Antipsychotic Medications Overview

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Questions and Answers

Which treatment is categorized as a first-generation antipsychotic?

Cariprazine

Haloperidol (correct)

Chlorpromazine (correct)

Aripiprazole

What mechanism does a dopamine D2 antagonist primarily target?

Presynaptic D2 receptors

Dopamine reuptake inhibitors

Post-synaptic D2 receptors (correct)

Serotonin receptors

What is a common side effect associated with prolonged use of D2 receptor antagonists?

Neuroleptic Malignant Syndrome

Weight gain

Insomnia

Tardive dyskinesia (correct)

How do third-generation antipsychotics like aripiprazole function in high levels of mesolimbic dopamine?

They act as a partial agonist to reduce hyperactivity. Signup and view all the answers

What percentage of patients do not respond to D2 receptor antagonists?

30% Signup and view all the answers

What percentage of the human brain is made up of fat?

29% Signup and view all the answers

What is hypofrontality associated with in relation to schizophrenia?

Depressed prefrontal cortex function Signup and view all the answers

Which of the following factors is NOT linked to an increased incidence of schizophrenia?

Excessive adolescent exercise Signup and view all the answers

What percentage chance does a child have of developing schizophrenia if a parent has the disease?

10% Signup and view all the answers

In what age period does schizophrenia typically begin to occur?

Late teens to early 20s Signup and view all the answers

Which of the following symptoms is commonly associated with schizophrenia?

Visual hallucinations Signup and view all the answers

Which area of the brain is noted to show changes in individuals with schizophrenia as indicated by MRI scans?

Prefrontal cortex Signup and view all the answers

Which of the following is considered a significant nutrient found in human brains?

Omega-3 fatty acid DHA Signup and view all the answers

What is a potential advantage of having long half-life drugs for schizophrenia patients?

They may have residual levels in the blood even after stopping. Signup and view all the answers

What factors need to be measured to determine appropriate dosing of a drug with a long half-life?

Both parent drug and metabolite levels in the blood. Signup and view all the answers

What could be a consequence of having long half-life drugs in the body?

They may require less frequent dosing. Signup and view all the answers

Which of the following associations is incorrect?

First pass metabolism involves renal excretion. Signup and view all the answers

Why is the pharmacokinetic profile essential for a drug's effectiveness?

It affects both efficacy and the degree of side effects. Signup and view all the answers

Which of the following is NOT considered a positive symptom of schizophrenia?

Blunted affect Signup and view all the answers

Which neurotransmitter imbalance is associated with positive symptoms of schizophrenia?

Dopamine hyperfunction Signup and view all the answers

What role does the blood-brain barrier (BBB) play in the brain's microenvironment?

It protects against circulating toxins while allowing vital nutrients to enter. Signup and view all the answers

How does serotonin mainly influence negative symptoms in schizophrenia?

Via modulation of glutamate activity Signup and view all the answers

What is a main characteristic of the specialized transporters in the BBB?

They facilitate the transport of both essential molecules and waste products. Signup and view all the answers

What type of cognitive impairment is commonly seen in schizophrenia?

Poor attention and memory Signup and view all the answers

What influences the frequency of drug administration?

The drug's elimination rate from the body. Signup and view all the answers

Why are schizophrenia symptoms difficult to diagnose?

Symptoms vary between individuals Signup and view all the answers

What does 'steady state' refer to in pharmacokinetics?

When drug intake equals elimination, keeping blood concentration stable. Signup and view all the answers

What does NMDA antagonism lead to in the context of schizophrenia?

Induction of negative symptoms Signup and view all the answers

How are metabolites formed during the metabolism of a drug?

Metabolites can be either active or inactive. Signup and view all the answers

What role does the PFC play in the mesocortical dopamine system in schizophrenia?

It regulates negative control Signup and view all the answers

Which of the following statements about drug clearance is true?

Most drugs are cleared through the kidney and urine. Signup and view all the answers

Which receptor subtype is predominantly involved in the negative symptom regulation of serotonin?

5-HT1A Signup and view all the answers

What behavioral pattern is common among many individuals with schizophrenia regarding smoking?

They often self-medicate with it Signup and view all the answers

What is the significance of the half-life (T1/2) in drug dosing?

It indicates how frequently to administer the drug. Signup and view all the answers

What is true about Cariprazine's pharmacokinetic profile?

