Exam 1 - Antipsychotics Flashcards
Dopamine
Produced in the Ventra Tegmental Area(Reward Pathway)
Associated with reward and pleasure
Involves 4 major pathways
Mesolimbic Pathway “reward/pleasure”
Associated with positive symptoms of schizophrenia (i.e. hallucinations, delusions etc)
However, excess DA in this pathway will produce positive psychotic sx (even in people abusing substances which increase DA and other disorders with psychosis)
Note: Dopamine inhibits prolactin.
Dopamine
Mesocortical Pathway
Associated with the negative symptoms of Schizophrenia (i.e. cognition, affect, apathy, behavior etc.)
It is believed that negative sx are related to a deficit of dopamine in this particular pathway
FGA can induce negative and cognitive symptoms as they block DA
Dopamine
Tuberoinfundibular Pathway
When functioning normally, the neurons in this pathway are active and INHIBIT prolactin release
Sx of elevated prolactin levels: galactorrhea, amenorrhea, possible sexual dysfunction
Note: Dopamine inhibits prolactin.
Therefore, blockade of dopamine= ↓DA= ↑ Prolactin
Dopamine
Nigrostriatal Pathway
Blockade of DA in this pathway produces increased motor movements
Deficient DA in this pathway causes movement disorders
e.g. EPS (Pseudo parkinsonism, Akathisia, dystonia & TD)
Neurotransmitters in schizophrenia
↑Dopamine in the mesolimbic area
↓Dopamine activity in the Mesocortical area
↓Serotonin (down regulation) in the frontal cortex
Most patients experience prodromal phase so symptoms before their first psychotic break (i.e. negative symptoms, cognitive deficits and social awkwardness (2-3 years before psychotic break)
10+% incidence with one parent with schizophrenia and 35+% with both parents with schizophrenia.
Antipsychotic polypharmacy can increase the risk ofor re-hospitalization, diabetes, EPS, sedation, seizures, metabolic effects, mortality and sudden cardiac death.
Red part
Antipsychotic polypharmacy can increase the risk ofor re-hospitalization, diabetes, EPS, sedation, seizures, metabolic effects, mortality and sudden cardiac death.
Psychotic Disorders:
Brief Psychotic Disorder
Schizophreniform disorder
Schizophrenia
Schizoaffective disorder (Bipolar type or depressive type)
Antipsychotics (Up to 6-8 weeks for response)
Etiology:
Impaired neuronal communication
↑ DA in mesolimbic pathway = positive symptoms
↓ DA in mesocortical pathway = negative symptoms
Excessive Glutamate
↓ GABA
↓ 5HT
NOTE: Majority of patients require lifelong medication.
Indication(s): Schizophrenia, schizoaffective disorder, depression w/ psychotic features, bipolar w/ psychotic features,
Positive Symptoms of Schizo/Psychotic disorders:
Delusions
Conceptual disorganization
Excitement
Grandiosity
Hostility
Hallucinations
Negative Symptoms of Schizo/Psychotic disorders:
Affects (generally flat, constricted)
Alogia (relative absence of speech
Avolition/Apathy ( lack of emotions, initiative)
Attention (poor or lacking)
Anhedonia (absence of pleasure/motivation
Asociality- withdrawal from normal social contact
Cognitive Symptoms
Manifestation of Positive Symptoms of Schizo/Psychotic disorders:
Delusions
Hallucinations
Conceptual disorganization
Hostility
Grandiosity
Manifestation of Negative Symptoms of Schizo/Psychotic disorders:
Affect (generally flat, constricted)
Alogia (relative absence of speech)
Avolition/Apathy(lack of emotion enthusiasm)
Attention (poor or lacking)
Anhedonia (absence of pleasure)
Antipsychotics: overview
Not just used for psychosis or schizophrenia
Used for mania and depression in bipolar d/o
Augmentation for mood
Off-label for many disorders including mood, anxiety, PTSD
Typical/1st Generation /Neuroleptics /Coventional
Introduced in the 1950’s
Block D2 receptors
Effective for positive symptoms
Can worsen negative symptoms secondary to ↓DA in the Mesocortical pathway
Long-acting forms available (Decanoate)
Atypical/2nd Generation
First line treatment
Fewer neurological S/E
Effective for both positive and negative symptoms
Serotonin-Dopamine antagonist (D2/5HT2A)
Can cause EPS but at a lower risk
↓ incidence of Tardive dyskinesia
Metabolic side effects : Weight gain, HLD, hyperglycemia, Diabetes, HTN, Cardiac and respiratory S/E
Some Antihistaminic, antiadrenergic and antimuscarinic effects
Elevated Liver function tests (LFTs)- check yearly
QTC Prolongation
Atypical/2nd Generation Antipsychotics are first line treatment.
NOTE: Antipsychotics can take up to 6-8 weeks for response
Factors affecting choice of antipsychotic medication
Side effect profile
Available route of administration (e.g. liquid vs. disintegrating forms)
Patient’s medical hx
Current medications
Preference
Low Potency Typical (1st Generation Antipsychotics)
Low affinity to DA receptors= ↑doses required
High incidence of antiadrenergic, anticholinergic and antihistaminic s/e
Lower risk of EPS
More lethal in overdose d/t QTC prolongation
e.g. Thorazine, Mellaril
Recap: Low potency= Low EPS= High antiadrenergic, anticholinergic and antihistaminic s/e
High Potency Typical (1st Generation Antipsychotics)
Greater affinity to DA receptors= ↓doses needed
Less incidence of antiadrenergic, anticholinergic and antihistaminic s/e
Greater risk of EPS
e.g. Haldol, Prolixin, Stelazine
Recap: High potency= High EPS= Low antiadrenergic, anticholinergic and antihistaminic s/e
Typical Antipsychotics
Chlorpromazine (Thorazine)
Can cause blue-gray skin discoloration and corneal/lens deposits
Causes orthostatic hypotension
Also used for N/V and intractable hiccups
Comes in po and IM formulation (effective for agitation in emergencies
Typical Antipsychotics
Thioridazine (Mellaril)
Associated with retinitis pigmentosa
Typical Antipsychotics
Loxapine (Loxitane)
Higher risk of seizures
Typical Antipsychotics
Haloperidol (Haldol)
Can be given PO/IM/IV; Decanoate (LAI)
Given in Acute agitation or psychosis
Typical Antipsychotics
Fluphenazine
PO/IM; Decanoate (LAI) available