Video OER Pharmacology Cases and Critical Thinking Chapter 1 Kinetics and Dynamics Part 1

This is Chapter 1, Part 1 of the Critical Thinking exercises in Chapter 1 of the OER Nursing Pharmacology book where I go over a little more detail on the answers to help you better understand pharmacology with the engagement of small case studies. 

Find the book here: https://geni.us/iA22iZ 

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Auto Generated Transcript:

Hey, welcome to the Memorizing Pharmacology podcast. I’m Tony Guerra, a pharmacology professor and author of the Memorizing Pharmacology and Memorizing Pharmacology Mnemonics series of books. What we’re going to do today is go over the critical thinking activities in chapter one of this Nursing Pharmacology OER book. That is, it’s an open educational resource so you can get it for free if you like. We’re just going to go over the critical thinking activities in the first chapter. So, we’re not going to be skipping around as much as we’re just going to kind of zero in on those activities that really focus on critical thinking. If you want more information, you can always go back to the book itself to check it out.

So, the way it works is we’re just going to go here and we see okay critical thinking activity 1.5. Metabolism can be influenced by many factors within the body. If a patient has liver damage, the patient may not be able to break down or metabolize medications as efficiently. Dosages are calculated according to the liver’s ability to metabolize and the kidneys’ ability to excrete. When caring for a patient with cirrhosis, how does this condition impact the doses prescribed for the patient?

So when we have somebody that has cirrhosis, the first thing we’re really kind of saying is that the liver is damaged right? So if these transformations or biotransformations as we call them are in the liver and normally are taken care of by liver enzymes and those liver enzymes are damaged and so forth then they’re not going to work as well.

So what happens? Well, what we really want to talk about here where if you have less and if you have more ability to metabolize these medications. So let’s think about it this way: The liver can normally metabolize some amount of medication right? If it’s damaged, it’s gonna be like when you’re at work and there’s one less person there and you can’t get things done as quickly.

So for example, it’s very often that you know you’re in a restaurant and they’ll tell you hey you know we just don’t have enough waiters tonight sorry times are a little bit slow okay all right so your food isn’t going to get there as quickly. When we’re talking about metabolism and medications that means that we’re going to have more or less medication hanging around.

Well if the liver’s job is to break down the medication then that means we’re actually going to have more medication sticking around okay and that means that we need to do what with the dosage? Okay, the dosage needs to go down because the amount of medicine still in the body because the liver can’t break it down is going up okay so we’re basically lowering dosages to decrease that toxicity okay.

So again as we go through these critical thinking activities you can kind of stop the recording say okay well let me try to answer it and then kind of go from there okay so we’re in now excretion so if we’re thinking about pharmacokinetics we have absorption distribution metabolism and excretion.

The liver is the organ that is most associated with the breakdown of medications or transformation of medications and Metabolism but when it comes to an excretion we’re talking about now how good is the kidney function okay so when providing care for a patient who has chronic kidney disease how does this disease impact medication excretion?

Well if many of these medications and metabolites, the kidney filters them when we are not able to get rid of them okay we might find that we are now getting reserved back into the bloodstream. The kidneys aren’t working they’re just kind of hanging around hanging around and we have a very similar effect to the liver but just to be clear: The liver hasn’t been able to break it down and we keep more medication around with chronic kidney disease.

The medication excretion okay is going to be slowed down because we just can’t get rid of it. The kidney is damaged okay all right let’s go on to the next one pharmacodynamics so we have pharmacokinetics and pharmacodynamics pharmacokinetics is really the absorption distribution metabolism and excretion pharmacodynamics now we’re going to talk a little bit about how a medication and its effects are going to create a need for an assessment or different type of assessment.

"Administration, well, let’s start by defining that word, inotropic. Okay, inotropes are generally going to increase or decrease the strength of contraction of the heart. Whether it’s a positive inotrope where it increases the strength of contraction or a negative inotrope where it reduces the strength of contraction. So, digoxin is a positive ionotrope. Other ones include dopamine, dobutamine, adrenaline or adrenaline. Those are positive ionotropes increasing the strength of contraction. Negative inotropes include like amiodarone.

