Drug therapy Flashcards
What is the logic of typical antipsychotics?
High dopamine at D2 receptors in subcortex, so are dopamine antagonists
How do typical antipsychotics work?
They block DA receptors, with a special affinity for the D2 receptors
What is the effect of typical antipsychotics?
They reduce dopamine levels in the subcortex and reduce positive symptoms
What are examples of typical antipsychotics?
Chlorpromazine and haloperidol
How effective are typical antipsychotics?
Effective for about 60% of pateints
What is the issue with typical antipsychotics?
They have many side effects, do nothing for negative symptoms and did not benefit 40% of pateints
What is the difference between typical and atypical antipsychotics?
They reduce positive symptoms like typical, but they bind less tightly to D2 receptors, reducing side effects
What are examples of atypical antipsychotics?
Clozapine and risperidone
How do atypical antipsychotics work?
They dont directly increase dopamine at D1 receptors, but they are seretonin antagonists as they reduce serotonin in pre-frontal cortex, which increases dopamine at D1
What is the effect of atypical antipsychotics?
They reduce both negative and positive symptoms, and they increase dopamine in other areas
What are the strengths of atypical antipsychotics over typical?
They can be used for negative symptoms, are slightly more effective, benefit half of those who aren’t helped by typical antipsychotics and fewer side effects
How do atypical antipsychotics reduce side effects?
They roughly balance levels of dopamine
What is research evidence for the effectiveness of typical antipsychotics?
Thornley’s meta analysis of clinical trials - cochrane review
What was Thornley’s meta-analysis?
Compared chlorpromazine, and found improvement in positive symptoms, reduction in symptom severity, much better functioning and lower relapse rates
What is research evidence of atypical antipsychotics?
Meltzer’s meta-analysis of clinical trials - cochrane review
What was Meltzer’s meta-analysis?
Compared clozapine to other typical and atypical, and found it was more effective for positive symptoms than other APs on measures of symptom severity, functioning and relapse and found effective for negative symptoms
What percentage of patients are treatment resistant?
25%
What are strengths of evidence for anti-psychotics?
They are meta-analysis, trials are field experiments and are cochrane reviews
How is the study being a meta-analysis a strentgh?
They provide the best estimate of effect size
How is the experiments being field a strength?
High ecological validity and control
How is the studies being a Cochrane review a strentgh?
They are independant and respected so analysis is objective, providing a valid set of data
What is a weakness of the studies being meta-analysis?
The file drawer problem, where findings from negative trials are not posted
What is the effect of the file drawer problem?
They results may exaggerate effectiveness and understate side effects
What are rare side effects of typical side effects?
Neuroleptic malignant syndrome which compromises various bodily systems and can be fatal
What are side effects of clozapine?
Agranulocytosis which a blood condition, and can be fatal
What are general side effects of antipsychotics?
Weight gain, sexual dysfunction, constipation, sedative effects and tardive dyskinesia
What is tardive dyskinesia?
Involuntary facial moments, such as grimacing
What is the issue with tardive dyskinesia?
It doesn’t always stop off medication, and is present with 32% of typical and 13% of atypical antipsychotics
What is the consequence of side effects?
Non-compliance with medication
What percentage of people are non-compliant with medication?
40%
