ANTI-PSYCHOTICS Flashcards
Typical anti-psychotic drugs (CFHT)
- Chlorpromazine (1st antipsychotic drug)
- Fluphenazine
- Haloperidol (one of the most commonly prescribed drug)
- Trifluoperazine
5 symptoms domains of schizophrenia
- Positive symptoms
- Negative symptoms
- Cognitive symptoms
- Anxiety/depression
- Aggressive symptoms
What is positive symptoms
Addition of abnormal behaviours
- most disrupting to others
- led to first referral to psychiatrist and diagnosis of schizophrenia
eg hallucinations, delusions, thought disorder, abnormal behaviours
What is negative symptoms
Subtraction of normal behaviours
- becomes more dominant over time as disease progress
- most disrupting to self
- frequently associated with depression resulting in suicide in 10% of cases
eg withdrawal from social contacts, flattening of emotional responses
EPS
Extrapyrimidal symptoms
- Acute dystonia
- Tardive Dyskinesia
- Akathisia
What is cognitive dysfunction
Impairment of working memory
Impairment of selective attention
- recently recognised to be a persistent core feature of the disease (not iatrogenic)
- important to predict level of social and vocational functioning than positive symptoms
3 main theories to the etiology of schizophrenia
- Dopamine theory (Amphetamine)
- dopamine agonist lead to schizophrenia
F>H>T>C - 5-HT theory (Lysergic acid diethylamide, LSD)
- 5-HT agonist lead to schizophrenia
- many atypicals have 5-HT antagonism (clozapine & olanzapine) - Glutamate theory (Ketamine, PCP)
- NMDA antagonist lead to schizophrenia
- no current drugs as NMDA agonist
They are mainly theories of positive symptoms
4 dopamine pathways of the brain
- Nigrostriatum pathway (voluntary movement & EPS)
- substantia nigra to dorsal striatum - Mesolimbic pathway (rewards & emotions)
- Mesocortical pathway (cognitive & attention)
- Tuberoinfundibular pathway (lactation & gynaecomastia)
- hypothalamus to anterior pituitary
- cos dopamine is involved in the negative feedback of prolactin production
- hence dopamine antagonist will allow prolactin production leading to lactation (even in non-pregnancy women) & gynaecomastia (males)
- Amisulpride
Side effects of H1 receptor antagonist
- Sedation
2. Weight gain
Side effects of M1 muscarinic receptor antagonist
- Dry mouth
- Constipation
- Blurred vision
Side effects of alpha1-adrenergic receptor antagonist
- Postural hypotension
- Dizziness
- Reflex tachycardia
Potential benefits of HT-7 receptor antagonist
Pro-cognitive
All anti-psychotics MOA
D2 dopamine receptor antagonist
What is acute dystonia?
- Parkinsonism-like syndrome
- due to nigrostriatum pathway inhibition
- reversible upon discontinuation of drug
What is tardive dyskinesia?
- involuntary movement
- develops over time
- irreversible
- most likely due to the upregulation of dopamine receptors in nigrostriatal pathway
- occur in 20-40% of patients on typical anti-psychotic
What is akathisia?
- compulsion to act associated with restlessness, anxiety & agitation
- linked to the duration of drug use
- irreversible
- most likely due to the upregulation of dopamine receptors in nigrostriatal pathway
- occur in 20-40% of patients on typical anti-psychotic