Drugs in Psychiatric Disorders Practice Questions

Q: Maximum increase in prolactin level is caused by:-

Risperidone (Potent D2 receptor antagonist). ***Risperidone (Potent D2 receptor antagonist)*** - Risperidone is a **potent D2 receptor antagonist**, meaning it blocks dopamine's action at these receptors. Since dopamine inhibits prolactin release, blocking D2 receptors leads to a significant increase in **prolactin levels**. - Its high affinity for D2 receptors in the **tuberoinfundibular pathway** is a primary reason for its pronounced effect on prolactin. *Olanzapine (Primarily blocks 5HT2 receptors)* - While olanzapine can cause some prolactin elevation, its primary mechanism involves **5HT2 receptor blockade**, with less potent D2 antagonism compared to risperidone. - The degree of **hyperprolactinemia** associated with olanzapine is generally milder than that seen with risperidone. *Aripiprazole (D2 partial agonist)* - Aripiprazole is a **D2 partial agonist**, meaning it acts as an antagonist when dopamine levels are high and an agonist when dopamine levels are low, effectively stabilizing dopamine activity. - Due to its partial agonism, aripiprazole typically has a **low risk of hyperprolactinemia** and can even normalize elevated prolactin levels caused by other antipsychotics. *Clozapine (Primarily blocks 5HT2 receptors)* - Clozapine primarily blocks **5HT2 receptors** and has relatively weak D2 receptor antagonism, especially transient D2 blockade. - It generally causes **minimal to no prolactin elevation** and is considered a prolactin-sparing antipsychotic.

Q: Use of lithium during pregnancy increases the risk of development of which of the following malformations in the baby?

Cardiac defects. ***Cardiac defects*** - Exposure to **lithium during pregnancy**, particularly in the first trimester, is associated with an increased risk of **cardiac malformations** in the fetus. - The most commonly associated cardiac defect is **Ebstein anomaly**, a rare congenital heart defect. *Urogenital defects* - While various medications can cause urogenital defects, **lithium is not specifically identified** as a primary teratogen for these types of malformations. - **ACE inhibitors**, for example, are known to cause renal dysfunction and urogenital anomalies. *Neural tube defects* - **Folic acid deficiency** and certain **antiepileptic drugs** (e.g., valproate) are well-known causes of neural tube defects. - **Lithium is not a primary risk factor** for neural tube defects. *Facial defects* - **Fetal alcohol syndrome** and certain anticonvulsants (e.g., phenytoin causing **fetal hydantoin syndrome**) are associated with facial dysmorphism. - **Lithium is not strongly linked** to specific facial defects.

Q: How does fluoxetine help in treating depression?

Inhibits serotonin reuptake. ***Inhibits serotonin reuptake*** - Fluoxetine is a **selective serotonin reuptake inhibitor (SSRI)**, meaning it blocks the reabsorption of serotonin into presynaptic neurons. - This action leads to increased concentrations of serotonin in the **synaptic cleft**, enhancing serotonergic neurotransmission and alleviating depressive symptoms. *Increases serotonin reuptake* - This statement is incorrect as increasing serotonin reuptake would **reduce serotonin availability** in the synapse, worsening depressive symptoms rather than improving them. - Antidepressants like fluoxetine aim to **increase serotonin levels**, not decrease them through increased reuptake. *Increases GABA levels* - Medications that increase **GABA (gamma-aminobutyric acid)** levels are typically anxiolytics or anticonvulsants (e.g., benzodiazepines), not primary antidepressants. - While GABAergic pathways can influence mood, fluoxetine's primary mechanism is specifically on **serotonin**. *Blocks dopamine receptors* - Blocking dopamine receptors is the mechanism of action for many **antipsychotic medications**, which are used to treat conditions like schizophrenia or bipolar disorder. - This action is generally **not the primary mechanism** by which antidepressants like fluoxetine exert their effects; in fact, blocking dopamine can sometimes worsen depression.

Q: How do SSRIs alleviate symptoms of depression?

By increasing synaptic serotonin levels. ***By increasing synaptic serotonin levels*** - **Selective Serotonin Reuptake Inhibitors (SSRIs)** block the reabsorption (reuptake) of **serotonin** by neurons, leading to higher concentrations of serotonin in the synaptic cleft. - Increased **synaptic serotonin** availability is believed to enhance neuronal communication and mood regulation, thus alleviating symptoms of depression. *By inhibiting GABA receptors* - Inhibiting **GABA receptors** would typically lead to increased neuronal excitability, potentially worsening anxiety or causing seizures, rather than alleviating depression. - Medications that act on GABA receptors, such as **benzodiazepines**, are primarily used for anxiety and sedation, not as first-line antidepressants. *By increasing norepinephrine degradation* - Increasing **norepinephrine degradation** would reduce the levels of norepinephrine, a neurotransmitter associated with alertness and mood, which would likely worsen depressive symptoms. - Many antidepressants, such as **SNRIs**, aim to *increase* norepinephrine levels, not degrade them. *By decreasing dopamine release* - Decreasing **dopamine release** would likely lead to symptoms of anhedonia, lack of motivation, and other features of depression, or even extrapyramidal symptoms if significantly reduced. - **Dopamine** is often associated with reward and pleasure pathways, and increasing its availability can be beneficial in some forms of depression.