It has an active metabolite with a longer half-life than the parent drug. Signup and view all the answers

Low levels of dopamine release in the PFC are associated with which type of symptoms?

Cognitive symptoms Signup and view all the answers

What aspect of glutamate's role in schizophrenia has been observed through pharmacological studies?

Glutamate dysfunction is associated with various symptom types Signup and view all the answers

Which property of the blood-brain barrier contributes to its selectivity?

It allows only small lipid-soluble drugs to pass. Signup and view all the answers

What impact do active metabolites have on the therapeutic effect of a drug?

They can contribute to either therapeutic effects or side effects. Signup and view all the answers

What type of side effects is associated with chlorpromazine, a medication for schizophrenia?

Reduced positive symptoms Signup and view all the answers

The principle action of amphetamines in schizophrenia is to:

Augment dopamine levels Signup and view all the answers

What is a common behavioral symptom associated with cognitive impairment in schizophrenia?

Difficulties with abstract thinking Signup and view all the answers

The balance of which neurotransmitters is crucial for understanding schizophrenia's symptoms?

Dopamine, serotonin, and glutamate Signup and view all the answers

What effect does a low dose D2 antagonist have in combination with NMDA agonists?

It decreases dopamine in the mesolimbic pathway. Signup and view all the answers

Which drug is an example of a 3rd generation antipsychotic that acts as a dopamine stabilizer?

Cariprazine Signup and view all the answers

What is the primary role of the cytochrome P-450 enzymes in pharmacokinetics?

They metabolize drugs in the liver. Signup and view all the answers

How does high protein binding affect a drug's efficacy?

It reduces the amount of free drug available. Signup and view all the answers

What is the primary consequence of first-pass metabolism on drug bioavailability?

It decreases the amount of drug entering systemic circulation. Signup and view all the answers

What is the significance of lipophilicity in drug distribution?

It affects how easily the drug crosses lipid membranes. Signup and view all the answers

Which of the following best describes how dopamine acts in the mesolimbic pathway at high levels?

As an antagonist competing with dopamine for the receptors. Signup and view all the answers

What is one consequence of a drug's lipophilicity on its pharmacokinetics?

It facilitates passive diffusion across membranes. Signup and view all the answers

Which drug class primarily targets cognitive symptoms in schizophrenia?

Atypical antipsychotics Signup and view all the answers

What role does the Blood-Brain Barrier (BBB) play in pharmacology?

It regulates the substances that can enter the brain. Signup and view all the answers

Which type of receptors are D2 partial agonists primarily associated with?

Dopamine receptors Signup and view all the answers

What aspect of drug distribution can be significantly limited by high protein binding?

Clinical efficacy of the drug Signup and view all the answers

What impact does grapefruit juice have on drug metabolism?

It inhibits cytochrome P-450 enzymes. Signup and view all the answers

What primary factor does NOT affect drug distribution to target tissues?

Chemical stability Signup and view all the answers

Study Notes

Human Brain Nutrition Facts

DHA, a vital omega-3 fatty acid, is concentrated in human brains.
The brain is approximately 29% fat and 20% protein.
It's a good source of vitamin C and iron.

Schizophrenia Symptoms

National Institute of Health considers schizophrenia a chronic, severe mental disorder affecting thoughts, feelings, and behaviours.
Individuals may be withdrawn, consumed with their own thoughts and delusions.
Typically emerges in the early 20s, disrupting peak productive years.
Approximately 30% of those diagnosed are institutionalized at some point.
MRI scans reveal smaller brains with larger ventricles (empty space) in affected individuals.
Prefrontal cortex function can be depressed, leading to issues with executive function, response inhibition, and problem-solving skills.

Environmental Factors Associated with Schizophrenia (Incorrect Association)

Excessive adolescent exercise is NOT an environmental factor linked to schizophrenia. Other factors (e.g., adolescence cannabis smoking, prenatal malnutrition, urban birth, C-sections, children of dry cleaners) have more substantial associations.

Schizophrenia and Month of Birth

Risk of schizophrenia may be slightly higher for individuals born in certain months.
Risk appears lowest around the months of early January through early February and slowly increases and peaks around early September through late October.

Genetic and Environmental Factors in Schizophrenia

Genetic predisposition plays a role; a family history of schizophrenia increases the risk of developing the condition by 10%.
Environmental factors such as late winter/early spring birth, infections, vitamin D deficiency, urban pollution, prenatal malnutrition, and smoking are also linked to schizophrenia.
Not all factors have a clear and definitive effect, and more work is needed to assess causal linkages.

