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: Floppy baby syndrome occurs due to fetal exposure to which of the following?

Lithium. **Explanation:** **Floppy Baby Syndrome** (neonatal hypotonia) occurs due to fetal exposure to **Lithium** during pregnancy. Lithium is a mood stabilizer used for bipolar disorder that crosses the placenta. When taken near term, it can cause neonatal lithium toxicity, characterized by lethargy, poor suck reflex, cyanosis, and marked hypotonia (the "floppy" appearance). Additionally, first-trimester exposure to Lithium is classically associated with **Ebstein’s anomaly** (tricuspid valve displacement). **Analysis of Incorrect Options:** * **Warfarin (A):** Exposure leads to **Fetal Warfarin Syndrome**, characterized by nasal hypoplasia, stippled epiphyses (chondrodysplasia punctata), and CNS defects. It does not typically present as acute neonatal floppiness. * **Valproate (B):** Primarily associated with **Neural Tube Defects** (e.g., spina bifida) due to interference with folate metabolism, as well as "Fetal Valproate Syndrome" (craniofacial dysmorphism). * **Phenytoin (C):** Causes **Fetal Hydantoin Syndrome**, presenting with midface hypoplasia, cleft lip/palate, and digital hypoplasia (hypoplastic nails/phalanges). **NEET-PG High-Yield Pearls:** * **Lithium Toxicity:** Apart from floppiness, it can cause neonatal diabetes insipidus and thyroid dysfunction. * **Management:** Most cases of Lithium-induced floppiness are self-limiting as the drug is cleared by the neonate’s kidneys; however, hydration is key. * **Other causes of Floppy Baby:** Must be differentiated from Down Syndrome (most common chromosomal cause), Spinal Muscular Atrophy (SMA Type 1), and Prader-Willi Syndrome. * **Drug of choice for Bipolar in Pregnancy:** Lamotrigine is often preferred over Lithium/Valproate due to a lower teratogenic profile.

Q: Which of the following drugs is known to cause hypothyroidism?

Lithium carbonate. **Explanation** **Lithium carbonate** is the correct answer. Lithium is a mood stabilizer primarily used for Bipolar Affective Disorder (BPAD). It is well-known for its endocrine side effects, specifically its ability to cause **hypothyroidism** and goiter. **Mechanism:** Lithium interferes with thyroid function at multiple levels: 1. It inhibits the uptake of iodine into follicular cells. 2. It interferes with the iodination of tyrosine. 3. Most significantly, it **inhibits the release of thyroid hormones (T3 and T4)** from the thyroid gland by interfering with thyroglobulin pinocytosis. This leads to a compensatory rise in TSH, which can cause a goiter. **Analysis of Incorrect Options:** * **Haloperidol (A):** A typical antipsychotic (D2 blocker). Its primary side effects are Extrapyramidal Symptoms (EPS) and hyperprolactinemia, not thyroid dysfunction. * **Clozapine (B):** An atypical antipsychotic. Its "dreaded" side effects include agranulocytosis, seizures, and metabolic syndrome (weight gain, diabetes), but it does not cause hypothyroidism. * **Amoxapine (D):** A tricyclic antidepressant (TCA) with dopamine-blocking properties. It is associated with EPS and anticholinergic effects, but not thyroid suppression. **High-Yield Clinical Pearls for NEET-PG:** * **Monitoring:** Before starting Lithium, baseline **Thyroid Function Tests (TFTs)** and Renal Function Tests (RFTs) are mandatory. * **Management:** If a patient develops hypothyroidism on Lithium, you do **not** necessarily stop the drug. Instead, continue Lithium and add **Levothyroxine** supplementation. * **Other Endocrine Effect:** Lithium can also cause **hyperparathyroidism** (leading to hypercalcemia). * **Renal Effect:** It is a common cause of **Nephrogenic Diabetes Insipidus** (treated with Amiloride).

Q: All are indications of lithium except?

