Okay let's talk about cholinergic effects.
Now this is part of the nursing
lingo you wanna be familiar with,
you want to know what anticholinergic
effects are and cholinergic effects.
So here's the deal, cholinergic drugs
enhance the effects of acetylcholine
Remember underline that word, "choline"
again just to help you remember
cause we're going after those
cholinergic type of receptors
So cholinergic drugs enhance
the effects of acetylcholine
and increase the actions of the
parasympathetic nervous system, right.
So cholinergic - I want you to connect
to parasympathetic nervous system.
Remember that's the rest and digest and sit
back and have a big old fat meal, right?
Yeah, lots of saliva and juices flowing and
your gut is moving and you're real relaxed
and your heart rate's slow - this is
more of a parasympathetic reaction.
Now an anticholinergic drug will competitively
block the effects of acetylcholine.
Yeah, competitive - that's what I mean.
Those drugs are racing to get to that
receptor because they want to get there first
so they can fill up that receptor,
sit down and claim their seat
and now will allow acetylcholine
to connect to that receptor.
So they competitively block the effects of
acetylcholine by sucking up that space on the receptor
and not allowing acetylcholine to get in.
That way you reduce the parasympathetic
actions and increase the sympathetic ones
Now, before we go on, let's
break that down a little bit
You know that you have these
receptors that we're talking about
the muscarinic receptors, you've
got them on your heart, right?
And we were talking about a parasympathetic
response versus a sympathetic response
Well, parasympathetic response - write
"parasympathetic" on the top of your notes
and write "sympathetic"
on the top of your notes
because i want to talk about
the two types of differences.
If we get a cholinergic type drug in there,
it's gonna enhance the effects of acetylcholine
Well that's the parasympathetic system so
we're gonna see the heart rate slow down
Now if we get an anticholinergic drug in there,
remember it 's gonna block the effects of acetylcholine
so we're not gonna have the
parasympathetic effect of slowing down,
we're gonna have the sympathetic
effect of speeding up.
So if I give a drug that's an anticholinergic
drug that hits a receptor on your heart,
you should see the heart rate increase.
Okay, so that kinda helps you get a feeling
for cholinergic versus anticholinergic,
the difference between
agonist and antagonists
so that's just a quick review that help you to
understand how we study these types of drugs
Now let me give you an even
better way to do it, okay.
How to study cholinergic drugs
Well you may have not thought you'll be doing
that today but this is gonna be really helpful.
Here's a tip - it also works
for adrenergic drugs too.
You look at the receptors that are
involved, now we're talking about a drug
so you look at the receptors that this drug involves,
identify if the drug is an agonist or an antagonist
and then we'll pretty much know what the
expected response of the drug is.
Woohoo! now you may not
be celebrating but I am
because this will help you to not have to memorize
the list after list after list after list,
this will help you really increase
the effectiveness of your studying.
So we're gonna look at some drugs and kinda
use this formula to walk through it.
You just have to know the name of the
drug, the receptors that are involved -
if it's an agonist or an antagonist and then we
shall be able to expect the response of the drug.
Are you ready?
We're gonna talk about a drug that
involves the muscarinic receptors,
which that's cool because that's
the title of this video series.
So we look at muscarinic, it's going to be an
agonist so I'm looking for a muscarinic agonist
Now remember an agonist means
it binds to a receptor,
in this case the muscarinic ones and it activates
that receptor to do what it's supposed to do.
Okay, well how do I know what the job is?
Well we gave you that chart right in
this earliest part of the presentations
to remind you what the muscarinic receptors are,
where they're located and what their jobs are.
So once we know it's a muscarinic agonist, we
know they're located on these parts of your body
and we know that we can expect the response of a
drug like Bethanechol, we know what it can do.
So this is the generic name, Bethanechol, now it hits the
receptors and selectively activates muscarinic receptors
that's an important point.
Not every drug hits all of the receptors.
So as you're studying these medications, you're gonna have
to pay attention to which muscarinic receptor it hits.
Now this drug in particular gives
us some parasympathomimetic responses
Now remember what those are.
These are all the things that happens.
So you got them right here, on the slide for you
Eyes -that's what happen, heart - that's
what happens, lungs - that's what happens
but this one is selective so we don't get
all of these responses with Bethanechol
In fact, we use bethanechol because it activates
the muscarinic receptors in the bladder,
Okay we say selectively - those
are the ones that goes after.
So increases the bladder pressure, relaxes
the smooth muscle of the sphincter
and allows the urine to leave the bladder.
Now if you feel like you hav to pee, this is really
really important that you'd be able to do that,
so it's therepeutic approved use for
the relief of urinary retention
That's what bethanechol is for because it
goes after those muscarinic receptors,
it acts like an agonist, it selects
the receptors on the urinary bladder.
Now we commonly use that for patients in
post-partum or having difficulty urinating
or for someone who has a
neurogenic atony of the bladder
Okay so think back through that, you know that
we are talking about the muscarinic receptors
It's an agonist, it specifically hits the ones on the bladder
and that's why we use it to relieve urinary retention.
Particularly after post-partum
patients and neurogenic atony
Okay so what are some things
we want to be careful of?
Well, theoretically, bethanechol can produce
all of these side effects that you see there.
All of these parasympathomimetic and that's a
really long word to say that it mimics - mimetic
the parasympathetic system, that's why
it's called a parasympathomimetic
I don't remember how to spell all of that but just remember
that's why we're using these words and terminology
to help you see how they all fit together
So theoretically or technically, it
can produce all of these side effects
but really we take this as an old
medications, it's pretty rare that it happens
So it just selectively activates the
muscarinic receptors on the bladder
but just because it might happen, we try to be careful with
the medication like bethanechol if the patient has asthma.
Well, why is that a problem?
Look over at that's
possible, remember it's rare,
that possible reaction to the parasympathomimetic,
it might constrict the airways
No for somebody with asthma,
What about cardiac problems?
Well, what does it do to the heart?
Well it might slow down the heart rate.
Okay, peptic ulcers - why
would that be a problem?
Well it could stimulate the
activity of the stomach
or an intestinal obstruction? same deal.
So keeping in mind, this isn't
a high risk with Bethanechol
but in NCLEX world, we're
always ultra ultra conservative.
See when you know what those receptors
do or what the possible reactions are,
you know why we don't give it to patients with asthma,
cardiac problems, peptic ulcers or an intestinal obstruction.