can be found here https://www.amazon.com/Memorizing-Pharmacology-A-Relaxed-Approach/dp/B01FSR7XZO/
Full Transcript:
Male speaker:
Welcome to the Pharmacy Leaders Podcast, with your host, Tony Guerra. The Pharmacy Leaders Podcast is a member of the Pharmacy Podcast Network. With interviews and advice on building your professional network, brand, and a purposeful second income from students, residents, and innovative professionals.
Welcome to Episode Six: Cardio Pharmacology.
Tony: Let's go over chapter six, cardiovascular. I'm going to start with just three OTC medications. There really aren't that many.
We start with OTC anti hyperlipidemics, you'll see these called anti-cholesterol drugs, or things like that. I put that they’re over-the-counter, but they're also by prescription, and it's a little bit goofy.
So, the omega-3 acid ethyl esters are actually Lovaza, which is a brand name for the prescription omega-3 acid ethyl esters, and then niacin has a brand name of Niaspan, but you can still find Niacin and fish oil over the counter which have essentially the same thing.
So, what's the what's the advantage of getting the prescription? The FDA has tested those particular medications, the omega-3 and the niacin and to know that it's FDA-approved. To know that it's at that level of purity can be an advantage
The big OTC cardio drug is something that's been around for a long time which is aspirin, but it's used a little bit differently. So, instead of the 325-milligram aspirin as an analgesic or for fever, we’re talking about 81 milligrams and we used to have something called children's aspirin. We now know that aspirin can cause Reye's syndrome spelled capital R-e-y-e-s, but pronounced rise, like I rise in the morning and this aspirin at 81 milligrams does a good job of keeping the platelets from getting sticky, and there's good outcomes with morbidity/mortality in terms of cardiac events like heart attack like stroke.
So, a daily aspirin, the physician tells the patient to take it, but they can just find them over-the-counter, but a very inexpensive way to help the patient. Then just a reminder that this brand name, Ecotrin is an "enteric coated aspirin" to help protect the stomach from this non-steroidal, but again this aspirin is not being used for pain it’s not being used for fever, it's being used because of its ability to thin the platelets.
Well the first prescription group we have is going to be the diuretics and with the diuretics what you want to do is in your mind picture the glomerulus and from the glomerulus we want to go to the proximal convoluted tubule, then to the Loop of Henle, then to the distal convoluted tubule, then to the collecting duct. I say distal convoluted tubule and collecting duct as separate but really, we're talking early distal convoluted tubule, but that doesn't really matter as much as getting the order right.
The reason this order is so important is that diuresis decreases as you get further away from the glomerulus. So, if you think about being on a waterslide at the top of the waterslide there's a lot of water coming out into that slide, but as you get to the bottom there's just a little trickle down at the bottom. The same thing's true here, so the osmotic diuretic Mannitol which is Osmitrol. This is used for brain edema, a very serious event but not used that often.
So, the next group are the loop diuretics. They work in the Loop of Henle, and we have furosemide, and this has a stem the -semide stem. So, there's torsemide, furosemide other diuretics and the brand name comes from the fact that it lasts six hours so, Lasix and this loop diuretic is used more for congestive heart failure or severe edematous states where there's a lot of fluid that needs to be taken off or it might be used if the fluid needs to be taken off quickly.
When you're talking about treating hypertension you could use furosemide, but more likely you'll use a thiazide diuretic like hydrochlorothiazide abbreviated HCTZ, one of the brand names is Microzide, it was the capsule form. These thiazide diuretics are more used for somebody who has hypertension. So, if you look at again the diuresis, the mannitol would be the most furosemide a little bit less Hydrochlorothiazide less than that.
The issue with both furosemide and hydrochlorothiazide is that they decrease potassium and because they decrease potassium we need to in some way get that potassium back. So, we have what's called a potassium sparing diuretic. Triamterene is one, it doesn't cause a significant amount of diuresis because it really works closer to the collecting duct and that triamterene is paired as a combination product with hydrochlorothiazide, again the -thiazide stem, and Triamterene’s brand name was Dyrenium. You take part of the hydrochlorothiazide or the ending to make the brand name Dyazide, so this was Dyrenium or used to be. But we don't really see that brand name on the shelf, ever.