Amlodipine, carvedilol, metoprolol, propranolol, ramipril, valsartan those types of things. So when we’re talking about these medications we’re looking and saying okay we have a beta blocker this is a negative ionotrope this is going to reduce the force of contraction okay but what’s it going to do as far as its chronotropic effect so again we want to define well what is a chronotropic effect so a positive chronotrope is one that’s going to increase heart rate get you closer to tachycardic and then a negative chronotrope is one that’s going to reduce heart rate it’s going to get you closer to bradycardic and again to define that bradycardia is right 60 beats per minute tachycardia is 100 beats per minute.

So to give you some examples if we talk about the positive chronotropes we would think like atropine, dopamine, dobutamine, epinephrine. If we think about the negative chronotropes we’re talking about digoxin, diltiazem, varapamil, metoprolol but really we could say beta blockers in general so it’s important that we see that atenolol has negative inotropic and chronotropic effect so what should the nurse assess before administration now that we know what these are for well it’s reasonable that if you’ve got something that’s going to reduce heart rate and maybe reduce heart blood pressure then the first thing that we want to do is we want to assess the patient’s pulse and blood pressure and make sure they’re normal.

What we don’t want to do is have somebody that maybe is already bradycardic and bring them even down lower okay now I run marathons or I run long distance so my normal heart rate is probably in the 50s so they would just check okay well that’s normal that’s fine it’s not that something is happening okay but that’s what we would do.

Alright let’s go on to 1.9 we have two parts to this one first at 05:00 number one at 05:00 your patient who had a total knee replacement yesterday rates his pain while walking at seven out of ten physical therapy is scheduled at nine patient oh 09:00 okay so 9 A.M. to us the patient has acetaminophen Tylenol 625 milligrams ordered every four hours as needed for discomfort what should you consider in relation to the administration and timing of the patient’s pain medication.

So there are really three things that we’re going to do here first we have 05:00 okay that’s what time it is now okay the patient needs medication will give them medication now right we know they’re going to need it in about four hours so what we can do is after about an hour check with the patient see how they’re doing see if their pain is improved then just before the physical therapy session we want to make sure that they get their medication because we don’t want them to have one dose at five then four hours later start their physical therapy session and be in pain while that’s happening so we want to make sure it’s a little ahead of time.

The last thing we want to do is we want to make sure that we don’t exceed the maximum Tylenol for the day and there’s a couple of numbers here generally we say that we really don’t want to be above 4 000 but if you actually talk to the makers of Tylenol they would prefer that number be even closer to 3 000 a much safer amount if the patient and this isn’t in the paragraph but if there were some alcohol disorder or patient as a drinker we would want to reduce that Tylenol even more because we want to be careful with the liver.

So 05:00 patient had a total knee replacement yesterday pain walking seven out of ten physical therapy scheduled at nine. We give the first dose at five then we check with them about an hour later make sure that it’s working then just before the physical therapy we give them another dose okay then four hours after that they’ll get another one and what we’re making sure is throughout the day that the patient isn’t going over the amount they should have now.

"We can do a quick calculation here if 625 is ordered every four hours let’s see what that total would be and I know what it is I can do it in my head but I’m just saying let’s let’s get the Google Calculator. Okay, so the first thing we want to do is we want to be careful we don’t multiply the 625 times 4 because it’s every four hours we would multiply the 625 times 6 and we see that that number 3750 milligrams is right there between three thousand and four thousand and what we want to make sure is that okay maybe it’s around the clock but maybe it’s not because this isn’t for inflammation Tylenol doesn’t acetaminophen doesn’t help with inflammation if the patient can sleep through the night then okay maybe one of those doses we won’t use will get a lot closer to that 3000 number or maybe it’ll go out a little bit further closer to the five hour mark something like that and we get down to three thousand but we’re really hovering on the edge so this is where we really want to be careful if someone says okay well the pain isn’t being taken care of let’s add some Vicodin or something like that and Vicodin in it or vicoprofen would have an additional or Vicodin not vicoprofen Vicodin would have an additional amount of acetaminophen so we definitely want to be careful of that okay.

