Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following tricyclic antidepressants is used in the management of nocturnal enuresis?

imipramine. **Explanation:** **Imipramine** is a tertiary amine Tricyclic Antidepressant (TCA) that has been traditionally used in the management of nocturnal enuresis (bedwetting) in children aged 6 years and older. Its efficacy is attributed to a dual mechanism: 1. **Anticholinergic effect:** It increases the bladder capacity by relaxing the detrusor muscle. 2. **Noradrenergic effect:** It increases the tone of the internal urethral sphincter. 3. **Sleep architecture:** It alters the sleep-wake pattern, making the child more easily arousable by a full bladder. **Analysis of Incorrect Options:** * **Fluoxetine and Sertraline (Options B & D):** These are Selective Serotonin Reuptake Inhibitors (SSRIs). While they are first-line for depression and anxiety, they do not possess the potent anticholinergic properties required to treat enuresis. * **Bupropion (Option C):** This is an Atypical Antidepressant (NDRI) used primarily for smoking cessation and depression. It lacks anticholinergic activity and is contraindicated in patients with seizure disorders. **Clinical Pearls for NEET-PG:** * **First-line treatment** for nocturnal enuresis is **Behavioral Therapy** (e.g., Bed-alarm/Enuresis alarm). * **Desmopressin (ADH analogue)** is the first-line pharmacological agent due to a better safety profile. * **Imipramine** is considered second-line or third-line due to its narrow therapeutic index and risk of **cardiotoxicity** (QT prolongation) in overdose. * **Other TCAs:** Clomipramine is the drug of choice for OCD; Amitriptyline is commonly used for neuropathic pain and migraine prophylaxis.

Q: Which drug, when given to a patient with alcohol dependence, can cause an adverse drug reaction if the patient consumes alcohol due to a drug interaction?

Disulfiram. **Explanation:** The correct answer is **Disulfiram**. This drug is used as **Aversion Therapy** in alcohol dependence. **1. Why Disulfiram is correct:** Disulfiram inhibits the enzyme **Aldehyde Dehydrogenase (ALDH)**. Normally, alcohol is metabolized into Acetaldehyde, which ALDH then converts into Acetic Acid. By blocking ALDH, Disulfiram causes a toxic accumulation of **Acetaldehyde** in the blood if alcohol is consumed. This leads to the **Disulfiram-Ethanol Reaction (DER)**, characterized by flushing, throbbing headache, nausea, vomiting, tachycardia, and hypotension. The fear of this unpleasant reaction deters the patient from drinking. **2. Why other options are incorrect:** * **Acamprosate:** It is an NMDA receptor antagonist used to maintain abstinence by reducing "protracted withdrawal" symptoms (craving). It does not cause a reaction with alcohol. * **Naltrexone:** An opioid antagonist that reduces the "reward" or euphoria associated with drinking by blocking mu-opioid receptors. It is the drug of choice for reducing cravings but has no interaction reaction. * **Naloxone:** An intravenous opioid antagonist used primarily for acute opioid overdose, not for the long-term management of alcohol dependence. **Clinical Pearls for NEET-PG:** * **Drug of Choice for Alcohol Withdrawal:** Benzodiazepines (e.g., Chlordiazepoxide, Diazepam). * **Drug of Choice to Reduce Craving:** Naltrexone. * **Other drugs causing Disulfiram-like reactions:** Metronidazole (most common), Cefotetan, Cefoperazone, Chlorpropamide, and Griseofulvin. * **Contraindication:** Disulfiram should never be administered if the patient has consumed alcohol within the last 12 hours or is in a state of intoxication.

Q: True regarding bupropion is?

