Drugs for personality disorders Flashcards
what is the single most important diagnostic feature of schizophrenia?
hallucination
what is schizophrenia ALWAYS accompanyed by?
decline in cognitive function
what are the features of Type1 schizophrenia?
auditory hallucinations
thought disorders
delusions
thought broadcasting
what are the features of Type 2 schizophrenia?
loss of drive
motor disturbances (catatonia)
social withdrawal
what evidence is there to support the dopamine theory of schizophrenia?
the use of D2 antagonists - helps reduce auditory hallucinations
the use of amphetamine, which causes an increase in dopamine, is associated with exacerbating schizophrenia
what evidence is there to support the 5HT theory of schizophrenia?
all drugs which cause hallucinations bind to the 5HT2A receptors
give an example of a typical drug?
advantages and disadvantages
how does it work?
chlorpromazine and halopiridol
they are D2 receptor antagonists: therefore reduce Dopamine affects in the nucleus accumbens, thereby reducing hallucinations
advantages:
- works to eliminate positive features
- have profound sedation
negatives:
- do not solve the negative features
- cause extra-pyrmidal side effects
- saliohorrea
- aplastic anaemai
- hyperprolactinaemia
- tardative dyskinesia (particularly of face) does not resolve even when drug is withdrawn
- malignant neuroleptic syndrome
what are some of of the pharmcokinetic aspects of phenothiazines
metabolism and other receptor actions
they have enterohepatic circulation, so take up to 4-6 weeks to be excreted from body - therefore must be very careful to not overdose
they have actions on H1 receptors - sedation
on A1 receptors - hypotension
on M receptors - ameliorate the EPS effects, infact they have less EPS than other typicals because of this
give an example of an atypical drug?
how does it work?
what are its side effects? and advantages
example: clozapine
drugs work by:
- antagonises 5HT2A/C receptors
- 5HT1/A agonist
- alpha 2 adrenoreceptor and muscurinic antagonists (associated with reduced EPS symptoms)
positive effects:
- effect both positive and negative symptoms of schizophrenia
- lower incidence of EPS and tardative dyskinesia
- can relief psychosis resistant to typical neuroleptics
relief of negative symptoms associated with 5HT1A agonist activity - increased dopamine release to mesocortical pathways
negative effects:
- weight gain, but in visceral fat (link to type II diabetes)
- weight gain associated with 5HT2A antagonism
- prolonged QT interval
- agranulocytosis
aripiprazole - what is its mechanism of action in schizophrenia?
3rd generation neuroleptic drug shows:
- D2 partial antagonism (less hallucinations)
- 5HT2A antagonism (less hallucinations)
5HT1 agonists (increased dopamine release in mesocortical pathway/less negative symptoms)
positive effects: - little effect on QT interval reduced EPS (As much as placebo) - reduced weight gain - safe in overdose
negative effects:
- hyperprolactinamia
- hypercholisternamiea
what is the treatment for bipolar disorder? side effects of treatment
the only present effective treatment is lithium salts
problem is large plasma concentration required, by low therapeutic index
side effects:
- nephrotoxicity
- hypothyrodism
- culumination in CNS causes coma and death
give an example of a
phenoxthiazine
butyrphenone
thioxanthes
- chlorpromazine
haloperiodal
flupenthixol
what is thioridizine?
this is a phenoxthiazine:
- has moderate sedation effects-
- the most anti-muscraninc (least EPS incidence)
what is chlorpromazine/
this is a phenoxthiazine:
- has profound sedation
- causes hypotension
- some anti-muscuranic action?
why does halperidol cause the most EPS?
- because it binds to D2 receptors with the highest affinity
- has no anti-muscaranic actions
when are the atypicals used, and why?
they’re only used when the patient is not responsive to the typicals, and this is because of the fact that they can cause agranulocytosis?
what are some EPS side effects?
- tardative dyskinsia (Which can persist after drug withdrawal)
- dystonia
- akathisia
- pseudo-parkinosnism
what is the biggest problem with hypnotic drugs
they carry a risk of dose escalation and dependance over long term use