Warfarin – Anticoagulant Drugs (Nursing)

by Prof. Lawes

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    00:01 Now, warfarin, you may have heard this called Coumadin, has this really bizarre beginning.

    00:07 They originally discovered when cattle were just bleeding out after eating spoiled clover.

    00:12 So you take some horrible event in nature, and some very clever people figured out how to turn spoiled clover into warfarin.

    00:21 Now, it's still used today as rat poison.

    00:23 Isn't that interesting? Like, I've actually taken this medication, obviously, in a much smaller dose than rat poison by body weight, but we use it in clinical applications, too.

    00:34 So, warfarin, originally founded because cows were dying, there were bleeding out after eating spoiled clover, and we use it for rat poison still today, and we can give it to you as a medicine.

    00:46 It's kind of scary sometimes where things come from.

    00:49 So, warfarin stops the activation of vitamin K, so there's less biosynthesis of the 4 vitamin K-dependent clotting factors.

    00:58 Okay, that is an important point.

    01:00 I want to make sure that you get that.

    01:02 4 of your vitamin K clotting factors are big players in your ability to make a clot.

    01:08 So, the drug warfarin stops these 4 factors from being activated, therefore, you don't make as many clots.

    01:17 So, it decreases the production of these factors by 30%-50%.

    01:23 So somebody on warfarin has 30%-50% less ability to use these 4 clotting factors.

    01:30 Now, it doesn't impact the clotting factors that are already circulating, right? So it's just the ones as they're being made.

    01:37 That's why you don't completely bleed out for taking just a dose of warfarin.

    01:41 So, remember, warfarin hits the clotting factors as they're being made, and it stops the activation of the vitamin K-dependent ones.

    01:50 So we don't use warfarin in emergency.

    01:52 If someone came into ER and they're having an MI from a big clot, warfarin is not our drug of choice.

    01:58 We would use something -- after making sure the patient was safe, we would use something like a thrombolytic, a clot buster, if it was appropriate.

    02:07 But warfarin, think of it as long-term treatment, not for emergencies.

    02:12 It may take several days to reach therapeutic and anticoagulant levels.

    02:16 So remember, when I was in the hospital for a pulmonary embolism, I got heparin right away in the hospital, and then I started warfarin a few days before I was discharged.

    02:26 But I went home on both; low-molecular-weight heparin and warfarin, until my lab values for the warfarin reached a therapeutic level.

    02:36 Lab values for warfarin are PT and INR.

    02:41 So you take this as a pill, that's a lot easier, and it doesn't burn like fire like low-molecular-weight heparin.

    02:46 We watch that PT/INR lab work, and they'll adjust the dosage based on what results they get.

    02:53 So when you're on warfarin, initially, as they're trying to get you to a therapeutic level, you'll have the test done really regularly.

    03:00 Then it'll get to be longer and longer periods of time, the more stable and therapeutic your PT/INR stays.

    03:07 So, you can actually monitor your INR at home.

    03:10 So we put a little monitor up there for you to see what it looks like.

    03:13 So patients can even do this.

    03:15 So, I don't necessarily have to always go into the lab once I'm established at a therapeutic level, and I'm not having any problems.

    03:22 The health care provider -- and I'm very compliant -- the health care provider may feel very comfortable with me checking my INR at home, much like diabetic patients check their glucose.

    03:33 Now, I want you to understand that PT/INR test because nurses need to understand the goals that we use lab to help us reach.

    03:42 So a therapeutic level and length of treatment will vary.

    03:47 So, first of all, if a normal INR for someone receiving warfarin is 1.0.

    03:52 -- So that's someone not receiving warfarin.

    03:54 That's where we start before they get it.

    03:57 The health care provider will decide what's the therapeutic level? What are we going for? But if somebody is on warfarin, that level has to be higher than 1.0 because normally you're a 1.0, we want that to be elevated because we want you to be less likely to make clots.

    04:14 So, I'm going to show you an example of a protocol.

    04:17 Every healthcare provider will have their own exact protocol that they like to use based on that patient's history and their status and their lab work.

    04:25 But let's just walk through an example just for fun.

    04:28 Okay, so it was my first episode of a DVT, we don't know what caused it.

    04:33 That's what idiopathic is, makes us sound way smarter.

    04:36 It just means, "Hey, we have no idea why that happened to you." So let's say we have a client who has a DVT, a deep vein thrombosis, that would be in their leg.

    04:45 It's their first episode and it's idiopathic.

    04:48 We don't know what caused it.

    04:50 What's our target INR? Well, normal INR is 1.0, but because we want you to be less likely to make more clots, and we don't want this clot to get bigger, we're going to shoot for 2.0-3.0.

    05:05 So, how long are you going to have to stay on this medication? At least 3 months.

    05:09 Now, you may not even realize right now, that is a pain in the -- I can't say it, all right? That's a pain to be on that medication.

