Psychopharmacology — MCQs

Psychopharmacology Indian Medical PG Practice Questions and MCQs

Question 191: Moclobemide is a type of:

A. Selective serotonin reuptake inhibitor (SSRI)
B. Antipsychotic drug
C. Monoamine oxidase inhibitor (MAOI) (Correct Answer)
D. Tricyclic antidepressant

Explanation: ### Explanation **Moclobemide** is a specific type of antidepressant known as a **Reversible Inhibitor of Monoamine Oxidase A (RIMA)**. It belongs to the broader class of Monoamine Oxidase Inhibitors (MAOIs). #### Why Option C is Correct: MAOIs work by inhibiting the enzyme monoamine oxidase, which breaks down neurotransmitters like serotonin, norepinephrine, and dopamine. Moclobemide specifically and reversibly inhibits **MAO-A**. Unlike older, irreversible MAOIs (like Phenelzine), Moclobemide has a lower risk of the "cheese reaction" (hypertensive crisis) because it can be displaced from the enzyme by tyramine. #### Why Other Options are Incorrect: * **Option A (SSRI):** These drugs (e.g., Fluoxetine, Sertraline) selectively inhibit the reuptake of serotonin from the synaptic cleft. They do not act on the MAO enzyme. * **Option B (Antipsychotic):** These drugs (e.g., Haloperidol, Risperidone) primarily act as dopamine (D2) receptor antagonists and are used to treat psychosis, not primarily as first-line antidepressants. * **Option D (Tricyclic Antidepressant):** TCAs (e.g., Amitriptyline, Imipramine) work by inhibiting the reuptake of both serotonin and norepinephrine and have significant anticholinergic side effects. #### High-Yield Clinical Pearls for NEET-PG: * **MAO-A vs. MAO-B:** MAO-A degrades Serotonin and Norepinephrine (targeted in depression). MAO-B degrades Dopamine (targeted in Parkinson’s, e.g., **Selegiline**). * **Cheese Reaction:** Occurs when irreversible MAOIs are taken with tyramine-rich food (aged cheese, wine). Moclobemide (RIMA) significantly reduces this risk. * **Serotonin Syndrome:** Always maintain a "washout period" (usually 2 weeks) when switching between MAOIs and SSRIs to prevent fatal serotonin syndrome. * **Drug of Choice:** SSRIs remain the first-line treatment for depression due to their safety profile; MAOIs are typically reserved for atypical or treatment-resistant depression.

Question 192: A patient on antipsychotics presents with muscle rigidity, fever, and tachycardia. Investigations reveal an elevated WBC count and increased creatinine phosphokinase levels. What is the drug of choice for this patient?

A. Paracetamol and IV Fluids
B. Dantrolene (Correct Answer)
C. Neostigmine
D. Paracetamol and Penicillin

Explanation: ### Explanation **Diagnosis: Neuroleptic Malignant Syndrome (NMS)** The clinical triad of **muscle rigidity** ("lead-pipe" rigidity), **autonomic instability** (fever, tachycardia, hypertension), and **altered mental status** in a patient taking antipsychotics is diagnostic of NMS. Laboratory findings typically show **elevated Creatinine Phosphokinase (CPK)** due to muscle necrosis (rhabdomyolysis) and **leukocytosis** (elevated WBC). **Why Dantrolene is the Correct Answer:** Dantrolene is a direct-acting skeletal muscle relaxant. It works by binding to the **ryanodine receptor (RyR1)** on the sarcoplasmic reticulum, inhibiting the release of calcium. This reduces muscle rigidity and heat production, addressing the core pathophysiology of the hypermetabolic state in NMS. **Analysis of Incorrect Options:** * **A & D (Paracetamol, IV Fluids, Penicillin):** While supportive care (IV fluids for hydration and cooling blankets) is essential, Paracetamol is insufficient to treat the underlying muscle-driven hyperthermia. Penicillin is irrelevant as the fever is not due to a bacterial infection. * **C (Neostigmine):** This is an acetylcholinesterase inhibitor used in Myasthenia Gravis or to reverse neuromuscular blockade. It has no role in NMS and could potentially worsen autonomic instability. **NEET-PG High-Yield Pearls:** 1. **Mechanism of NMS:** Primarily due to potent **D2 receptor blockade** in the nigrostriatal pathway and hypothalamus. 2. **Drug of Choice (Pharmacological):** **Dantrolene** is the specific muscle relaxant. **Bromocriptine** or **Amantadine** (Dopamine agonists) are also used to restore dopaminergic tone. 3. **First Step in Management:** Immediately **discontinue** the offending antipsychotic agent. 4. **Differential Diagnosis:** Unlike Serotonin Syndrome, NMS is characterized by "lead-pipe" rigidity and bradyreflexia, whereas Serotonin Syndrome presents with hyperreflexia and myoclonus.

