Biological Therapies; Drugs Flashcards
Taking drugs…
- Either orally or by injection if patients are unreliable in doing so themselves
- This forms a depot which releases slowly into the body
Typical anti-psychotics
- These were discovered to benefit patients with schizophrenia which revoluntionised the treatment
- The major anti-psychotics are:
- Chlorpromazine
- Haloperidol
- These drugs pass the blood/brain barrier and then act at receptor sites in the brain
- Typical anti-psychotics black D2 receptor sites
Effectiveness
- In trials comparing placebo and Chlorpromazine it was found to:
- Reduce relapse rates
- Improve functioning
- These findings were supported by a meta-analysis
Side effects:
- Extrapyramidal side effects (EPS) movement and coordination disorders including:
- Parkinsons
- Tardive Dyskinesia (involuntary movements of jaw and tongue)
- Loss of sexual function
- Weight gain
Atypical anti-psychotics
- Many are resistant to typical anti-psychotics; they are also not very useful for negative symptoms of schizophrenia.
- Atypical anti-psychotics were developed to help those who are resistant and those with negative symptoms
- The major atypical anti-psychotics are Clozapine and respiredone
- These act on receptor sites, but they can have an effect on serotonin receptor sites
Effectiveness
- In trials and meta-analyses comparing clozapine and typical anti-psychotics:
- Reduction of symptoms
- Fewer relapses
- Reduction in positive and negative symptoms
- Benefits for those resistant to typical anti-psychotics
Side effects
- Atypical anti-psychotics have fewer side effects than typical anti-psychotics
- One major side effect is that it kills white blood cells; but this is always monitored
- Fewer movement and motor effects
- Increased drowsiness, hypersalivation and temperature
Evaluation of research evidence
- Meta analyses show that the findings are in support of the effectiveness of the drugs is consistent
- The trials themselves are well-controlled experiments, involving s control condition, random allocation and blind procedures.
- However there is questionable findings in trials sponsored by drug companies:
- Burying of data- the file draw problems, but with financial motivation
- Biased data collection- their own drug is more likely to beat other companies’ drugs leading to contradictory results overall
History
- Antipsychotics were discovered in the 1950s by a french doctor who decided to administer chlorpromazine and a de-stressor
- Delay & Deniker then discovered it had therapeutic effects of schizophrenic patients and alleviated symptoms. The introductions of antipsychotics (neuroleptics) specifically chlorpromazine, revolutionised the treatment of schizophrenia.
Typical antipsychotics (URAP):
U- Reduces the positive symptoms of schizophrenia
R- Based on the theory that schizophrenia results from an excess of dopamine activity at certain synaptic sites
A- The aim of chlorpromazine is to reduce dopamine activity at receptor sites
P- It works by blocking the D2 dopamine receptors, reducing the ability of dopamine to bind on the post-synaptic receptor, lessening the response.
Atypical antipsychotics (URAP):
U- Used to treat schizophrenia without the previous problems of side effects
R- Based on the theory that schizophrenia results from an excess of dopamine activity at certain synaptic sites. Also based on the idea that an imbalance in other neurotransmitters, such as serotonin, are linked to schizophrenia
A- The aim of clozapine is to target serotonin and dopamine receptors in the brain
P- The precise biochemical mechanisms are unknown. They do appear to have a major impact on serotonin receptors, blocking these receptors.
Adams et al. meta-analysis A Cochrane Review
Method:
-The review looks into chlorpromazine versus placebo for schizophrenia, with 349 trials but 299 were excluded because of flaws in research methods or the reporting of data
Results:
-They found chlorpromazine reduces relapse over the short and medium term but data are heterogeneous (varied)
-Longer term homogeneous (similar) data also favoured chlorpromazine
-Chlorpromazine provided a global improvement in a persons symptoms
-Fewer people allocated to chlorpromazine left trials early compared with placebo
Side Effects:
-There are many adverse effects: its sedating, increases chances of acute movement disorder, Parkinsonism. Causes lowering of blood pressure with dizziness and considerable weight gain.
Essali et al. meta-analysis (A Cochrane Review)
Method:
-Reviewed the effects of clozapine in people with schizophrenia compared with typical antipsychotics.
Results:
-Supports the notion that clozapine is more effective than typical antipsychotic drugs for people with schizophrenia.
-Clinical improvements were seen more frequently in those taking clozapine.
-BPRS scores showed greater reduction of symptoms in those taking clozapine and fewer relapses
-34% of treatment-resistant pps had a clinical improvement with clozapine.
Side effects:
-Less movement adverse effects than typical antipsychotics, but serious blood-related effects, 3.4% in clozapine and 0% in other typical antipsychotics
NICE effectiveness and side effects of drug treatments for schizophrenia
- A significant proportion of service users- up to 40% have a poor response rate to conventional antipsychotic drugs and continue to show moderate to severe symptoms.
- Many of the side effects can be extremely disabling and distressing
Effectiveness of drug treatment
- The two Cochrane reviews are important because they are all randomised controlled trials
- The advantage of having these meta-analysis is that it reviews lots of data from different studies and therefore has a large sample size.
- 26.4% Of patients are resistant to all drug treatment
- Ben Goldacre article: A drug company AstraZeneca cherry picked their data; they found that their drug improved recall and published that- they did not publish that their drug increases relapse and could cause diabetes.
- Davis et al: Reviewed head-head studies sponsored by drug companies
- 33/42 of the authors were sponsored by a pharmaceutical company
- 90% of the studies were in favour of the sponsored drug.
