Welcome back. Today we are talking about alpha-glucosidase inhibitors.
Now glucosidase is a natural enzyme that we have in our body and it helps to
break down carbohydrates into smaller units so we can use that energy that we
call glucose for cell functions. We're going to talk about why we want to stop
that in the treatment of type 2 diabetes, or at least slow it down, in the
treatment of type 2 diabetes right after this. Welcome back my name is Tammy and
this is NurseMinder and on this channel we do everything nursing, so if you're
new here consider subscribing below so that you get the next video when it's
released. Now an alpha glucosidase inhibitor does just that- it inhibits the
use our body's ability to use glucosidase. So it's a competitive inhibitor
which means it's going to go and bind at that site so that the enzyme can't do
its job, so it is a competitive inhibitor of digestive enzymes and the goal, the
target, is to decrease the amount of glucose that we have in our bloodstream.
Alpha glucosidase are enzymes that are found inside the intestinal wall in
a place called the brush border. So let's just first take a quick look and what
that is before we get into how it works and why we want to stop it. So this is
our intestinal wall. We have our food that comes in and mechanically um and
we mechanically and digestively start to break it down with our teeth
and our saliva and as we swallow and it goes through our stomach and into the
intestine, that's where sugar glucose is absorbed primarily. So you see that this
intestinal walls kind of irregular and so we take a little snapshot of it -
here's my intestinal border wall there - I've got all these projections with
these fingers on them we call those villa and you can see that they have a blood
supply, this is the red arterial blood going in and the blue is the venous
blood returning because each of these are cells. Now the villa are covered with
cells called enterocytes, and enterocytes here as you see
them, they also have these finger-like projections on them and we call that
microvilla. The enterocytes are responsible for secreting enzymes and
these are the digestive enzymes are gonna help to break down our starches
and carbohydrates into sugars that our body can use that for energy. Now we
begin the process with mechanical breakdown and chemical breakdown in our
mouth with chewing and amylase is one of our pancreatic digestive enzymes that
starts that process in the mouth. Now as food travels down further our
carbohydrates are still in long chains and they're very complex and they need
to be broken down into mono, meaning single, saccharides - and that's where
these digestive enzymes come into play. so glucoamylase helps break down
starches, and nutrients sucrase helps break down table sugar, now this is an
important one to remember, when we start talking about treatment of hypoglycemia
and we're going to come back to that. Maltase is those yeast kind of - your malt shakes,
your malt foods, yeast breads and isomaltase works with those more complex ones
that maltase and amylase cannot break down - and then of course we have other
enzymes like lactase and trehalase. Now these ones are orange because the drug
we're talking about does not impact these ones or other digestive enzymes, it
specifically is targeting, and in this order of preference, glucoamylase, sucrase
Maltese, and isomaltase. So this alpha-glucosidase inhibitors is
selective for these particular four digestive enzymes. Okay so we have this
cell, and this cell is going to be producing the enzyme glucoamylase and
these enzymes are sitting out here waiting - I'll make that a little bigger -
waiting for a complex carbohydrate to come along. Now I'm going to use an
example of a disaccharide.
which means it has two glucose and their bonded together. When they come in contact
with my glucoamylase, there's a hydrolysis process that occurs and these
two bonds are broken, and then what happens is it releases two single - so
these are now mono -
saccharides and then those can be absorbed by facilitated diffusion or a
secondary active transport into the cell and then through into the bloodstream. So
now let's look at how the alpha-glucosidase inhibitor works.
Remember it's a competitive inhibitor so at these receptor sites where these
enzymes are sitting and resting on that microvilla, the alpha-glucosidase
inhibitors come and binds here and it prevents my disaccharide or my more
complex glucose molecules from attaching; which means this is going to continue
its journey out through the intestine. Now you see that there are still some
open which means we are only decreasing the amount of glucose because I can have
one bind here and that's gonna break it down into monosaccharides, and then this
one is blocked competitively inhibited - maybe this one is blocked, and so the net
effect is decreased glucose availability. The alpha-glucosidase inhibitors - that's
a tongue twister - their primary function is to lower the glucose that is
available in the blood stream. So that's an important distinction because it has
no effect on insulin production, meaning it doesn't actually stimulate or stop
insulin production. It simply limits the amount of sugar,
glucose molecules, in the blood stream. That will signal the pancreas to do its
job. So we have a functioning pancreas in patients who are taking this medication.