Schizophrenia Symptoms: Categories

Symptoms grouped into three categories:
Positive symptoms: include hallucinations, delusions, illogical thinking, and disorganized speech.
Negative symptoms: characterized by loss of normal pleasures, blunted affect, and social withdrawal.
Cognitive impairment: involves difficulties with attention, learning, memory, and abstract thinking.
Individual experiences vary, making diagnosis challenging. Symptoms can fluctuate over time.

Range of Symptoms and Associated Brain Sites

Mesolimbic and mesocortical neuronal circuits are associated with different symptoms of schizophrenia.
Positive symptoms typically correlate with activity in the mesolimbic circuit, while negative symptoms and cognitive issues are linked to the mesocortical circuit.
Emotions can be absent or inappropriate.

Biochemistry of Schizophrenia (Dopamine)

Dopamine dysfunction, alongside other neurotransmitters, plays a significant role in schizophrenia.
Early pharmacology studies using amphetamines and levodopa demonstrated the relation between dopamine and schizophrenia.
Chlorpromazine, a dopamine antagonist, effectively reduces schizophrenia positive symptoms.

Biochemistry of Schizophrenia (Glutamate)

NMDA antagonists exacerbate schizophrenia symptoms.
Hypoactivation in the mesocortical dopamine system is linked to negative symptoms due to low local glutamate/NMDA activity.

Biochemistry of Schizophrenia (Serotonin)

Serotonin modulates dopamine and glutamate, and affects primarily negative symptoms
5-HT1A, an inhibitory receptor, is activated by some anti-psychotics, and 5-HT2A, an excitatory receptor, may contribute to hypofrontality.

Biochemistry of Schizophrenia: Acetylcholine

Nicotinic acetylcholine receptors (nACh), particularly α7, are involved in cognitive functions.
Schizophrenic patients have decreased nACh receptor levels and increased rates of smoking.
Nicotine may be a form of self-medication for some schizophrenics.

Drug Inducing Schizophrenia-like Symptoms

Drugs interfering with dopamine reuptake can induce symptoms similar to schizophrenia, likely related to mesolimbic dopamine hyperfunction.

Classical Treatments of Schizophrenia

First-generation antipsychotics (dopamine D2 antagonists) were initially the primary treatment.
Approximately 30% of patients don't respond effectively to these drugs, necessitating research into other options.
Tardive dyskinesia and other side effects are possible.

Third-Generation Treatments of Schizophrenia

3rd generation antipsychotics feature partial D2 dopamine agonists (e.g., aripiprazole).
These drugs reduce hyperactivity in mesolimbic dopamine circuits, but partially activate the hypoactivity in mesocortical Dopamine circuits

Pharmacodynamics

Pharmacodynamics refers to how drugs impact the body.

Biodistribution: Blood-Brain Barrier

The blood-brain barrier hinders the entry of many substances into the brain and requires specialized transporters.

Metabolism

Drugs are broken down in the body, often by enzymes in the liver.
Metabolites can be inactive or active; some active metabolites have different (or similar) effects compared to the original drug.

Excretion

Eliminating drugs and their metabolites from the body, typically via the kidneys, occurs through excretion.

Steady-State

A period where drug concentration in the bloodstream remains relatively constant due to balanced intake and elimination.
Steady-state must be reached to accurately determine efficacy.

Cariprazine (Vraylar)

Cariprazine is a third-generation atypical antipsychotic. It acts as a partial agonist at dopamine D2 receptors and as antagonists at other receptors (e.g., 5-HT2A).
It has good oral bioavailability, rapidly crosses the blood-brain barrier, and has a relatively long half-life, which makes it useful for patients who may miss doses.

Summary

Schizophrenia is a complex neurological disease with heterogeneous presentation and unknown cause.
While dopamine plays a pivotal role, other neurotransmitters are also involved.
Genetic and environmental factors contribute to a predisposition and can impact the course of the disorder.
Both first and third-generation pharmacologic therapies are employed, although significant challenges and side effects remain.

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Description

Test your knowledge on antipsychotic medications with this quiz. It covers first-generation and third-generation antipsychotics, their mechanisms of action, common side effects, and treatment responses. Perfect for students of psychology and psychiatry.