So, that was looking at oral route.
Now let's look at IV.
Remember we talked about if I was in pain,
would I want an oral med or an IV med?
No, this is what I would want, and let me tell you why.
Because the rate of time to the
bloodstream is…instantaneous, okay?
It's immediate, because you put
the drug into the bloodstream.
That's why it's called IV or intravenous.
Now, what's the impact of the first pass effect?
Now I see that it says "none" there,
but pause the video for just a second
and see if you can think through
why there isn't an impact of first
pass effect with an IV medication.
Hopefully, you were able to
think through that the reason
there's no impact of first pass effect is because
it doesn't go through the GI tract, right?
Only oral medications go through the GI tract.
We're talking about IV meds are
directly right into the blood vessels.
Time of onset, very fast.
Remember, oral is the slowest of the
routes, but this one is very fast.
Now, the amount of fluid volume.
Sometimes, you have a high volume of fluid.
Now, this is good for drugs that
need large volumes of water.
So, if I have a medication that needs
to be in a large volume of fluid,
I want to give it IV versus IM or subQ.
Your body can't handle that much
medication given intramuscularly or subQ.
So if it needs a lot of fluid
volume for the drug to be diluted
where it doesn't cause harm to the
patient, IV fluid is a great route.
Irritant drugs are really good to be given IV
because the body's normal blood flow will
help dilute that and minimize tissue damage.
Well, this is usually pretty costly,
and it's not super convenient, right?
You have to have an IV started.
We can do those some at home, but predominately,
that's done in the hospital setting.
Now, safety factors are different
for IV than it is for oral
because you do have a risk for infection,
because you have to break the skin.
Anytime you break the skin,
you have risk for infection.
Also, fluid volume overload can be a real problem.
If we have a patient who is…their heart's not
doing well or their kidneys aren't doing well,
or they're really prone to a very
sensitive fluid volume balance,
if we have to give something IV
that might also be a problem.
Now we talked about
reversibility with oral meds.
Remember, that was one of the
positives of oral medications.
But with IV medications, there is no turning back.
Once you give the drug, it goes
right into the bloodstream,
so we have a very short period of time
to try and reverse that medication.
Okay, so we've looked at oral,
we've looked at intravenous.
Now we're going to look at IM; nobody's favorite.
Nurses don't like to give
this type of medications
and patients don't like to receive it,
but if you do it well, it shouldn't
be as painful for your patients.
So you really want to pay
attention to the techniques
that they'll teach you in your clinical labs.
So, intramuscular goes in the
interstitial space of the muscle tissues.
So, rate of time to the bloodstream, yeah,
here's another one that's variable.
Remember IV, immediate.
Oral, really variable.
Also IM is variable, it just
depends on the drug solubility.
Is it water soluble?
Then it'll go faster.
Is there good blood flow to the site?
Then they'll make it faster.
Does it have to pass through capillary walls
versus cell membranes to
get into the bloodstream?
That will also impact the time.
So the takeaway point for IM medications is
the rate of time to the bloodstream…
So it just depends on lots of things
that have to do with solubility.
Okay, let's talk about amount of fluid volume.
Remember with IV medications, you can
actually use larger volumes of fluid.
For IM medications it's good for drugs
that don't dissolve well in water.
They're not good IV candidates, but you
can't put them in very much volume.
Time of onset is actually relatively
fast, usually 10 to 30 minutes.
Now, we can also use what we call depot
IM and it can last for hours or weeks.
And that's where you inject it into the muscle, and
it's intended to last over a long period of time.
But most drugs are given just straight IM.
It's relatively fast within 10 to 30 minutes.
So what's the disadvantages?
Well, it's not as expensive as IV, but
it's not necessarily as convenient.
Now, a patient can take a pill a lot easier,
but it doesn't require as much equipment to use
an IM medication as it would an IV medication.
Now safety risk, once again, you're breaking the
skin, so there's risk for infection or bleeding.
And if someone's taking an anticoagulant,
something that's like a blood thinner,
then they're going to bleed longer
after you give the IM medication.
So the rate of time to bloodstream.
Now we take subQ, it's just subcutaneous.
It means that we're not giving
it deep into the muscle.
We're giving it right in the tissue.
So the rate of time in the
bloodstream is, again, variable.
So when you're looking at the different routes,
really, the only one that was
consistent was IV, right?
You had oral, is variable; IM is variable.
IV was the only one that was super consistent
because we put it right into the bloodstream.
But the rate of time for subQ is variable.
Again, it's back to drug solubility,
just like we talked about with
the other routes of medication.
As far as the amount of fluid, this is also good
for drugs that don't dissolve well in water,
so they wouldn't be great as IVs, just
like we talked about with the IM.
Time of onset, look, this should look
familiar to you, relatively fast;
10 to 30 minutes or slow, just
like it was for the IM depot.
Similar to IM, cost and convenience.
You're also…you can teach patients
to give themselves subQ medication,
but that does require a lot of patient education
and not a lot of people are
comfortable with sticking themselves.
So that does require some extra time with
them to help them feel comfortable for it.
Anytime you break the skin, you
have risk for infection or bleeding.
And if you've got someone
on anticoagulant therapy,
you want to keep pressure on that
for an extended period of time.