Let’s move on to Tylenol toxicity
or acetaminophen toxicity.
This is incredibly common.
We see it all the time
and we frequently see it in adolescents
who are attempting suicide.
It can also happen as a result
of too frequent dosing in
young infants who have fever
with overly concerned parents.
So typically, a dose of
acetaminophen may be toxic
if more than 150 mg per
kilo has been given
or in young children if they’re
getting repeated overdoses.
Tylenol, when it gets into the body, first
burns through the body’s glutathione.
So glutathione is in our
system, in our liver,
and it’s allowing the liver to degrade the
toxic phenomenon that is acetaminophen.
Once that glutathione is used up,
the acetaminophen then starts
causing liver toxicity.
So we can tolerate small
doses, not large doses.
It typically occurs in patients who have
ingested a large dose of medication
or infants who are
getting small doses
or even normal doses at too frequent
interval for too long the period of time.
So patients usually have abdominal pain and
nausea when they take too much Tylenol.
We are going to use nomogram to
determine if treatment is indicated.
So here’s the nomogram, so
typically what we do is we
draw a level of Tylenol level
and we look in the plasma and
see what is the Tylenol level.
We estimate when the most
likely time of ingestion was.
If a patient was alone
between again 8 and 11 p.m.,
we’re going to guess that it was at 8.
We want to imagine the worst case scenario
and then we will draw how many
hours out and will plot a point,
the level and how many hours out
from when they ingested the drug.
If the dot is above the
line, we will treat.
If the dot is below the
line, we will not treat.
Different nomogram looks
I would urge you to find one and look
online and you can see how we do it.
The key thing here though
is that for an infant
who has been ingesting this over a period
of time, we can’t use the nomogram.
This is because the patient
over, say, the first day of use
was using up their glutathione levels,
now an appropriate dose could
cause liver toxicity.
So the nomogram is only for a one time
overdose, more consistent with adolescent.
So if you plot them on a
nomogram or in infants' cases,
they are just having bumped LFTs and
you’re worried about Tylenol toxicity,
we’re going to treat them
with IV n-acetyl-cysteine.
N-acetyl-cysteine allows for
the degradation of Tylenol
without needing the glutathione that
the patient doesn’t have anymore.
So we’re going to treat
typically for a full course,
it usually lasts around 18 hours and
then we will track those Tylenol levels
and watch them come down.
So we will also get liver enzymes
typically after day two,
because getting them originally at the
time of admission to the hospital
may lull you into a sense of security.
Remember, those LFTs
don’t typically spike
until day two or day three
after the ingestion.
If they are going up, early transferal to a
transplant center is critically important
because we need to get those patients on a
liver transplant list as soon as we can.
So let’s switch gears again
to another type of overdose
which is when patients have overdoses
related to their anticholinergic receptors.
So, the cholinergic receptors
or the acetylcholine receptors
are all through the body and
have different responsibilities.
Typically, we see anticholinergic response
to overdoses of very particular medications,
but one of them is very common and
that’s Benadryl or diphenhydramine.
Sometimes, we see patients
overdose on diphenhydramine
because this is commonly
what’s in the closet,
that would be adolescents or
children get into it and overdose.
We can also see
to patients who overdose on other
drugs like tricyclic antidepressants
or meds such as glycopyrrolate
which are used for some patients
for drying out the
The muscarinic receptors are
responsible for sweating,
motility, urinary excretion,
pupillary constriction and
decreased heart rate.
The nicotinic receptors are responsible
for the sympathetic ganglia
and the neuromuscular junction
and the CNS receptors are
responsible for memory,
cognition and of course
So we have to remember that
all of these receptors
can be affected in an
So there’s a mnemonic for
anticholinergic side effects
which many of us like to use,
we probably seen and heard
before which is "blind as a bat."
These patients will have dilated
pupils, remember it’s anticholinergic.
"Red as a beet," they will have vasodilation
in the skin resulting in erythroderma.
"Hot as a hare," they will be hypothermic.
"Dry as a bone," they will have dry mucous
membranes especially in the mouth.
"Mad as a hatter," they will often
have mental status changes.
"Bloated as a toad," they may have
urinary retention or intestinal ileus,
so their abdominal
distension may be there.
And "the heart runs alone" means
they have some tachycardia.
So if we see that
pattern of symptoms,
that’s a sign that a patient may have
overdosed on something like Benadryl.
So what do we do for
Well, again, activated charcoal is important
if it’s within an hour of ingestion
and if it’s a young patient,
who won’t take the charcoal,
drop an NG and put
it in there for them.
We can give benzodiazepines
for the agitation.
And in severe cases, we may
which is an anticholinesterase and
could boost the acetylcholine
present in the neuromuscular junction
and in other junctions between nerves.