Generalized anxiety disorder. **Explanation:** Lithium is the gold standard mood stabilizer primarily used for Bipolar Affective Disorder (BPAD) [1]. **Generalized Anxiety Disorder (GAD)** is the correct answer because Lithium has no established role in its management. GAD is typically treated with SSRIs, SNRIs, or Benzodiazepines (for short-term relief). **Analysis of Options:** * **Neutropenia:** Lithium induces **leukocytosis** (specifically neutrophilia) by stimulating the production of colony-stimulating factors in the bone marrow. This "side effect" is therapeutically utilized to treat iatrogenic neutropenia (e.g., post-chemotherapy or Clozapine-induced). * **Major Depression:** While not a first-line monotherapy, Lithium is a well-established **augmentation strategy** for treatment-resistant Major Depressive Disorder (MDD) [3]. It is also the only drug proven to reduce the risk of suicide in patients with mood disorders. * **Vasculogenic Headaches:** Lithium is a first-line agent for the prophylaxis of **Cluster Headaches** (a type of trigeminal autonomic cephalalgia/vasculogenic headache). **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Inhibits Inositol Monophosphatase (IP3/DAG pathway) and Glycogen Synthase Kinase-3 (GSK-3). * **Therapeutic Window:** Narrow (0.6–1.2 mEq/L). Toxicity starts >1.5 mEq/L. * **Side Effects (LITHIUM mnemonic):** **L**eukocytosis, **I**nsipidus (Nephrogenic Diabetes Insipidus), **T**remors/Teratogenicity (Ebstein’s Anomaly) [2], **H**ypothyroidism [2], **I**ncreased **U**rine, **M**others (avoid in pregnancy) [2]. * **Drug Interactions:** Thiazides, NSAIDs, and ACE inhibitors increase Lithium levels by decreasing its renal clearance.

Q: Long term use of lithium is known to cause which of the following?

Hypothyroidism. **Explanation:** Lithium is the gold-standard mood stabilizer for Bipolar Affective Disorder (BPAD), but its long-term use is associated with specific endocrine and renal side effects due to its narrow therapeutic index. **Why Hypothyroidism is Correct:** Lithium interferes with thyroid function at multiple levels. It inhibits the uptake of iodine into follicular cells, interferes with the iodination of tyrosine, and—most significantly—**inhibits the release of T3 and T4** from the thyroid gland. Over time, this leads to a compensatory rise in Thyroid Stimulating Hormone (TSH), resulting in **Lithium-induced hypothyroidism** (seen in 5–15% of patients) and occasionally a non-toxic goiter. **Analysis of Incorrect Options:** * **A. Peripheral neuropathy:** This is not a classic side effect of Lithium. Lithium toxicity typically presents with central nervous system symptoms like coarse tremors, ataxia, and dysarthria. * **C. Anaemia:** Lithium does not cause anemia; in fact, it is known to cause **leukocytosis** (increased WBC count) by stimulating granulopoiesis, which is sometimes used therapeutically in Felty’s syndrome. * **D. Jaundice:** Lithium is not metabolized by the liver (it is excreted unchanged by the kidneys); therefore, it is not hepatotoxic and does not cause jaundice. **High-Yield Clinical Pearls for NEET-PG:** * **Renal Side Effects:** Long-term use can cause **Nephrogenic Diabetes Insipidus** (resistance to ADH) and chronic interstitial nephritis. * **Monitoring:** Before starting Lithium, baseline **Thyroid Function Tests (TFTs)** and **Renal Function Tests (RFTs)** are mandatory. * **Teratogenicity:** Use in pregnancy is linked to **Ebstein’s Anomaly** (atrialization of the right ventricle). * **Therapeutic Range:** 0.6–1.2 mEq/L (Prophylaxis: 0.6–0.8; Acute Mania: 0.8–1.2). Toxicity usually starts >1.5 mEq/L.

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 medications is known to cause sialorrhea?

