00:01
Hi. Welcome to our Pharmacology
for Older Adults video.
00:06
In this video,
we're going to talk
about safe medication
for adults who are 65 years
of age and older.
00:12
Okay, before we get into this,
I want you to just take a minute,
stop and pause,
and see if you can write down the 4 pharmacokinetic
processes in the margin of your notes.
00:26
Okay. As a quick review,
just check your answers.
00:29
The 4 pharmacokinetic
processes are absorption,
distribution, metabolism, and excretion.
00:39
Now, the body's gone
through a lot of changes
by age 65 years and older,
and that's what we're
going to talk about,
how those changes impact drugs.
00:48
So, when we talk about absorption,
we're talking about oral medications,
because remember,
absorption is from the point
of entry into the bloodstream.
00:57
So if we're talking
about oral medications,
people who are 65 years and
older have delayed gastric emptying,
so the rate of their oral drug
absorption is going to be slower.
01:08
Now, their gastric acidity,
the pH, is actually lower.
01:12
Now, that won't impact the amount
of the oral drugs are absorbed,
most of it will be the same as
a middle-aged adult, but it may reduce
the absorption of high
acidity dissolving drugs.
01:23
So, when it comes to absorption,
the gastric emptying
is slower or delayed,
and the gastric acidity is lower.
01:31
So while that may not affect
the amount of drugs are absorbed,
it might reduce absorption
of high acidity drugs.
01:38
Okay, next, distribution,
that's going from
the bloodstream to the target.
01:44
Now, here's some sad news.
01:46
At least, I think it's sad
as I age. As we age,
you end up with an increased
percentage of body fat,
and a decreased percentage
of lean muscle mass.
01:55
Well, lipid soluble drugs
are actually stored in fat,
so the impact on our elderly
patient is that the plasma levels,
or the blood levels,
of lipid soluble drugs are reduced.
02:05
You got all that storage space,
so the drugs end up having
a less intense effect.
02:10
So if you're a nurse
for an elderly client,
and you're giving them
a lipid soluble drug,
they're probably going to have
a less intense effect than an average,
healthy, middle-aged adult.
02:22
Now, and we talked about
that decreased lean body mass,
they also have decreased
total body water.
02:27
So, water soluble drugs are
distributed in relatively smaller amounts.
02:32
That means you're going to
have an increased
concentration of drugs in the plasma,
and you're going to
have a more intense effect.
02:38
So determining if a drug
has a more intense effect
or a less intense effect depends
if it is lipid soluble or water soluble.
02:49
Also, the elderly have
a reduced serum albumin.
02:52
It's significantly reduced if
the patient is malnourished,
and our elderly clients are really
at risk to become malnourished.
02:58
So someone who isn't eating enough
ends up not having enough
albumin in their blood.
03:04
So, they have fewer protein
binding sites for drugs,
they have increased free drugs,
and they may have a more intense effect.
03:12
So as you're studying
through these concepts,
you might want to make yourself a chart.
03:16
What are the things that put a elderly
client at risk for an intense effect?
What are the things that put them
at risk for a less intense effect?
Now, when it comes to metabolism,
that also declines with age,
so some of the half-lives
of drugs may be increased.
03:34
So if a drug had a 4-hour half-life in
an average healthy middle aged adult,
it might be longer than
4 hours in an elderly client.
03:43
First pass effect is also diminished.
03:45
So, remember, the first pass effect is
what happens with that metabolism,
it kind of gets the drug.
It's inactivated by the liver.
03:51
Because the liver is kind of aging out,
they're not going to have
a significant or first pass effect.
03:57
So, the dosage for an elderly
client compared to a healthy,
middle-aged adult might
need to be made smaller,
or you increase the time
interval between the doses,
make it lengthened.
04:09
Either way, the patient is going
to get less of the medication,
if the dosage smaller and the time
in between each dose is lengthened.
04:17
Okay, lastly, we're
coming up to excretion.
04:19
Remember, that's how you
get the drug out of the body.
04:22
Now there is several changes here.
04:24
They have less renal blood flow.
04:26
They have a decreased
glumerulofiltration rate,
and you usually see that as GFR.
04:32
They don't have as many
healthy functioning nephrons,
and they have decreased
tubular secretions.
04:38
Okay. That was just
a mouthful to tell you
their kidney is not functioning
as efficiently as a healthy,
middle-aged adult.
04:44
Less blood flow and less
ability to really filter things.
04:48
So, the rate in decline in a renal
function varies among individuals.
04:53
So, don't assume just because they're
old that their kidneys aren't working.
04:58
It depends on what other
things or co-morbidities
they've had in their history.
05:02
But, if we know their kidney is declining,
you can expect that there
could be an increased
accumulation of drugs that are
normally excreted through the kidneys.
05:11
That makes sense because if the kidneys
are not functioning as
efficiently as they used to,
they're going to have a harder
time excreting those drugs,
and that's why they'll have an
increased level of those drugs.
05:22
They also might have
extended and more intense
effects of the drugs because they
have an increased accumulation.
05:29
Now I want to tell you
about a more clinically
accurate test for our elderly clients.
05:35
Usually, we look at
BUN and creatinine in
an average healthy middle aged person,
but for the elderly clients,
creatinine clearance is much
more accurate for older adults.
05:45
That's because they
have a decrease in
lean muscle mass that
equals their renal decline.
05:50
So if you really want
an accurate picture of
the kidney function
of an elderly patient,
you don't want just a creatinine test,
you want a creatinine clearance.
06:01
Okay, now take a minute
and pause and think about,
in what ways are medication safety risks
similar for elderly and
pediatric patients?