Pharmacology, part 21: Nervous System Medications - Antipsychotics
by Cathy Parkes February 25, 2021 Updated: August 09, 2023 4 min read
In this article, we cover some antipsychotic medications used to treat schizophrenia, including the most important differences between first and second-generation antipsychotics. The Nursing Pharmacology video series follows along with our Pharmacology Flashcards, which are intended to help RN and PN nursing students study for nursing school exams, including the ATI, HESI, and NCLEX.
When you see this Cool Chicken, that indicates one of Cathy's silly mnemonics to help you remember. The Cool Chicken hints in these articles are just a taste of what's available across our Level Up RN Flashcards for nursing students!
Schizophrenia is defined as a psychotic disorder characterized by disturbances in thought, behavior, and perception. In order to gain the most understanding of how drugs for schizophrenia work, let's first review the positive and negative symptoms of schizophrenia.
When we discuss positive symptoms of schizophrenia, that means the patient is presenting with certain atypical behaviors or actions because of schizophrenia. The term positive in this case, means something in addition to what is typical. The positive symptoms of schizophrenia include delusion, which are false beliefs and hallucinations, which are false sensory perceptions, including auditory, visual, tactile, gustatory (taste), or olfactory.
When we discuss negative symptoms of schizophrenia, that means the patient is not presenting with certain typical behaviors or actions, because of schizophrenia. The term negative in this case, means the absence of. The negative symptoms of schizophrenia include anergia (lack of energy), or anhedonia (lack of pleasure in doing things). The an- prefix can help you remember that these are negative symptoms because it means without.
If you would like to learn more about schizophrenia, it is covered in detail in our Psychiatric Mental Health Nursing flashcards!
Typical/first-generation antipsychotics - chlorpromazine (Thorazine), haloperidol (Haldol), and droperidol (Inapsine)
Typical or first-generation antipsychotics like chlorpromazine, haloperidol, and droperidol, are used to help control the positive symptoms associated with schizophrenia, like delusions or hallucinations.
They are called first-generation because they were the first antipsychotic medications, developed in the 1950s; second-generation antipsychotics were developed in the 1980s.
If you have hallucinations, you might need haloperidol.
Mode of action
Typical or first-generation antipsychotics like chlorpromazine, haloperidol, and droperidol work by altering the action of dopamine in the central nervous system.
There are many, many side effects associated with typical or first-generation antipsychotics like chlorpromazine, haloperidol, and droperidol. If you look up these medications in a drug reference guide, you will see a long list of side effects. Here, we'll cover the most key side effects for your nursing exams and nursing practice.
Extrapyramidal side effects
When a patient is taking first-generation antipsychotics, extrapyramidal side effects are common.
In anatomy, the extrapyramidal system is a part of the brain that controls involuntary movement. Extrapyramidal side effects include dystonia (involuntary muscle contractions), and Parkinson's-like symptoms including muscle rigidity and a shuffling gait. Extrapyramidal side effects can also include tardive dyskinesia, which includes things like lip smacking and tongue rolling, and akathisia, which includes restlessness and pacing.
If your patient is experiencing extrapyramidal side effects from their first-generation antipsychotics, the Parkinson's drug benztropine can be used to help reduce those symptoms. Benztropine is covered later in this series!
Neuroleptic malignant syndrome (NMS)
Another key side effect with typical antipsychotics is neuroleptic malignant syndrome (NMS). NMS symptoms include fever blood pressure fluctuations, as well as dysrhythmias and muscle rigidity.
If your patient is experiencing neuroleptic malignant syndrome as a side effect from their typical antipsychotics, the direct-acting skeletal muscle relaxant dantrolene can be used to help reduce those symptoms. Dantrolene is covered later in this series!
Other side effects
More side effects for typical antipsychotics include agranulocytosis, which is a decrease in white blood cell count, increasing the risk of infection; anticholinergic side effects including dry mouth, blurry vision, constipation and urinary retention; along with orthostatic hypotension, seizures, and sedation.
Atypical/Second-generation antipsychotic medications - risperidone (Risperdal), olanzapine (Zyprexa), and clozapine (Clozaril)
Atypical or second-generation antipsychotics include risperidone, olanzapine, and clozapine are used to help control both positive and negative symptoms of schizophrenia.
You might notice that clozapine sounds similar to the hypertension drug clonidine. It's important to remember which one is for schizophrenia.
Don't confuse cloZapine (for schiZophrenia) with cloNidine (Not for schizophrenia).
Mode of action
Atypical or second-generation antipsychotics like risperidone, olanzapine, and clozapine act as serotonin and dopamine antagonists in the body.