Q: Which of the following antipsychotic drugs is known for its high risk of agranulocytosis?

Clozapine. ***Clozapine*** - **Clozapine** is an atypical antipsychotic with a unique efficacy for **treatment-resistant schizophrenia**, but its use is restricted due to a significant risk of **agranulocytosis**. - Due to this risk, patients on clozapine require **regular blood monitoring** (weekly to biweekly, then monthly) to check their **white blood cell count (WBC)** and **absolute neutrophil count (ANC)**. *Haloperidol* - **Haloperidol** is a typical (first-generation) antipsychotic primarily known for its risk of **extrapyramidal symptoms (EPS)** and **tardive dyskinesia**, but not agranulocytosis. - While it can cause leukocytosis or mild neutropenia, it does not carry the same high risk of **severe agranulocytosis** as clozapine. *Olanzapine* - **Olanzapine** is an atypical antipsychotic associated with a higher risk of **metabolic side effects** such as weight gain, hyperglycemia, and dyslipidemia. - Although it can cause neutropenia in rare cases, its risk of **agranulocytosis** is very low and not considered a defining adverse effect on par with clozapine. *Aripiprazole* - **Aripiprazole** is an atypical antipsychotic known for its unique mechanism as a **partial dopamine agonist** and a lower incidence of metabolic side effects compared to other atypicals. - While it can cause some hematological changes, the risk of **agranulocytosis** is exceedingly rare and not a significant concern with its use.

Q: Which neuroleptic is most commonly associated with causing tardive dyskinesia?

Haloperidol. ***Haloperidol*** - **Haloperidol** is a **first-generation (typical) antipsychotic** that acts as a strong **dopamine D2 receptor antagonist**. This potent blockade increases the risk of **extrapyramidal symptoms (EPS)**, including tardive dyskinesia, especially with long-term use. - **Tardive dyskinesia (TD)** is characterized by involuntary, repetitive movements, particularly of the face, mouth, and tongue. Its development is strongly linked to the duration and dosage of typical antipsychotics like haloperidol. *Clozapine* - **Clozapine** is a **second-generation (atypical) antipsychotic** known for its very low risk of causing **tardive dyskinesia** and other **extrapyramidal symptoms**. - Its mechanism involves both dopamine and serotonin receptor antagonism, with a weaker, more transient D2 blockade. *Olanzapine* - **Olanzapine** is also a **second-generation (atypical) antipsychotic** with a relatively low risk of causing **tardive dyskinesia** compared to first-generation agents. - While it can cause EPS, its incidence is significantly lower than that of typical antipsychotics. *Risperidone* - **Risperidone** is an **atypical antipsychotic** that, at higher doses, can have a **stronger D2 receptor blockade** compared to other atypicals, making its risk of **extrapyramidal symptoms** (including tardive dyskinesia) somewhat higher than other second-generation agents, though still lower than typical antipsychotics. - Its D2 antagonism is more pronounced than drugs like clozapine or quetiapine.

Q: A patient with schizophrenia is prescribed an atypical antipsychotic that has potent blockade of both serotonin 5-HT2A and dopamine D2 receptors and is commonly used as a first-line agent. Which drug is appropriate?

Olanzapine. ***Olanzapine*** - **Olanzapine** is an **atypical antipsychotic** with **potent blockade** of both **dopamine D2** and **serotonin 5-HT2A** receptors [4]. - This balanced dual receptor antagonism contributes to its efficacy in treating positive and negative symptoms of schizophrenia with a lower risk of **extrapyramidal side effects** compared to typical antipsychotics [4]. - It is widely used as a **first-line atypical antipsychotic** with a well-established safety profile [2]. *Haloperidol* - **Haloperidol** is a **first-generation (typical) antipsychotic** that primarily acts as a potent **dopamine D2 receptor antagonist** [3]. - It has minimal affinity for **serotonin 5-HT2A receptors** and is associated with a higher incidence of **extrapyramidal symptoms (EPS)** [3]. *Clozapine* - **Clozapine** is an **atypical antipsychotic** with antagonism at **5-HT2A** receptors, but its **D2 receptor binding** is characterized by **rapid dissociation** (loose binding) [4]. - It is reserved for **treatment-resistant schizophrenia** due to serious side effects including **agranulocytosis**, **myocarditis**, and **metabolic syndrome** [1]. - Not used as a first-line agent due to mandatory blood monitoring requirements [1]. *Aripiprazole* - **Aripiprazole** is an **atypical antipsychotic** that acts as a **dopamine D2 partial agonist** (not a pure antagonist) and **serotonin 5-HT1A partial agonist**, along with **5-HT2A antagonism**. - Its **partial agonist** mechanism at D2 receptors distinguishes it from agents that have pure antagonist blockade of both D2 and 5-HT2A receptors.

