Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders Indian Medical PG Practice Questions and MCQs

Question 291: Which of the following antipsychotic drugs is known for its high risk of agranulocytosis?

A. Haloperidol
B. Clozapine (Correct Answer)
C. Olanzapine
D. Aripiprazole

Explanation: ***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.

Question 292: A patient on antipsychotic therapy develops tardive dyskinesia. What is the underlying cause?

A. Serotonin receptor dysfunction and imbalance
B. Histamine receptor hypersensitivity
C. Chronic blockade of dopamine receptors leading to upregulation of dopamine receptors (Correct Answer)
D. GABA receptor downregulation

Explanation: ***Chronic blockade of dopamine receptors leading to upregulation of dopamine receptors*** - **Tardive dyskinesia** is primarily attributed to a chronic blockade of **dopamine D2 receptors** by antipsychotic medications, leading to a compensatory **upregulation and hypersensitivity** of these receptors. - When dopamine is released, these hypersensitive receptors over-respond, causing involuntary and repetitive movements, particularly in the face and limbs. *Serotonin receptor dysfunction and imbalance* - While some antipsychotics affect **serotonin receptors**, dysfunction in these receptors is not considered the primary underlying cause of tardive dyskinesia. - Serotonin modulation is more commonly associated with the efficacy of **atypical antipsychotics** in reducing psychotic symptoms and their potentially lower risk of extrapyramidal side effects compared to older drugs. *Histamine receptor hypersensitivity* - Hypersensitivity of **histamine receptors** is not directly linked to the pathophysiology of tardive dyskinesia. - Histamine blockade can contribute to side effects such as **sedation and weight gain** with some antipsychotics, but not the specific motor symptoms of tardive dyskinesia. *GABA receptor downregulation* - Downregulation of **GABA receptors** is not considered the main etiological factor for tardive dyskinesia. - GABAergic system involvement is linked more to conditions like **anxiety and epilepsy**, and while it can indirectly influence motor control, it's not the central mechanism.

Question 293: A patient with a history of opioid addiction is given a drug for long-term relapse prevention in opioid use disorder. Which drug is most suitable for this purpose?

A. Naloxone
B. Methadone
C. Buprenorphine
D. Naltrexone (Correct Answer)

Explanation: ***Naltrexone*** - **Naltrexone** is an **opioid antagonist** that blocks opioid receptors, preventing both the euphoric and respiratory depressant effects of opioids. - It is used for **relapse prevention** in opioid use disorder by reducing cravings and blocking the effects of any opioids consumed. *Naloxone* - **Naloxone** is a short-acting **opioid antagonist**, primarily used to **reverse acute opioid overdose** by rapidly displacing opioids from receptors. - It is not typically used for long-term **relapse prevention** due to its short half-life and route of administration (injectable for overdose reversal). *Methadone* - **Methadone** is a **long-acting opioid agonist** used in opioid maintenance therapy to reduce cravings and withdrawal symptoms. - While it helps prevent relapse by stabilizing the patient, it is an **opioid itself** and can cause dependence, unlike naltrexone which is an antagonist. *Buprenorphine* - **Buprenorphine** is a **partial opioid agonist** used in opioid replacement therapy; it reduces cravings and withdrawal symptoms without producing the same high as full agonists. - It is similar to methadone in its use for maintenance therapy but is not a pure antagonist like naltrexone for blocking effects.

Question 294: Which drug, used to treat alcohol dependence, works by inhibiting aldehyde dehydrogenase and leads to an unpleasant reaction when alcohol is consumed?

A. Naltrexone
B. Acamprosate
C. Disulfiram (Correct Answer)
D. Baclofen

Explanation: ***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 295: 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?

A. Haloperidol
B. Clozapine
C. Aripiprazole
D. Olanzapine (Correct Answer)

Explanation: ***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.

Question 296: A patient with bipolar disorder is on valproate and presents with symptoms of lethargy, confusion, and elevated ammonia levels. What condition is most likely associated with these symptoms?

A. Hyperammonemia due to valproate use (Correct Answer)
B. Toxicity from lithium
C. Toxicity from carbamazepine
D. Rash induced by lamotrigine

Explanation: ***Hyperammonemia due to valproate use*** - Valproate can inhibit the urea cycle, leading to impaired ammonia detoxification and subsequent hyperammonemia - Symptoms like lethargy and confusion are common manifestations of elevated ammonia levels, particularly in the absence of liver failure - This is a well-recognized adverse effect that can occur even with therapeutic valproate levels *Toxicity from lithium* - Lithium toxicity typically presents with symptoms such as tremor, polyuria, polydipsia, and potentially seizures or arrhythmias, which are not described here - While it can cause neurological symptoms, it is not directly associated with elevated ammonia levels *Toxicity from carbamazepine* - Carbamazepine toxicity often involves ataxia, nystagmus, and diplopia, and in severe cases, coma - It does not primarily lead to hyperammonemia; instead, it can cause hyponatremia or blood dyscrasias *Rash induced by lamotrigine* - Lamotrigine-induced rash is a dermatological manifestation, ranging from benign maculopapular rash to severe conditions like Stevens-Johnson syndrome - It does not cause lethargy, confusion, or elevated ammonia levels

Question 297: Which neuroleptic is most commonly associated with causing tardive dyskinesia?

A. Olanzapine
B. Haloperidol (Correct Answer)
C. Clozapine
D. Risperidone

Explanation: ***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.

Question 298: A 45-year-old female with schizophrenia is prescribed an antipsychotic drug. Which of the following drugs is most commonly associated with extrapyramidal side effects?

