Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following is not an atypical antipsychotic?

Amoxapine. ### Explanation **Correct Answer: B. Amoxapine** **1. Why Amoxapine is the correct answer:** Amoxapine is a **Tricyclic Antidepressant (TCA)** belonging to the dibenzoxazepine class. While it is unique among antidepressants because its metabolite (7-hydroxyamoxapine) possesses significant **Dopamine D2 receptor blocking activity**—which can lead to extrapyramidal side effects—it is primarily classified and used as an antidepressant, not an atypical antipsychotic. **2. Analysis of Incorrect Options:** * **A. Aripiprazole:** A third-generation atypical antipsychotic. It is unique as a **partial agonist** at D2 and 5-HT1A receptors and an antagonist at 5-HT2A receptors (often called a "Dopamine System Stabilizer"). * **C. Clozapine:** The "prototype" atypical antipsychotic. It is the most effective drug for **treatment-resistant schizophrenia** but requires mandatory WBC monitoring due to the risk of **agranulocytosis**. * **D. Zotepine:** An atypical antipsychotic that blocks D2 and 5-HT2 receptors. It also inhibits norepinephrine reuptake, which may help with the negative symptoms of schizophrenia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Atypical vs. Typical:** Atypical antipsychotics (Second Generation) are defined by a lower risk of Extrapyramidal Symptoms (EPS) and greater efficacy against **negative symptoms** compared to typicals (like Haloperidol). * **Mechanism:** Most atypicals act as **5-HT2A + D2 antagonists** (SDA - Serotonin Dopamine Antagonists). * **Metabolic Side Effects:** Remember the mnemonic **"COZ"** (Clozapine, Olanzapine, Zotepine) for drugs with the highest risk of weight gain and metabolic syndrome. * **Amoxapine Fact:** Because of its D2 blocking metabolite, it is the TCA most likely to cause **Tardive Dyskinesia** or Neuroleptic Malignant Syndrome.

Q: Buspirone is used as a:

Anxiolytic. **Explanation:** **Buspirone** is a non-benzodiazepine drug used primarily as an **anxiolytic** (Option A). Its mechanism of action involves acting as a **selective partial agonist at the 5-HT1A receptors**. Unlike benzodiazepines, it does not interact with the GABA-A receptor complex, which accounts for its unique clinical profile. **Why other options are incorrect:** * **Sedative (Option B):** Buspirone lacks significant sedative properties. It does not cause psychomotor impairment or drowsiness, making it preferable for patients who need to remain alert. * **Muscle relaxant (Option C) & Anticonvulsant (Option D):** These are classic features of Benzodiazepines (due to GABA-A modulation). Buspirone lacks these properties entirely; it has no effect on muscle tone and cannot be used to treat seizures. **High-Yield Clinical Pearls for NEET-PG:** 1. **Delayed Onset:** Unlike benzodiazepines, Buspirone has a slow onset of action. It takes **2–4 weeks** to show therapeutic effects, making it unsuitable for "as needed" (PRN) use or acute panic attacks. It is used for **Generalized Anxiety Disorder (GAD)**. 2. **Lack of Dependence:** It carries **no risk of tolerance, physical dependence, or withdrawal symptoms**. It is not a controlled substance. 3. **No Interaction with Alcohol:** It does not potentiate the CNS depressant effects of alcohol. 4. **Side Effects:** Most common side effects include dizziness, nausea, and headache. It does not cause significant weight gain or sexual dysfunction.

Q: Appetite is decreased by which of the following medications, except?

Olanzapine. ### Explanation The correct answer is **Olanzapine**. **1. Why Olanzapine is the correct answer:** Olanzapine is a **Second-Generation (Atypical) Antipsychotic**. One of its most significant and notorious side effects is **significant weight gain and increased appetite (hyperphagia)** [1]. This occurs primarily due to its potent antagonism at **H1 (histamine)** and **5-HT2C (serotonin)** receptors, which are key regulators of the satiety center in the hypothalamus. Among atypical antipsychotics, Olanzapine and Clozapine carry the highest risk for metabolic syndrome, dyslipidemia, and Type 2 Diabetes Mellitus [1], [3]. Olanzapine has also shown clinical efficacy in improving weight gain in patients with eating disorders or psychogenic vomiting [2]. **2. Why the other options are incorrect:** * **Methylphenidate (Option A):** This is a CNS stimulant used in ADHD. It increases norepinephrine and dopamine levels, which suppresses the appetite center. Growth monitoring is essential in children on this medication due to potential weight loss. * **Fluoxetine & Sertraline (Options C & D):** These are **SSRIs**. While some SSRIs can be weight-neutral in the long term, **Fluoxetine** is specifically known for causing initial weight loss and decreased appetite [2]. It is, in fact, the only FDA-approved drug for Bulimia Nervosa because it helps reduce binge-eating episodes. **3. High-Yield NEET-PG Pearls:** * **Weight Gain Hierarchy:** Clozapine > Olanzapine > Quetiapine > Risperidone > Ziprasidone/Aripiprazole (Weight neutral) [1]. * **Drug of choice for Bulimia Nervosa:** Fluoxetine (High dose: 60mg). * **Anorexiant agents:** Sibutramine (withdrawn), Lorcaserin (withdrawn), and Phentermine. * **Metabolic Monitoring:** Patients on Olanzapine must have regular monitoring of BMI, waist circumference, fasting blood glucose, and lipid profile.

