14.09 Parasympatholytics (Anticholinergics)

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Okay, so, in this video, we gonna cover parasympatholytic medication. And you know, like before running any ANS medication, I really wanna review this chart, so we know like what effect parasympathetic nervous system has on our body and what does the sympathetic. So, in this one, we gonna focus on this one. So, parasympathetic nervous, so we gonna talk about the drugs that goes and binds to the parasympathetic receptors and blocks them, and blocks their activity. So, whatever is happening when you are looking at here, whenever is happening, when you excite the parasympathetic nervous system, it’s gonna happen exactly opposite thing. So, let’s say, if it is gonna decrease heart rate, the parasympathetic medication that blocks the receptor is gonna increase the heart rate. It gonna cause the relaxation of bronchiole muscles, constriction of arteries, and so forth. So, it’s like totally effect of the parasympathetic nervous system on our body because we are blocking the parasympathetic nervous system receptors.

Next slide is just showing the main recep, mean your transmitter for the parasympathetic nervous system is Acetylcholine. Parasympathetic nervous system has 2 receptors, muscaranic receptors, nicotinic receptors. Muscaranic receptors are present in heart and all other parasympathetic target organs. And, Nicotinic receptors are present in the smooth muscles. This is a really important thing to remember especially for the parasympatholytic medications, okay? By the nicotinic and muscaranic receptors, nicotinic in the smooth muscle.

Alright. Let me see. Alright. So, the parasympatholytics medication. First, in this categories, we gonna talk about this medication that goes and blocks the muscaranic receptors. We’re not talking about the nicotinic right now, the only muscaranic. So, it will not have any effect on smooth muscles. As we know, the nicotinic receptors are present only in smooth muscles, while the muscaranic is on the heart and on the targeted parasympathetic nervous system receptors, okay? So, this blocks the Muscaranic receptors of the parasympathetic nervous system and we gonna talk about the each drug in this category.

First one is a really really important drugs is Atropine. Okay. Atropine has a wide variety of use. First one is to increase in the heart rate, so, if you know the ACLS algorithm or the medication, the atropine is really mean like if you give this medication for bradycardia, to increase the heart rate. To inhibit vagal response. Can give this medication to dilate pupils. Now when we block the parasympathetic nervous system, it’s gonna relax the GI and GU is gonna slow down. So, we can give this medication for relaxation of GI and GU system. And also, as we talked, if you have reviewed the parasympathomimetic drugs, there is a class that’s called indirect acting parasympathomimetic drugs and whenever there is a poisoning of indirect acting parasympathomimetic drugs, the heart rate goes down and in order to bring the heart rate up, atropine is often used as an antidote for the heart rate. So, that’s the important thing to remember, atropine.

Scopolamine. That’s a drug it’s used to decrease the GI motility, to decrease the nausea and vomiting associated with a high GI motility and also for the pupil dilation.

Benztropine Trihexyphenidyl. That one’s also to reduce tremors and muscle rigidity in Parkinson Disease. So, this muscle, this actually relax the whole skeletal muscles thing and very often used as Benztropine, is very often use for the relaxation of muscles, if they are having muscle spasms.

Ipratropium and Tiotropium is used for asthma. Now, that’s another thing to remember about this drugs is this one is used for asthma management. Now, what does that mean? If you know about the Albuterol, that’s the sympathomimetic drug. Albuterol has a really, it works really fast like it works in minutes. So, if someone is having asthma attack, you will give albuterol. You cannot give Ipratropium and Tiotropium because these drugs will take about 15 minutes to start working. So, these medications are used for the asthma management, not for the asthma attack. That’s the important thing to remember, okay? Ipratropium and Tiotropium.

Oxybutynin is for incontinence, you know, like a parasympathetic nervous system. This is actually increases the urinary system and it contracts the urinary bladder. But when you block that parasympathetic nervous system effect on the urinary system by giving these drugs, it will decrease the contraction, and it will decrease the incontinence. That’s the other, this drug Tolterodine, that’s also for overactive bladder and urinary urgency and frequency. It’s been used like if someone is having urinary urgency and frequency. These drugs actually will decrease the urgency and frequency as well. It works on the urinary bladder well.

