Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following is not a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)?

Bupropion. **Explanation:** The correct answer is **D. Bupropion**. **1. Why Bupropion is the correct answer:** Bupropion is classified as a **Norepinephrine-Dopamine Reuptake Inhibitor (NDRI)**. Unlike SNRIs, it does not significantly inhibit the reuptake of Serotonin. Its primary mechanism involves increasing the synaptic concentration of Dopamine and Norepinephrine. Clinically, this unique profile makes it useful for treating depression without the common serotonergic side effects like sexual dysfunction or weight gain. **2. Why the other options are incorrect:** * **Venlafaxine (Option A):** A prototypical SNRI. At low doses, it primarily acts on serotonin; at higher doses (>150 mg), it significantly inhibits norepinephrine reuptake. * **Duloxetine (Option B):** A potent SNRI used not only for depression but also for chronic pain conditions like diabetic neuropathy and fibromyalgia. * **Milnacipran (Option C):** An SNRI with a higher selectivity for norepinephrine reuptake compared to serotonin. It is frequently used in the management of fibromyalgia. **3. High-Yield NEET-PG Clinical Pearls:** * **Bupropion & Seizures:** Bupropion is strictly contraindicated in patients with **epilepsy** or eating disorders (bulimia/anorexia) as it lowers the seizure threshold. * **Smoking Cessation:** Bupropion is a first-line pharmacological aid for smoking cessation. * **SNRI Indications:** SNRIs are preferred over SSRIs in patients where depression is accompanied by chronic pain (e.g., Duloxetine). * **Desvenlafaxine:** This is the active metabolite of Venlafaxine and is also a common SNRI.

Q: Extrapyramidal side effects are commonly seen with which of the following drugs?

Haloperidol. **Explanation:** **Haloperidol** is a high-potency, typical (first-generation) antipsychotic. Its primary mechanism of action is the potent blockade of **D2 receptors** in the brain. Extrapyramidal side effects (EPS) occur due to the blockade of D2 receptors in the **nigrostriatal pathway**, which disrupts the balance between dopamine and acetylcholine. High-potency drugs like Haloperidol have a high affinity for these receptors and low anticholinergic activity, making them the most common culprits for EPS. **Analysis of Incorrect Options:** * **Clozapine:** This is an atypical (second-generation) antipsychotic. It has a higher affinity for 5-HT2A receptors than D2 receptors and dissociates rapidly from D2 receptors. Consequently, it has a very low risk of EPS and is often the drug of choice when EPS occurs with other agents. * **Tetracycline:** This is a broad-spectrum antibiotic that inhibits protein synthesis (30S subunit). It is not associated with dopaminergic pathways or EPS. * **Ketoconazole:** This is an antifungal agent (imidazole) that inhibits ergosterol synthesis. While it can cause endocrine side effects (due to inhibition of cytochrome P450 enzymes), it does not cause EPS. **High-Yield Clinical Pearls for NEET-PG:** * **EPS Spectrum:** Includes Acute Dystonia (earliest), Akathisia (most common), Parkinsonism, and Tardive Dyskinesia (late-onset/potentially irreversible). * **Treatment of Acute Dystonia:** Centrally acting anticholinergics like **Benztropine** or **Promethazine**. * **Drug of Choice for Akathisia:** Propropanol (Beta-blockers). * **Hyperprolactinemia:** Also caused by D2 blockade in the tuberoinfundibular pathway, common with Haloperidol and Risperidone.

Q: True about Imipramine is:

Antidepressant. **Explanation:**1. Why Option B is Correct:Imipramine is a prototype drug belonging to the **Tricyclic Antidepressants (TCAs)** class [1, 2]. Its primary mechanism of action involves the non-selective inhibition of the reuptake of norepinephrine (NE) and serotonin (5-HT) from the synaptic cleft into the presynaptic nerve terminals [1, 2]. By increasing the concentration of these monoamines in the brain, it effectively alleviates the symptoms of clinical depression [2].2. Why Other Options are Incorrect:* **Option A (Antiepileptic):** Imipramine actually **lowers the seizure threshold**. It is contraindicated in patients with epilepsy as it can precipitate seizures.* **Option C (Anxiolytic):** While TCAs may be used for panic disorders, they are not classified as primary anxiolytics (like Benzodiazepines). In fact, initial doses can sometimes worsen agitation.* **Option D (Antipsychotic):** Antipsychotics (e.g., Haloperidol, Risperidone) primarily act by blocking Dopamine (D2) receptors. Imipramine does not possess significant antipsychotic properties.3. Clinical Pearls & High-Yield Facts for NEET-PG:* **Nocturnal Enuresis:** Imipramine is the drug of choice for bedwetting in children (above 5 years) due to its anticholinergic effect, which increases bladder capacity.* **Side Effect Profile:** TCAs are notorious for "3Cs": **C**oma, **C**onvulsions, and **C**ardiotoxicity (arrhythmias due to Na+ channel blockade).* **Anticholinergic Effects:** Common side effects include dry mouth, blurred vision, constipation, and urinary retention [1].* **Metabolism:** It is a tertiary amine that is metabolized into **Desipramine** (an active metabolite) [1, 2].

