00:00
Let's take a look at one of the most commonly prescribed
thiazide diuretics, hydrochlorothiazide.
00:09
I have to say that slowly because it is a tongue twister for
me which is why you often see it
abbreviated as HCTZ. Now, let's talk about how
hydrochlorothiazide works. It's the most commonly
prescribed one, it blocks the reabsorption of sodium and
chloride in the early distal convoluted
tubule. Now, if I'm studying for a pharmacology exam, you
don't necessarily have to remember
that it's early in the distal convoluted tubule. We just put
that on there as a frame of reference for you.
00:38
Remember it's not as strong as furosemide.
00:43
Most diuretics like, you know, all of them blocks some type
of electrolyte. Right? That's why we
tell the body not to reabsorb the electrolyte because water
will follow it which is our goal. So,
mechanisms of actions will sound kind of similar to you.
They're harder on certain electrolytes
than others but that's the common denominator when it comes
to the mechanism of action of diuretics.
01:05
They are going to tell the body to get rid of these
electrolytes and water follows. Now the
difference with hydrochlorothiazide is because it's a
thiazide diuretic, the GFR, the
glomerulofiltration rate of your kidney needs to be greater
than 15-20 mL/min so the GFR needs to be
greater than 15-20 mL/min in order for this drug to work.
So, this is not the drug that we would use
if your patient is in renal failure and I keep stressing
that because that's a really important
concept for you to understand in pharmacology. Furosemide or
other loop diuretics are what we would
use for patient who's in renal failure. Hydrochlorothiazide
is a mild diuretic that we use for
people, we just want to lower their blood pressure a little
or pull off a little extra fluid. We
just can't use it as an effective medication for people
whose kidneys are really struggling. Let's
talk about what it feels like as a patient to take
hydrochlorothiazide. Well, once you take a tablet
you'll notice in about 2 hours an increase need to go to the
bathroom and that could last for up
to 12 hours. So as a nurse, what do you think about the
timing of this medication? Well hopefully
what's registering to you is that you should educate your
patient "take this pill in the morning"
because if they take it at nighttime they're going to be up
and down, up and down all night long
having to go to the bathroom. So it will take about 2 hours
to kick in, after that it will last for
up to 12 hours so make sure your patient knows to take this
first thing in the morning. Now for
this patient, we're likely treating essential hypertension,
meaning it's just a little bit high.
02:47
If we pull off some fluid, we should bring down their blood
pressure or some mild edema but not
for patients in renal failure. Let's look at the adverse
effects of hydrochlorothiazide. The kind
of cool thing is they're similar to furosemide. So if you've
already studied that medication, you've
got some of these down. Now ototoxicity is a side effect of
furosemide, not a problem with HCTZ.
03:13
So that's cool. Now electrolyte imbalances are still an
issue as they are with all diuretics but
with hydrochlorothiazide we're still going to watch our
patient for low potassium, low sodium,
and low chloride. That can be problematic with some other
types of drugs. So watch for signs
of electrolyte imbalances. Any diuretic, what it does, well
it can do over well as I say and your
patient might end up dehydrated. If they get too dehydrated,
they can end up with hypotension,
low blood pressure. Remember that dehydration, low blood
pressure, then they're at risk for falling,
orthostatic hypotension. So teach them "Hey go from lying to
sitting and sitting to standing very
slowly cause you might be a little dizzy." Hyperglycemia is
an elevated blood sugar. Furosemide
can cause that as can hydrochlorothiazide. So if your
patient is diabetic, you want to monitor
their blood sugar closely and if they have any problems
controlling their blood sugar, they need
to contact their healthcare provider. We talked about
hyperuricemia. That means hyper, high; uric is
uric acid; emia in the blood. When you have elevated uric
acid in your blood, you're at risk for
gout. So if your patient has a history of gout we want to
watch that very very closely and
again educate your patient if they have any problems with
joint pain they need to contact
their healthcare provider. Here's a sad news, it can also
increase the LDL and decrease the
HDL so we're going to keep an eye on those and all our
patients. The last electrolyte we're
talking about, this will also increase the excretion of
magnesium. So we kind of grouped potassium,
sodium, and chloride together because that's probably going
to take the biggest hit but we
didn't want you to miss that it can also increase the
excretion of magnesium. So, the drug
interactions with hydrochlorothiazide are also similar to
loop diuretics. I love it when a plan
comes together. This makes studying so much easier when you
can look for things that are the
same amongst drug families. So we know that
hydrochlorothiazide causes a risk for low potassium.
05:25
We know low potassium for any reason increases the risk for
dig toxicity. So, if your patient is
on hydrochlorothiazide and they're taking dig, you want to
watch that really closely. Look for
signs of low potassium and likely the health care provider
will order some type of potassium
replacement for your patient. Now, low sodium can cause an
increased risk of lithium toxicity.
05:51
Remember low sodium for any reason will cause the body to
think "Hey, hang on to sodium" and if the
patient is taking lithium they'll also hang on to the
lithium so that's what increases the risk for
lithium toxicity. Now, this isn't just trivia. This could be
really open areas for test questions to
be asked. You may get the name of a patient, the age of a
patient, some multiple diagnoses
and medications that they're on. You're expected as a
professional nurse to recognize dangerous drug
combinations. So these are 2 key ones to make sure that you
have in your own brains.