Question 193: Polycystic ovarian syndrome is a potential side effect of which mood stabilizer?

A. Valproate (Correct Answer)
B. Carbamazepine
C. Lithium
D. Lamotrigine

Explanation: **Explanation:** **Valproate (Sodium Valproate)** is the correct answer. It is a broad-spectrum antiepileptic and mood stabilizer frequently associated with endocrine and metabolic side effects. The association with **Polycystic Ovarian Syndrome (PCOS)** is significant, particularly in young women. Valproate can cause hyperinsulinemia and weight gain, which disrupts the hypothalamic-pituitary-ovarian axis, leading to hyperandrogenism (hirsutism, acne), menstrual irregularities, and polycystic ovaries on ultrasound. **Analysis of Incorrect Options:** * **B. Carbamazepine:** While it can cause weight gain and is an enzyme inducer (leading to oral contraceptive failure), it is not classically associated with the development of PCOS. * **C. Lithium:** The most high-yield side effects for Lithium are **hypothyroidism**, nephrogenic diabetes insipidus, and Ebstein’s anomaly (teratogenicity). It does not cause PCOS. * **D. Lamotrigine:** Generally considered "weight-neutral" and has a favorable side-effect profile regarding endocrine function, making it a preferred choice for women of childbearing age. **Clinical Pearls for NEET-PG:** * **Monitoring:** Baseline and periodic monitoring of weight, menstrual cycle, and BMI is essential for female patients on Valproate. * **Teratogenicity:** Valproate is highly teratogenic, causing **Neural Tube Defects** (specifically Spina Bifida). * **Other Side Effects:** Remember the mnemonic **"VALPROATE"**: **V**omit, **A**lopecia (transient), **L**iver toxicity (Hepatotoxicity), **P**ancreatitis, **R**etention of fat (Weight gain), **O**edema, **A**norexia, **T**remor/Thrombocytopenia, **E**ncephalopathy (due to hyperammonemia).

Question 194: All are true about Clozapine except:

A. More potently blocks D2 as compared to D1 receptors
B. Blood level below 350 ng/ml should be maintained to avoid agranulocytosis (Correct Answer)
C. Should not be used along with Carbamazepine
D. Should be discontinued if the WBC count is below 3,000/mm cells

Explanation: **Explanation:** **Clozapine** is the prototype atypical antipsychotic and the "gold standard" for treatment-resistant schizophrenia. **Why Option B is the Correct Answer (The False Statement):** Therapeutic drug monitoring for Clozapine aims for a plasma level of **>350 ng/mL** to ensure clinical efficacy. There is **no correlation** between plasma levels and the risk of agranulocytosis; this adverse effect is an idiosyncratic (non-dose-dependent) reaction, likely immunological. Therefore, maintaining levels below 350 ng/mL does not prevent agranulocytosis and may lead to subtherapeutic treatment. **Analysis of Other Options:** * **Option A:** Unlike typical antipsychotics, Clozapine has a unique receptor profile. It has a **higher affinity for D1, D4, and 5-HT2A receptors** than for D2 receptors. Its weak D2 blockade is why it rarely causes Extrapyramidal Side Effects (EPS). * **Option C:** Carbamazepine is a potent bone marrow suppressant. Combining it with Clozapine significantly increases the risk of **agranulocytosis** and should be avoided. * **Option D:** Strict hematological monitoring is mandatory. Clozapine must be discontinued if the **Total Leukocyte Count (TLC) falls below 3,000/mm³** or the Absolute Neutrophil Count (ANC) falls below 1,500/mm³. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Treatment-resistant schizophrenia (failed 2 other antipsychotics) and reducing suicidal behavior in schizophrenia. * **Side Effects:** Sialorrhea (hypersalivation), sedation, weight gain, and **lowering of seizure threshold** (dose-dependent). * **ECG Change:** Myocarditis and tachycardia. * **Benefit:** Only antipsychotic proven to reduce suicide risk and the only one that does not cause Tardive Dyskinesia.