Q: Which drug, used to treat alcohol dependence, works by inhibiting aldehyde dehydrogenase and leads to an unpleasant reaction when alcohol is consumed?

Disulfiram. ***Disulfiram*** - **Disulfiram** inhibits **aldehyde dehydrogenase**, leading to an accumulation of **acetaldehyde** when alcohol is consumed. - The accumulation of acetaldehyde causes an unpleasant reaction, including flushing, nausea, vomiting, dizziness, and headache, which serves as a deterrent to drinking. *Naltrexone* - **Naltrexone** is an **opioid antagonist** that blocks the **euphoric and reinforcing effects** of alcohol. - It works by reducing cravings and the pleasure associated with alcohol consumption, rather than inducing adverse physical reactions. *Acamprosate* - **Acamprosate** is believed to restore the balance of **GABA and glutamate neurotransmission** in the brain, which is disrupted by chronic alcohol use. - It helps reduce cravings for alcohol and maintain abstinence, but it does not cause an acute physiological reaction to alcohol. *Baclofen* - **Baclofen** is a **GABA-B receptor agonist** primarily used as a muscle relaxant. - While it has shown some promise in reducing alcohol cravings in certain populations, its mechanism is distinct from inhibiting aldehyde dehydrogenase and it does not cause an unpleasant reaction to alcohol consumption.

Question 1

Maximum increase in prolactin level is caused by:-

Accepted Answer

Risperidone (Potent D2 receptor antagonist)

Answer

Olanzapine (Primarily blocks 5HT2 receptors)

Answer

Aripiprazole (D2 partial agonist)

Answer

Clozapine (Primarily blocks 5HT2 receptors)

Question 2

Use of lithium during pregnancy increases the risk of development of which of the following malformations in the baby?

Accepted Answer

Cardiac defects

Answer

Urogenital defects

Answer

Neural tube defects

Answer

Facial defects

Question 3

How does fluoxetine help in treating depression?

Accepted Answer

Inhibits serotonin reuptake

Answer

Increases serotonin reuptake

Answer

Increases GABA levels

Answer

Blocks dopamine receptors

Question 4

Which antipsychotic is most likely to cause metabolic syndrome?

Accepted Answer

Clozapine

Answer

Olanzapine

Answer

Haloperidol

Answer

Risperidone

Question 5

How do SSRIs alleviate symptoms of depression?

Accepted Answer

By increasing synaptic serotonin levels

Answer

By inhibiting GABA receptors

Answer

By increasing norepinephrine degradation

Answer

By decreasing dopamine release

Question 6

Which of the following antipsychotic drugs is known for its high risk of agranulocytosis?

Accepted Answer

Clozapine

Answer

Haloperidol

Answer

Olanzapine

Answer

Aripiprazole

Question 7

A patient on antipsychotic therapy develops tardive dyskinesia. What is the underlying cause?

Accepted Answer

Chronic blockade of dopamine receptors leading to upregulation of dopamine receptors

Answer

Serotonin receptor dysfunction and imbalance

Answer

Histamine receptor hypersensitivity

Answer

GABA receptor downregulation

Question 8

Which neuroleptic is most commonly associated with causing tardive dyskinesia?

Accepted Answer

Haloperidol

Answer

Olanzapine

Answer

Clozapine

Answer

Risperidone

Question 9

A patient with schizophrenia is prescribed an atypical antipsychotic that has potent blockade of both serotonin 5-HT2A and dopamine D2 receptors and is commonly used as a first-line agent. Which drug is appropriate?

Accepted Answer

Olanzapine

Answer

Haloperidol

Answer

Clozapine

Answer

Aripiprazole

Question 10

Which drug, used to treat alcohol dependence, works by inhibiting aldehyde dehydrogenase and leads to an unpleasant reaction when alcohol is consumed?

Accepted Answer

Disulfiram

Answer

Naltrexone

Answer

Acamprosate

Answer

Baclofen

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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