Nicotinic receptor antagonist. **Explanation:** **Bupropion** is an atypical antidepressant with a unique mechanism of action compared to SSRIs or TCAs. 1. **Why Option D is correct:** Bupropion acts as a **non-competitive antagonist at nicotinic acetylcholine receptors (nAChR)**. This specific action is responsible for its effectiveness in **smoking cessation**, as it reduces the rewarding effects of nicotine and minimizes withdrawal symptoms. 2. **Why other options are incorrect:** * **Option A:** Bupropion is a **Dopamine and Norepinephrine Reuptake Inhibitor (DNRI)**, not a stimulator. It increases the synaptic concentration of these neurotransmitters. * **Option B:** Bupropion is primarily an **antidepressant**. Unlike SSRIs, it is generally not effective for anxiety disorders and may occasionally worsen anxiety or agitation due to its stimulating properties. * **Option C:** Bupropion is notorious for **lowering the seizure threshold**. It is contraindicated in patients with seizure disorders, eating disorders (bulimia/anorexia), or those undergoing alcohol withdrawal. **High-Yield Clinical Pearls for NEET-PG:** * **Sexual Dysfunction:** Unlike SSRIs, Bupropion does **not** cause sexual dysfunction or weight gain, making it a preferred choice for patients concerned about these side effects. * **Smoking Cessation:** It is FDA-approved for smoking cessation (often marketed as Zyban). * **Contraindications:** Always avoid in patients with a history of seizures or head injury. * **Active Metabolite:** Hydroxybupropion is its major active metabolite.

Q: Absolute contraindication to lithium therapy is:

Pregnancy. **Explanation:** **1. Why Pregnancy is the Correct Answer:** Lithium is a known **teratogen** and is classified under FDA Pregnancy Category D. Its use during the first trimester is strongly associated with **Ebstein’s Anomaly**, a congenital cardiac defect characterized by the downward displacement of the tricuspid valve into the right ventricle ("atrialization" of the ventricle). While some modern guidelines suggest lithium can be used in severe refractory cases with close monitoring, for the purpose of NEET-PG, it remains an absolute contraindication in early pregnancy due to this specific morphological risk. **2. Analysis of Incorrect Options:** * **Angioma:** There is no clinical or pharmacological correlation between lithium therapy and the progression or occurrence of angiomas. * **Glaucoma:** Unlike Tricyclic Antidepressants (TCAs) or Antipsychotics with anticholinergic properties, lithium does not affect intraocular pressure and is safe to use in glaucoma patients. * **Epilepsy:** Lithium is not contraindicated in epilepsy. In fact, it can sometimes be used in patients with comorbid mood disorders, though caution is required as lithium toxicity can lower the seizure threshold. **3. High-Yield Clinical Pearls for NEET-PG:** * **Therapeutic Index:** Lithium has a narrow therapeutic index (0.6–1.2 mEq/L). Toxicity starts >1.5 mEq/L. * **Renal Function:** Since lithium is excreted 100% by the kidneys, **Renal Failure** is a major contraindication. * **Drug Interactions:** Thiazides, NSAIDs, and ACE inhibitors increase lithium levels (decreasing clearance), leading to toxicity. * **Side Effects:** Remember the mnemonic **LITHIUM**: **L**eukocytosis, **I**nsipidus (Diabetes Insipidus), **T**remors/Teratogenicity, **H**ypothyroidism, **I**ncreased Weight, **U**nderactive heart (Sinus node dysfunction), **M**others (Ebstein’s).

Q: Which of the following is NOT a serotonin-norepinephrine reuptake inhibitor?

Tianeptin. **Explanation:** The question asks to identify the drug that does **not** belong to the Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) class. **1. Why Tianeptine is the Correct Answer:** Tianeptine is a unique antidepressant that is chemically classified as a **Selective Serotonin Reuptake Enhancer (SSRE)**. Unlike SSRIs or SNRIs, it paradoxically increases the presynaptic uptake of serotonin, thereby decreasing serotonin levels in the synaptic cleft. It also modulates glutamate neurotransmission and has neuroprotective effects. It is primarily used for Major Depressive Disorder but does not inhibit the reuptake of norepinephrine or serotonin. **2. Why the Other Options are Incorrect:** * **Venlafaxine (A):** The first SNRI introduced. At low doses, it primarily inhibits serotonin reuptake; at higher doses, it significantly inhibits norepinephrine reuptake. * **Duloxetine (B):** A potent SNRI used widely for depression, diabetic neuropathy, fibromyalgia, and stress urinary incontinence. * **Milnacipran (C):** An SNRI with a more balanced inhibition of both serotonin and norepinephrine reuptake compared to venlafaxine. It is frequently used in the management of fibromyalgia. **3. NEET-PG High-Yield Pearls:** * **SNRIs vs. TCAs:** SNRIs are often preferred over Tricyclic Antidepressants (TCAs) because they lack the potent antihistaminic, alpha-adrenergic blocking, and anticholinergic side effects. * **Desvenlafaxine:** This is the active metabolite of venlafaxine. * **Clinical Use:** SNRIs are first-line for depression associated with chronic pain (e.g., Duloxetine). * **Side Effects:** Hypertension is a notable side effect of SNRIs (especially Venlafaxine) due to increased norepinephrine levels.