Question 195: Which of the following is used in the management of Electroconvulsive Therapy (ECT)?

A. Succinylcholine (Correct Answer)
B. Cefepime
C. Clozapine
D. Chlorpromazine

Explanation: **Explanation:** In modern **Modified Electroconvulsive Therapy (ECT)**, the goal is to induce a therapeutic seizure in the brain while preventing the physical complications of a generalized tonic-clonic convulsion. **A. Succinylcholine (Correct):** This is a short-acting depolarizing neuromuscular blocking agent. It is the drug of choice in ECT to produce skeletal muscle relaxation. By blocking the nicotinic acetylcholine receptors at the neuromuscular junction, it prevents forceful muscle contractions that could otherwise lead to bone fractures, joint dislocations, or tongue bites during the induced seizure. Its rapid onset and short duration of action make it ideal for the brief nature of ECT. **B. Cefepime:** This is a fourth-generation cephalosporin antibiotic. It has no role in ECT management and is used for treating bacterial infections. **C. Clozapine:** An atypical antipsychotic used for treatment-resistant schizophrenia. While ECT is sometimes used adjunctively with Clozapine, the drug itself is not a component of the ECT procedure. Notably, Clozapine lowers the seizure threshold, which can be a risk factor if not monitored. **D. Chlorpromazine:** A low-potency typical antipsychotic. Like Clozapine, it is used to treat psychosis but is not part of the standard ECT premedication protocol. **High-Yield Clinical Pearls for NEET-PG:** * **Standard ECT Premedication:** 1. **Atropine/Glycopyrrolate:** Anticholinergic to reduce secretions and prevent vagally-mediated bradycardia. 2. **Methohexital/Propofol:** Short-acting anesthetic agents to induce unconsciousness. 3. **Succinylcholine:** Muscle relaxant. * **Gold Standard Indication:** Severe depression with suicidal ideation or catatonia. * **Absolute Contraindication:** Increased intracranial pressure (ICP).

Question 196: Hyponatremia is a known side effect of which of the following medications?

A. Olanzapine
B. Lithium
C. Carbamazepine (Correct Answer)
D. Clonazepam

Explanation: **Explanation:** **Carbamazepine** is a well-known cause of **hyponatremia** (occurring in up to 10-15% of patients). The underlying mechanism is the stimulation of **Antidiuretic Hormone (ADH)** release and the sensitization of renal tubules to ADH, leading to a condition similar to SIADH (Syndrome of Inappropriate Antidiuretic Hormone secretion). This effect is dose-dependent and more common in elderly patients or those taking concomitant diuretics. **Analysis of Incorrect Options:** * **Olanzapine (A):** An atypical antipsychotic primarily associated with metabolic side effects such as weight gain, dyslipidemia, and hyperglycemia. It does not typically cause electrolyte imbalances. * **Lithium (B):** Unlike Carbamazepine, Lithium is associated with **Hypernatremia**. It causes Nephrogenic Diabetes Insipidus (NDI) by antagonizing the effects of ADH on the collecting ducts, leading to polyuria and dilute urine. * **Clonazepam (D):** A benzodiazepine that acts on GABA-A receptors. Its primary side effects are sedation, ataxia, and cognitive impairment; it has no significant effect on sodium regulation. **High-Yield Clinical Pearls for NEET-PG:** * **Oxcarbazepine**, a derivative of carbamazepine, carries an even **higher risk** of hyponatremia. * **SSRIs** (e.g., Fluoxetine, Sertraline) are the most common class of psychotropic drugs associated with SIADH/hyponatremia in the elderly. * **Monitoring:** When prescribing Carbamazepine, baseline and periodic serum sodium levels should be checked, especially if the patient develops symptoms like confusion, lethargy, or seizures. * **HLA-B*1502:** Always screen for this allele in Asian populations before starting Carbamazepine to prevent Stevens-Johnson Syndrome (SJS).

