Psychopharmacology — MCQs

Psychopharmacology Indian Medical PG Practice Questions and MCQs

Question 11: Which of the following drugs is used in Electroconvulsive Therapy (ECT)?

A. Atropine (Correct Answer)
B. Labetalol
C. Clonazepam
D. Cefixime

Explanation: **Explanation:** In Electroconvulsive Therapy (ECT), **Atropine** is the standard premedication used as an **anticholinergic (antimuscarinic) agent**. Its primary role is to prevent the profound vagal stimulation (parasympathetic surge) that occurs during the initial tonic phase of the seizure. This prevents complications such as severe bradycardia, arrhythmias, and transient asystole. Additionally, it helps reduce tracheobronchial and salivary secretions, minimizing the risk of aspiration. **Analysis of Options:** * **A. Atropine (Correct):** Used to block vagal bradycardia and dry secretions. Glycopyrrolate is a common alternative as it does not cross the blood-brain barrier. * **B. Labetalol:** While beta-blockers are sometimes used to manage the secondary hypertensive surge (sympathetic phase) in high-risk cardiac patients, they are not a standard premedication for all ECT patients and can interfere with seizure duration. * **C. Clonazepam:** This is a benzodiazepine with potent anticonvulsant properties. It is generally avoided or tapered before ECT because it raises the seizure threshold, potentially making the treatment ineffective. * **D. Cefixime:** This is a third-generation cephalosporin antibiotic and has no role in the psychiatric or anesthetic management of ECT. **High-Yield NEET-PG Pearls:** * **Standard ECT Premedication Sequence:** Anticholinergic (Atropine) → Induction Agent (Methohexital is gold standard; Propofol/Thiopental are alternatives) → Muscle Relaxant (Succinylcholine is the drug of choice). * **Absolute Contraindication:** Increased Intracranial Pressure (ICP) is the only absolute contraindication for ECT. * **Most Common Side Effect:** Retrograde amnesia and post-ictal confusion. * **Gold Standard for Depression:** ECT is the most effective treatment for severe, treatment-resistant depression and catatonia.

Question 12: A female suffering from psychosis, taking phenothiazines now complains of sudden onset of high grade fever, muscle rigidity, and altered sensorium. What is the diagnosis?

A. Malignant hyperthermia
B. Neuroleptic malignant syndrome (Correct Answer)
C. Tardive dyskinesia
D. Akathesia

Explanation: ### Explanation The clinical presentation of **high-grade fever, muscle rigidity ("lead-pipe" type), and altered sensorium** in a patient taking antipsychotics (phenothiazines) is a classic description of **Neuroleptic Malignant Syndrome (NMS)**. #### Why the Correct Answer is Right NMS is a life-threatening idiosyncratic reaction to dopamine antagonists (typical antipsychotics like Haloperidol or Phenothiazines). The underlying pathophysiology involves **massive dopamine blockade** in the nigrostriatal pathway (causing rigidity) and the hypothalamus (causing thermoregulatory failure/fever). * **Key Tetrad:** Fever, Rigidity, Mental status changes, and Autonomic instability (tachycardia, labile BP). * **Lab findings:** Elevated Creatine Phosphokinase (CPK) due to muscle necrosis and leukocytosis. #### Why Other Options are Incorrect * **Malignant Hyperthermia:** While it presents with fever and rigidity, it is triggered by **volatile inhalation anesthetics** (e.g., Halothane) or succinylcholine, not antipsychotics. It involves a genetic defect in the ryanodine receptor. * **Tardive Dyskinesia:** A late-onset extrapyramidal side effect characterized by involuntary choreoathetoid movements (e.g., lip-smacking), but it does not cause fever or rigidity. * **Akathisia:** A subjective feeling of inner restlessness and the urge to move. It is the most common extrapyramidal side effect but lacks systemic symptoms like fever. #### NEET-PG High-Yield Pearls * **Drug of Choice:** **Dantrolene** (muscle relaxant) or **Bromocriptine** (dopamine agonist). * **Immediate Step:** Stop the offending antipsychotic and provide aggressive cooling/hydration. * **Mnemonic (FEVER):** **F**ever, **E**ncephalopathy, **V**itals unstable, **E**levated CPK, **R**igidity. * **Differentiation:** Unlike Serotonin Syndrome, NMS is characterized by "lead-pipe" rigidity rather than hyperreflexia/myoclonus.

