Antipsychotic treatment in
pharmacology is an important topic.
Let’s go over the highlights here.
So antipsychotics are medications
also known as neuroleptics,
and they are categorized in
terms of typical and atypical.
They work by blocking dopamine receptors
and thereby reduce psychotic symptoms.
These are used to treat psychotic
disorders, and also, psychosis
that goes along with other disorders.
So throughout the lecture series,
you’ve learned that psychosis can actually
appear as a symptom of severe depression.
It can also come up
during times of dementia.
So there are a lot of
uses for antipsychotics
and they can occur in
other patients who
don’t only have a primary
psychotic disorder as well.
So let’s go through the two
types, typical and atypical.
Well, examples of typical neuroleptics
Atypical examples are things like
risperidone and ziprasidone.
So, the typical neuroleptics, these
are D2, dopamine 2 antagonists.
They have a pretty high potency.
Now, atypical neuroleptics
do antagonize dopamine 2.
However, they’re lower
potency for that
and they actually also will target
serotonin and histamine receptors as well.
The typical neuroleptics tend to be really
good at treating positive symptoms.
But the atypicals are actually better
at treating the negative symptoms,
which we think of as the core
of the psychotic symptoms.
Typical neuroleptics, because
of their dopamine blockade,
they can really cause a lot of
extrapyramidal side effects.
That doesn’t happen as much
with the atypical neuroleptics.
However, these are more likely to
cause side effects like sedation,
and also, weight gain
or metabolic problems.
When it comes to the typical neuroleptics,
there are again two subtypes.
There’s the high potency
and also, low potency
So we’ll talk a little bit
more about those later.
And for the atypical
neuroleptics, as I said before,
these tend to not only block dopamine
but they also have a strong
affinity for serotonin,
alpha receptors, histamine
receptors as well, and serotonin.
So, the antipsychotics, basically, again,
this targets dopaminergic neurons.
That’s really the key,
and there are few different dopamine
pathways that you should be familiar with;
the nigrostriatal, the mesolimbic,
and the tuberoinfundibular.
Now, neuroleptics are
highly fat soluble,
and therefore, there are a
lot of options for giving
these intramuscularly or
through an injection.
We’re going to review that
later, but as a teaser,
it’s important to know that when it comes
to taking an antipsychotic medication,
sometimes, patients are very
agitated in the hospital setting
and it’s really nice to have the option
to do an injection of medication.
Likewise, some people don’t
like taking a pill every day,
and the long acting injectable
antipsychotics actually allow for
bi-monthly or monthly dosing, which
can be a nice option for patients.
So there are a lot of different
uses for antipsychotic medications.
Some are, of course, the
primary psychotic disorders,
also mood disorders like mania and
depression, and Tourette’s syndrome.
They can also be helpful there.
So, let’s talk a little bit more
about the typical antipsychotics,
and let’s start with
the low potency one.
These have a little bit of a lower
affinity for the dopamine receptor.
And examples include chlorpromazine
Now, there’s a higher incidence of
anticholinergic effects with these medications,
and a lower incidence of the
extrapyramidal side effects
that can be very
upsetting to patients,
also a little bit of a lower incidents
of neuroleptic malignant syndrome,
which can be a deadly side effect
of antipsychotic medication.
The high potency
have a very high affinity
for dopamine blockade.
These include haloperidol, fluphenazine,
and some other examples listed here.
There’s a very high incidence of
EPS or extrapyramidal symptoms
with these medications, and also,
neuroleptic malignant syndrome;
lower incidence of anticholinergic
and antihistamine problems.
So, what are actual
extrapyramidal side effects?
You might be wondering, “Is this very
important to know for your boards?”
Extrapyramidal side effects
come from dopamine blockade,
typically through that
And the earliest signs of
this can be acute dystonia.
Now, this might manifest in your patient
as something like an oculogyric crisis
where their eyes kind of
roll up in their head.
It can also be seen as
torticollis or neck stiffness.
