Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders Indian Medical PG Practice Questions and MCQs

Question 171: Which of the following is a side effect of fluoxetine?

A. Weight gain
B. Sweating
C. Urinary retention (Correct Answer)
D. Diarrhoea

Explanation: **Explanation:** Fluoxetine is a prototype **Selective Serotonin Reuptake Inhibitor (SSRI)**. While SSRIs primarily increase synaptic serotonin levels, they can exert secondary effects on other neurotransmitter systems. **Why Urinary Retention is the Correct Answer:** Although SSRIs are generally known for lacking the heavy anticholinergic burden of Tricyclic Antidepressants (TCAs), **Fluoxetine** possesses mild **antimuscarinic (anticholinergic) activity**. This can lead to symptoms such as dry mouth and, notably, **urinary retention** due to the inhibition of detrusor muscle contraction. In the context of this specific question, it is the recognized side effect among the choices provided. **Analysis of Incorrect Options:** * **A. Weight Gain:** Most SSRIs, especially Fluoxetine, are associated with **weight loss** or are weight-neutral during initial therapy. Significant weight gain is more characteristic of TCAs or Mirtazapine. * **B. Sweating:** While diaphoresis can occur in Serotonin Syndrome, it is not a classic side effect of standard Fluoxetine therapy compared to the anticholinergic "drying" effects. * **D. Diarrhoea:** While SSRIs often cause GI upset (nausea/loose stools) due to 5-HT3 stimulation, the anticholinergic profile of Fluoxetine specifically leans toward decreased GI motility and urinary hesitancy. **High-Yield Clinical Pearls for NEET-PG:** * **Longest Half-life:** Fluoxetine has the longest half-life (2–3 days) among SSRIs; its active metabolite, **norfluoxetine**, lasts 7–10 days. * **Washout Period:** Due to its long half-life, a 5-week washout period is required before starting an MAO inhibitor to avoid **Serotonin Syndrome**. * **Drug of Choice:** Fluoxetine is the preferred SSRI for **Bulimia Nervosa** and Depression in children/adolescents. * **Common Side Effects:** Sexual dysfunction (most common long-term), Akathisia, and Insomnia.

Question 172: All of the following are atypical antipsychotic drugs except?

A. Clozapine
B. Risperidone
C. Olanzapine
D. Loxapine (Correct Answer)

Explanation: **Explanation:** The classification of antipsychotics is based on their mechanism of action and side-effect profile. Antipsychotics are divided into **Typical (First Generation)** and **Atypical (Second Generation)** drugs. **Why Loxapine is the correct answer:** Loxapine is a **Typical (First Generation) Antipsychotic** belonging to the dibenzoxazepine class. Like other typical antipsychotics (e.g., Haloperidol, Chlorpromazine), its primary mechanism is the potent blockade of **Postsynaptic D2 receptors** in the mesolimbic pathway. While it has some serotonin-blocking properties, it is traditionally categorized as a first-generation agent due to its high affinity for D2 receptors and its potential to cause Extrapyramidal Symptoms (EPS) at higher doses. **Why the other options are incorrect:** * **Clozapine (Option A):** The prototype atypical antipsychotic. It has a low affinity for D2 receptors and a high affinity for D4 and 5-HT2A receptors. It is the drug of choice for **treatment-resistant schizophrenia**. * **Risperidone (Option B):** A benzisoxazole derivative and a potent 5-HT2A and D2 antagonist. It is a common atypical agent but is notable for causing hyperprolactinemia. * **Olanzapine (Option C):** A thienobenzodiazepine derivative. It is an atypical antipsychotic known for causing significant **weight gain and metabolic syndrome**. **High-Yield Clinical Pearls for NEET-PG:** * **Atypical vs. Typical:** Atypicals are defined by a lower risk of EPS and higher 5-HT2A/D2 receptor blockade ratio. * **Clozapine Monitoring:** Requires mandatory WBC count monitoring due to the risk of **agranulocytosis** (most serious side effect). It also lowers the seizure threshold. * **Quetiapine:** The atypical antipsychotic with the lowest risk of EPS; often preferred in Parkinson’s disease patients with psychosis. * **Aripiprazole:** Known as a "D2 partial agonist" or dopamine system stabilizer.

Question 173: Which is the drug of choice for schizophrenia?