Q: All are atypical antipsychotic drugs except?

Loxapine. **Explanation:** The classification of antipsychotics is based on their mechanism of action and side-effect profile. Antipsychotics are divided into **Typical (First Generation)** and **Atypical (Second Generation)** drugs. **Why Loxapine is the correct answer:** Loxapine is a **Typical Antipsychotic** belonging to the tricyclic subclass (dibenzoxazepine). It primarily acts by blocking **D2 receptors** in the mesolimbic and nigrostriatal pathways. Unlike atypical drugs, typical antipsychotics like Loxapine have a higher propensity to cause Extrapyramidal Side Effects (EPS) and do not significantly block 5-HT2A receptors. **Why the other options are incorrect:** * **Clozapine:** The prototype atypical antipsychotic. It is a "loose" D2 blocker with high affinity for 5-HT2A, D4, and Muscarinic receptors. It is the gold standard for treatment-resistant schizophrenia. * **Risperidone:** A potent atypical agent that blocks both D2 and 5-HT2A receptors. At higher doses (>6mg), it behaves more like a typical antipsychotic, increasing the risk of EPS and hyperprolactinemia. * **Olanzapine:** An atypical drug structurally related to clozapine. It is effective for both positive and negative symptoms but is notorious for causing significant weight gain and metabolic syndrome. **High-Yield Clinical Pearls for NEET-PG:** * **Atypical vs. Typical:** Atypicals are defined by a **high 5-HT2A:D2 blockade ratio**, lower risk of EPS, and better efficacy against negative symptoms. * **Clozapine Safety:** Requires mandatory WBC monitoring due to the risk of **agranulocytosis** (1%). It also lowers the seizure threshold. * **Loxapine Unique Fact:** While classified as typical, it is sometimes considered "atypical-like" at low doses, but for exam purposes, it remains in the Typical category. An inhaled formulation is used for acute agitation. * **Weight Gain:** Clozapine and Olanzapine cause the most weight gain; Ziprasidone and Aripiprazole cause the least.

Q: Which of the following adverse effects may be seen in a patient treated with risperidone?

Neuroleptic malignant syndrome. **Explanation:** **Risperidone** is a second-generation (atypical) antipsychotic that acts primarily as a potent **D2 receptor antagonist** and a 5-HT2A receptor antagonist. **Why Option B is Correct:** **Neuroleptic Malignant Syndrome (NMS)** is a rare but life-threatening idiosyncratic reaction to dopamine antagonists, including risperidone. It is characterized by the "tetrad" of **hyperthermia, muscular "lead-pipe" rigidity, autonomic instability, and altered mental status.** The underlying mechanism involves massive dopamine blockade in the nigrostriatal pathway and hypothalamus. **Why Other Options are Incorrect:** * **A. Weight loss:** Risperidone is associated with **weight gain** and metabolic syndrome (dyslipidemia, hyperglycemia), not weight loss. * **C. Hypopigmentation:** Antipsychotics do not cause hypopigmentation. Historically, high-dose Chlorpromazine was associated with *hyperpigmentation* (blue-grey skin discoloration). * **D. Prolactin deficiency:** Risperidone is unique among atypicals for causing significant **Hyperprolactinemia**. By blocking dopamine in the tuberoinfundibular pathway, it removes the inhibitory effect on prolactin, leading to galactorrhea, amenorrhea, and gynecomastia. **High-Yield Clinical Pearls for NEET-PG:** * **NMS Treatment:** Immediate discontinuation of the drug, aggressive cooling, and pharmacotherapy with **Dantrolene** (muscle relaxant) or **Bromocriptine** (dopamine agonist). * **Lab findings in NMS:** Elevated Creatine Kinase (CK) and leukocytosis. * **Risperidone Fact:** It has the highest risk of **Extrapyramidal Side Effects (EPS)** among atypical antipsychotics, especially at doses >6mg.

Q: What is the primary site of action for disulfiram?