And acute dystonia can be very
distressing to a patient,
and it can occur immediately
or within hours.
Next, another EPS symptom is
bradykinesia or parkinsonian symptoms.
So this can look like masked facies where
somebody doesn’t have a lot of expression.
It can also look like cogwheel
rigidity, which you might test for
when you’re doing your
physical exam on a patient.
Some patients have this
bradykinesia or slowed movements.
And they also can have a gate where
they do something, which is
called turning on block,
meaning that they will make a sudden
stop and then turn their whole body.
So it’s not very easy for them to shift
in maneuver as it is for the rest of us.
They may also get a tremor which
can be a cardinal feature
of a Parkinsonian side
effect from this medication.
Another problem that can
occur within months of
starting an antipsychotic
medication is akathisia.
This is highly
distressing to patients.
So, what akathisia is is it’s an
internal sense of restlessness.
It will often manifest
as a patient pacing,
maybe tapping their foot or
their hand on their leg.
They’ll often describe to their doctor that
they just feel like they want
to crawl out of their skin.
So, that’s a sign of akithisia,
which again is very distressing.
And then a really important
side effect of antipsychotics
to know about is
Now, it can take years and even decades for
a patient to develop tardive dyskinesia.
A little pearl for your exam is
that elderly Caucasian women
are at highest risks for
developing tardive dyskinesia
when they’re treated
with an antipsychotic.
So what this actually looks like is
abnormal movements of somebody’s face.
So you may see someone sticking
their tongue out repeatedly
or smacking their lips together.
And the really unfortunate thing about
tardive dyskinesia is that in most cases,
it’s actually not reversible.
So it can be very permanent and
a disfiguring side effect.
Both traditional and
have similar efficacies in terms of
treating positive symptoms of psychosis.
And you might remember the positive
symptoms of psychosis or things like
However, when it comes to treating
the negative symptoms of psychosis,
things like having a flat affect, little
motivation, poor energy, speech alogia,
that’s better treated with one of the newer
antipsychotics or atypical antipsychotics.
So the traditional antipsychotic
side effects to review them are
antidopaminergic, anti-HAM, which we’ll
go over that in more detail in a minute,
and of course, tardive dyskinesia, in dystonia,
or in other words, the EPS symptoms,
including bradykinesia and akathisia,
neuroleptic malignant syndrome,
which we’ll talk about in more details,
is also a serious side effect.
So in terms of tardive dyskinesia,
we talked about it before
but another little pearl to know, this is
writhing movements of the mouth and tongue.
when your patient is described as
having that, think tardive dyskinesia.
The antidopaminergic side effects are
of course the extrapyramidal symptoms.
and this is due to interference of dopamine
in the tuberoinfundibular pathway.
So patients can actually end up
with so much dopamine blockade
that they get a surge in prolactin,
and this can manifest as actually
lactation from the breast,
and it can occur in
women, but also in men.
And the neuroleptic malignant
syndrome is another
very noteworthy side
effect to look out for.
So I mentioned anti-HAM
side effects before.
Let’s talk about what that means.
So the H is antihistamine, where
patients can become very sedated.
The A is anti-alpha
adrenergic side effects.
This can look like orthostatic hypotension,
cardiac arrhythmias and
The antimuscarinic side effects include
dry mouth, tachycardia, urinary retention,
blurry vision, and constipation,
all things that are of course
undesirable to your patient.
They may also get weight gain,
elevated liver enzymes.
They may have eye problems
or ophthalmologic problems,
And because tardive dyskinesia
is so incredibly important
and a potentially irreversible
and disfiguring side effect,
we’re mentioning it a lot here.
It’s really important to
know about for your exam.
And it’s really important to note that it
can lead to that permanent disfiguration.
If you have a patient showing
signs of tardive dyskinesia,
you really want to consider lowering
their dose of antipsychotic,
giving them a drug holiday
from their antipsychotic
or switching them to another agent,
preferably, and atypical antipsychotic.