Now, side effects, it’s the same thing. So if you’re giving a drug, let’s say to treat something urinary frequency and urinary urgency, now, this drug is also gonna go to a different organ and gonna bind to parasympathetic muscaranic receptors and then gonna block that one too. And that effects are basically the side effects. Let’s say, the drug, let’s talk about the drug, for example, Oxybutynin. This one. You give this one for incontinence, it should work on the urinary bladder. But, at the same time, it will go to the heart and blocks the parasympathetic receptors that will increase the heart rate. It will go to the eye and it will constrict the pupils. Or, I’m sorry. It will dilate the pupils and will cause an increase in intraocular pressure. It will like decrease the salivation because it’s gonna go to the salivary gland and block the parasympathetic nervous system. So, it’s gonna decrease the salivation, it’s gonna cause a dry mouth. Basically, those effects on the other organs that we don’t want but we do not have any control over it. It’s the side effects. So, blurred vision, increase intraocular pressure, weakness, dizziness, insomia and confusion, dry mouth, nausea and constipation, heartburn, paralytic ileus, because like it’s gonna go to the gastrointestinal system, it’s gonna slow down GI system as well. It can cause that one. It can worsen the urinary hesitancy and it can cause urinary retention as well. This medication as I said, like it gonna go to the heart and gonna block the parasympathetic nervous system. The receptor is gonna increase the heart rate, it can cause heart palpitation and cardiac arrhythmia as well. So, those are the side effects for these drugs.

Now, we talked about blocking the muscaranic receptors, so, those the parasympatholytic are blocking all the previous drugs blocks the muscaranic receptor. Now, what if we block the nicotinic receptors which is present at the smooth muscles? What it will do, so this medication, another class, falls under the parasympatholytic medications. They block the nicotinic receptors of the parasympathetic nervous system, that’s why it’s also known as neuromuscular blockers. Now, when it blocks this nicotinic receptor at the smooth muscles, it will paralyze those smooth muscles, basically. Like anyone entering, anyone entering, both. So, actually, it will cause, that’s why they are also called as a paralyzing agent as well. And they’re oftenly used with anesthesia, like for the intubation, if a patient has a, if they are in a ventilator and they’re fighting ventilator, then they’ll give this medication to paralyze, do not fight the ventilator and increase their respiratory system function. But it has to be used under the supervision of physician and they’re not really oftenly used in ICU. They’re more used in operating rooms, OR, and IR. The different categories in this too, it’s depolarizing agents and non-depolarizing agents. I’m not gonna go in detail of these each mechanism of action for depolarizing and non-depolarizing because it’s too in depth. And as nurses, we don’t really need to know. But just remember there are two different types, there are two different categories of these neuromuscular blockers. Depolarizing and non-depolarizing agent.

Depolarizing agent is Succinylcholine chloride and Non-Depolarizing is Atracurium, Mivacurium, Pancuronium, so, it has all -curonium mostly. It has the same suffix. Rocuronium, Tubocurarine, that’s the only different one but mostly they have the same last 4-5 letters. Yeah. They are used mostly for paralyzing agent for surgical procedures. Or, also, they are used for depolarizing agents for the patient receiving electroconvulsive therapy. To paralyze them, as well.

What are the side effects and contraindication? It causes the persistent paralyzing status obviously, and depolarizing agent because of their different mechanism of action. It can cause the high potassium level and it can cause the malignant hyperthermia, and muscle pain. Now, here’s a main thing to remember as a nurse. Malignant Hyperthermia. It’s not like increase in temperature of patient to 101 Fahrenheit or 102, I mean. But the patient temperature will go like 105 Fahrenheit right after they come from a surgery or a couple of hours. So, that’s why it’s really important to watch patient’s temperature when they come back from surgery if they have these agents, if they have received these agents. And basically, malignant hyperthermia is an emergency and you need all the help in malignant hyperthermia, you give dental and sodium medication. It’s basically anesthesiologist or certified registered nurse anesthetic who run this gored malignant hyperthermia and you definitely like you give a saline in order to decrease the temperature of the patient. You put ice bags, cooling blankets, dental and sodium medications that prevents the tremors and shivering, it prevents the muscle breakdowns, so yeah, it’s really an emergency and as a nurse, you really need to, need to know what to look for whenever you have a patient gonna having malignant hyperthermia. And it’s really emergency. You need to act within minutes.

So, these are about the information about the parasympatholytic medications. I hope you understand them very well. But if you have any questions, let us know and thanks for watching it.
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