CNS - Drugs for antipsychotics Flashcards
what are the 2 main categories of antipsychotics?
typical vs atypical
*both block dopamine (D2) receptors
= decrease hyperactivity of the limbic system
**think about it this way, if a person is not happy enough (i.e. too little dopamine), they become too sad = psychotic
= they need dopmaine receptor inhibition to increase the amount of dopmaine in their system, so that they can feel happier = be less psychotic
what are 1st generation typical antipsychotics
chlor|pro|mazine (low potency)
halo|peridol (high potency)
what is the MoA and following side effects of typical antipsychotics
- block D2 > 5HT2 receptors
= more EPS - antagonises histamine receptors
= sedation - antagonises cholinergic receptors
= anticholinergic effects
= increase sympathetic NS effects
= constipation, dry mouth. etc - antagonises alpha adrenergic receptors
= more vasodilation
= postural hypotension
what are the ATYPICAL antipsychotics
clo|zapine
olan|zapine
ris|peridone
quint|eia|pine
what is the MoA and following side effects of atypical antipsychotics
block 5HT2 > D2 receptors
- rare: neuroepileptic malignant syndrome
- hyperlipidaemia, hyperglycemia
what are the specific side effects of the atypical antipsychotics?
COR
**clo|zapine = agranulocytosis, sedation
olan|zapine = sedation
ris|peridone = EPS
quetia|pine = metabolic syndrome
all cause weight gain
what are the EPS reactions?
(read up more about this)
- acute dystonia
- parkinsonism
- akathisia
- maligant syndromes
- tardive dyskinesia
what are antipsychotics used for?
schizophrenia
what are the extrapyramidal side effects?
- acute dystonia
- parkisonism
- akathisia
- neuroepileptic malignant syndrome
- tardive dyskinesia
what are the neurotransmitter pathways affected in schizophrenia?
- dopamine pathway
what is the dopamine hypothesis?
HYPERactivity in mesoLIMBIC pathway
= too MUCH dopamine causes EXCESSIVE signalling
= positive symptoms (presence of abnormal signs)
HYPOactivity in mesoCORTICAL pathway
= too LITTLE dopamine causes reduced signalling
= negative symptoms (absence of normal signs)
what are the symptoms of schizophrenia?
positive symptoms: degeneration in the TEMPORAL lobe (emotions, inteperets language, emotion, and facial recognition)
- delusion
- hallucination
- disorganised thinking
negative symptoms: degeneration in the FRONTAL lobe (forward planning, decision making)
- avolition (no energy)
- inability to plan
- poor concentration
what is the dopamine hypothesis of psychosis?
excessive dopamine signalling in the brain (specifically to D2 receptors)
= hyperactive MESOLIMBIC system
= psychosis
compare and contrast D1 and D2 receptors?
in the nigrostriatal pathway…
D1: excitatory (pro-movement) = stimulate DIRECT pathway = stimulates WANTED movement
D2: inhibitory (anti-movement) = stimulate INDIRECT pathway = inhibits unwanted movement
** both are located in the basal ganglia
what happens when there is a D2 antipsychotic blockade?
D2 dopamine blockade: extrapyramidal symptoms
- acute dystonia –> involuntary muscle jerks
- akathisia –> restlessness (uncontrolled urge to move)
- drug induced parkinsonism –> bradykinesia, rigidity, resting tremor
- tardive dyskinesia –> involuntary orofacial movements
