Sc - Drug therapy Flashcards
Atypical antipsychotics
What side effects do they have?
What are they beneficial in treating?
Who are they suitable for?
- Carry a lower risk of extrapyramidal side effects.
- Have a beneficial effect on negative symptoms and cognitive impairment.
- Suitable for treatment-resistant patients.
Drug therapy
Involves treatment of mental disorders such as SZ through the use of antipsychotics to reduce the symptoms of the disorder.
What are typical antipsychotics described as?
Explain why
Dopamine antagonists in that they bind to but do not stimulate dopamine receptors and so reduce the symptoms of SZ.
When are antipsychotics usually recommended?
As the initial treatment for the symptoms of SZ.
After initial treatment with antipsychotics what do clinicians use to treat patients with SZ?
A combination of medication and psychological therapy to manage the disorder.
How do all antipsychotics work?
By reducing dopaminergic transmission, i.e. reducing the action of the NT dopamine in areas of the brain associated with the symptoms of SZ.
Example of a typical antipsychotic
Chlorpromazine
What are typical antipsychotics used primarily to do?
Combat the positive symptoms of SZ such as hallucinations and thought disturbances - products of an overactive dopamine system.
Example of an atypical antipsychotic
Clozapine
What are atypical antipsychotics used primarily to do?
Combat the positive symptoms of SZ and additionally it is claimed that they have some beneficial effects on negative symptoms as well.
Basic mechanism of typical antipsychotics
Reduce effects of dopamine and so reduce the symptoms of SZ.
Typical antipsychotics - dopamine agonists or antagonists?
Antagonists
What does it mean by typical antipsychotics being dopamine antagonists?
They bind to but do not stimulate dopamine receptors (particularly the D2 receptors in the mesolimbic dopamine pathway), thus blocking their action.
What do typical antipsychotics eliminate by reducing stimulation of the dopamine system in the mesolimbic pathway?
The hallucinations and delusions experienced by people with SZ.
How long does it take before delusions and hallucinations to be diminished by medication?
Usually within a few days of beginning medication.
What symptoms are usually the first to be diminished by typical antipsychotics?
Delusions and hallucinations.
How long does it take before symptoms beside delusions and hallucinations to be significantly improved by medication?
Several weeks after beginning medication.
What did the effectiveness of the dopamine antagonists in reducing the symptoms of SZ lead to the development of?
The dopamine hypothesis of SZ.
How many D2 receptors in the mesolimbic pathway must be blocked for typical antipsychotics to be effective?
Estimated between 60% and 75% (Kapur et al., 2000).
What has to happen in order to block D2 receptors in the mesolimbic pathway?
A similar number of D2 receptors in other areas of the brain must also be blocked, leading to undesirable effects.
What are the negatives about typical antipsychotics?
There are several dopamine pathways in the brain, and it appears that blocking dopamine receptors in only one of them is useful, whereas blocking dopamine receptors in the remaining pathways may be harmful for the person.
How has the problem of ‘There are several dopamine pathways in the brain, and it appears that blocking dopamine receptors in only one of them is useful, whereas blocking dopamine receptors in the remaining pathways may be harmful for the person’ been addressed?
By the development of atypical antipsychotics.
What are the 3 main differences of atypical antipsychotics compared to typical antipsychotics?
- Carry a lower risk of extrapyramidal side effects.
- Have a beneficial effect in negative symptoms and cognitive impairment.
- Suitable for treatment-resistant patients.
How do atypical antipsychotics work?
As with typical antipsychotics, they also act on the dopamine system by blocking D2 receptors. However, they only temporarily occupy the D2 receptors and then rapidly dissociate to allow normal dopamine transmission.
