antipsychotic drugs Flashcards
(13 cards)
what are antipshychotic drugs
Antipsychotic drugs are mainly used to treat schizophrenia, but they can also help with other psychotic or manic conditions.
They help reduce symptoms like hallucinations and delusions, but they don’t cure the illness or completely stop long-term thinking problems.
Using them involves a balance between the benefits (relief from symptoms) and the risk of side effects.
These drugs can help people with schizophrenia live more normally in a supportive setting.
what is Schizophrenia
Schizophrenia is a long-term mental illness where a person may experience delusions, hallucinations (like hearing voices), and confused thinking.
It usually begins in late teenage years or early adulthood and affects about 1% of people.
It is a serious and disabling condition that tends to last a lifetime.
The cause is partly genetic and may involve problems in brain development and in dopamine pathways, especially in areas called the mesolimbic and mesocortical systems.
what is psychosis
Psychosis is a mental health condition characterized by a loss of contact with reality. It can involve:
Core Symptoms:
Hallucinations – Seeing, hearing, or feeling things that aren’t there (e.g. hearing voices).
types are: auditory, visual, tactile, olfactory
Delusions – Strongly held false beliefs (e.g. believing you’re being watched or controlled)
.
Disorganized thinking – Trouble organizing thoughts or connecting them logically.
types of schizophrenia symptoms
positive: excess of distorted functioning
negative: diminished functioning
cognitive: reduced ability to understand or make plans
diagnosis requires more than 2 of the DSM5
- delusions
- hallucinations
- disorganised speech
- disorganised or catatonic behaviour
- negative symptoms
it is associated with altered dopamine activity, increase in serotonergic activity and decreased dendritic branching
heavy canibis use at a young age can increase risk
TREATMENT: atypical antipsychotics are first line
what are the dopaminergic pathways and what is it altered by
altered by drug like antipsychotic and movement disorders e,g Parkinson’s
. Mesolimbic Pathway
From: Ventral tegmental area (VTA)
To: Nucleus accumbens (part of the limbic system)
Function: Reward, pleasure, addiction, and reinforcement
Clinical relevance:
↑ Dopamine here is linked to positive symptoms of schizophrenia (e.g., hallucinations, delusions).
🧠 2. Mesocortical Pathway
From: Ventral tegmental area (VTA)
To: Prefrontal cortex
Function: Cognition, emotion, executive function
Clinical relevance:
↓ Dopamine here is associated with negative symptoms (e.g., flat affect, avolition) and cognitive symptoms in schizophrenia.
🧠 3. Nigrostriatal Pathway
From: Substantia nigra (pars compacta)
To: Dorsal striatum (caudate and putamen)
Function: Regulation of movement
Clinical relevance:
↓ Dopamine → Parkinson’s disease (bradykinesia, tremor, rigidity)
Dopamine antagonists (e.g., antipsychotics) → Extrapyramidal side effects (EPS) like dystonia, akathisia.
🧠 4. Tuberoinfundibular Pathway
From: Hypothalamus
To: Pituitary gland (specifically the anterior pituitary)
Function: Inhibits prolactin secretion
Clinical relevance:
Dopamine antagonists can cause ↑ prolactin → galactorrhea, gynecomastia, amenorrhea.
how are the antipsychotic drugs divided
divided into first- and second generation agents.
first-generation drugs are further classified as “low potency” or “high potency.“
This classification does not show clinical effectiveness of the drugs but it specifies affinity for the dopamine D2 receptor can influence the adverse effect of the drug.
First-generation (or conventional) antipsychotic drugs
First-generation (or conventional) antipsychotic drugs work by blocking dopamine D2 receptors in the brain.
Although they affect many receptors, their main effect on psychosis comes from blocking dopamine.
These drugs are more likely to cause movement-related side effects, called extrapyramidal symptoms (EPS), especially strong ones like haloperidol.
Second-generation (or atypical) antipsychotics
Second-generation (or atypical) antipsychotics cause fewer movement side effects (EPS) than first-generation drugs.
However, they are more likely to cause metabolic problems like weight gain, high cholesterol, and diabetes.
These drugs work by blocking both serotonin and dopamine receptors in the brain.
typical antipsychotics
haloperidol, trifluoperazine, flupherazine ( high potency)
thioridazine, chlorpromazine,( low potency)
primpzide
mechanism: blocks D2 receptors causing increase in c AMP
adverse: lipid soluble -> stored in body fat -> slow to be removed from the body
weight gain, metabolic dysliperdemia, hyperglycaemia, QT prolongation
atypical antipsychotics
aripiprazole, asenapine, clozapine, olanapine, quetapine, rispweidone, lurasidone
mechanism: not completely understood, most are D2 agonist and aripiprazole is D2partial agonist
used for schizophrenia - both positive and negative symptoms and bipolar disorder, OCD, anxiety and torttes
clozapine is used for treatment resistant schizophrenia and schizoaffective disorder
adverse effects: prolonged QT,
clozapine: agranulocytosis and seizures
olanzapine -> obesity
adverse effects based on endings of the drugs and also aripiprazole
“PINES” (like olanzapine, quetiapine) are antipsychotics that:
Cause fewer movement side effects (EPS)
But have a higher risk of causing weight gain and metabolic problems
“DONES” (like haloperidol, risperidone) are antipsychotics that:
Cause more movement side effects (EPS)
Also carry a higher risk of heart rhythm problems (QT prolongation)
Aripiprazole (another antipsychotic) can cause unusual side effects like:
Loss of impulse control (leading to gambling, binge eating, compulsive shopping)
Other side effects like pancreatitis, headaches, dizziness when standing up (orthostatic hypotension), and rarely low blood sugar.
Neuroleptic malignant syndrome
Neuroleptic malignant syndrome is a rare but serious side effect of antipsychotic drugs.
It causes stiff muscles, high fever, confusion, unstable blood pressure, and muscle breakdown.
If this happens, the antipsychotic medicine must be stopped, and the person needs supportive care.
Medicines like dantrolene or bromocriptine can help treat it.
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