Second-generation antipsychotics don't have quite as many serious side effects as first-generation antipsychotics, but they still have a lot of important side effects you will need to remember.
Second-generation antipsychotics can cause diabetes, weight gain, increased cholesterol, sedation, orthostatic hypotension, anticholinergic effects, menorrhagia, and decreased libido. Clozapine specifically carries a risk for agranulocytosis, which is a decrease in white blood cell count that increases the risk of infection.
Unfortunately, this long list of unpleasant side effects can make it difficult for patients with schizophrenia to stay on a medication regimen.
If you have a patient taking second-generation antipsychotics like risperidone, olanzapine or clozapine, it's important to monitor their blood glucose and monitor them for infection during therapy, due to the risks of diabetes and agranulocytosis.
In this video, we are going to talk about medications that are used to treat psychotic disorders.
Before we get into specific medications, I do want to do a quick review of the positive and negative symptoms associated with schizophrenia.
So when I say positive symptoms, that means that there are things present in the patient who has schizophrenia that should not be there. So this includes delusions and hallucinations. So patients who suffer from schizophrenia will have these things present. They shouldn't be there. Those are the positive symptoms.
And then, these patients will also have negative symptoms. So they will be lacking in things that should be there. So a patient with schizophrenia, they may have anergia, which is lack of energy, or anhedonia, which is lack of pleasure in doing things. They should have those things present, but they are not there, and those are negative symptoms.
So let's now talk about typical or first-generation antipsychotics, which includes medications such as chlorpromazine, haloperidol, and droperidol.
These medications are typically used to help control the positive symptoms associated with schizophrenia and they work by altering the action of dopamine in the central nervous system.
So the way I remember at least one of these medications is that if you you have hallucinations, then you may need haloperidol to help control those. So they both start with hallucinations. It's got that H-A-L. Haloperidol also starts with H-A-L.
So in terms of side effects, there are many, many side effects with this class of medication and if you look up any one of these drugs in a drug reference guide, you're going to see a huge laundry list of side effects. So I'm going to go over some of the key ones here.
So with typical antipsychotics, extrapyramidal side effects are common. So this includes dystonia, which are involuntary muscle contractions. It also includes Parkinson's-type symptoms such as muscle rigidity and a shuffling gait. It can also include tardive dyskinesia, which includes things like lip smacking and tongue rolling, as well as akathisia, which includes restlessness and pacing.
If your patient is having some of these EPS symptoms, you can give them benztropine to help reduce those symptoms.
Another key side effect with typical antipsychotics is neuroleptic malignant syndrome or NMS.
NMS symptoms include fever, blood pressure fluctuations, as well as dysrhythmias and muscle rigidity.
If your patient is having NMS symptoms, you can give them dantrolene to help reduce those symptoms.
Other side effects with typical antipsychotics include agranulocytosis, which, if you recall from some of my previous videos, that decreases the amount of white blood cells a patient has and increases the risk for infection. In addition, anticholinergic side effects are common with this class, which means it's very drying. So if you remember my previous mnemonic, "can't see, can't pee, can't spit, and can't poop."
And then, orthostatic hypotension, seizures, and sedation are possible side effects with this class of medication.
Now, let's talk about second-generation or atypical antipsychotic medications. Medications that fall within this class include risperidone, olanzapine, and clozapine.
So it's going to be really important to differentiate clonidine from clozapine. So clonidine is used for hypertension, right? And clozapine is used for schizophrenia like we're going to talk about here. Clozapine has that Z in the drug name, and that will help you remember that it's used for schizophrenia with also has that Z. If it doesn't have that Z, then it is not for schizophrenia.
Okay. So this class, these atypical or second-generation antipsychotics, they are used to help control both the positive and negative symptoms of schizophrenia.
They act as a serotonin and dopamine antagonist in the body.
There are a lot of side effects with this class of medication as well, maybe not quite as many as we saw with the typical antipsychotics, but there's a lot of really yucky ones here on this list which makes it hard for patients to stay on a medication regimen when they have schizophrenia because side effects can include diabetes, weight gain, increased cholesterol, as well as sedation, orthostatic hypotension, anticholinergic effects, menorrhagia, decreased libido. And if we're taking clozapine, then, that also carries a risk for agranulocytosis which, again, that means that the patient's white blood cell count is going to come down, which places them at risk for infection.
So if your patient is on a second-generation or atypical antipsychotic medication, you're definitely going to want to monitor their blood glucose during therapy because of that risk for diabetes, and then you're definitely going to also want to monitor them for infection because of that agranulocytosis risk.
Okay. In my next video, we will be finishing up our mental health medications. This includes ADHD medications, medications for alcohol abuse, opioid dependence, as well as smoking cessation. Hang in there with me!
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