Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following is NOT a monoamine oxidase inhibitor?

Maprotiline. **Explanation:** The correct answer is **Maprotiline** because it belongs to the class of **Tetracyclic Antidepressants (TeCAs)**, not Monoamine Oxidase Inhibitors (MAOIs). Its primary mechanism of action is the selective inhibition of norepinephrine reuptake; it has minimal effect on serotonin or dopamine reuptake and does not inhibit the MAO enzyme. **Analysis of Options:** * **Tranylcypromine:** A non-selective, irreversible MAO inhibitor. It is a derivative of cyclopropylamine and is structurally related to amphetamine. * **Isocarboxazide:** A non-selective, irreversible MAO inhibitor belonging to the hydrazine group. * **Phenelzine:** Another hydrazine-derivative, non-selective, irreversible MAO inhibitor used primarily in treatment-resistant depression. **Clinical Pearls for NEET-PG:** 1. **Classification of MAOIs:** * **Non-selective (MAO-A & B):** Phenelzine, Isocarboxazide, Tranylcypromine. * **Selective MAO-A:** Moclobemide (Reversible Inhibitor of MAO-A or RIMA). * **Selective MAO-B:** Selegiline, Rasagiline (used in Parkinson’s disease). 2. **Cheese Reaction:** MAOIs (especially non-selective ones) can cause a hypertensive crisis when taken with tyramine-rich foods (cheese, wine) due to the displacement of norepinephrine. 3. **Drug Interactions:** Always maintain a "washout period" (usually 2 weeks) when switching between MAOIs and SSRIs to prevent **Serotonin Syndrome**. 4. **Maprotiline Specifics:** It is known for a higher incidence of **seizures** compared to other antidepressants, especially at high doses.

Q: Fluoxetine causes all of the following side effects, except:

Sedation. **Explanation:** Fluoxetine is a prototype **Selective Serotonin Reuptake Inhibitor (SSRI)**. Unlike older tricyclic antidepressants (TCAs), SSRIs lack significant antihistaminic and anticholinergic properties, which are the primary drivers of sedation. **Why Sedation is the Correct Answer:** Fluoxetine is unique among SSRIs because it is **activating** rather than sedating. It has a stimulant-like effect on the CNS, which is why it is typically administered in the morning. Sedation is a characteristic side effect of TCAs (like Amitriptyline) or certain atypical antidepressants (like Mirtazapine), but not Fluoxetine. **Analysis of Incorrect Options:** * **Diarrhoea:** SSRIs increase serotonin levels in the gut, stimulating 5-HT3 receptors. This leads to gastrointestinal side effects, including nausea, vomiting, and diarrhoea. * **Insomnia:** Due to its activating nature and increased serotonergic neurotransmission in the brainstem, Fluoxetine frequently causes sleep disturbances and difficulty falling asleep. * **Anxiety:** In the initial stages of therapy, the stimulant effect of Fluoxetine can paradoxically worsen anxiety, agitation, or restlessness (akathisia-like symptoms). **High-Yield Clinical Pearls for NEET-PG:** 1. **Longest Half-life:** Fluoxetine has the longest half-life (2–4 days) among SSRIs, and its active metabolite, **norfluoxetine**, lasts 7–15 days. 2. **Washout Period:** Due to its long half-life, a 5-week washout period is required before starting an MAO inhibitor to avoid **Serotonin Syndrome**. 3. **Drug of Choice:** Fluoxetine is the preferred SSRI for treating depression in children and adolescents and is also used in Bulimia Nervosa.

