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Flashcards in Antipsychotics Deck (18):
1

Schizophrenia

schizo- divided
phrenos- mind
Impaired perception of reality
social and/or occupational dysfuntion
Disorganized thinking
Delusions and sometimes hallucinations

2

Schizophrenia Symptoms

Positive: Delusions- false personal beliefs that are not subject to reason, Hallucinations- perceptions that occur without connection to appropriate source, Disorganized speech, grossly disorganized or catatonic behavior, Thought disorder- disruptions of the norml flow of thoughts throughout the day, disorganized thinking

Negative: Emotional Flatness, lack of expression, inability to start and follow through with an activity, brief speech phrases that lack content

3

Antipsychotics- Indication

Acute and maintenance treatment of schizophrenia
Psychosis associated with acute mania and depression
Adjunctive treatment for agitation due to psychiatric conditions, delirium, tremors and dementia
Psychosis from any number of medical causes

4

Typical Antipsychotic

Primarily Dopamine2 receptor antagonist

5

Atypical Antipsychotic

Block both dopamine and serotonin receptors

6

Atypical (3rd gen) Antipsychotic

Partial agonist for Dopamine d2 and 5-HT1a, antagonist at 5-HT2a
Abilify
Partial agonist may actually modulate dopamine activity in areas where it might be high or low, superior to simply blocking

7

Antipsychotic Pharmacology

Central blockade of dopamine receptors
limbic areas--> antipsychotic effects
basal ganglia --> extrapyramidal side effects
brainstem chemoreceptors --> antinausea and antiemetic effects
hypothalamus--> block dopamine inhibition of anterior pituitary prolactin release --> increased prolacting

8

Pharmacology Typicals (General)

Peak levels in 1-4 hours, half lives for 8-36 hours
Metabolized by liver
Most have active metabolites
Have limited oral bioavailability but IM injection can result in 2-3 times higher blood levels
Both low and high potency drug exist
Low- require relatively larger doses, more likely to produce sedation, hypotension, and anticholinergic effects

9

Typicals Delay

Delay in clinical efficacy that could lead to non-compliance and relapse
D2 blockade not sufficient
Initial response, presynaptic blockade that leads to increase in dopamine
Tolerance to presynaptic effects allows postsynaptic blockage to be more effective

10

Typicals

Decades of new experience with these agents
- New and serious side effects are being discovered with the 2nd generation atypical drug
Availability of long acting decanoate preparations of haloperidol and fluphenazine
Much less expensive and well tolerated

11

Typicals Side effects

Anticholinergic- Dry mouth, blurred vision, Constipation, Memory and concentration difficulties
Alpha-adrenergic blockade- Hypothension
Antihistaminergic Side effects- Sedation, drowsiness, weight gain
Akathisa- Subjective or observable restlessness, persists until dose is lowered
Tardive dyskinesia- Syndrome of abnormal involuntary movements

12

Atypicals

Fewer extrapyramidal side effects, increased compliance, fewer relapses
Can be more effective for first break patients
Recommended to elderly patients- more at risk for hypotension and tachycardia
Treat both positive and negative symptoms

13

Risperidone- Atypical 2nd

Injectable
extended release microspheres
Provides long acting coverage, deep intramuscular injection every 2 weeks

14

Negative Symptoms Typicals vs Atypicals

negative symptoms due to dopamine hypofunction in the cortex
Typicals not effective for negative symptoms
Atypicals have great affinity for blocking serotonin receptors than for dopamine
This indirectly increases DA levels in cortex, blocks psychotic effects of excess DA in limbic system

15

Mechanism of Action Atypicals

Antagonism of 5-HT receptors also increases glutamate levels in cortex
Blockade of NMDA glutamate can produce hallucinations- glutamate- NMDA hypofunction model of schizophrenia
NMDA hypofunction leads to excess release of glutamate in frontal cortex, damaging cortical neurons leading to schizophrenia
Hyperdomamine activity lead to positive symptoms and glutamate leads to negative symptoms

16

Atypicals Side Effects

Dizziness
Somnolence
Weight gain- Strongly correlated with affinity for alpha1 and h1 receptors, affect diverse neurotransmitter involved in food intake regulation
insomnia
hyperglycemia
diabetes

17

Typical vs Atypical

Both treat positive symptoms, reduce hallucination, control agitation, aid in restructuring disordered thinking
Atypicals attenuate negative symptoms- flat affect, avolition, impoverised thought and speech

Both medications did equally as well in certain trials

18

Schizophrenia and Drug Abuse

50% with schizophrenia also qualified for drug abuse- primarily on nicotine
May be self-regulating of negative symptoms
Most begin to smoke in teens, before schizophrenic symptoms
Nicotine may regulate dysfunctional mesolimbic dopamine system