Biological therapies Flashcards
(13 cards)
Describe typical antipsychotics
Chlorpromazine
They work as an antagonist in the dopamine system.
They block dopamine receptors in the synapses of the brain, reducing the action of dopamine.
When a patient. initially takes chlorpromazine dopamine levels build up, but then its production is reduced.
Why do typical antipsychotics work
Dopamine antagonists effect normalises neurotransmitters in key areas of the brain reducing positive symptoms like hallucinations.
Chlorpromazine is also an effective sedative as we believe it has an effect on the histamine receptors. Its is often used to calm patients not only with schizophrenia but also other conditions.
Syrup is absorbed faster than tablets so this is used when using Chlorpromazine as a sedative
How is Chlorpromazine used as a sedative
Chlorpromazine is also an effective sedative as we believe it has an effect on the histamine receptors. Its is often used to calm patients not only with schizophrenia but also other conditions.
Syrup is absorbed faster than tablets so this is used when using Chlorpromazine as a sedative
Describe Chlorpromazine
Typical antipsychotic
It can be taken as tablets, syrup or injections.
If taken orally it is administered daily up to a maximum of 1000mg.
Initial doses ae much smaller and for most it is gradually increased to a maximum of 400 to 800mg. Typical prescribed doses have declined over the last 50 years
What are two Atypical antipsychotics
Clozapine
Risperidone
Describe Clozapine
was discovered to be more effective than typical antipsychotics
Used today but with caution as patients have to take regular blood tests.
Due to the risks dosage does not come as an injection and the dosage is less that Chlorpromazine at 300-450mg a day.
How does Clozapine work
Clozapine binds to dopamine receptors but also acts on serotonin and glutamate receptors.
This action improves mood reducing depression and anxiety in patients.
Atypical drugs also address the negative symptoms such as avolition.
Due to this effect clozapine is sometimes prescribed to patients with a high risk of suicide. (30-50% of people with schizophrenia attempt suicide at some point)
Describe Risperidone
This is a more recently developed antipsychotic
It was developed to be as effective as Clozapine but without the side effects.
It can be taken as a tablet, syrup or by an injection that lasts up to 2 weeks. As with other antipsychotics you start with a small does and gradually increase it, a daily dose of 4-8mg (maximum 12mg).
How does Risperidone work
It binds to the dopamine and serotonin receptors but has a stronger bond and is therefore effective in much smaller doses, with evidence suggesting this leads to fewer side effects.
What is a strength of a the biological treatments for schizophrenia
evidence for its effectiveness
What is a limitation of biological treatments for schizophrenia
side effects
depends on the dopamine hypothesis
Evaluate evidence for the effectiveness as a strength for biological treatments for schizophrenia
P: We have evidence to suggest drug therapy is highly effective. There is a large body of evidence to support the idea that both typical and atypical antipsychotics are at least moderately effective in tackling the symptoms of schizophrenia.
E: Thornley et al reviewed studies comparing the effects of Chlorpromazine to control conditions in which patients received a placebo so their experiences were identical except for the presence of Chlorpromazine in their medication. Data from 13 trials with a total of 1121 participants showed that Chlorpromazine was associated with better overall functioning and reduced symptom severity. Data from three trials with a total of 512 participants showed that relapse rate was also lower when Chlorpromazine was taken.
E: In addition, there is support for the benefits of atypical antipsychotics in a review Meltzer conducted that Clozapine is more effective than typical antipsychotics and other atypical antipsychotics, and that it is effective in 30-50% of treatment-resistant cases where typical antipsychotics have failed. However, it is not effective in all patients and does not provide a cure
Evaluate side effects as a limitation of biological treatments to schizophrenia
P: A problem with antipsychotic drugs is the likelihood of side effects, ranging from the mild to the serious and even fatal.
E: Typical antipsychotics are associated with a range of side effects including dizziness, agitation, sleepiness, stiff jaw, weight gain and itchy skin. Long-term use can result in tardive dyskinesia, which is caused by dopamine super sensitivity and manifests as involuntary facial movements such as grimacing, blinking and lip smacking. The most serious side effect of typical antipsychotics is neuroleptic malignant syndrome (NMS). This is believed to be caused because the drug blocks dopamine action in the hypothalamus, an area of the brain associated with the regulation of a number of body systems.
Atypical antipsychotics were developed to reduce the frequency of side effects and generally this has succeeded
E: However, side effects still exist and patients taking Clozapine have to have regular blood tests to alert doctors to early signs of agranulocytosis.
L: Side effects are thus still a significant weakness of antipsychotic drugs. However, There are fewer side effects associated with newer atypical antipsychotics which means that patients are more likely to continue with their medication and thus see more benefits.