Question 13: Which of the following is/are not a side effect of lithium?

A. Seizure
B. Hyporeflexia (Correct Answer)
C. Nephrogenic diabetes insipidus
D. Alopecia

Explanation: **Explanation:** Lithium is a gold-standard mood stabilizer with a narrow therapeutic index (0.6–1.2 mEq/L). Understanding its side effects is crucial for NEET-PG, as toxicity often manifests through neurological and renal symptoms. **Why Hyporeflexia is the Correct Answer:** Lithium toxicity characteristically causes **Hyperreflexia**, not hyporeflexia. As lithium levels rise, patients develop neuromuscular irritability, leading to tremors, ataxia, myoclonus, and brisk deep tendon reflexes (hyperreflexia). Hyporeflexia is more commonly associated with magnesium toxicity or certain sedative-hypnotic overdoses. **Analysis of Incorrect Options:** * **Seizure (A):** Lithium lowers the seizure threshold. In cases of severe toxicity (>2.5 mEq/L), neurological complications like seizures, encephalopathy, and coma are common. * **Nephrogenic Diabetes Insipidus (C):** This is the most common renal side effect. Lithium accumulates in the collecting ducts and interferes with ADH (Vasopressin) action, leading to polyuria and polydipsia. * **Alopecia (D):** Dermatological side effects of Lithium include thinning of hair (alopecia), acneiform eruptions, and the exacerbation of psoriasis. **High-Yield Clinical Pearls for NEET-PG:** * **L-I-T-H-I-U-M Mnemonic for Side Effects:** **L**eukocytosis, **I**nsipidus (NDI), **T**remors/Teratogenicity (Ebstein’s Anomaly), **H**ypothyroidism, **I**ncreased Weight, **U**nderactive Heart (Bradycardia/T-wave flattening), **M**uscle twitching/Hyperreflexia. * **Drug Interactions:** Thiazides, NSAIDs, and ACE inhibitors increase Lithium levels (decreasing clearance), while Caffeine and Theophylline decrease levels. * **Monitoring:** Thyroid Function Tests (TFT) and Renal Function Tests (RFT) must be performed before and during treatment.

Question 14: Which antipsychotic medication is associated with fewer extrapyramidal side effects?

A. Loxapine
B. Pimozide
C. Quetiapine (Correct Answer)
D. Risperidone

Explanation: ### Explanation **Correct Answer: C. Quetiapine** The risk of **Extrapyramidal Side Effects (EPS)** is primarily determined by a drug’s affinity for and occupancy of **Dopamine D2 receptors** in the nigrostriatal pathway. **Quetiapine** is a Second-Generation Antipsychotic (SGA) characterized by "loose" binding and rapid dissociation from D2 receptors. It also possesses potent **5-HT2A receptor antagonism**, which increases dopamine release in the striatum, further mitigating EPS. Among all antipsychotics, Quetiapine and Clozapine carry the lowest risk of EPS, making Quetiapine the drug of choice for treating psychosis in patients with **Parkinson’s Disease**. **Analysis of Incorrect Options:** * **A. Loxapine:** A typical (first-generation) antipsychotic of the dibenzoxazepine class. It has a high D2 affinity and a significant risk of EPS, especially at higher doses. * **B. Pimozide:** A high-potency typical antipsychotic used primarily for Tourette’s syndrome and Delusional Disorder (Monosymptomatic hypochondriacal psychosis). It has a very high risk of EPS and QT prolongation. * **C. Risperidone:** While an SGA, Risperidone is "atypical" only at low doses. At doses >6mg, its D2 occupancy increases significantly, making it the SGA with the **highest risk of EPS** and hyperprolactinemia. **High-Yield Clinical Pearls for NEET-PG:** * **Lowest EPS Risk:** Clozapine > Quetiapine. * **Highest EPS Risk (Typical):** Haloperidol, Fluphenazine. * **Highest EPS Risk (Atypical):** Risperidone. * **Metabolic Syndrome:** Quetiapine and Olanzapine carry high risks of weight gain and dyslipidemia (Clozapine is highest). * **Drug of Choice for Psychosis in Parkinson’s:** Quetiapine (Clozapine is also effective but requires blood monitoring).