Aldehyde dehydrogenase. **Explanation:**1. Mechanism of Action (Why A is correct):Disulfiram is used as an aversion therapy for chronic alcoholism. Its primary site of action is the irreversible inhibition of the enzyme Aldehyde Dehydrogenase (ALDH) [1]. Normally, alcohol is metabolized into acetaldehyde by alcohol dehydrogenase, and then acetaldehyde is converted into acetic acid by ALDH. By blocking ALDH, disulfiram causes a toxic accumulation of acetaldehyde in the blood. This leads to the Disulfiram-Ethanol Reaction (DER), characterized by flushing, tachycardia, nausea, vomiting, and hypotension, which discourages the patient from consuming alcohol [1].2. Analysis of Incorrect Options:B. Alcohol Dehydrogenase: This enzyme converts ethanol to acetaldehyde. It is inhibited by Fomepizole, which is used in methanol or ethylene glycol poisoning, not disulfiram.C. G6PD: Glucose-6-phosphate dehydrogenase is an enzyme in the pentose phosphate pathway. Its deficiency leads to hemolytic anemia; it is not a target for alcohol-related drugs.D. Acetate Dehydrogenase: This is not a primary target in human ethanol metabolism. Acetic acid (acetate) is typically converted to Acetyl-CoA by acetyl-CoA synthetase.3. NEET-PG High-Yield Clinical Pearls:Disulfiram-like reaction: Several other drugs can cause a similar reaction when taken with alcohol. High-yield examples include Metronidazole (most common), Cefotetan, Tinidazole, and Sulfonylureas (Chlorpropamide).Contraindication: Disulfiram should never be administered if the patient has consumed alcohol within the last 12 hours or is in a state of intoxication [2].Acamprosate vs. Naltrexone: While Disulfiram is for aversion, Acamprosate is used to maintain abstinence (NMDA antagonist), and Naltrexone (Opioid antagonist) is used to reduce cravings [1].

Q: All of the following drugs are monoamine oxidase inhibitors except?

Duloxetine. **Explanation:** The correct answer is **Duloxetine** because it belongs to the class of **Serotonin-Norepinephrine Reuptake Inhibitors (SNRIs)**, not Monoamine Oxidase Inhibitors (MAOIs). It works by inhibiting the reuptake of both serotonin and norepinephrine in the synaptic cleft. **Breakdown of Options:** * **Moclobemide:** It is a **RIMA** (Reversible Inhibitor of MAO-A). Unlike older MAOIs, it has a lower risk of the "cheese reaction" because it can be displaced from the enzyme by tyramine. * **Tranylcypromine:** It is a **Non-selective, Irreversible MAOI** (inhibits both MAO-A and MAO-B). It is one of the older, "classical" antidepressants. * **Selegiline:** It is a **Selective Irreversible MAO-B Inhibitor**. At low doses, it is used primarily in Parkinson’s disease to increase dopamine levels. At higher doses, it loses selectivity and can act as an antidepressant. **High-Yield Clinical Pearls for NEET-PG:** 1. **Cheese Reaction:** Occurs when patients on non-selective MAOIs consume tyramine-rich food (aged cheese, wine). Tyramine displaces stored NE, leading to a **hypertensive crisis**. Treatment of choice: **Phentolamine** (Alpha-blocker). 2. **Serotonin Syndrome:** A dangerous interaction occurring when MAOIs are combined with SSRIs or SNRIs (like Duloxetine). Always maintain a **washout period** of at least 14 days when switching between these classes. 3. **Duloxetine Indications:** Apart from MDD and GAD, it is a first-line drug for **Diabetic Neuropathy**, Fibromyalgia, and Stress Urinary Incontinence.

Q: Which of the following drugs is classified under FDA teratogenic risk category B for pregnancy?

Clozapine. **Explanation:** The classification of drugs in pregnancy is a high-yield topic for NEET-PG. While the FDA has transitioned away from the old A-B-C-D-X lettering system, these categories remain frequently tested in competitive exams. **1. Why Clozapine is Correct:** **Clozapine** is the only atypical antipsychotic traditionally classified under **FDA Category B**. This means animal reproduction studies have failed to demonstrate a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women. While it is the "gold standard" for treatment-resistant schizophrenia, its use in pregnancy requires careful monitoring for maternal agranulocytosis and gestational diabetes. **2. Analysis of Incorrect Options:** * **Phenytoin (Option A):** Classified as **Category D**. It is a known teratogen associated with **Fetal Hydantoin Syndrome** (craniofacial anomalies, hypoplastic phalanges, and growth retardation). * **Risperidone (Option B):** Classified as **Category C**. Animal studies have shown adverse effects on the fetus, and there are no adequate human studies. Most atypical antipsychotics (like Quetiapine and Aripiprazole) fall into this category. * **Olanzapine (Option C):** Also classified as **Category C**. While commonly used, it carries a higher risk of significant maternal weight gain and gestational metabolic complications compared to other agents. **3. NEET-PG Clinical Pearls:** * **Lithium:** Category D; specifically associated with **Ebstein’s Anomaly** (tricuspid valve displacement). * **Valproate:** Category X/D; highest risk for **Neural Tube Defects** (Spina Bifida). * **SSRIs:** Most are Category C, except **Paroxetine**, which is Category D (risk of fetal cardiac malformations). * **Drug of Choice:** For psychosis in pregnancy, **Haloperidol** (typical) has the most extensive safety data, though Clozapine remains the Category B outlier among atypicals.