Q: Which of the following antidepressants is used for smoking cessation?

Bupropion. **Bupropion** is an atypical antidepressant that acts as a **Norepinephrine-Dopamine Reuptake Inhibitor (NDRI)** [2]. It is the only antidepressant FDA-approved for smoking cessation [1]. Its efficacy lies in its ability to increase dopamine levels in the nucleus accumbens (the brain's reward center), which mimics the effect of nicotine and reduces withdrawal symptoms and the urge to smoke [1].**Analysis of Options:** * **Fluoxetine (Option A):** An SSRI (Selective Serotonin Reuptake Inhibitor) primarily used for Depression, OCD, and Bulimia. It has no proven efficacy in smoking cessation.* **Reboxetine (Option C):** A Selective Norepinephrine Reuptake Inhibitor (SNRI) used for depression; it does not play a role in nicotine addiction management.* **Venlafaxine (Option D):** A Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) used for Major Depressive Disorder and Anxiety disorders, but not for smoking cessation.**High-Yield Clinical Pearls for NEET-PG:** * **Mechanism in Smoking:** Bupropion (Sustained Release) is typically started 1–2 weeks *before* the patient's "quit date."* **Contraindication (Must Know):** Bupropion lowers the seizure threshold. It is strictly contraindicated in patients with **Seizure disorders** or **Eating disorders** (Anorexia/Bulimia) due to increased risk of convulsions [1].* **Weight Neutrality:** Unlike many other antidepressants, Bupropion is associated with weight loss or is weight-neutral, making it a preferred choice in obese patients [1].* **Sexual Dysfunction:** It does not cause sexual dysfunction (unlike SSRIs), making it useful for patients experiencing SSRI-induced side effects [1].* **Other Smoking Cessation Drugs:** **Varenicline** (Partial agonist at α4β2 nicotinic receptors) is currently considered the most effective pharmacological agent for smoking cessation.

Q: Which of the following drugs is considered to have dual reuptake inhibition?

All of the above. ### Explanation The term **"Dual Reuptake Inhibition"** refers to the pharmacological action of inhibiting the reuptake of both **Serotonin (5-HT)** and **Norepinephrine (NE)** from the synaptic cleft. This increases the concentration of both neurotransmitters, providing a potent antidepressant effect. **Why "All of the above" is correct:** 1. **Clomipramine:** Although classified as a Tricyclic Antidepressant (TCA), it is unique because it is the most potent serotonin reuptake inhibitor among TCAs, while its active metabolite (desmethylclomipramine) strongly inhibits norepinephrine reuptake. 2. **Amitriptyline:** A classic Tertiary Amine TCA. It non-selectively inhibits the reuptake of both 5-HT and NE. 3. **Venlafaxine:** This drug belongs to the **SNRI (Serotonin-Norepinephrine Reuptake Inhibitor)** class. At lower doses, it primarily inhibits serotonin reuptake, but at medium to higher doses, it significantly inhibits norepinephrine reuptake as well. **Clinical Pearls for NEET-PG:** * **Clomipramine** is the drug of choice (DOC) for **Obsessive-Compulsive Disorder (OCD)**. * **Venlafaxine** is known for causing **dose-dependent hypertension** due to its noradrenergic activity. * **TCAs vs. SNRIs:** While both provide dual reuptake inhibition, SNRIs (like Venlafaxine and Duloxetine) are preferred in modern practice because they lack the "dirty" side-effect profile of TCAs (i.e., they do not significantly block alpha-1, H1-histamine, or muscarinic receptors). * **Duloxetine** (another SNRI) is frequently asked as the DOC for **Diabetic Neuropathy** and Fibromyalgia.

Q: Which antipsychotic drug has the longest elimination half-life?

