Antipsychotic Agents - Filtz Flashcards
What is the primary mechanism of action of antipsychotic agents?
D2 antagonism
What is the difference between psychoses and neuroses?
Psychoses are mental disorders characterized by rifts in rational thought, inappropriate processing of sensory information, and disturbed views of reality. Generally not recognized as psychotic symptoms by the sufferer (not sure which are real and which are not).
Neuroses are abnormal reactions to an external state that is generally recognized as such by the sufferer.
What are positive symptoms of psychoses?
Overt symptoms: delusions, paranoia, hallucinations (usually auditory), disordered thoughts, bad sense of time, loose ideation, inappropriate emotional response.
What is synesthesia?
The production of one sense by stimulating another sense or part of the body.
What is good about loose ideation?
It is thought that people with a little bit of loose ideation are kind of geniuses in their own way… less inhibition and different ways of thinking than most people.
What disease states involve psychoses?
schizophrenia Delirium in dementia Manic psychoses PTSDs Drug-induced (amphetamine, steroid, LSD, ketamine, PCP, sedative/hypnotic)
What % of the population is affected with schizophrenia?
about 1%
Are men or women more affected by schizophrenia?
Men and women equally
Is there just one type of schizophrenia?
No, there are many subtypes.
What is the age of onset of schizophrenia?
15-25 years
What type of symptoms preceded psychosis?
Positive symptoms, such as odd behaviors, talking to oneself, etc. In kids, they are usually socially withdrawn, flat affect, keep to themselves, talk to themselves (more than most).
What is the mortality rate with schizophrenia? Outlook?
This is a chronic disease state for most individuals, but a fraction of people “break out” after meds and care home, and it doesn’t come back. Variable. High mortality rate (10%). Often the hallucinations tend to diminish by age 55 or so if they are left untreated and make it through.
What is the best measure/prodromal sign of whether a kid has schizophrenia or will soon have it?
Illicit drug use by the age of 9: self-medication.
What negative symptoms are involved in schizophrenia?
Flat affect
Anhedonia and apathy
Lack of volition
Social and emotional withdrawal
Disorganized speech, thinking, and behavior
Impaired attention (because of running commentary)
Poor self-care
What is the biggest take-away when treating people with schizophrenia?
They need empathy, not judgement. Try to understand what they are going through, and the reasons that it is hard for them to stay compliant.
What does the development of schizophrenia have to do with?
It is a neurodevelopment disorder, with genetic and environmental causes. Anatomic irregularities are present, such as enlarged cerebral ventricles, reduced cortical mass (gray matter), hypofrontality (reduced processing in the prefrontal cortex).
What increases susceptibility to schizophrenia?
Perinatal insults and traumatic early life events
What kind of treatment options are out there to treat schizophrenia?
Frontal lobotomy (permanently debilitating)
Psychotherapy (ineffective by itself)
Cognitive Behavioral Therapy (improve social skills, life skills, personal hygiene, etc - teach them)
Self-medication with nicotine (very common)
Antipsychotics
What does treatment with antipsychotics usually do in schizophrenia?
Reduces auditory hallucinations
Brings awareness of running commentary, and a recognition that it is not real
Which method is most effective? How effective is it? What changes about the relapse rate?
Neuroleptics or major tranquilizers (aka antipsychotics) are the most effective means of treating psychotic symptoms. Less effective on social problems, still need CBT.
Effective on 70% of psychotic patients (still 30% untreatable)
Reduces 12 month relapse rate from 90% w/o drugs to 40% w/ drugs.
When do the effects begin?
- Tranquilizer
- Diminished psychotic symptoms
- Full antipsychotic effects
- Improvement may be seen up to…
Tranquilizing effects may be seen in minutes to hours (vitamin I)
Diminished psychotic symptoms within 24-28 hours
Full antipsychotic effects evolve over 2-8 weeks
Improvement may continue for up to 6 months
What do the antipsychotics have in common about how they work?
They are all D2 dopamine receptor antagonists or weak partial agonists.
The antipsychotic affinity for D2 receptors correlates with average clinical dose (approximating potency)
What subtypes of dopamine receptors are D2?
D2, D3, D4
True or false: in antipsychotics, potency and affinity of drugs are directly related?
True
In the G-alpha-i receptor, what happens to adenylyl cyclase?
It decreases
What type of symptoms do antipsychotics cause?
PD-like symptoms from the nigrostriatal pathway
What are the dopaminergic pathways in the brain?
- mesocortical (VTA to frontal and prefrontal cortex)
- mesolimbic (VTA to nucleus accumbent in limbic area)
- nigrostriatal (Substantia nigra to striatum in basal ganglia)
- tuberoinfundibular (hypothalamus to pituitary) - endocrine
What does VTA stand for?
ventral tegmental area
What are the 1st gen antipsychotics?
- Phenothiazines and related thioxanthines
- Butyrophenones and related
What are the phenothiazines and related thioxanthines?
Chlorpromazine
Thioridazine
Fluphenazine
Thiothixene
Which is the “grandparent of all antipsychotics?”
Chlorpromazine
What are the butyrophenones and related antipsychotics?
These are more D2 selective:
- Haloperidol (still in use, effective and cheap)
- Pimozide (for terets)
What are the 2nd generation antipsychotics?
Dibenzazepines (clozapine, loxapine, olanzapine, quetiapine)
Others (risperidone, ziprasidone, aripiprazole, lurasidone, etc.)
What drug is the gold standard as an antipsychotic? Why?
clozapine. It seems to treat a subset of people that would otherwise be unreached.
What are the side effects of antipsychotics on the nigrostriatal pathway?
- initiation and control of movement and muscle tone
- Selectively degenerated in PD
- Involved in OCD
- Antagonism of D2 receptor in the basal ganglia produces extrapyramidal side effects (EPS)
What do EPS symptoms look like? How soon after dosing do they usually occur?
- Akathisia (constant movement) - after a few months
- Dystonia (torticollus, spasms of neck and face muscles, ocular dysfunction) - early, within 1-2 doses
- Respiratory distress - pharyngeal/laryngeal dysfunction
- Pseudo-PD - around 6 months
If you see dyskinesias, does it necessarily mean that you are seeing EPS effects?
No, it could be several things, such as EPS, psychosis itself, or PD-like dyskinesias associated with the disease or treatment.
When you use a D2 antagonist, what is the effect?
You are inhibiting an inhibition of ACh, so you get a greater response than if there was no D2 agonists at all. Response is greater.