A. Olanzapine (Correct Answer)
B. Haloperidol
C. Lithium
D. Chlorpromazine

Explanation: **Explanation:** The management of schizophrenia has evolved from typical antipsychotics to **Atypical Antipsychotics (Second-Generation Antipsychotics)**, which are now considered the first-line treatment (Drug of Choice) for most patients. **1. Why Olanzapine is Correct:** Olanzapine is a potent atypical antipsychotic that acts as an antagonist at $D_2$ and $5-HT_{2A}$ receptors. It is preferred because it effectively treats both **positive symptoms** (hallucinations, delusions) and **negative symptoms** (apathy, social withdrawal) of schizophrenia. Crucially, it has a significantly lower risk of **Extrapyramidal Side Effects (EPS)** compared to older drugs, making it better tolerated for long-term use. **2. Why the other options are incorrect:** * **Haloperidol (Option B):** A high-potency typical antipsychotic. While effective for acute psychosis, it is no longer the first-line choice due to a very high incidence of EPS (dystonia, parkinsonism, akathisia). * **Lithium (Option C):** This is the drug of choice for **Bipolar Affective Disorder (BPAD)** and acute mania, not schizophrenia. It is a mood stabilizer, not an antipsychotic. * **Chlorpromazine (Option D):** A low-potency typical antipsychotic. It was the first antipsychotic discovered but is rarely used as a first-line agent today due to side effects like severe sedation, orthostatic hypotension, and skin pigmentation. **High-Yield Clinical Pearls for NEET-PG:** * **Clozapine** is the "Gold Standard" for **Treatment-Resistant Schizophrenia**, but it is not first-line due to the risk of **agranulocytosis** (requires mandatory WBC monitoring). * **Side Effects of Olanzapine:** Significant weight gain, hyperglycemia, and dyslipidemia (Metabolic Syndrome). * **Hyperprolactinemia** is common with typical antipsychotics and Risperidone, but less common with Olanzapine and Aripiprazole.

Question 174: What is a known side effect of phenothiazines?

A. Epithelial keratopathy
B. Cataract
C. Central chorioretinopathy
D. Lens and corneal pigmentation (Correct Answer)

Explanation: **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.

Question 175: Which of the following is NOT a use of fluoxetine?

A. Treatment of delayed ejaculation (Correct Answer)
B. Treatment of premature ejaculation
C. Treatment of impulse control disorder
D. Treatment of paraphilia

Explanation: Fluoxetine is a **Selective Serotonin Reuptake Inhibitor (SSRI)**. The core pharmacological concept to remember for NEET-PG is that SSRIs increase synaptic serotonin, which leads to a **delay in ejaculation** as a common side effect. **Explanation of the Correct Answer:** * **Option A (Treatment of delayed ejaculation):** This is the correct answer because fluoxetine *causes* delayed ejaculation; it is never used to treat it. Using an SSRI in a patient who already has delayed ejaculation would worsen the condition. **Explanation of Incorrect Options:** * **Option B (Premature ejaculation):** Because SSRIs significantly prolong the ejaculatory latency time, they are used "off-label" to treat premature ejaculation. (Note: **Dapoxetine** is the specific SSRI approved for this due to its short half-life). * **Option C (Impulse control disorder):** SSRIs are first-line treatments for various impulse control disorders (like kleptomania or trichotillomania) and Obsessive-Compulsive Disorder (OCD) by modulating serotonergic pathways in the prefrontal cortex. * **Option D (Paraphilia):** In cases of hypersexuality or paraphilic disorders, fluoxetine is used to reduce libido and compulsive sexual urges. **NEET-PG High-Yield Pearls:** 1. **Half-life:** Fluoxetine has the longest half-life among SSRIs (due to its active metabolite **norfluoxetine**), requiring a 5-week washout period before starting an MAO inhibitor to avoid **Serotonin Syndrome**. 2. **Drug of Choice:** Fluoxetine is the preferred SSRI for **Bulimia Nervosa** and **Depression in children/adolescents**. 3. **Side Effects:** Common side effects include GI upset, insomnia, and sexual dysfunction (decreased libido and anorgasmia).

Question 176: What is the drug of choice for substitution therapy in morphine dependence?

A. Methadone (Correct Answer)
B. Clonidine
C. Naloxone
D. Nalmefene

Explanation: **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.

Question 177: Depot preparations are available for which of the following drugs?

A. Haloperidol
B. Risperidone (Correct Answer)
C. Olanzapine
D. Imipramine

Explanation: **Explanation:** Depot preparations are long-acting injectable (LAI) formulations designed to release the drug slowly over weeks, improving treatment adherence in chronic conditions like schizophrenia. **Why Risperidone is the correct answer:** Risperidone was the first atypical (second-generation) antipsychotic to be available as a depot preparation (e.g., Risperidone Consta). It is administered intramuscularly every 2 weeks. While Haloperidol and Olanzapine also have depot forms, in the context of standard NEET-PG questions and recent clinical focus, **Risperidone** is frequently highlighted as the prototype for atypical depot antipsychotics. **Analysis of Incorrect Options:** * **Haloperidol (Option A):** While Haloperidol Decanoate exists as a depot, it is a first-generation (typical) antipsychotic. In many MCQ formats, if both are present, the question often tests knowledge of newer atypical depots. However, technically, Haloperidol is also available as a depot. * **Olanzapine (Option C):** Olanzapine Pamoate is a depot formulation, but it is less commonly used due to the risk of **Post-injection Delirium Sedation Syndrome (PDSS)**, requiring mandatory 3-hour observation. * **Imipramine (Option D):** This is a Tricyclic Antidepressant (TCA). TCAs are administered orally; there are no depot preparations for antidepressants. **High-Yield Clinical Pearls for NEET-PG:** * **Common Depot Drugs:** Fluphenazine decanoate, Haloperidol decanoate, Risperidone, Paliperidone, and Aripiprazole. * **Indication:** Primarily used for patients with poor compliance or "revolving door" schizophrenia. * **Mechanism:** These are usually esterified in oil (typical) or microsphere-encapsulated (atypical) to slow absorption. * **Avoid:** Depot injections should never be given intravenously; they are strictly for deep intramuscular (IM) use.