Question 15: Administration of which of the following drugs requires monitoring?

A. Lithium (Correct Answer)
B. Haloperidol
C. Diazepam
D. Acetazolamide

Explanation: **Explanation:** **Lithium** is the correct answer because it is a drug with a **narrow therapeutic index**, meaning the difference between a therapeutic dose and a toxic dose is very small. Regular **Therapeutic Drug Monitoring (TDM)** is mandatory to ensure efficacy and prevent toxicity. The therapeutic range for Lithium is typically **0.6 to 1.2 mEq/L**. Levels above 1.5 mEq/L are considered toxic, and levels above 2.0 mEq/L constitute a medical emergency. **Incorrect Options:** * **Haloperidol:** A typical antipsychotic. While it requires monitoring for extrapyramidal side effects (EPS), it does not require routine blood level monitoring. * **Diazepam:** A benzodiazepine used for anxiety and seizures. It has a wide therapeutic window; monitoring is clinical (respiratory rate/sedation) rather than through blood levels. * **Acetazolamide:** A carbonic anhydrase inhibitor used in glaucoma and altitude sickness. It requires monitoring of electrolytes (potassium/bicarbonate) in specific cases, but not routine drug level monitoring. **High-Yield Clinical Pearls for NEET-PG:** * **Sample Timing:** Lithium levels should be checked **12 hours after the last dose** (Trough level). * **Steady State:** It takes about **5 days** (5 half-lives) to reach a steady state before the first level should be checked. * **Toxicity Triggers:** Dehydration, low-sodium diets, and drugs like **NSAIDs, Thiazides, and ACE inhibitors** can increase Lithium levels, leading to toxicity. * **Side Effects:** Look for "LITH" mnemonic: **L**eukocytosis, **I**nsipidus (Diabetes Insipidus), **T**remors/Teratogenicity (Ebstein's Anomaly), **H**ypothyroidism.

Question 16: What is the drug of choice for psychosis in Parkinson's disease?

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

Explanation: ### Explanation **1. Why Clozapine is the Correct Answer:** Psychosis in Parkinson’s Disease (PD) is often a side effect of dopaminergic therapy (like Levodopa). The management is challenging because traditional antipsychotics block **D2 receptors** in the nigrostriatal pathway, which severely worsens motor symptoms (rigidity and tremors). **Clozapine** is the drug of choice because it has a very **low affinity for D2 receptors** and a high affinity for D4 and 5-HT2 receptors. This allows it to treat psychotic symptoms (hallucinations/delusions) without exacerbating the underlying motor deficits of Parkinsonism. **2. Why the Other Options are Incorrect:** * **B. Haloperidol:** This is a high-potency typical antipsychotic with strong D2 blockade. It is strictly contraindicated in PD as it can cause acute worsening of motor symptoms and potentially lead to a rigid, akinetic state. * **C. Lithium:** Lithium is a mood stabilizer used primarily for Bipolar Disorder. It has no role in treating acute psychosis and can sometimes cause tremors, which would complicate the PD clinical picture. * **D. Risperidone:** While an atypical antipsychotic, Risperidone has a dose-dependent D2 blockade. Even at low doses, it carries a significant risk of inducing Extrapyramidal Side Effects (EPS) in PD patients compared to Clozapine. **3. High-Yield Clinical Pearls for NEET-PG:** * **Pimavanserin:** A selective serotonin inverse agonist (SSIA) that targets 5-HT2A receptors. It is the only FDA-approved drug specifically for PD-associated psychosis that does not touch dopamine receptors at all. (If both Clozapine and Pimavanserin are options, Pimavanserin is often preferred in modern guidelines, but Clozapine remains the classic "gold standard" in exams). * **Quetiapine:** Often used in clinical practice as a first-line alternative to Clozapine because it does not require mandatory blood monitoring (for agranulocytosis), though Clozapine is more efficacious. * **Rule of Thumb:** In PD patients, always avoid "Typical" antipsychotics and high-potency "Atypicals" (like Risperidone or Olanzapine).