Potassium sparing, so some triamterene alone is potassium sparing, spironolactone is another one. It's known as Aldactone and while there's no stem here know that spironolactone affects aldosterone and that a-l-d that's in the front of Aldactone is really referring to that aldosterone that will retain sodium and water and then by blocking that sodium and water then we'll have some amount of diuresis and we'll hold on to the potassium, so they'll be an exchange.
Electrolyte replenishment, often with loop diuretics just adding a potassium sparing diuretic wouldn't be enough, so you would need to have electrolyte replenishment with potassium chloride and to make the brand name they took the K from Kalium which is the Symbol on the periodic table of elements for potassium and then D-U-R for duration, long duration. So, a potassium supplement that has a long duration.
And again, with diuretics you really want to memorize them in this order. From the glomerulus to the proximal convoluted tubule up the ascending Loop of Henle to the distal convoluted tubule and then to the collecting duct to remember which has the most diuresis, which has the least, where are the potassium sparing all the way on the other side by the collecting duct.
So, from the diuretics we're going to go to the alpha antagonist, the alpha agonist, the beta blockers, talk a little bit about hypertension.
So, the first thing I want to go over is alpha and beta. If you weren't in a Greek letter society you might not know the Greek alphabet, but the first two letters of the Greek alphabet are like our A and B except we call it Beta [Bay-tuh]. If you were to go to the UK they call it Beta [Bee-tuh], which actually makes a little more sense that it sounds like the B and our A and B in the first two letters of the alphabet, but the important thing to know is that if you block the alpha 1 receptor you're going to get vasodilation and then if you activate it you get vasoconstriction.
So, to treat hypertension we want a lower blood pressure. To lower blood pressure we would need to vasodilate, so we would use an alpha 1 antagonist or alpha 1 blocker, and then it looks like a little fish with a 1 if you want to make the little Greek form of the Alpha, but the -azosin is the stem and there's other drugs: terazosin, doxazosin [docks AH zo sin] I've also heard it pronounced doxazosin [docks uh ZO sin] but I've always pronounced it doxazosin [docks AH zo sin] and then Cardura, it alludes a bit to cardiac or some kind of long-duration drug. The alpha-2 agonist clonidine, you can see this as a patch and clonidine it's also used with ADHD treatments, but in this case you want to maybe think about the brand name as "Catabolize blood pressure" or to lower blood pressure in some way or another and again I put up the fish or backwards fish, the alpha-2 is how most people will refer to it just because it's a lot easier than writing out a-l-p-h-a 2.
Beta Blockers fall into three generations. There's the important part of the beta blocker name or the stem is the -o-l-o-l and if you put those l's together o-l-o-l you get two backwards Bs, and you can think beta-blocker. Inderal is the brand name [of propranolol] and the way that you want to think about it is it blocks all of the beta receptors, so first-generation beta blocker it's non-selective it affects beta-1 and beta-2. So that it affects beta-1 is good, it reduces heart rate. That it affects beta-2 is not good because in an asthmatic this can be problematic. If you have a something that blocks beta 2 receptors, then you would cause bronchoconstriction. So just remember we have one heart beta-1, we have two lungs beta-2.
Beta blockers second-generation, so atenolol metoprolol are all very common beta blockers. The difference is that we're only affecting beta one. So, in this way atenolol and metoprolol are similar but what I want to call your attention to are these salts and these aren't stems, these are salts, and if it's a tartrate salt then it is short acting or shorter acting and if it's succinate then it's longer-acting. So, somebody might take one tablet a day versus two tablets a day depending on which salt they have. So, if you just say metoprolol sometimes you're not giving enough information to let us know which one did you mean?
Beta-Blocker third generation, so carvedilol. I see a lot of videos that say the -lol is a stem, it’s not -alol is a stem. -olol is a stem and -dil- is a stem or at least an approved stem. What it looks like they've done with this generic is they've recognized that Coreg affects Beta 1 receptors Beta 2 receptors but also has a vasodilator property to it, so having that d-i-l in there lets you know that it's a vasodilator and that di really took the place of what would have been that first o to make -olol. So, to remember it just think, "Okay, I would have had -olol, but I added this di and then I have the dil to let me know it's a vasodilator, and it has beta blocking activity as well".