Q: Which among the following selective serotonin reuptake inhibitors is longest acting?

Fluoxetine. **Explanation:** The correct answer is **Fluoxetine**. **1. Why Fluoxetine is correct:** Fluoxetine is unique among Selective Serotonin Reuptake Inhibitors (SSRIs) due to its exceptionally long half-life. The parent drug has a half-life of approximately **2 to 3 days**, but it is metabolized into an active metabolite, **Norfluoxetine**, which has a half-life of **7 to 9 days**. This prolonged duration of action means that the drug remains in the system for several weeks even after discontinuation. This property makes it the safest SSRI to discontinue abruptly, as it essentially "self-tapers," resulting in the lowest risk of **SSRI Discontinuation Syndrome**. **2. Why the other options are incorrect:** * **Fluvoxamine:** It has the shortest half-life (approx. 15 hours) among the SSRIs and often requires twice-daily dosing. * **Sertraline:** It has an intermediate half-life (approx. 26 hours). While it also has an active metabolite (Desmethylsertraline), it is significantly less potent than Norfluoxetine. * **Paroxetine:** It has a half-life of about 21 hours. Notably, it is associated with the highest risk of Discontinuation Syndrome because it lacks active metabolites and has a relatively short half-life. **3. High-Yield Clinical Pearls for NEET-PG:** * **Washout Period:** Due to its long half-life, a **5-week washout period** is required when switching from Fluoxetine to a Monoamine Oxidase Inhibitor (MAOI) to avoid **Serotonin Syndrome** (other SSRIs usually require only 2 weeks). * **Drug of Choice:** Fluoxetine is the preferred SSRI for treating depression in **children and adolescents**. * **Side Effects:** Paroxetine is the most "sedating" and has the most significant anticholinergic effects, whereas Fluoxetine is often considered "activating" (can cause insomnia/anxiety initially).

Q: A patient was treated with amitriptyline for depression and developed urinary retention, constipation, and blurring of vision. What is the most likely cause of these symptoms?

Anticholinergic side effects. ### Explanation **Correct Option: B. Anticholinergic side effects** Amitriptyline is a **Tricyclic Antidepressant (TCA)**. While its primary therapeutic action is the inhibition of norepinephrine and serotonin reuptake, it also possesses significant antagonist activity at several other receptors, most notably **Muscarinic (M1) receptors**. The symptoms described—**urinary retention, constipation, and blurring of vision** (due to cycloplegia/mydriasis)—are classic manifestations of **anticholinergic toxicity**. By blocking muscarinic receptors, TCAs inhibit the parasympathetic nervous system ("rest and digest"), leading to "drying" effects: * **Mydriasis/Cycloplegia:** Blurred vision. * **Decreased Secretions:** Dry mouth (xerostomia). * **Smooth Muscle Relaxation:** Constipation and urinary retention. --- **Why other options are incorrect:** * **Option A:** Persistent depression typically presents with mood symptoms (anhedonia, low energy) rather than acute autonomic physical signs like urinary retention. * **Option C:** "Depression medicamentosa" refers to depression induced by drugs (e.g., Reserpine or Propranolol). It does not describe the physical side effects of antidepressants themselves. --- ### High-Yield NEET-PG Pearls: * **TCA Receptor Profile:** Remember the "Side Effect Profile" of TCAs: 1. **Anti-Muscarinic:** Dry mouth, blurred vision, constipation, urinary retention. 2. **Anti-Alpha 1:** Orthostatic hypotension. 3. **Anti-Histaminic (H1):** Sedation and weight gain. * **Cardiac Toxicity:** In TCA overdose, the most dangerous effect is **Sodium channel blockade**, leading to QRS prolongation and arrhythmias. **Sodium Bicarbonate** is the antidote for TCA-induced cardiac toxicity. * **Contraindication:** Due to anticholinergic effects, TCAs should be avoided in patients with **Benign Prostatic Hyperplasia (BPH)** and **Narrow-angle Glaucoma**.