Question 17: Which of the following drugs is used for lithium-induced tremors?

A. Valproate
B. Propranolol (Correct Answer)
C. Trihexyphenidyl
D. Tetrabenazine

Explanation: **Explanation:** **Lithium-induced tremors** are a common side effect of lithium therapy, typically presenting as a fine, symmetric, postural tremor of the hands. 1. **Why Propranolol is Correct:** The physiological mechanism behind lithium-induced tremors is thought to involve the stimulation of peripheral **beta-adrenergic receptors**. **Propranolol**, a non-selective beta-blocker, is the drug of choice because it effectively antagonizes these receptors, reducing the amplitude of the tremor. It is preferred over cardioselective beta-blockers because it crosses the blood-brain barrier and acts on both peripheral and central components of the tremor. 2. **Why Other Options are Incorrect:** * **Valproate:** While used as a mood stabilizer like lithium, it can actually *cause* or worsen tremors rather than treat them. * **Trihexyphenidyl:** This is an anticholinergic used for Parkinsonian (resting) tremors or extrapyramidal symptoms (EPS) caused by antipsychotics. Lithium tremors are postural, not Parkinsonian, and do not respond to anticholinergics. * **Tetrabenazine:** This is a VMAT2 inhibitor used for hyperkinetic movement disorders like Huntington’s chorea or Tardive Dyskinesia; it has no role in managing lithium toxicity or side effects. **High-Yield Clinical Pearls for NEET-PG:** * **Fine Tremors:** Occur at therapeutic lithium levels (0.6–1.2 mEq/L). * **Coarse Tremors:** A hallmark sign of **Lithium Toxicity** (>1.5 mEq/L); the first step in management is to check serum lithium levels. * **Management Tip:** Before starting Propranolol, always try reducing the lithium dose or switching to a sustained-release preparation. * **Contraindication:** Avoid Propranolol in patients with bronchial asthma or bradycardia.

Question 18: What is the most common complication of electroconvulsive therapy?

A. Antegrade amnesia
B. Retrograde amnesia (Correct Answer)
C. Depression
D. Cognitive defects

Explanation: **Explanation:** Electroconvulsive therapy (ECT) is a highly effective treatment for severe depression and psychosis, but it is associated with specific cognitive side effects. **Why Retrograde Amnesia is correct:** Retrograde amnesia (loss of memory for events occurring *before* the treatment) is the **most common** and characteristic side effect of ECT. It typically follows **Ribot’s Law**, where recent memories are more vulnerable than remote ones. While most memory functions recover within weeks, some gaps in memory for events immediately preceding the ECT course may persist permanently. **Analysis of Incorrect Options:** * **Antegrade Amnesia:** This refers to the inability to form new memories *after* the treatment. While it occurs during the course of ECT, it is usually transient and resolves much faster than retrograde amnesia (typically within 1–2 weeks post-treatment). * **Depression:** ECT is an *indication* for depression, not a complication. It is the most effective treatment for treatment-resistant depression and suicidal ideation. * **Cognitive Defects:** While "cognitive impairment" is a broad term that includes memory loss, it is not the specific "most common" complication. Modern techniques (brief pulse, unilateral electrode placement) have significantly minimized global cognitive deficits. **High-Yield Clinical Pearls for NEET-PG:** * **Most common side effect overall:** Confusion (post-ictal) and Headache. * **Most common memory deficit:** Retrograde amnesia. * **Mortality rate:** Approximately 0.01% (similar to minor surgery under general anesthesia); usually due to cardiovascular complications. * **Electrode placement:** Unilateral (d'Elia placement) causes less memory impairment than bilateral (Bifrontotemporal) placement. * **Absolute Contraindication:** Increased Intracranial Pressure (ICP).