Why would this be something that we want to do? Well if you lower heart rate, then your body is naturally going to vasoconstrict to get the blood pressure back up, the bloody doesn't want the blood pressure to be down. So, by vasodilating and lowering heart rate then we're doing two things to maintain that hypertensive patient and a normotensive state. So that's the alphas and betas.
This next group comes from something called the RAAS, so the Renal Angiotensin Aldosterone System. So, Rina is an enzyme that converts angiotensinogen, it's a zymogen. If you want to think of a fire extinguisher with the pin in it that would be a zymogen and if you pull the pin, then you can use the fire extinguisher. So, angiotensinogen becomes angiotensin 1, but you still have to do something before the fire extinguisher will fire. So, you can think of angiotensin converting enzyme as the hand that actually pushes that fire extinguisher making I guess would be carbon dioxide, I'm not sure what gas is in there, make it work. So, by going from Angiotensinogen to angiotensin 1 to angiotensin 2 you now have a postinvaso constrictor, so that's how it works physiologically to raise blood pressure.
What we want to do though is lower blood pressure, so we would block that second enzyme the angiotensin converting enzyme itself and we have an ace inhibitor, so an angiotensin converting enzyme inhibitor and sometimes people call them the prills because they always end in -pril or enalopril lisinopril. So, the renan was that first enzyme, the angiotensin is second the angiotensin one is second, then angiotensin II is third, but then what about this aldosterone? Well aldosterone retains sodium and water as its physiologic purpose, so we're going to want to block that to allow for the secretion of sodium and water and then in secreting the sodium it exchanges from potassium as a potassium sparing medication.
So, understanding the way that the electrolytes work is critical in the raas, and then it all comes together as a system, but what if a patient develops a dry unproductive cough and this can happen with angiotensin converting enzyme because of its effect on Bradykinin. What we do is not treat it. We don't give them codeine, or we don't give them Dextromethorphan. What we do is we switch them to an arb or an angiotensin II receptor blocker. So instead of affecting the enzyme we're going to block the receptor itself and some people call these the sar tans because they all end in [Sar] [tan] or S-A-R-T-A-N and you can see some clues to cardiac in the raas if you look at [Kosar] backwards it would be [ra] az or looks like [raas] and then benicar benefit cardiac. Never came up with anything for diovan, but the van and diovan takes the V in the last two letters of sartan.
So, again understanding that ace inhibitors, we've known them for a long time. They work very well, but you might switch a patient over to an arb if there's some kind of non-productive cough caused by the ace inhibitor.
So, let's go to calcium channel blockers and two very different kinds of calcium channel blocker. One that vasodilates and affects the heart and one that just vasodilates.
The nondihydropyridine CCB's, or calcium channel blockers, are the ones that affect both the heart and cause vasodilation. Why is this important? Well beta blockers can be used as antidysrhythmics, calcium channel blockers can be used as antidysrhythmics if they're in this nondehydropyridine class. So, diltiazem has the -tiesm stem which is cardizem, and you can see cardiac in there and verapamil, which ends in -pamil with the pamil stem and you can see the brand name Kalyan the Ca for calcium or the Cal for calcium and then -an for antagonists or part of channel. There are a number of different ways you can look at it to remember it's a calcium channel blocker.
What's important, and I'll give you a story, is that my daughter's when they were -- after my cerclage procedure to keep them in she needed a calcium channel blocker to keep the children from coming back out and the calcium channel would would block -- if we used nondihydropyridines then we would suppress heart rate, not only in my wife, but also in the three fetuses, and we wouldn't want to do that. So, the choice was one of these two and amlodipine and nifedipine and we ended up having nifedipine prescribed, but nifedipine only vasodilates and it was a very low dose. So, just used as something off-label, but there is a huge difference between the two and that both groups vasodilate but only the nondihydropyridines affect the heart directly.