So when it comes to looking at side-effects glucose is being kicked out
through the intestine and we know that glucose is an osmotic pull for water so
if we think about side effects,
we're gonna have the increased glucose in the intestine - increased water - that's
going to probably cause diarrhea. And I don't know if you've ever had this sugar
binge but it really causes a lot of bloating and upset stomach so we have
that as well, causes gas. Now of course this is an oral medication so anything
you put in the stomach can cause nausea and vomiting so those are also side
effects to watch for. But just in terms of understanding what the mechanism of
the drug is - I'm getting less sugar in the body to manage my glucose levels so
actually want that to happen and the pancreas will work out the rest - but the
key thing is is it's actually keeping sugar in the intestine to be excreted.
And so this is where a lot of our side effects and our signs and symptoms of
overdose or toxicity come from. Now on its own as a mono therapy, it is often
used in conjunction with diet and exercise to manage sugar levels. It is
not at risk of causing hypoglycemia because our pancreas is still
functioning and managing those ups and downs of the sugar. When it's used in
combination therapy with a biguanide such as metformin, and we've talked about
that before, sulfonylureas - we've talked about those before, there is a higher
risk of hypoglycemia when used in combination therapy. So if we have a
hypoglycemic patient remember we talked about this blocking complex
carbohydrates and so sucrose, is another name for our table
sugar, it's a complex carbohydrate. So treating a low blood sugar with a sucrose , a
table sugar mix, is actually not going to have the desired effect as quickly as we
want because it's being blocked by this medication. So what we want to actually do is
treat it with oral glucose which is known as dextrose because it is already
broken down into monosaccharide and it can simply be
absorbed through the channels at the microvilli .Some of the drugs that you
may hear in clinical practice are called acarbose, or miglitol - I don't know if
I'm saying those right - maybe it's miglitol or acarbose - at either
rate these are the drugs that we might see. Now that's ... let us
next come up with a visual so you can teach our patients how these drugs are
working. Now I think pharmacology should be fun and I really work with
visuals well and it kind of helps me understand how things are functioning
inside at the cellular level. I'm going to try and break down the
alpha-glucosidase inhibitors and use an example as to how we can explain the
whole process to our patients . You can see that I have drawn the intestine here,
we'll consider that to be the city, the villa are the different communities in
the different city blocks so if I were to stand here and look down I would see
all of those rows and rows of houses and then the microvilla that are all of my
homes on my street, and so in order for things to come in and out of the home
there needs to be a port. And so we'll consider the door to be our enzyme
sitting out here. So the enzyme it's equal to the door. Now sometimes we want
our family to come over, and sometimes we want our friends to come over ,and
sometimes we want the politicians to come over - it is election season right
now and some people want to hear from them. So we have different ways of
inviting people in. So these enzymes will consider to be the door opening so that
people can get in to the house, do their business - a visit, maybe they're selling
you insurance - whatever that might be and then exit again. Okay. So they don't stay
in the house just like we don't stay in our houses and then they move on their
path. Now the drug - if we think of acarbose, I break this down
into a car blocks glucose. so I'm going to draw a car here now - I'm not very good
at drawing cars - but this car is now blocking the path to
get into that house. So these people are going to have to go right past to the
next house in order to get in. So a car blocks glucose - acarbose. When it
comes to miglitol, I actually switch up the syllables and I call it little
Mig and this is the house where little Mig lives. So miglitol. And that's
just one way that which I try to put all those elements into a storyline that can
help people understand. So little Mig doesn't like company, it's the equivalent of
having a know solicitor sign on the doorway. So this person - not going there
either. So that's kind of a way to explain to your patients how the
alpha-glucosidase inhibitors work to competitively block off these doors so
that glucose cannot be allowed in. So be sure to comment, like, subscribe to this
video and if you have another way that helps you remember how alpha - alpha
glucosidase inhibitors works, please share your story in the comments section
below because together we're stronger. Until next time, make it a great day! :)