Antipsychotics Flashcards
What is Psychosis`
Its an abnormal mental condition describes as “loss of conatct with reality”
Signs exhibited by Psychotic patients
Personality changes
Thought disorders
Unusual/bizarre behavior
Difficulty making social interactions.
Impairment in carrying out daily activities
What is Schizophrenia
Its a type of psychosis
Characteristics of Schizophrenia
Delusions, hallucinations and though disorder (positive symptoms)
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Social withdrawal, blunted emotion responses often dementia (negative symptoms)
Aetiology of Schizophrenia
unknown but its agreed that its Dopamine Hyperactivity that cause +ive symptoms
When does Schizophrenia begin
In adolescence/young adult life and tend to either follow a relapsing and remitting course or to be chronic and progressive
Treatment goals for Schizophrenia
-reduction of psychotic symptoms
-prevent recurrences of symptomatic episodes and associated deterioration of functioning
MOA of Neuroleptics/Antipsychotic drugs
- Block postsynaptic D2 Rs: antipsychotic activation
Neuroleptics (most) also block Cholinergic, A-adrenergic, Serotonin and Histamine Receptors= adverse effects
Which are the Typical /Conventional Antipsychotics
Phenothiazines (Chlorpromazine, Fluphenazine)
Butyrophenones (Haloperidol)
Thioxanthines (Fluphenthixol)
MOA of Typical Antipsychotics
Act primarily by blocking D2 Receptors
High Potency drugs: high affinity for D2 R and less for a-adrenergic and muscarinic Rs
Low Potency drugs: less affinity for D2 Rs and more for a-adrenergic and muscarinic Rs
Example of High and Low potency Neurolepticsa
High: Haloperidol
Low: Chlopromazine
What does the choice of drug depend on?
AE profile
Route of administration
Pateint responses to drug
Which are the Atypical Antipsychotics
CORQ
Clozapine
Olanzapine
Risperidone
Quetiapine
MOA of Atypical Antipsychotics
-Block Dopamine Rs more selectively than typical antipsychotics
-are less likely to cause Extrapyramidal SE
Incr. Prolactin release (slighly): Risperidone
Incr. risk of metabolic syndrome than typical=
SEs: diabetes mellitus, weight gain,)
Extrapyramidal SEs may cause
Parkinsonism: esp. in older pateinets; tardive dyskinesia, akathisia, hyperprolactinaemia
Which are the Low Potency SGAs
Clozapine
Quetiapine
Which are the High potency SGAs
Risperidone
MOA of Chlorpromazine
Low potency: has more affinity for a-adrenergic, Muscarinic and 5HT2 Receptors
Blockade of D2«<5HT2A Receptors
Effects of Chlorpromazine
Improves disturbed thought and blunted effect
Changes withdrawal and autistic behvaiour
Reduces Hallucinations
Potent sedative: effective for restless aggressive patients and patients who are difficult to control
Dosage of Chlorpromazine
Start with 25mg, incr. gradually unti control
Once stable administer as single bedtime dose
What is the usual Maintenace dose of Chlorpromazine
75-300 mg
AE of Chlorpromazine
Extrapyramidal symptoms incl. Parkinson
Anticholinergic effects
Sedation
Weight gain
MOA of Haloperidol
Most potent D2 antagonist
Blockade of D2 Rs»>5HT2A Rs
When is Haloperidol used?
For both acute and chronic Schizoprhenia
Dosage of Haloperidol
5-10 mg IM or PO, repeat every 4-6hrs
What is the common maintenance dose of Haloperidol
4 mg PO at bedtime
AE of Haloperidol
Extrapyramidal symptoms
Akathisia (motor restlessness)
Anticholinergic effects
MOA of Clozapine
Weak D2 Receptor antagonist
Blockade of 5HT2A R»> D2 Receptor
Effects of Clozapine
USed in patients unresponsive to other antipsychotics
Improves both negative and postive symptoms
Has few or no motor AEs, minimal risk of tardive dyskinesia
Dosage of Clozapine
12.5mg PO,OD or BD
Incr. daily in increments of 25-50mg/day
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