Then both of the brand names, Norvasc you can think of vasculature and then Procardia, cardia has to do with the heart. Then this -dipine you can find the in Hydropyridine, you can find the D-I-P-I-N-E and you actually have more choices, but my students looked at it as we see the dipine, but we also think of a dip in blood pressure, so the -dip and then the -in as a way to remember what it's for.
So, moving from those vasodilators to single vasodilator nitroglycerin -nitro is the stem. I didn't see it on the USANC, but I did see it on the World Health Organization and the brand name Nitrostat means certainly we're using nitro, and we're doing it very quickly or stat.
The HMG-Coareductase inhibitors. These are known as the statins because of this ending and this is the stem, statin but you really don't want to use just statin. You want to use this infix -va or the -va statin because there's an antifungal called Nystatin that has this S-T-A-T-I-N at the end as well, and you don't want to confuse those. So, atorvastatin is Lipitor, sounds like the lipid gladiator, and then rosuvastatin is Crestor, and you can think of cholesterol. There's a couple letters from cholesterol in Crestor. The fibric acid derivative, so the fibrate is the stem, and this is Tricor and the reason they named it that way is because these fibric acid derivatives affect the triglycerides or help with triglyceride lowering. So those are some medications again for hypertension, some other uses for cholesterol.
Let's go and finish up with some anticoagulants. Cardiac glycoside and then one anticholinergic. So, the big difference between the anticoagulants is if they're parental or enteral. So, enoxaparin ends with -parin and that's the stem and that's Lovenox. Then heparin, I didn't want to put a brand name because we've been using it so long it doesn't really, it does sort of have one, but I just left it like that. But notice that the parenteral and -parin are sort of alike. This parenteral role isn't parent like someone had a child, it's the word para, meaning outside of, enteral, and we just got rid of the second A. So, something parenteral is outside the GI. Something enteral is taken by mouth or orally?
It looks like I forgot to put one up there which is dabigatran, which is Pradaxa, and -gatran is the stem. Then warfarin and dabigatran are very similar in that they're both oral anticoagulants, but warfarin requires INR measurements to make sure that the patient has the right amount of coagulation to the point where they're going to be bleeding or isn't to the point where they're more likely to get a stroke or something like that. So, you can see the letters. I N and R at the end of warfarin to remind you of that. Another thing my students used warfare, that warfare is bloody as a way to remember that bleeding is a side effect or possible side effect of warfarin.
The antiplatelet, so where the anticoagulants tend to work in the veins, very slow-moving areas where coagulation happens because of stasis or where the blood slows down. Something like clopidogrel, an antiplatelet, which is comparable to aspirin in the way that it works has the -grel stem and it works on platelets, and you can see the -pla from platelets in the word Plavix, so it vexes platelets.
Cardiac glycoside, so there's no stem here but it comes from the plant Digitalis Lanata and it looks like little fuzzy fingers. So, the -dig comes from digitalis and -lan comes from Lanata. So, digoxin and Lanoxin are both, I guess, homages to the flower itself that this came from, foxglove, but digoxin is a cardiac glycoside. So, it's a positive inotrope, increases the strength and force of contraction of the heart, but it also works as an antidysrhythmic. So, it used to be used all the time back in the mid-90s, but then they found that sometimes there's a bit of a danger with it because a patient that has very low potassium and digoxin could go digitoxic.
Anticholinergic. So, the tropes stem lets you know there's a cholinergic component, but the tropine really lets you know that it's a tertiary nitrogen compound versus the [tro] [p.m.], which is a quaternary compound, and this is atropen. What we use an anticholinergic for is anticholinergics would cause tachycardia or increase in heart rate. In some procedures were really worried about bradycardia or very low heart rate. So, by giving atropine we prevent low heart rate by giving a drug that causes high heart rate. It's one of the four drugs in the lean acronym which is L-E-A-N. So, lidocaine epinephrine atropine and Naloxone and then these are the drugs for emergencies for various reasons.
So that's cardiac.
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Australia, it’s the go to resource to ease the pharmacology challenge. Available on Audible, iTunes, and Amazon.com in print, eBook, and audio book.
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