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

Paroxetine. **Explanation:** The core of this question lies in distinguishing between different classes of antidepressants based on their mechanism of action. **1. Why Paroxetine is the correct answer:** **Paroxetine** is a potent and selective **Selective Serotonin Reuptake Inhibitor (SSRI)**. It works by specifically inhibiting the reuptake of serotonin (5-HT) at the presynaptic terminal, increasing its availability in the synaptic cleft. It does not significantly inhibit the reuptake of norepinephrine, which is why it is **not** classified as an SNRI. **2. Analysis of other options:** * **Venlafaxine:** This is the prototype **Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)**. At lower doses, it primarily affects serotonin, but at higher doses, it significantly inhibits norepinephrine reuptake. * **Mianserin:** This is an **Atypical Antidepressant** (specifically a tetracyclic antidepressant). While its primary mechanism is blocking presynaptic $\alpha_2$-adrenoceptors (increasing NE release), it also inhibits the reuptake of norepinephrine. In many pharmacological classifications used for competitive exams, it is grouped with drugs that enhance noradrenergic transmission, distinct from pure SSRIs. * **None of the above:** Incorrect, as Paroxetine clearly fits the criteria for an SSRI. **Clinical Pearls for NEET-PG:** * **SNRIs:** Include Venlafaxine, Desvenlafaxine, Duloxetine, and Milnacipran. * **Duloxetine** is the drug of choice for diabetic neuropathy and fibromyalgia. * **Paroxetine** has the shortest half-life among SSRIs and is most associated with **Discontinuation Syndrome**. It is also notably associated with weight gain and anticholinergic side effects compared to other SSRIs. * **Fluoxetine** has the longest half-life and is the SSRI of choice in children and adolescents.

Q: All of the following are Selective Serotonin Reuptake Inhibitors (SSRIs) except?

Mirtazapine. **Explanation:** The correct answer is **Mirtazapine**. **1. Why Mirtazapine is the correct answer:** Mirtazapine is not an SSRI; it is classified as a **Noradrenergic and Specific Serotonergic Antidepressant (NaSSA)** [2]. Its mechanism of action involves blocking **presynaptic $\alpha_2$-autoreceptors**, which increases the release of both norepinephrine and serotonin. It also blocks 5-$HT_2$ and 5-$HT_3$ receptors, which helps reduce the common side effects associated with SSRIs, such as anxiety and nausea [1]. **2. Why the other options are incorrect:** * **Paroxetine (A):** A potent SSRI often used for panic disorders and OCD [2], [3]. It has a relatively short half-life and is known for having the highest risk of "discontinuation syndrome" among SSRIs. * **Escitalopram (B):** The S-enantiomer of citalopram [1]. It is considered the most selective SSRI with the fewest drug-drug interactions, making it a first-line choice for depression [3]. * **Fluvoxamine (C):** An SSRI primarily indicated for Obsessive-Compulsive Disorder (OCD) [2], [3]. It is unique for its potent inhibition of CYP enzymes. **3. NEET-PG High-Yield Clinical Pearls:** * **SSRIs** are the first-line treatment for Depression, OCD, Panic Disorder, and Social Phobia. * **Mirtazapine** is a "weight-positive" antidepressant. It is a preferred choice for depressed patients suffering from **insomnia and significant weight loss** due to its side effects of sedation (H1 blockade) and increased appetite [2]. * **Sexual dysfunction** is a common side effect of SSRIs (Options A, B, C) [1], but **Mirtazapine** is "serotonin-sparing" in this regard and is often used when patients cannot tolerate the sexual side effects of SSRIs. * **Drug of choice for OCD:** Fluoxetine/Fluvoxamine. * **Drug of choice for Depression:** SSRIs (Escitalopram is frequently preferred).