Q: Which of the following is NOT a common side effect of chlorpromazine?

Osteoporosis. **Explanation:** Chlorpromazine is a **typical (first-generation) antipsychotic** belonging to the phenothiazine class. It acts primarily by blocking dopamine ($D_2$) receptors in various brain pathways. **Why Osteoporosis is the correct answer:** While long-term use of antipsychotics can theoretically lead to decreased bone mineral density due to hyperprolactinemia (which suppresses estrogen/testosterone), **osteoporosis is not considered a "common" or classic side effect** of chlorpromazine. In the context of NEET-PG, the other three options represent well-documented, hallmark side effects of this drug class. **Analysis of Incorrect Options:** * **Parkinsonism (B):** Chlorpromazine blocks $D_2$ receptors in the **nigrostriatal pathway**, leading to Extrapyramidal Side Effects (EPS), including pseudoparkinsonism (rigidity, tremors, and bradykinesia). * **Skin Rash (C):** Chlorpromazine is notorious for dermatological side effects, including **photosensitivity** and a unique "blue-grey" skin discoloration in sun-exposed areas. * **Amenorrhea (D):** By blocking $D_2$ receptors in the **tuberoinfundibular pathway**, chlorpromazine removes the inhibitory effect of dopamine on prolactin. The resulting **hyperprolactinemia** causes galactorrhea, amenorrhea, and infertility. **High-Yield Clinical Pearls for NEET-PG:** 1. **Low Potency:** Chlorpromazine is a low-potency antipsychotic; it has a high affinity for $H_1$, $\alpha_1$, and $M_1$ receptors, leading to significant sedation, hypotension, and anticholinergic effects. 2. **Ocular Deposits:** A classic exam fact is that chlorpromazine causes **stellate corneal and lenticular opacities**, whereas Thioridazine causes retinitis pigmentosa. 3. **Weight Gain:** It is associated with significant metabolic side effects and weight gain compared to high-potency drugs like Haloperidol.

Question 1

Which of the following tricyclic antidepressants is used in the management of nocturnal enuresis?

Accepted Answer

imipramine

Answer

fluoxetine

Answer

bupropion

Answer

sertraline

Question 2

Which drug, when given to a patient with alcohol dependence, can cause an adverse drug reaction if the patient consumes alcohol due to a drug interaction?

Accepted Answer

Disulfiram

Answer

Acamprosate

Answer

Naloxone

Answer

Naltrexone

Question 3

True regarding bupropion is?

Accepted Answer

Nicotinic receptor antagonist

Answer

Dopamine reuptake stimulator

Answer

It is an antianxiety drug

Answer

No precipitation of seizures

Question 4

Which of the following adverse effects can occur even after the offending drug has been withdrawn a long time back?

Accepted Answer

Tardive dyskinesia

Answer

Paradoxical tachycardia

Answer

Malignant hyperthermia

Answer

Gynaecomastia

Question 5

Absolute contraindication to lithium therapy is:

Accepted Answer

Pregnancy

Answer

Angioma

Answer

Glaucoma

Answer

Epilepsy

Question 6

A hospital nurse is taking Imipramine for a phobic anxiety disorder, and her patient is being treated with chlorpromazine for a psychotic disorder. Which of the following adverse effects is likely to occur in both of them?

Accepted Answer

Orthostatic hypotension

Answer

Excessive salivation

Answer

Pupillary constriction

Answer

Seizure

Question 7

Which of the following is NOT a serotonin-norepinephrine reuptake inhibitor?

Accepted Answer

Tianeptin

Answer

Venlafaxine

Answer

Duloxetine

Answer

Milnacipran

Question 8

Which among the following selective serotonin reuptake inhibitors is longest acting?

Accepted Answer

Fluoxetine

Answer

Fluvoxamine

Answer

Sertraline

Answer

Paroxetine

Question 9

A patient was treated with amitriptyline for depression and developed urinary retention, constipation, and blurring of vision. What is the most likely cause of these symptoms?

Accepted Answer

Anticholinergic side effects

Answer

Symptoms of depression persisting

Answer

Depression medicamentosa

Answer

Any of the above

Question 10

Which of the following is NOT a common side effect of chlorpromazine?

Accepted Answer

Osteoporosis

Answer

Parkinsonism

Answer

Skin rash

Answer

Amenorrhea

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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