Q: Which antipsychotic medication is known to cause agranulocytosis?

Clozapine. **Explanation:** **Clozapine** is the correct answer. It is an atypical (second-generation) antipsychotic reserved for treatment-resistant schizophrenia. Its most serious and life-threatening side effect is **agranulocytosis** (a severe decrease in the absolute neutrophil count, typically defined as <500/mm³), which occurs in approximately 1% of patients. This reaction is idiosyncratic and usually occurs within the first 18 weeks of treatment. Due to this risk, mandatory hematological monitoring (CBC with ANC) is required for all patients on Clozapine. **Analysis of Incorrect Options:** * **A. Lithium:** This is a mood stabilizer, not an antipsychotic. Interestingly, Lithium causes **leukocytosis** (an increase in white blood cell count) rather than agranulocytosis, and is sometimes used off-label to counteract drug-induced neutropenia. * **B. Risperidone:** An atypical antipsychotic primarily associated with dose-dependent extrapyramidal symptoms (EPS) and significant **hyperprolactinemia**. It does not carry a significant risk of agranulocytosis. * **C. Aripiprazole:** A partial dopamine agonist known for its "weight-neutral" profile and low sedative effect. It is not associated with bone marrow suppression. **High-Yield Clinical Pearls for NEET-PG:** * **Clozapine Monitoring:** ANC must be checked weekly for the first 6 months, every 2 weeks for the next 6 months, and monthly thereafter. * **Other Side Effects:** Clozapine is also notorious for causing **seizures** (dose-dependent), **sialorrhea** (excessive drooling), myocarditis, and severe constipation. * **Benefit:** It is the only antipsychotic proven to reduce the risk of **suicide** in patients with schizophrenia. * **Metabolic Syndrome:** Clozapine and Olanzapine carry the highest risk of weight gain and diabetes among antipsychotics.

Question 1

Which of the following is not an atypical antipsychotic?

Accepted Answer

Amoxapine

Answer

Aripiprazole

Answer

Clozapine

Answer

Zotepine

Question 2

Buspirone is used as a:

Accepted Answer

Anxiolytic

Answer

Sedative

Answer

Muscle relaxant

Answer

Anticonvulsant

Question 3

Appetite is decreased by which of the following medications, except?

Accepted Answer

Olanzapine

Answer

Methylphenidate

Answer

Fluoxetine

Answer

Sertraline

Question 4

All are atypical antipsychotic drugs except?

Accepted Answer

Loxapine

Answer

Clozapine

Answer

Risperidone

Answer

Olanzapine

Question 5

Which of the following adverse effects may be seen in a patient treated with risperidone?

Accepted Answer

Neuroleptic malignant syndrome

Answer

Weight loss

Answer

Hypopigmentation

Answer

Prolactin deficiency

Question 6

What is the primary site of action for disulfiram?

Accepted Answer

Aldehyde dehydrogenase

Answer

Alcohol dehydrogenase

Answer

G6PD

Answer

Acetate dehydrogenase

Question 7

What is the primary mechanism of action of Fluoxetine?

Accepted Answer

Inhibition of axonal uptake of 5-HT

Answer

GABA inhibition

Answer

Adrenergic neuron blocking agent

Answer

Alpha adrenergic stimulation

Question 8

All of the following drugs are monoamine oxidase inhibitors except?

Accepted Answer

Duloxetine

Answer

Moclobemide

Answer

Tranylcypromine

Answer

Selegiline

Question 9

Which of the following drugs is classified under FDA teratogenic risk category B for pregnancy?

Accepted Answer

Clozapine

Answer

Phenytoin

Answer

Risperidone

Answer

Olanzapine

Question 10

Which antipsychotic medication is known to cause agranulocytosis?

Accepted Answer

Clozapine

Answer

Lithium

Answer

Risperidone

Answer

Aripiprazole

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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