    05:17 People don't like taking medication.

    05:19 It's really not that problematic, except for there are serious diet modifications.

    05:25 We'll talk about those in a minute, but just know that at least 3 months is nothing to sneeze at.

    05:30 That's going to impact their life.

    05:32 So DVT, first episode, normal PT/INR or a normal INR is 1.0.

    05:37 We're going to shoot for 2.0-3.0.

    05:39 So you're going to be that much higher than normal, because we don't want that clot to get bigger or you to make any more clots.

    05:45 Now into a bigger problem, a pulmonary embolism.

    05:48 The target INR is the same, 2.0-3.0, and at least 3 months.

    05:54 That was a very long year for me.

    05:56 I hated dealing with that, but I should be very thankful that my PE had a different ending than my first patient.

    06:04 Now, finally, patients who are on prosthetic or aortic heart valves, we want them a little bit higher.

    06:09 Look, they go 2.5-3.5, and you may also consider adding aspirin on to that.

    06:15 They'll likely be on that for the rest of their life because some of those heart valves are really prone to developing clots, and that's why the patient would be on it for the rest of their life.

    06:25 Okay, so say you're my nurse and we're starting this warfarin.

    06:29 And let's say that I'm in for a pulmonary embolus, right, and because that's what I was.

    06:34 You look at my INR and it is 1.8.

    06:38 What should you do? Well, is it safe for you to give the next dose of the medication? Well, the target the healthcare providers told me is 2.0 to 3.0, and I'm at 1.8.

    06:49 That is lower than what our target was, so absolutely, it's safe to give the next dose, but you should contact the health care provider and let them know where you are in the process.

    06:59 Now, when you're actually practicing, you'll know how they want to be notified, but it is perfectly safe to give that medication.

    07:06 Let's take another example.

    07:08 If I'm in for a pulmonary embolism, you don't know why it happened, now my INR is 4.5.

    07:15 Should you give the medication? No, because, look, my goal was 2.0 to 3.0, I'm at 4.5.

    07:22 You should absolutely hold that medication and contact the healthcare provider immediately.

    07:28 Now I'm a big risk for bleeding in very inappropriate and very dangerous places.

    07:34 See, that's how nurses use evaluating the effectiveness of medication therapy by comparing it to lab results.

    07:42 Now, when I told you it was inconvenient, I used to have a lot more risk factors for clots.

    07:47 I was carrying a lot more weight, I was a lot more immobile, and so, I ended up being on Coumadin for over a year.

    07:54 So, you know when you have a major health event, you want to get healthy, but here's the problem.

    07:59 Vitamin K is the antidote to Coumadin.

    08:02 If like -- when I was at 4.5, you would have been giving me vitamin K as the antidote to bring that INR back down to under 3.0.

    08:11 But as a patient, you have to keep in mind that there's lots of foods that contain vitamin K.

    08:18 So, I went through this major life event, I'm like, "I'm going to eat healthier." Well, look at your screen.

    08:23 Everything that's on that screen is healthy and it contains Vitamin K.

    08:28 Okay? So, you have to educate patients that vitamin K is in foods they would never suspect.

    08:34 It made eating out really difficult.

    08:36 It made planning my lunch very difficult.

    08:39 And you couldn't just sit down and eat a salad because that's really high -- green leafy things are very high in vitamin K.

    08:47 So it was a radical life change for me.

    08:49 I had to learn what foods had vitamin K.

    08:52 We had to severely limit the foods with vitamin K.

    08:57 That is not as easy as it sounds.

    08:59 And in fact, when I teach these classes, a lot of times, I'll have students actually plan 1 day and follow a low vitamin K diet or a low sodium diet, so we can have empathy for our patients that what we're telling them they need to do is not that easy.

    09:14 Now, if your patient is like, "I am very committed to a kale salad.

    09:19 I must have one." Well, here's what we can do.

    09:22 They're going to have to eat that kale salad same size, same time of day, every day for the treatment time.

    09:29 Okay.

    09:29 So that means if you want that kale salad at lunch every day, then you're going to have to eat a kale salad at lunch every day, and the same size, and around the same time, because they're going to base your Coumadin dosage, your warfarin dosage, on that you intake that much vitamin K every day.

    09:47 So, if suddenly people become less committed to absolutely having to have something because it really impacts our therapeutic plan.

    09:56 Also know that most people are resistant to this.

    09:59 They're not going to follow the diet plan as well as is in their best interest.

    10:05 So, be patient, be kind, don't be judgmental, but make sure you show them a list of all the foods that have vitamin K, and the weird ones that they may not expect, so they can at least make an educated and informed guess.

    10:21 Now, if I had a patient, like I told you -- if my INR was 4.5, then what you would give me is vitamin K.

    10:27 It reverses the anticoagulant effects of warfarin.

    10:30 It's why you can't eat a lot of it in your diet, and it helps those 4 vitamin K-dependent clotting factors.

