This is chapter five neuro and in this video, we'll be talking about antipsychotics.
Antipsychotics are typically used in schizophrenia, and schizophrenia is a
psychiatric disorder that involves psychosis.
Psychosis is a mental disturbance that involves a loss of contact with reality or
misinterpretation of perceptions.
Patients with schizophrenia can have a couple different kinds of symptoms - they can have positive, negative, or cognitive symptoms.
Positive symptoms are the typical kind of symptoms you think of with schizophrenia,
so those are the psychotic symptoms like hallucinations, being delusional,
having really disorganized speech and behavior.
Negative symptoms are those that are associated with a loss of function, so
things like social withdrawal,
having no motivation and kind of not taking very good care of themselves.
The cognitive symptoms are just things like poor concentration,
inability to plan, and inability to make decisions.
Here are the medications that we're going to discuss today. There are two different
basically categorizations of antipsychotics - we have the first generation and the second generation.
First generation antipsychotics can also be known as typical antipsychotics
and those are used for the positive symptoms of schizophrenia, so the delusions and the hallucinations.
Those are also historically the older class of drugs, and they can be divided into low and high potency
depending on their dopamine blockade.
The first drug is
haloperidol and the brand name is Haldol, and that is a high potency first generation antipsychotic,
which we know from the '-peridol' stem that just means high potency. When a first generation
antipsychotic is high potency, then we know that it works more on dopamine than a low potency agent, so high potency
antipsychotics lead to more extrapyramidal symptoms, which just are different types of movement disorders that can be pretty
discomforting to patients.
The next medication, chlorpromazine or Thorazine is a low potency first-generation
antipsychotic. The low potency agent works on dopamine a little bit less,
so it is associated with fewer extrapyramidal side effects, but it is more likely to cause sedation.
We can remember that Thorazine is a mythical god, and that can help us remember that chlorpromazine
helps with positive effects of delusions.
The second generation antipsychotics, also known as atypical antipsychotics,
also have an effect on dopamine
but, unlike the first generations, have an effect on blocking serotonin.
Second-generation antipsychotics work on both the positive symptoms, so the delusions and the hallucinations,
and also the negative symptoms, so the depression and being withdrawn.
They don't usually have the extrapyramidal symptoms,
but they can cause pretty serious metabolic effects like weight gain,
diabetes and increased cholesterol. Those are concerning because patients that have
schizophrenia are also less likely to take care of themselves,
so they're also at higher risk of those metabolic effects to begin with. The different
second-generation antipsychotics can have other side effects just depending on the receptors that they hit and the things that they do.
There are three second-generation or atypical
antipsychotics we'll discuss today.
Risperidone or Risperdal,
The '-peridone' stem looks like '-peridol', which is the stem of haloperidol.
We can remember that 'risper-' rhymes with whisper, and
risperidone can quiet whispering voices, so can help with the the positive symptoms.
Quetiapine, the '-tiapine' stem means second-generation.
The brand name of that one is Seroquel. Clozapine or Clozaril is also a second-generation
antipsychotic. Let's go through some practice questions.
Practice question one - 'A first-generation
antipsychotic that is low potency is?'
We have our couple of first generation antipsychotics and then our three second generation antipsychotics.
The correct answer for this one is
chlorpromazine - that is a low pertinency first generation
medication. With it being low potency,
we are less potently blocking dopamine
so you won't have those extrapyramidal side effects like the the high potency ones,
but we will have more sedation. Now we'll go through
a couple more questions, and we'll make each different answer correct.
Practice question three, make B) correct - 'A first-generation
antipsychotic that can cause extrapyramidal symptoms or EPS is?'
The correct answer is B) haloperidol. The '-peridol' ending reminds us that it's a first generation
antipsychotic, and first generation antipsychotics, since they block dopamine more potently,have more chance for those movement disorders.
Chlorpromazine, A), is incorrect because it is a low potency first generation antipsychotic,
so we'll see more sedation with that one. C), D), and E) are incorrect - some of the second-generation or atypical
antipsychotics can have some
EPS symptoms, but generally it's not as big of an effect.
Practice question four, make C)
correct - 'A second-generation antipsychotic that can cause prolactin elevation is?' C) risperidone.
This is a second-generation
medication and we can get hyperprolactinemia.
A high prolactin
level can lead to different side effects in men and women. In women, it can lead to a decrease in
menstruation and some some other sexual side effects. In men it can lead to a decreased libido,
some more sexual dysfunction as seen in women, and then also
gynecomastia, which is enlarged breasts.
A) and B) are incorrect because those are first generation antipsychotics.
D) and E) are incorrect because although they are second-generation antipsychotics,
there's no elevation in prolactin.
Practice question five, make D)
correct - 'A second-generation antipsychotic that can cause weight gain, diabetes, and high cholesterol
is?' and so for this question, we will select all that apply.
Quetiapine and clozapine
are two that have pretty common metabolic side effects. A) and B) are incorrect because they don't really have many
metabolic side effects being first-generation
or typical
antipsychotics. C) risperidone, it is a second-generation
antipsychotic, but there is a smaller risk of diabetes and high cholesterol.
Knowing the differences between the side effect profiles of the different antipsychotics and then looking at different
things like patients specifics can kind of help you choose an
antipsychotic that might fit your patients' profile best.
The last question here is question six - 'A second-generation antipsychotic that can cause severe
agranulocytosis is?' and the correct answer is E) clozapine
Agranulocytosis is a depletion of white blood cells,
and if they get very severely low it can lead to infections and even sometimes death.
Clozapine is one of the most effective
antipsychotics that we have, and it is unique in the fact that it actually decreases the risk of suicide,
which is really important especially in schizophrenia patients who who might attempt that.
Even though clozapine is really effective, it's usually not used
first-line - it's usually used after you have failed a couple of other antipsychotics because it has a lot of nasty side effects.
Like we just mentioned before,
so does quetiapine and those both have a lot of metabolic effects like diabetes,
hypercholesterolemia,
metabolic symptoms, weight gain, but clozapine can also increase our risk of seizures, it can also increase the risk of severe
drooling which is kind of an unwanted side effect, and then, as mentioned here, the agranulocytosis.
You need an absolute neutrophil count above
1500 to initiate clozapine,
and then you have to be monitored pretty closely when you do start the therapy.
If the ANC falls below 500, then we have to discontinue clozapine
and we can never use it again. If the absolute neutrophil count is between 500 and 1000, we need to stop until that
ANC gets back above 1,000 and then we can restart.