Antipsychotics Flashcards
Atypical (Second-generation) Antipsychotics drug list
Aripiprazole Brexpiprazole Cariprazine Iloperidone Lurasidone Quetiapine Risperidone Ziprasidone
Special Use Atypical Antipsychotics
drug list
Clozapine
Olanzapine
Typical (First-generation) Low-Potency Agents drug list
Chlorpromazine
Typical (First-generation) High-Potency Agents drug list
Haloperidol
Things that fall under psychosis
Positive symptoms:
hallucinations
delusions
disorganized thinking or speech
Negative symptoms:
declining self care
flattened affect
anhedonia
Biological basis of schizophrenia
glutamate, serotonin, dopamine
Major Dopamine Pathways
Mesolimbic-mesocortical pathways
- Behavior and cognitive function
- Excess mesolimbic DA likely causes positive symptoms
- DA loss likely mediates negative symptoms
- DA blockade mediates antipsychotic action
Nigrostriatal pathway
- Coordination of voluntary movement
- Dopamine imbalance leads to EPS
Tuberoinfundibular system
- Dopamine inhibits prolactin secretion
Therapeutic Potency of Typical Antipsychotics
What you need to know:
Efficacy Correlates with D2, but not D1 (top), receptor binding affinity
Measured by displacing selective antagonists
D2 affinity also correlates with extrapyramidal toxicity
Dopaminergic Sites of Antipsychotic Action
on preynaptic membrane– shuts off release
on post-synaptic membrane
Regulation of receptor expression as an adaptive response
Summary: Mechanism of Action- typical drugs
Block dopamine receptors
- Especially D2
- Clinical efficacy correlates with this action
Messy pharmacology; side effects result from action at muscarinic, histamine, and adrenergic receptors
Summary: Mechanism of Action- atypical drugs
Exhibit higher affinity for 5-HT2A receptors than D2 receptors
Also block DA receptors, including D2
- Clinical efficacy is not necessarily correlated with D2 blockade
Newer agents are partial agonists at 5-HT1A and D2 receptors and antagonists at 5-HT2A receptors
Drug Choice: Compare and Contrast
Typical (1st Gen):
Relatively high risk of EPS and tardive dyskinesia
Highly effective against positive symptoms
Overall efficacy may be equivalent
Intermediate risk of weight gain
Lower cost
Atypical (2nd Gen)
Less prone to cause EPS and tardive dyskinesia
Efficacious for positive and negative symptoms
Overall efficacy may be equivalent
Variable risk of weight gain
Higher cost
General Adverse Effects
More Common: Extrapyramidal Symptoms (EPS) - Akathisia - Parkinsonism - Dystonias Tardive dyskinesia Metabolic dysfunction Prolactin elevation Anticholinergic effects Sedation
Rare: Seizures Orthostatic hypotension Neuroleptic malignant syndrome QT prolongation Sudden death
Adverse effects - manifestations and mechanisms- Autonomic nervous system
Loss of accommodation, dry mouth, difficulty urinating, constipation– Muscarinic cholinoceptor blockade
Orthostatic hypotension, dizziness, sedation, failure to ejaculate, impotence–α-Adrenoceptor blockade
Adverse effects - manifestations and mechanisms- Central nervous system
EPS: Parkinson’s syndrome, akathisia, dystonias- Dopamine-receptor blockade
Tardive dyskinesia- Supersensitivity of dopamine receptors
Adverse effects - manifestations and mechanisms- Endocrine system
Amenorrhea-galactorrhea, infertility, impotence
– DA-receptor blockade; hyperprolactinemia
Adverse effects - manifestations and mechanisms- other
Weight gain - Possibly combined H1 and 5-HT2 blockade
Adverse Motor System Effects- acute onset
Extrapyramidal symptoms
Usually occurs within days of treatment initiation
Direct result of D2 blockade in basal ganglia
Treatable