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

Weight loss. **Explanation:** Amitriptyline is a **Tricyclic Antidepressant (TCA)**. The side effect profile of TCAs is determined by their multi-receptor antagonism, specifically blocking Muscarinic (M1), Histaminic (H1), and Alpha-1 (α1) receptors. **Why Weight Loss is the Correct Answer:** Amitriptyline is notorious for causing **weight gain**, not weight loss. This occurs primarily due to its potent **H1-receptor antagonism**, which increases appetite and slows metabolism. In clinical practice, weight gain is a common reason for patient non-compliance with TCAs. **Analysis of Incorrect Options:** * **Constipation & Dry Mouth (Options A & D):** These are classic **Anticholinergic (Antimuscarinic)** side effects. TCAs block M1 receptors, leading to the "dry" symptoms: dry mouth (xerostomia), constipation, urinary retention, and blurred vision. * **Fine Tremors (Option B):** TCAs inhibit the reuptake of Norepinephrine (NE). Increased synaptic NE levels can lead to sympathetic overactivity, manifesting as fine tremors, tachycardia, or sweating. **NEET-PG High-Yield Pearls:** 1. **Mechanism:** TCAs inhibit the reuptake of both Serotonin (5-HT) and Norepinephrine (NE). 2. **Cardiac Toxicity:** The most serious side effect in overdose is **cardiotoxicity** (arrhythmias and QRS prolongation) due to Sodium (Na+) channel blockade. The antidote is **Sodium Bicarbonate**. 3. **The 3 C’s of TCA Overdose:** **C**oma, **C**onvulsions, and **C**ardiotoxicity. 4. **Contraindication:** Avoid in patients with Glaucoma (due to mydriasis) and Benign Prostatic Hyperplasia (due to urinary retention).

Q: Which of the following is not a side effect of Quetiapine?

Diarrhoea. **Explanation:** Quetiapine is a second-generation (atypical) antipsychotic that acts as an antagonist at multiple receptors, including Dopamine (D2), Serotonin (5-HT2A), Histamine (H1), and Alpha-1 adrenergic receptors. It also possesses significant **anticholinergic** properties. **Why Diarrhoea is the correct answer:** Quetiapine, like many antipsychotics, has potent anticholinergic effects. Anticholinergic activity leads to decreased gastrointestinal motility, which typically causes **constipation**, not diarrhoea. Therefore, diarrhoea is not a characteristic side effect of this drug. **Analysis of Incorrect Options:** * **Weight Gain:** Atypical antipsychotics are notorious for metabolic side effects. Quetiapine causes significant weight gain and dyslipidemia, primarily due to its H1 and 5-HT2C receptor antagonism. * **Somnolence:** This is the most common side effect of Quetiapine. It is caused by its potent **H1-receptor blockade** (antihistaminic effect). Because of this, it is often used off-label as a sedative. * **Blurring of Vision:** This is a classic **anticholinergic** side effect resulting from the blockade of muscarinic receptors, leading to cycloplegia (paralysis of accommodation). **High-Yield Clinical Pearls for NEET-PG:** * **"Cataract Risk":** Historically, Quetiapine was associated with lens changes; though less common now, periodic eye exams are often mentioned in boards. * **Lowest EPS:** Quetiapine has one of the lowest risks of Extrapyramidal Side Effects (EPS) and hyperprolactinemia among antipsychotics, making it a preferred choice in **Parkinson’s Disease** patients with psychosis. * **Metabolic Syndrome:** Always monitor blood glucose and lipid profiles when a patient is on Quetiapine.

Q: What is a known side effect of phenothiazines?

Lens and corneal pigmentation. **Explanation:** Phenothiazines, particularly **Chlorpromazine**, are known for causing specific ocular toxicities when used in high doses over long periods. **Why Option D is correct:** Chlorpromazine has a high affinity for melanin-containing tissues. It undergoes photochemical reactions when exposed to light, leading to the deposition of fine, particulate, brownish-yellow granules in the **anterior lens capsule** and the **posterior corneal endothelium**. These deposits typically follow a "star-shaped" or "stellate" pattern on the lens. While these deposits are often asymptomatic, they are a classic high-yield side effect of typical antipsychotics. **Analysis of Incorrect Options:** * **A. Epithelial keratopathy:** This is more commonly associated with drugs like **Amiodarone** (vortex keratopathy/cornea verticillata) or Chloroquine, rather than phenothiazines. * **B. Cataract:** While severe lens pigmentation can theoretically interfere with vision, phenothiazines do not typically cause standard senile or metabolic cataracts. However, **Quetiapine** (an atypical antipsychotic) requires periodic slit-lamp exams in some protocols due to a theoretical risk of cataracts. * **C. Central chorioretinopathy:** This is not a feature of phenothiazines. However, **Thioridazine** (another phenothiazine) is famous for causing **Retinitis Pigmentosa** (brownish discoloration of the retina) if the daily dose exceeds 800 mg. **NEET-PG High-Yield Pearls:** 1. **Chlorpromazine:** Think **C**orneal and **C**apsular (Lens) deposits. 2. **Thioridazine:** Think **T**oxic **R**etinopathy (Salt and pepper fundus). 3. **Mnemonic:** "Chlorpromazine for the Cornea, Thioridazine for the Retina." 4. Always monitor the "800 mg/day" ceiling dose for Thioridazine to prevent irreversible blindness.