Question 19: What is the drug of choice for the treatment of neuroleptic malignant syndrome?

A. Dantrolene (Correct Answer)
B. Beta blocker
C. Central anticholinergic
D. None of the above

Explanation: **Explanation:** **Neuroleptic Malignant Syndrome (NMS)** is a life-threatening idiosyncratic reaction to antipsychotic drugs (dopamine antagonists). It is characterized by the clinical tetrad of **muscle rigidity ("lead-pipe"), hyperthermia, autonomic instability, and altered mental status.** **1. Why Dantrolene is the Correct Answer:** The primary goal in treating NMS is the immediate cessation of the offending agent and supportive care. **Dantrolene** is the specific pharmacological drug of choice. It is a direct-acting skeletal muscle relaxant that works by binding to the ryanodine receptor (RyR1), inhibiting the release of calcium from the sarcoplasmic reticulum. This reduces muscle rigidity and heat production, directly addressing the hyperthermia and rhabdomyolysis associated with NMS. **2. Why Other Options are Incorrect:** * **Beta-blockers:** While they may help manage tachycardia, they do not address the underlying pathophysiology of muscle rigidity or dopamine deficiency. * **Central Anticholinergics (e.g., Benztropine):** These are used for Extrapyramidal Symptoms (EPS) like acute dystonia. However, in NMS, they are generally avoided as they can worsen hyperthermia by inhibiting sweating. **3. High-Yield Clinical Pearls for NEET-PG:** * **Dopamine Agonists:** **Bromocriptine** or Amantadine are also used to restore dopaminergic tone. * **Lab Findings:** Look for significantly elevated **Creatine Phosphokinase (CPK)** levels and leukocytosis. * **NMS vs. Serotonin Syndrome:** NMS features "lead-pipe" rigidity and bradyreflexia, whereas Serotonin Syndrome features hyperreflexia and myoclonus. * **First Step in Management:** Immediate discontinuation of the antipsychotic drug.

Question 20: A 30-year-old patient with mania, prescribed haloperidol one week ago, has become restless and has been pacing for the last day. On examination, hand tremors are noted. What is the most likely diagnosis?

A. Anhedonia
B. Dystonia
C. Restless leg syndrome
D. Akathisia (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Akathisia** **Why it is correct:** Akathisia is a common **Extrapyramidal Side Effect (EPS)** associated with high-potency first-generation antipsychotics like Haloperidol. It is characterized by a subjective feeling of inner restlessness and an objective need to move. Clinically, this manifests as pacing, inability to sit still, or shifting weight from foot to foot. It typically occurs within days to weeks of starting or increasing the dose of an antipsychotic. The presence of hand tremors in this patient suggests concurrent drug-induced parkinsonism, which often co-exists with akathisia. **Why the other options are incorrect:** * **A. Anhedonia:** This refers to the inability to feel pleasure, a core symptom of depression or negative symptoms of schizophrenia, not a motor side effect. * **B. Dystonia:** Acute dystonia involves sudden, involuntary, sustained muscle contractions (e.g., torticollis, oculogyric crisis). It usually occurs within hours to the first few days of treatment, rather than presenting as continuous pacing. * **C. Restless Leg Syndrome (RLS):** While clinically similar, RLS typically occurs at night, is associated with uncomfortable sensations in the legs, and is relieved by movement. Akathisia is persistent throughout the day and is specifically linked to dopamine-blocking agents. **NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** For Akathisia, the first-line treatment is **Propranolol** (Beta-blocker). Centrally acting anticholinergics (like Benztropine) are less effective for akathisia than for dystonia. * **Timeline of EPS:** 1. **Acute Dystonia:** Hours to days. 2. **Akathisia:** Days to weeks. 3. **Parkinsonism:** Weeks to months. 4. **Tardive Dyskinesia:** Months to years (long-term use). * **Mechanism:** Akathisia is thought to result from dopamine (D2) blockade in the nigrostriatal pathway.

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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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