    10:36 But it takes about 24 hours to have the maximum effect.

    10:41 So, usually, taking vitamin K oral dose is the safest route to do that.

    10:45 That doesn't mean, as nurses, we wheel a giant salad into their room.

    10:49 We'll actually give them oral vitamin K as a medication.

    10:54 Now, part of being good nurses is we always want to know who shouldn't take a medication or who is it unsafe for for them to take the medication? If someone is currently severely bleeding, we don't want to give them warfarin.

    11:07 If they're not very compliant with the medication, or they don't follow up with monitoring, or they don't follow their dietary restrictions, we might have to try and look for a better plan.

    11:17 I'm not saying it would be as effective, but we might need to look for another plan.

    11:20 And there are some other medications we could use to have similar impact on the patient's body, but they're usually a lot more expensive, and you'll see commercials for them on TV.

    11:32 Pregnant women also should not take warfarin.

    11:35 Okay, so, who shouldn't take it? Someone who's already bleeding, someone who's going to have a difficult time following the medication or the diet plan, or someone who's pregnant.

    11:47 Now, your job is to think back through those lists and make sure you can answer why should someone who's currently severely bleeding not take warfarin, and don't let yourself off the hook.

    11:57 Don't just say, "Because they'll bleed more." Think through that what warfarin does, and the why you wouldn't want someone to be on it.

    12:04 Work through the other 2 answers as you pause the video.

    12:14 Okay, now let's continue to work through the people who it's not really safe for them to take warfarin.

    12:21 Uncontrolled hypertension or someone with severe liver disease is also not safe for this.

    12:27 Uncontrolled hypertension, that means they've had hypertension that hasn't been treated with medications, it's been out of control, they may be at risk for bleeding in a really inappropriate part.

    12:38 Now, severe liver disease, remember those clotting factors and where they're built? Okay, so if they already have liver disease, their clotting factors are going to be way out of whack.

    12:48 Warfarin is going to make that worse.

    12:50 If they've had recent surgery, particularly on their central nervous system, their spinal column, or in their eye, we don't want to risk bleeding there, because there's the tiniest margin for bleeding in those areas.

    13:01 So if they've had recent surgery, we're going to stop the warfarin before they have it, and we're going to stop it for a long period of time afterwards.

    13:09 So then, if they are on any other medications that increase the risk of bleeding with Coumadin, including over-the-counter drugs.

    13:15 So when I was taking warfarin, if I had a headache, I couldn't take aspirin or NSAIDs So while you're on warfarin, you don't want to take any of these regular, over-the-counter medications without really running it through your health care provider.

    13:31 But you think about that every time you have a headache, or an ache, or a pain and it seems like some joint in my body is always complaining at some point, you can't use what we normally would: aspirin or an NSAID.

    13:44 But special note to that is remember, heparin may be used with Coumadin until the Coumadin reaches those therapeutic levels.

    13:51 I went home on low-molecular-weight heparin, the shots in my abdomen, and Coumadin until my PT/INR was at a normal level.

    About the Lecture

    The lecture Warfarin – Anticoagulant Drugs (Nursing) by Prof. Lawes is from the course Cardiovascular Medications (Nursing). It contains the following chapters:

    • Warfarin
    • PT/INR Test
    • Warfarin and Vitamin K
    • Who Should Not Take Warfarin

    Included Quiz Questions

    1. Vitamin K
    2. Vitamin B
    3. Vitamin C
    4. Vitamin D
    1. 30%–50%
    2. 10%–30%
    3. 50%–70%
    4. 70%–90%
    1. Factor X
    2. Factor VIII
    3. Factor VII
    4. Factor IX
    5. Prothrombin
    1. Emergencies
    2. Long-term treatment
    3. Preventative treatment
    4. Deep vein thrombosis
    1. 2.5–3.5
    2. 1.0–3.0
    3. 2.0–3.0
    4. 2.5–4.5
    1. 2.0–3.0
    2. 2.5–3.5
    3. 1.0–3.0
    4. 2.5–4.5
    1. Current severe bleeding
    2. Pregnancy
    3. Uncontrolled hypertension
    4. Pulmonary embolism
    5. Deep vein thrombosis

    Author of lecture Warfarin – Anticoagulant Drugs (Nursing)

     Prof. Lawes

    Prof. Lawes

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    Love this instructor.
    By Andria V. on 06. September 2020 for Warfarin – Anticoagulant Drugs (Nursing)

    Again I love how she connects the dots and use examples. Not at all boring.

    Great job!
    By lingdi W. on 21. November 2019 for Warfarin – Anticoagulant Drugs (Nursing)

    thank you! your lecture is super, very useful, easy to remember

    By Dr. Norliza M. on 29. April 2019 for Warfarin – Anticoagulant Drugs (Nursing)

    Very clear explanation. Relating the topic to her own experience is a bonus. She instills empathy in her lecture