Cholinergics Video Pharmacology SLUDGE CAT

In this episode, I go over how you can use SLUDGE CAT, to remember the cholinergics and what that means for pharmacology indications and adverse effects in that drug group.

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Welcome to the Memorizing Pharmacology podcast. I'm Tony Guerra, pharmacist and author of the Memorizing Pharmacology book series, bringing you mnemonics, cases, and advice for succeeding in Pharmacology. Sign up for the email list at memorizingfarm.com to get your free suffixes cheat sheet or find our mobile-friendly self-paced online pharmacology review course at residency.teachable.com. Let's get started with the show.

Okay, if you ran into this video before you ran into the anticholinergic Bud cat, I recommend that you go to episode 62 and go check that out. But the cholinergic sludge CAD is gonna get us through the opposite effects of antichrominergic anti-anti and we're going to kind of make a U-turn here. So again, we are making a U-turn. We're going from anticholinergic to cholinergic so many of the things that you'll see are somewhat familiar but what we want to do is make sure that we have these clear in our head.

The first thing is to get the vocabulary clear. If something is cholinergic, it is also a muscarinic Agonist. Again, this is our muscarin mushroom and this is where it all began. So people use that as synonyms or use them interchangeably. Oh that's cholinergic oh that's muscarinic they don't say this as much but it also counts it is parasympathomimetic.

Okay, so what were the opposites right? The opposite of cholinergic is anti-cholinergic. The opposite of muscarinic is anti-muscarinic or muscarinic antagonist. The opposite of parasympathomimetic is parasympatholytic.

Okay, so let's kind of look at how we can use these opposites. We learned but the wide-eyed tachycardic cat how that gives us the anticholinergics so let's go to the opposite which is cholinergic Crisis that is we have way too much cholinergic activity too much acetylcholine and what we'll do is we'll kind of take a look at our new cat so our last cat was wide-eyed in the desert very dry our new cat Sledge cat is in the water with pinpoint pupils and is a bit bradycardic.

Okay so the mnemonic itself sludge will get to but the Cat part is that it is a cholinergic starts with C Agonist begins with a ends with t okay all right so here are the Opposites so on the left hand side we have Bud cat from our anticholinergic presentation and blurry vision because of dry eyes urinary retention dry mouth or xerostomia constipation and hydrosis which is a lack of sweat and was tachycardic so again we had to say wide-eyed tachycardic Bud cat because there is a b and a t in the mnemonic and madriasis again is that wide-eyed m-y-d-r-i-a-s-i-s.

Now you've probably seen the sludge mnemonic but what I want to do is show you where it comes from so the opposite of blurry vision because of dry eyes is lacrimation now yours starts with an L now you're still blurry it's just for a different reason before it was because your eyes were so dry now it's because your eyes are so wet urinary retention the opposite is urinary incontinence dry mouth the opposite of salivation constipation obviously the opposite is diarrhea and hydrosis is sweating and then the opposite of tachycardia is bradycardia.

Now to be fair you will have initial tachycardia in the presentation but it'll eventually go to bradycardia and then meiosis the pinpoint pupils are the opposite of madriasis oh so let's put those in the sludge order now and add the other pieces so we saw the salivation the lacrimation urinary incontinence and diarrhea and then we have the GI cramping and emesis so I have this crisis just ahead signpost with a big thunderstorm lots of rain coming to remind you that sludge is sludge because it's so wet where does this come from well cholinergic crisis can come from pesticides and organophosphates.

So I'll put a little chalkboard thing here but the idea is that okay where where's someone gonna get it okay it's going to be the farm okay but we have two competing conditions we have a myosthenic crisis and we have a colon urgent crisis. The issue is that both of them are going to look very similar on presentation but one is because of low acetylcholine stimulation and then the other is because of excess acetylcholine stimulation. So I have a question down at the bottom which explains it better, but we use an antibody test now which can let us know which it is. But why did edrifonium, an acetylcholinesterase inhibitor, result in improvement in myasthenic crisis but worsening of cholinergic crisis?

Well, if hydrophonium is an acetylcholinesterase inhibitor (capital A, capital C, little h, capital E), that means that it stops the breakdown of acetylcholine and there'll be more of it around. So we're basically adding acetylcholine. If we add acetylcholine to myasthenic crisis where we have low acetylcholine, it makes sense that they're going to improve. It's actually the class of drugs we'll give, though this is not the one we'll give because that one only lasted a very short amount of time.

However, if you are in cholinergic crisis and you give them more acetylcholine in addition, well now you're in trouble. Now you're doing the wrong thing. So the reason we don't give it anymore is because well we were adding it and making it a little bit worse and we don't want to make it worse.

So treatments on the myasthenic crisis side where we have too much acetylcholine right too little acetylcholine take it back so myostendic crisis too little acetylcholine we give an acetylcholine State race acetylcholine esterase inhibitor because what we want to do is have them have more acetylcholine so we stop the breakdown. It's also an immune condition so we give immunosuppressants cyclosporin azathioprine steroids to suppress the immune attacking itself or the immune system attacking itself.