Q: What is the drug of choice for substitution therapy in morphine dependence?

Methadone. **Explanation:** The management of opioid dependence (e.g., morphine or heroin) involves two phases: detoxification and maintenance (substitution) therapy. **Why Methadone is the Correct Answer:** **Methadone** is a long-acting synthetic µ-opioid agonist. In substitution therapy, it replaces the abused drug to prevent withdrawal symptoms and reduce "drug-seeking" behavior. Its efficacy lies in its **long half-life (24–36 hours)** and high oral bioavailability. This allows for once-daily dosing, providing a stable plasma concentration that avoids the rapid "high" (euphoria) and subsequent "crash" associated with short-acting opioids like morphine. **Analysis of Incorrect Options:** * **Clonidine:** An $\alpha_2$ agonist used to suppress the **autonomic symptoms** of opioid withdrawal (tachycardia, hypertension, sweating). It is not a substitute for the opioid itself and does not reduce craving. * **Naloxone:** A short-acting pure opioid antagonist. It is the drug of choice for **acute opioid poisoning** (overdose). If given to a dependent patient, it will precipitate immediate, severe withdrawal. * **Nalmefene:** A long-acting opioid antagonist (similar to Naltrexone). It is used for alcohol dependence or post-detoxification maintenance to prevent relapse, but never for substitution during active dependence. **High-Yield Clinical Pearls for NEET-PG:** * **Buprenorphine** (a partial µ-agonist) is another first-line agent for substitution therapy; it has a lower risk of overdose due to its "ceiling effect." * **Naltrexone** is used for **relapse prevention** only *after* the patient has been opioid-free for 7–10 days. * **Methadone side effect:** It can cause **QT interval prolongation**, requiring ECG monitoring.

Q: Metabolic syndrome is a known side effect of which of the following medications?

Clozapine. **Explanation:** **Clozapine** is a Second-Generation (Atypical) Antipsychotic (SGA) notorious for causing significant metabolic side effects [1]. The underlying mechanism involves its high affinity for **H1 (histamine)** and **5-HT2C (serotonin)** receptors, which leads to increased appetite, sedation, and profound weight gain. This often progresses to **Metabolic Syndrome**, characterized by dyslipidemia, insulin resistance, and hyperglycemia (Type 2 Diabetes Mellitus). Among all SGAs, Clozapine and Olanzapine carry the highest risk for these complications [1]. **Analysis of Incorrect Options:** * **Aripiprazole:** Known as a "metabolically neutral" SGA [1]. It is a partial D2 agonist and has a much lower risk of weight gain or glucose intolerance. * **Topiramate:** An antiepileptic often used off-label for weight loss. It is associated with weight loss and decreased appetite, rather than metabolic syndrome. * **Ziprasidone:** Another metabolically neutral SGA [1]. Its primary clinical concern is QTc interval prolongation rather than metabolic dysfunction. **Clinical Pearls for NEET-PG:** * **Monitoring:** Patients on Clozapine require baseline and periodic monitoring of BMI, waist circumference, fasting blood glucose, and lipid profiles. * **The "Clozapine Rule":** While it is the most effective drug for treatment-resistant schizophrenia, it is reserved as a 3rd-line agent due to **Agranulocytosis** [1] (requires mandatory WBC monitoring) and **Seizures** (dose-dependent). * **Sialorrhea:** Paradoxically, Clozapine causes excessive salivation (wet pillow sign) despite its anticholinergic profile.