Alright, well let’s look at the second one here. Number two, your patient is prescribed NPH insulin to be given breakfast and supper. As a student nurse, you know that insulin is used to decrease blood levels in patients with diabetes mellitus. During a report, you hear that this patient has been ill with GI upset during the night and the nursing assistant just inform you he refused this breakfast tray. While reviewing this medication order, you consider the purpose of the medication and information related to the medication onset peak and duration again we’re talking about the NPH insulin right now when reviewing the drug reference you find that NPH insulin has an onset of about one to three hours after medication administration. What should you consider in relation to the administration and timing of the patient’s insulin?

So let’s take a minute to think about it. Alright, so you’re back and let’s think about this. So the insulin is supposed to decrease blood sugar levels but the patient’s stomach’s been hurting quite a bit and he’s just not hungry. Well wait a minute, insulin can be used to reduce blood glucose levels but our expectation is that glucose levels are going to be increased each time the patient eats. If the patient is not eating well then we need to really make sure that we’re not going to cause hypoglycemia. So again hyperglycemia is glucose that is too high in the bloodstream hypoglycemia is when it’s too low so insulin is one of those high alert medications and so if this continues to happen, the patient keeps refusing the food but keeps getting the insulin, we could be in a lot of trouble so we want to make sure that we work with the patient make sure that we’re checking if they’re eating and make sure that the insulin dose is appropriate for how much they’re eating and we would do that by doing some blood glucose tests throughout the day to make sure that those blood glucose and blood sugar levels are where we want them to be.

Alright, here is critical thinking activity 1.10 a Mr Parker has been receiving Gentamicin 80 milligrams this is under medication safety has been receiving Gentamicin 80 milligrams IV three times daily to treat his infective endocarditis he has his Gentamicin level checked one hour after the end of his previous Gentamicin infusion was completed. The result is 30 micrograms per ml based on the results in the above patient scenario what action will the nurse take based on the result of the Gentamicin level of 30 micrograms per ml okay so I’ll give you a minute.

Alright, the normal lab value okay that’s kind of the first thing that we have to do okay it’s like five to ten mcgs or micrograms per ml right or if you’re using micro moles it’s like 10 to 20. It’s a little higher okay per liter what we can do is see if this patient has good kidney function there might be some kind of renal impairment that is not helping with excretion and we need to make sure that we adjust the dose on the next time so again we’ve got a result. We compare the result to the normal Gentamicin levels, we see that the level is high and now we’re going to check maybe kidney function what’s going on because Gentamicin itself is ototoxic damaging to the ears but also nephrotoxic and can actually damage the kidney itself.

Alright, I’m actually going to stop it there before we go to 1.12 module learning activities. I think that you know that 15 minutes or somewhere between 15 and 20 minutes is a good amount of time so again you can go to the nursing pharmacology book and we went through 1.5 metabolism, 1.6 excretion, 1.7 pharmacodynamics, 1.9 okay we’re examining the effect, 1.10 medication safety okay so again if you want to check out a course on pharmacology that has all those mnemonics and things like you’re welcome to check out the self-paced pharmacology course with mobile quizzes and videos at residency.teachable.com forward slash P forward slash mobile and you can always get half off h-a-l-f-o-f-f again it’s h-a-l-f-o-f-f to get half off.

Like to learn more?

Find my book here: https://geni.us/iA22iZ

or here: https://www.audible.com/pd/B01FSR7HLE/?source_code=AUDFPWS0223189MWT-BK-ACX0-059486&ref=acx_bty_BK_ACX0_059486_rh_us

and subscribe to my YouTube Channel TonyPharmD here: https://www.youtube.com/c/tonypharmd

Here is the Link to my Pharmacy Residency Courses: residency.teachable.com