Question 178: Lithium may produce which of the following conditions?

A. Hyperthyroidism
B. Hypothyroidism (Correct Answer)
C. Hyperparathyroidism
D. Hypoparathyroidism

Explanation: **Explanation:** Lithium is the gold-standard mood stabilizer for Bipolar Disorder, but it has a narrow therapeutic index and significant endocrine side effects. **1. Why Hypothyroidism is Correct:** Lithium is actively concentrated by the thyroid gland. It inhibits the synthesis and release of thyroid hormones ($T_3$ and $T_4$) by interfering with **iodine organification** and inhibiting **thyroglobulin colloid pinocytosis**. This leads to a compensatory rise in Thyroid Stimulating Hormone (TSH). Approximately 5–15% of patients on long-term Lithium therapy develop clinical or subclinical hypothyroidism. It is more common in females and those with pre-existing thyroid antibodies. **2. Analysis of Incorrect Options:** * **A. Hyperthyroidism:** While rare cases of Lithium-induced thyrotoxicosis have been reported (usually due to painless thyroiditis), the classic and most frequent association is hypothyroidism. * **C & D. Parathyroid Effects:** Interestingly, Lithium actually tends to cause **Hyperparathyroidism** (not hypo-). It increases the "set-point" of the calcium-sensing receptor in the parathyroid gland, leading to increased PTH secretion and subsequent **Hypercalcemia**. **3. High-Yield Clinical Pearls for NEET-PG:** * **Monitoring:** Check TSH levels every 6–12 months in patients on Lithium. * **Management:** Lithium-induced hypothyroidism is managed by adding **Levothyroxine**; Lithium does *not* necessarily need to be discontinued. * **Renal Side Effect:** Lithium most commonly causes **Nephrogenic Diabetes Insipidus** (resistance to ADH). * **Teratogenicity:** Use in pregnancy is associated with **Ebstein’s Anomaly** (atrialization of the right ventricle). * **Drug Interactions:** Thiazides, NSAIDs, and ACE inhibitors increase Lithium levels, leading to toxicity.

Question 179: Which of the following is a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI)?

A. Duloxetine (Correct Answer)
B. Sertraline
C. Citalopram
D. Isoniazid

Explanation: ### 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 180: Chronic use of anti-psychotic drugs can lead to which of the following side effects?

A. Orthostatic hypotension
B. Parkinsonism
C. Tardive dyskinesia
D. All of the above (Correct Answer)

Explanation: **Explanation:** Antipsychotic drugs, particularly Typical Antipsychotics (First Generation), act primarily by blocking Dopamine ($D_2$) receptors and various other neuroreceptors, leading to a wide spectrum of side effects. 1. **Tardive Dyskinesia (Option C):** This is the hallmark of **chronic (long-term)** antipsychotic use. It occurs due to the "up-regulation" or supersensitivity of dopamine receptors in the nigrostriatal pathway after prolonged blockade. It manifests as involuntary choreoathetoid movements, typically involving the tongue (fly-catching) and face. 2. **Parkinsonism (Option B):** This is a part of Extrapyramidal Symptoms (EPS). It occurs because $D_2$ blockade in the nigrostriatal pathway creates a functional deficiency of dopamine, mimicking Parkinson’s disease (tremors, rigidity, bradykinesia). While it can occur early, it often persists with chronic therapy. 3. **Orthostatic Hypotension (Option A):** Many antipsychotics (especially low-potency drugs like Chlorpromazine) block **$\alpha_1$-adrenergic receptors**. This prevents compensatory vasoconstriction when standing, leading to a drop in blood pressure. **Clinical Pearls for NEET-PG:** * **Tardive Dyskinesia:** Unlike other EPS, it may worsen if the antipsychotic dose is reduced or stopped. Treatment involves switching to **Clozapine** or using VMAT-2 inhibitors (e.g., Valbenazine). * **Hyperprolactinemia:** Chronic $D_2$ blockade in the tuberoinfundibular pathway leads to increased prolactin, causing galactorrhea and gynecomastia. * **Metabolic Syndrome:** More common with Atypical (Second Generation) antipsychotics like **Olanzapine** and **Clozapine**.

Practice by Chapter

Antipsychotics: Typical and Atypical

Practice Questions

Antidepressants: SSRIs and SNRIs

Practice Questions

Tricyclic Antidepressants

Practice Questions

MAO Inhibitors

Practice Questions

Mood Stabilizers

Practice Questions

Anxiolytics

Practice Questions

Drugs for ADHD

Practice Questions

Drugs for Sleep Disorders

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Drugs for Dementia

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Drug-Induced Psychiatric Symptoms

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