Q: Which of the following is a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)?

Duloxetine. ### Explanation **Correct Option: A. Duloxetine** Duloxetine is a **Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)** [1]. It works by inhibiting the reuptake of both serotonin (5-HT) and norepinephrine (NE) in the synaptic cleft, thereby increasing their availability [1], [3]. * **Clinical Concept:** Unlike Selective Serotonin Reuptake Inhibitors (SSRIs), SNRIs have a dual mechanism [1]. Duloxetine is particularly unique because it is FDA-approved not just for depression and anxiety, but also for **chronic pain conditions** like diabetic neuropathy, fibromyalgia, and chronic musculoskeletal pain [2], as norepinephrine modulation helps inhibit descending pain pathways in the spinal cord. **Incorrect Options:** * **B. Sertraline & C. Citalopram:** Both belong to the **SSRI** class [1]. They selectively inhibit the reuptake of serotonin [3]. SSRIs are generally considered first-line treatment for depression due to a better side-effect profile compared to older antidepressants. * **D. Isoniazid:** This is an **anti-tubercular drug** (cell wall synthesis inhibitor). While it historically led to the discovery of MAO inhibitors (due to its structural similarity to Iproniazid), it is not used as an antidepressant. **High-Yield NEET-PG Pearls:** 1. **Other SNRIs:** Venlafaxine (can cause dose-dependent hypertension), Desvenlafaxine, and Milnacipran [1], [2]. 2. **Duloxetine & Stress Incontinence:** Duloxetine is also used in some countries for stress urinary incontinence (increases urethral sphincter tone). 3. **Side Effects:** SNRIs can cause increased blood pressure, heart rate, and insomnia due to the noradrenergic component. 4. **Contraindication:** Avoid SNRIs/SSRIs with MAO inhibitors to prevent **Serotonin Syndrome**.

Question 1

Which of the following is NOT a monoamine oxidase inhibitor?

Accepted Answer

Maprotiline

Answer

Tranylcypromine

Answer

Isocarboxazide

Answer

Phenelzine

Question 2

Fluoxetine causes all of the following side effects, except:

Accepted Answer

Sedation

Answer

Diarrhoea

Answer

Insomnia

Answer

Anxiety

Question 3

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

Accepted Answer

Paroxetine

Answer

Mianserin

Answer

None of the above

Answer

Venlafaxine

Question 4

All of the following are Selective Serotonin Reuptake Inhibitors (SSRIs) except?

Accepted Answer

Mirtazapine

Answer

Paroxetine

Answer

Escitalopram

Answer

Fluvoxamine

Question 5

Which of the following is NOT a side effect of amitriptyline?

Accepted Answer

Weight loss

Answer

Constipation

Answer

Fine tremors

Answer

Dry mouth

Question 6

Which of the following is not a side effect of Quetiapine?

Accepted Answer

Diarrhoea

Answer

Weight gain

Answer

Somnolence

Answer

Blurring of vision

Question 7

What is a known side effect of phenothiazines?

Accepted Answer

Lens and corneal pigmentation

Answer

Epithelial keratopathy

Answer

Cataract

Answer

Central chorioretinopathy

Question 8

What is the drug of choice for substitution therapy in morphine dependence?

Accepted Answer

Methadone

Answer

Clonidine

Answer

Naloxone

Answer

Nalmefene

Question 9

Metabolic syndrome is a known side effect of which of the following medications?

Accepted Answer

Clozapine

Answer

Aripiprazole

Answer

Topiramate

Answer

Ziprasidone

Question 10

Which of the following is a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)?

Accepted Answer

Duloxetine

Answer

Sertraline

Answer

Citalopram

Answer

Isoniazid

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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