On the coal energy crisis side, we treat, we remove the acetylcholinesterase inhibitor and we provide ventilation if they need it and then IV atropine. Why does IV atropine make sense? If you get that then you know you've gotten what I'm throwing down. Well Ivy atropine makes sense because you had a situation where you have too much acetylcholine. Atropine is anti-cholinergic so it goes against that acetylcholine.

Okay, let me give you a visual make me make it a little more clear so here's Myasthenia on the left is the normal neuromuscular Junction and then on the right we have Myasthenia with the antibodies against the receptor and those antibodies are not letting acetylcholine get through so the idea is we need more acetylcholine but we don't do it directly we don't say here you go here's some more acetylcholine just the way that you know when we have certain conditions that in the blood-brain barrier we just can't give dopamine well we have ways around it okay.

So what we do is we treat myasthenia gravis which I call missing acetylcholine Gravely so just play on words to try to remember what the problem is by creating a situation where there will be more acetylcholine because we stop breaking it down okay one of the more telling signs is this ptosis ptosis which is where the upper eyelid droops over the eye okay all right so let's move on to the symptoms.

So myasthenia gravis symptoms: The D's because everything seems to start with D so diplopia double vision drooping of one or both eyelids difficulty swallowing difficulty speaking chewing difficulty using your arms and hands and holding up your head because muscles are weak and so what do we do well if you need acetylcholine we're going to use an acetylcholinesterase inhibitor and just kind of do this again and my autocorrect keeps correcting that Capital C to a lowercase C it's capital a capital c lower h um acetylcholinesterase Inhibitors mechanism of action okay.

We block the enzyme that breaks down acetylcholine called acetylcholine esterase ache, so you have more acetylcholine. If you have more acetylcholine, it enhances cholinergic action. Okay, how do we recognize acetylcholinesterase inhibitors? Well, they're probably going to end with stigmine. Now some of them are for other conditions: isostigmine usually for toxicity and glaucoma, neostigmine from myasthenia gravis, pyridostigmine from myasthenia gravis. Doesn't mean it's the only thing they're for like neostigmine, you can use as a reversal agent for pancuronium which is a neuromuscular blocker.

So again, I haven't gotten into nmbs in here but that's the kind of toxicity we can talk about. Okay, alright well so we've talked a little bit about what cholinergic can do for Myasthenia and how it's kind of the opposite of anticholinergic but let's talk about the bladder control that we talked about with anticholinergic.

So in anticholinergic, we had medications for an overactive bladder. Okay and that made sense. Okay so if the overactive bladder, we want to use the urinary retention that an anticholinergic causes but with bethenticol you're a choline or devoid or two of the brand names we can use the U and the sludge mnemonic that cholinergics cause urinary incontinence.

It's a side effect but for people with atonic bladder or urinary retention it is a therapeutic effect. So again it's a side effect for those that are taking you know cholinergics but if you have a tonic bladder or urinary retention it's actually a therapeutic effect. It's a relief that you can now void or you couldn't okay.

So the mechanism of action itself is to activate those cholinergic receptors and help someone as the brand name said do void so we just spell it d-o-v-o-i-d okay okay all right there are some considerations though with the then a call and and these cholinergic drugs remember a petropium as an anticholinergic that opened up the Airways well if you're gonna give bethen a call and you're going to give a cholinergic then asthma is a concern because it can constrict the Airways okay.

If we think about that bradycardia which is the opposite of the tachycardia in Bud cat right when you decrease heart rate you can decrease blood pressure decrease blood pressure you can end up with orthostasis when you think of cholinergic the opposite of the anticholinergic constipation we would have diarrhea or defecation but if you have these kind of GI issues like a peptic ulcer or intestinal obstruction you could perf or perforate that ulcer which would be terrible or you can worsen the condition of intestinal obstruction.

So imagine someone is impacted for example and you give them a laxative well if that impaction is uh you know some kind of obstruction something's in the way it's just going to make it worse. You're just gonna make it so that you're trying to get through this wall but it's not working okay.

So these would be the things that I really consider or to some extent contraindications asthma orthostasis um that's more kind of a side effect um peptic ulcers and intestinal obstruction disclaimer this information is provided to you for your informational purposes only and is not intended to provide it should not be relied upon for medical or any other advice.

I urge readers and listeners to consult with a medical professional with any medical condition foreign thanks for listening to the memorizing pharmacology podcast. You can find episodes cheat sheets and more at memorizingfarm.com again you can sign up for the email list at memorizingfarm.com to get your free suffixes cheat sheet or find our mobile-friendly self-paced online pharmacology review course at residency.teachable.com forward slash P forward slash Melbourne thanks again for listening!

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 YouTube Channel TonyPharmD here: https://www.youtube.com/c/tonypharmd