Aripiprazole. **Explanation:** The correct answer is **Aripiprazole**. **1. Why Aripiprazole is correct:** Aripiprazole is a third-generation atypical antipsychotic characterized by a unique mechanism of action as a **D2 partial agonist**. Among the oral antipsychotics, it possesses an exceptionally long elimination half-life, averaging approximately **75 hours** (extending up to 94 hours in poor metabolizers of CYP2D6). This long half-life allows for once-daily dosing and provides a "buffer" against missed doses, as plasma levels decline slowly. **2. Why the other options are incorrect:** * **Loxapine:** A typical (first-generation) antipsychotic of the dibenzoxazepine class. It has a relatively short half-life of approximately **4 to 8 hours**. * **Quetiapine:** An atypical antipsychotic known for rapid dissociation from D2 receptors. It has one of the shortest half-lives among second-generation drugs, approximately **6 to 7 hours**, often requiring twice-daily dosing or extended-release formulations. * **Ziprasidone:** An atypical antipsychotic with a short half-life of approximately **7 hours**. It must be taken with food (at least 500 calories) to ensure adequate absorption. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Aripiprazole acts as a "Dopamine Stabilizer" (Partial agonist at D2 and 5-HT1A; antagonist at 5-HT2A). * **Side Effect Profile:** It has the lowest risk of weight gain, hyperprolactinemia, and sedation among atypical antipsychotics. However, it is frequently associated with **Akathisia**. * **Long-acting Injectable (LAI):** Aripiprazole is also available as a monthly depot (Aripiprazole Maintena), but even in its **oral form**, it has the longest half-life of the options provided. * **Metabolism:** It is primarily metabolized by **CYP2D6** and **CYP3A4**.

Q: Which of the following drugs is not associated with an increase in prolactin levels?

Quetiapine. **Explanation:** The regulation of prolactin secretion is primarily controlled by the **Tuberoinfundibular pathway** in the brain. In this pathway, dopamine acts as a "Prolactin Inhibiting Factor" by stimulating **D2 receptors** on lactotroph cells in the anterior pituitary. Antipsychotic drugs that block these D2 receptors remove this inhibition, leading to **hyperprolactinemia**. **Why Quetiapine is the correct answer:** Quetiapine is a **Second-Generation (Atypical) Antipsychotic**. It is characterized by "loose" binding and rapid dissociation from D2 receptors. Because it does not maintain prolonged blockade of D2 receptors in the pituitary, it is considered **prolactin-sparing**. Along with Aripiprazole and Clozapine, Quetiapine is least likely to cause prolactin elevation. **Analysis of incorrect options:** * **Haloperidol & Chlorpromazine:** These are **First-Generation (Typical) Antipsychotics**. They are potent D2 receptor antagonists with high affinity. They significantly block the tuberoinfundibular pathway, frequently causing side effects like galactorrhea, amenorrhea, and gynecomastia. * **Hydroxysulpiride (and Sulpiride/Amisulpiride):** These are substituted benzamides. Despite being classified as atypical in some contexts, they are notorious for causing the **highest** increases in prolactin levels because they do not cross the blood-brain barrier well and concentrate in the pituitary (which lies outside the BBB). **NEET-PG High-Yield Pearls:** 1. **Highest Prolactin Elevation:** Risperidone, Paliperidone, and Amisulpiride. 2. **Lowest Prolactin Elevation:** Aripiprazole (D2 partial agonist), Quetiapine, and Clozapine. 3. **Clinical Sign:** Hyperprolactinemia can lead to decreased bone mineral density (osteoporosis) due to suppressed GnRH/estrogen.

Question 1

Which of the following is not a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)?

Accepted Answer

Bupropion

Answer

Venlafaxine

Answer

Duloxetine

Answer

Milnacipram

Question 2

Which food should not be consumed by a patient taking Monoamine Oxidase Inhibitors (MAOIs)?

Accepted Answer

All of the above

Answer

Cheese

Answer

Beer

Answer

Fish

Question 3

Extrapyramidal side effects are commonly seen with which of the following drugs?

Accepted Answer

Haloperidol

Answer

Clozapine

Answer

Tetracycline

Answer

Ketoconazole

Question 4

Which of the following is true regarding tricyclic antidepressants?

Accepted Answer

Tricyclic antidepressants should not be used in patients with glaucoma.

Answer

Tricyclic antidepressants increase the antihypertensive effect of guanethidine.

Answer

Tricyclic antidepressants have anticonvulsant activity.

Answer

Tricyclic antidepressants may increase oral absorption of levodopa.

Question 5

True about Imipramine is:

Accepted Answer

Antidepressant

Answer

Antiepileptic

Answer

Anxiolytic

Answer

Antipsychotic

Question 6

Which of the following antidepressants is used for smoking cessation?

Accepted Answer

Bupropion

Answer

Fluoxetine

Answer

Reboxetine

Answer

Venlafaxine

Question 7

Which of the following is a short-acting benzodiazepine?

Accepted Answer

Lorazepam

Answer

Diazepam

Answer

Flurazepam

Answer

Chlordiazepoxide

Question 8

Which of the following drugs is considered to have dual reuptake inhibition?

Accepted Answer

All of the above

Answer

Clomipramine

Answer

Amitriptyline

Answer

Venlafaxine

Question 9

Which antipsychotic drug has the longest elimination half-life?

Accepted Answer

Aripiprazole

Answer

Loxapine

Answer

Quetiapine

Answer

Ziprasidone

Question 10

Which of the following drugs is not associated with an increase in prolactin levels?

Accepted Answer

Quetiapine

Answer

Haloperidol

Answer

Chlorpromazine

Answer

Hydroxysulpiride

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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