A. Clozapine
B. Olanzapine
C. Haloperidol (Correct Answer)
D. Risperidone

Explanation: ***Haloperidol*** - **Haloperidol** is a **first-generation antipsychotic** (FGA) that primarily blocks D2 dopamine receptors in the **mesolimbic pathway**, but also significantly in the **nigrostriatal pathway**, leading to a high incidence of extrapyramidal side effects (EPS). - EPS include **dystonia, akathisia, parkinsonism, and tardive dyskinesia**, due to the strong antagonism of dopamine in the basal ganglia. *Clozapine* - **Clozapine** is a **second-generation antipsychotic** (SGA) known for its very low risk of EPS. - Its unique pharmacological profile includes weak D2 receptor blockade and strong serotonergic (5-HT2A) receptor antagonism, along with other receptor interactions, which contribute to its efficacy and minimal EPS. *Olanzapine* - **Olanzapine** is an **SGA** with a relatively low risk of EPS compared to FGAs like haloperidol, but it is not entirely free of this risk. - Its primary side effects are metabolic, including **weight gain, hyperglycemia, and dyslipidemia**, due to its broad receptor affinity. *Risperidone* - **Risperidone** is an **SGA** that has a dose-dependent risk of EPS; at higher doses, its D2 receptor blockade becomes more pronounced, increasing the likelihood of EPS. - While generally having a lower EPS risk than FGAs, it is considered to have a higher EPS risk among SGAs, often presenting with **akathisia** at therapeutic doses.

Question 299: A 45-year-old man with a long history of smoking presents with irritability, anxiety, and cravings for cigarettes after attempting to quit. What is the most appropriate treatment?

A. Bupropion (Correct Answer)
B. Amitriptyline
C. Haloperidol
D. Alprazolam

Explanation: ***Bupropion*** - **Bupropion** is an antidepressant that acts as a **norepinephrine-dopamine reuptake inhibitor** and a non-competitive antagonist of neuronal nicotinic acetylcholine receptors, making it effective for reducing **nicotine cravings** and withdrawal symptoms. - Its use is indicated for **smoking cessation** and can also treat **depression**, which can be comorbid with smoking. **Amitriptyline** - **Amitriptyline** is a **tricyclic antidepressant** primarily used for treating depression, neuropathic pain, and migraines. - It is not a first-line treatment for **nicotine withdrawal** or **smoking cessation**. **Haloperidol** - **Haloperidol** is a **first-generation antipsychotic** used to treat psychosis, schizophrenia, and acute agitation. - It has a significant side effect profile, including **extrapyramidal symptoms**, and is not indicated for smoking cessation. **Alprazolam** - **Alprazolam** is a **benzodiazepine** primarily used to treat anxiety disorders and panic attacks. - While it can reduce anxiety, it is associated with **dependence** and **sedation** and is not recommended as a primary treatment for smoking cessation.

Question 300: Which antipsychotic drug blocks serotonin 5-HT2A receptors and dopamine D2 receptors to treat schizophrenia while presenting a lower risk of extrapyramidal side effects?

A. Haloperidol
B. Clozapine
C. Quetiapine
D. Olanzapine (Correct Answer)

Explanation: ***Olanzapine*** - **Olanzapine** is a **second-generation (atypical) antipsychotic** that potently blocks both dopamine D2 and serotonin 5-HT2A receptors, which contributes to its efficacy in treating both positive and negative symptoms of schizophrenia. - Its **higher affinity for 5-HT2A receptors compared to D2 receptors** is believed to be the reason for a **significantly lower risk of extrapyramidal side effects (EPS)** compared to first-generation antipsychotics. - **Olanzapine is a first-line atypical antipsychotic** with a favorable balance of efficacy and tolerability, making it a standard choice for schizophrenia treatment. *Haloperidol* - **Haloperidol** is a **first-generation (typical) antipsychotic** that primarily acts as a potent D2 antagonist. - It is associated with a **high risk of extrapyramidal side effects (EPS)** including acute dystonia, parkinsonism, and akathisia due to its selective blockade of D2 receptors. - It has **minimal affinity for serotonin 5-HT2A receptors**, which distinguishes it from second-generation agents and contributes to its higher EPS risk. *Clozapine* - **Clozapine** is an atypical antipsychotic that blocks both D2 and 5-HT2A receptors and actually has the **lowest EPS risk** of all antipsychotics. - However, it is **reserved for treatment-resistant schizophrenia** due to its serious adverse effects, including **agranulocytosis** (requires regular blood monitoring), **seizures**, **myocarditis**, and significant metabolic effects. - It is **not a first-line agent** due to its adverse effect profile and monitoring requirements. *Quetiapine* - **Quetiapine** also blocks D2 and 5-HT2A receptors and has a **low risk of EPS**, similar to olanzapine. - However, it is characterized by **rapid dissociation from D2 receptors**, which contributes to its lower EPS but may also result in less robust antipsychotic efficacy for positive symptoms compared to olanzapine. - It is more commonly associated with **sedation, orthostatic hypotension**, and **somnolence**, which can limit its use as a first-line agent.

Practice by Chapter

Antipsychotics: Typical and Atypical

Practice Questions

Antidepressants: SSRIs and SNRIs

Practice Questions

Tricyclic Antidepressants

Practice Questions

MAO Inhibitors

Practice Questions

Mood Stabilizers

Practice Questions

Anxiolytics

Practice Questions

Drugs for ADHD

Practice Questions

Drugs for Sleep Disorders

Practice Questions

Drugs for Dementia

Practice Questions

Drug-Induced Psychiatric Symptoms

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free