Clozapine. **Explanation:** **Clozapine** is the correct answer. While most antipsychotics cause dry mouth (xerostomia) due to potent muscarinic blockade, Clozapine is unique for causing **sialorrhea (excessive salivation)**, particularly at night. **Underlying Mechanism:** The exact mechanism is paradoxical. Although Clozapine has anticholinergic properties, its metabolite acts as a **full agonist at M1 receptors** and an **antagonist at alpha-2 adrenergic receptors**. Alpha-2 blockade prevents the inhibition of salivary secretion, leading to hypersecretion. Additionally, Clozapine impairs the swallowing reflex during sleep, causing "wet pillow syndrome." **Analysis of Incorrect Options:** * **Amisulpride:** A substituted benzamide that primarily blocks D2/D3 receptors. It has minimal affinity for muscarinic receptors and is more likely to cause hyperprolactinemia than salivary changes. * **Olanzapine:** A thienobenzodiazepine derivative. Like most atypical antipsychotics, its side effect profile includes weight gain and metabolic syndrome, but it typically causes dry mouth due to anticholinergic activity. * **Aripiprazole:** A partial D2 agonist. It is generally "weight-neutral" and has a low side-effect profile regarding autonomic symptoms; it does not cause sialorrhea. **High-Yield Clinical Pearls for NEET-PG:** 1. **Management of Clozapine Sialorrhea:** Treat with sublingual **Atropine drops** or oral **Glycopyrrolate** (peripherally acting anticholinergics). 2. **Clozapine Monitoring:** Mandatory WBC count monitoring is required due to the risk of **Agranulocytosis** (most serious side effect). 3. **Seizures:** Clozapine is associated with dose-dependent lowering of the seizure threshold. 4. **Indication:** It is the gold standard for **Treatment-Resistant Schizophrenia**.

Q: What is the common side effect associated with fluoxetine therapy?

Loose stools. **Explanation:** Fluoxetine is a Selective Serotonin Reuptake Inhibitor (SSRI). The mechanism involves increasing synaptic serotonin levels, which not only affects the brain but also acts on peripheral receptors. **Why "Loose Stools" is correct:** Approximately 90% of the body's serotonin is located in the **enterochromaffin cells of the GI tract**. SSRIs like fluoxetine increase serotonergic activity at **5-HT3 and 5-HT4 receptors** in the gut. This stimulates gastrointestinal motility and fluid secretion, leading to common side effects such as nausea, abdominal cramps, and **loose stools/diarrhea**. **Analysis of Incorrect Options:** * **A. Seizure:** While some antidepressants (like Bupropion or Maprotiline) significantly lower the seizure threshold, SSRIs are generally considered safe and have a very low risk of inducing seizures at therapeutic doses. * **B. Anxiety:** Although some patients experience "jitteriness" or transient activation syndrome during the first week of SSRI therapy, it is less common than GI side effects. Fluoxetine is actually used to *treat* chronic anxiety disorders. * **C. Hypotension:** SSRIs do not typically cause orthostatic hypotension. This side effect is more characteristic of Tricyclic Antidepressants (TCAs) due to alpha-1 adrenergic blockade. **High-Yield Clinical Pearls for NEET-PG:** * **Fluoxetine** has the **longest half-life** (4–6 days; its metabolite norfluoxetine lasts up to 16 days) among SSRIs, making it the least likely to cause discontinuation syndrome. * **Most common side effect of SSRIs:** GI upset (Nausea is #1, followed by diarrhea). * **Most common long-term side effect:** Sexual dysfunction (delayed ejaculation/anorgasmia). * **Drug of choice:** SSRIs are the first-line treatment for Depression, OCD, Panic Disorder, and Bulimia Nervosa (specifically Fluoxetine).

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

Floppy baby syndrome occurs due to fetal exposure to which of the following?

Accepted Answer

Lithium

Answer

Warfarin

Answer

Valproate

Answer

Phenytoin

Question 3

Which of the following drugs is known to cause hypothyroidism?

Accepted Answer

Lithium carbonate

Answer

Haloperidol

Answer

Clozapine

Answer

Amoxapine

Question 4

All are indications of lithium except?

Accepted Answer

Generalized anxiety disorder

Answer

Neutropenia

Answer

Major Depression

Answer

Vasculogenic Headaches

Question 5

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 6

Long term use of lithium is known to cause which of the following?

Accepted Answer

Hypothyroidism

Answer

Peripheral neuropathy

Answer

Anaemia

Answer

Jaundice

Question 7

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 8

Which antipsychotic drug has the longest elimination half-life?

Accepted Answer

Aripiprazole

Answer

Loxapine

Answer

Quetiapine

Answer

Ziprasidone

Question 9

Which of the following medications is known to cause sialorrhea?

Accepted Answer

Clozapine

Answer

Amisulpride

Answer

Olanzapine

Answer

Aripiprazole

Question 10

What is the common side effect associated with fluoxetine therapy?

Accepted Answer

Loose stools

Answer

Seizure

Answer

Anxiety

Answer

Hypotension

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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