Question 197: A 19-year-old boy with chronic schizophrenia is treated with haloperidol 20 mg/day. One week after starting the medication, he exhibits restlessness, fidgeting, irritability, and an inability to remain still. What is the most appropriate management strategy?

A. Increase the dose of haloperidol
B. Add an anticholinergic drug
C. Add a beta-blocker (Correct Answer)
D. Add another antipsychotic drug

Explanation: ### Explanation **Diagnosis: Akathisia** The patient is presenting with classic symptoms of **Akathisia**, a common Extrapyramidal Side Effect (EPS) associated with high-potency first-generation antipsychotics like Haloperidol. It is characterized by subjective feelings of inner restlessness and objective signs of motor agitation (fidgeting, pacing, inability to sit still). **Why Option C is Correct:** The first-line pharmacological treatment for antipsychotic-induced akathisia is a **lipophilic beta-blocker**, specifically **Propranolol**. Propranolol crosses the blood-brain barrier effectively and acts on central receptors to alleviate the restlessness. Other options include benzodiazepines or reducing the antipsychotic dose. **Why Other Options are Incorrect:** * **Option A (Increase dose):** This would worsen the condition. Akathisia is dose-dependent; increasing Haloperidol would increase D2 receptor blockade, exacerbating the EPS. * **Option B (Add an anticholinergic):** While anticholinergics (e.g., Benztropine, Trihexyphenidyl) are the treatment of choice for *Acute Dystonia* and *Parkinsonian symptoms*, they are generally **ineffective** for Akathisia. * **Option D (Add another antipsychotic):** Polypharmacy increases the side-effect burden and does not address the underlying movement disorder. **High-Yield Clinical Pearls for NEET-PG:** * **Timeline of EPS:** 1. **Acute Dystonia:** Hours to days (Treatment: Anticholinergics). 2. **Akathisia:** Days to weeks (Treatment: Beta-blockers). 3. **Drug-induced Parkinsonism:** Weeks to months (Treatment: Anticholinergics). 4. **Tardive Dyskinesia:** Months to years (Treatment: Switch to Clozapine/VMAT2 inhibitors). * **Propranolol Dosage:** Usually 30–90 mg/day is effective for akathisia. * **Key Differentiator:** Akathisia is often mistaken for worsening psychosis/agitation. Always check for "inner restlessness" before increasing antipsychotic doses.

Question 198: Which of the following statements is true about Paliperidone?

A. It is a D2 and 5-HT2A receptor antagonist.
B. It is used for the treatment of schizophrenia.
C. It can cause Neuroleptic Malignant Syndrome.
D. All of the above are true. (Correct Answer)

Explanation: **Explanation:** Paliperidone is a second-generation (atypical) antipsychotic and is the primary active metabolite of Risperidone (9-hydroxyrisperidone). 1. **Mechanism of Action (Option A):** Like most atypical antipsychotics, Paliperidone acts primarily as a **D2 and 5-HT2A receptor antagonist**. By blocking dopamine D2 receptors in the mesolimbic pathway, it treats positive symptoms, while 5-HT2A antagonism in the mesocortical pathway helps alleviate negative symptoms and reduces the risk of extrapyramidal side effects (EPS). 2. **Clinical Use (Option B):** It is FDA-approved for the treatment of **Schizophrenia** and **Schizoaffective disorder** (both as monotherapy and as an adjunct to mood stabilizers or antidepressants). 3. **Adverse Effects (Option C):** Although atypical antipsychotics have a lower risk of neurological side effects compared to typical ones, they can still cause **Neuroleptic Malignant Syndrome (NMS)**, a life-threatening neurological emergency characterized by muscle rigidity, fever, autonomic instability, and altered mental status. **High-Yield Facts for NEET-PG:** * **Metabolism:** Unlike Risperidone, Paliperidone undergoes minimal hepatic metabolism and is primarily excreted unchanged by the kidneys. This makes it a preferred choice in patients with mild-to-moderate liver impairment. * **Formulations:** It is available as an extended-release oral tablet (using OROS technology) and as long-acting injectable (LAI) formulations (e.g., *Sustenna* - monthly; *Trinza* - 3-monthly). * **Side Effects:** It is notably associated with **hyperprolactinemia** (similar to Risperidone) and QTc prolongation.

Question 199: What is the drug of choice for depression in elderly patients?

A. Fluoxetine (Correct Answer)
B. Buspirone
C. Amitriptyline
D. Imipramine

Explanation: **Explanation:** The drug of choice for depression in elderly patients is a **Selective Serotonin Reuptake Inhibitor (SSRI)**, such as **Fluoxetine** or Sertraline. SSRIs are preferred because they have a superior safety profile, better tolerability, and a lower risk of side effects compared to older antidepressants. **Why Fluoxetine is correct:** In the elderly, physiological changes necessitate drugs with minimal cardiovascular and anticholinergic effects. Fluoxetine effectively treats depressive symptoms without causing significant sedation or orthostatic hypotension, which are major risks for falls in this age group. **Why the other options are incorrect:** * **Amitriptyline & Imipramine (TCAs):** These Tricyclic Antidepressants are generally avoided in the elderly due to their potent **anticholinergic effects** (causing confusion, urinary retention, and constipation) and **quinidine-like cardiotoxicity**. They also cause orthostatic hypotension, significantly increasing the risk of hip fractures. * **Buspirone:** This is an **anxiolytic** (5-HT1A partial agonist) used for Generalized Anxiety Disorder (GAD). It is not an antidepressant and is not used as a primary treatment for depression. **High-Yield Clinical Pearls for NEET-PG:** * **First-line for Elderly:** SSRIs (Sertraline is often preferred over Fluoxetine if drug-drug interactions are a concern due to its shorter half-life). * **Hyponatremia:** Elderly patients on SSRIs should be monitored for **SIADH**, a common side effect in this population. * **Pseudodementia:** Always rule out "Depressive Pseudodementia" in elderly patients presenting with cognitive decline; it is reversible with antidepressants. * **TCA Side Effects:** Remember the mnemonic "3 Cs" for TCA toxicity: Coma, Convulsions, and Cardiotoxicity (Arrhythmias).

Question 200: Which drug is NOT used in the prophylaxis of bipolar disorder?

A. Haloperidol (Correct Answer)
B. Lithium
C. Carbamazepine
D. Valproate

Explanation: **Explanation:** The management of Bipolar Disorder is divided into two phases: **Acute Management** (treating current manic or depressive episodes) and **Prophylaxis/Maintenance** (preventing future relapses). **1. Why Haloperidol is the correct answer:** Haloperidol is a high-potency typical antipsychotic. While it is highly effective in the **acute management** of manic episodes to control agitation and psychosis, it is **not used for prophylaxis**. Long-term use of Haloperidol is avoided in bipolar patients due to the high risk of Extrapyramidal Side Effects (EPS) and Tardive Dyskinesia. Furthermore, some studies suggest that typical antipsychotics may increase the risk of post-manic depression. **2. Why the other options are incorrect:** * **Lithium (Option B):** The "Gold Standard" for bipolar prophylaxis. It is effective in preventing both manic and depressive relapses and is the only drug proven to reduce suicide risk in these patients. * **Valproate (Option D):** A first-line mood stabilizer, especially effective for **Rapid Cycling** bipolar disorder and Mixed Episodes. * **Carbamazepine (Option C):** A second-line mood stabilizer used for prophylaxis, particularly in patients who do not respond to Lithium or Valproate. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for Prophylaxis:** Lithium. * **DOC for Rapid Cycling (>4 episodes/year):** Sodium Valproate. * **Atypical Antipsychotics for Prophylaxis:** Unlike Haloperidol, certain atypical antipsychotics (e.g., **Quetiapine, Olanzapine, Aripiprazole**) are FDA-approved for maintenance therapy. * **Lamotrigine:** Specifically used for the prophylaxis of **Bipolar Depression** (not effective for acute mania). * **Therapeutic Index:** Lithium has a narrow therapeutic index (0.6–1.2 mEq/L for maintenance).

Practice by Chapter

Principles of Psychopharmacology

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Antipsychotic Medications

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Antidepressant Medications

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Mood Stabilizers

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Anxiolytics and Hypnotics

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Stimulants and Cognitive Enhancers

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Pharmacokinetics and Pharmacodynamics

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Drug Interactions

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Adverse Effects and Management

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Pharmacogenomics in Psychiatry

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Special Populations Considerations

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Treatment Algorithms and Guidelines

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