Drugs in Psychiatric Disorders Practice Questions

Q: Which of the following is a primary use of 5-HT1 agonists?

Anti-anxiety drugs. **Explanation:** The correct answer is **A. Anti-anxiety drugs.** **Mechanism of Action:** The primary drug in this category is **Buspirone**, which acts as a **selective 5-HT1A partial agonist**. It is used for the treatment of Generalized Anxiety Disorder (GAD). Unlike benzodiazepines, it does not cause sedation, muscle relaxation, or physical dependence, making it an ideal choice for chronic anxiety management. Its effect typically takes 1–2 weeks to manifest. **Analysis of Incorrect Options:** * **B. Antipsychotic drugs:** Conventional antipsychotics primarily block **D2 receptors**. While some atypical antipsychotics (like Clozapine or Risperidone) involve 5-HT2A antagonism, 5-HT1 agonism is not their primary mechanism for treating psychosis. * **C. Gastroesophageal reflux disease (GERD):** Drugs used here include Proton Pump Inhibitors (PPIs) or H2 blockers. Prokinetic agents like Metoclopramide act via **5-HT4 agonism** and D2 antagonism, not 5-HT1. * **D. Chemotherapy-induced vomiting:** This is managed using **5-HT3 antagonists** (e.g., Ondansetron). Blocking 5-HT3 receptors in the Chemoreceptor Trigger Zone (CTZ) and the GI tract prevents the emetic reflex. **High-Yield NEET-PG Pearls:** * **Buspirone (5-HT1A):** "No Sedation, No Addiction, No Interaction with Alcohol." It is the "Safe" anxiolytic for elderly patients or those with a history of substance abuse. * **Sumatriptan (5-HT1B/1D):** Another class of 5-HT1 agonists used specifically for the **acute attack of Migraine** (causes vasoconstriction of cranial vessels). * **Tegaserod/Prucalopride (5-HT4):** Used for chronic constipation/IBS-C. * **Lorcaserin (5-HT2C):** Used as an appetite suppressant for obesity management.

Q: All of the following are side effects of Lithium except?

Leucopenia. **Explanation:** Lithium is a monovalent cation used as a gold-standard mood stabilizer. The correct answer is **Leucopenia** because Lithium actually causes **Leucocytosis** (an increase in white blood cell count), not a decrease. **Why Leucopenia is the correct answer (The Exception):** Lithium stimulates granulopoiesis in the bone marrow by increasing the production of Colony Stimulating Factors (CSFs). This leads to a harmless, reversible increase in the neutrophil count (Leucocytosis). In fact, Lithium is sometimes used off-label to treat neutropenia caused by chemotherapy or Clozapine. **Analysis of Incorrect Options:** * **Hypothyroidism (A):** Lithium inhibits the release of thyroid hormones (T3 and T4) and interferes with iodine organification. It is a common side effect, often requiring Levothyroxine supplementation rather than discontinuation of Lithium. * **Diabetes Insipidus (B):** Lithium causes **Nephrogenic Diabetes Insipidus (NDI)** by antagonizing the action of ADH (Vasopressin) on the collecting ducts of the kidney. This leads to polyuria and polydipsia. Amiloride is the drug of choice to treat Lithium-induced NDI. * **Hypercalcemia (C):** Lithium can increase the set-point of the calcium-sensing receptor in the parathyroid gland, leading to **Hyperparathyroidism** and subsequent Hypercalcemia. **High-Yield Clinical Pearls for NEET-PG:** * **Teratogenicity:** Ebstein’s Anomaly (atrialization of the right ventricle). * **Therapeutic Index:** Very narrow (0.6–1.2 mEq/L). Toxicity starts >1.5 mEq/L. * **ECG Changes:** T-wave flattening or inversion (similar to hypokalemia). * **L-I-T-H-I-U-M Mnemonic:** **L**eucocytosis, **I**nsipidus (NDI), **T**remor/Teratogenicity, **H**ypothyroidism, **I**ncreased Weight, **U**nder-active heart (Bradycardia), **M**others (Ebstein's).

Q: Which of the following drugs is associated with the stated adverse drug reaction?

Haloperidol. ***Haloperidol*** - **Typical antipsychotic** that blocks **dopamine D2 receptors**, leading to **receptor upregulation** and **tardive dyskinesia** with chronic use. - Long-term **D2 receptor blockade** causes compensatory changes resulting in **involuntary choreiform movements** of face, tongue, and extremities. *Aripiprazole* - Acts as a **partial D2 agonist** rather than complete antagonist, providing **dopamine system stabilization**. - Actually **FDA-approved to treat tardive dyskinesia** due to its unique mechanism that doesn't cause receptor upregulation. *Benztropine* - **Anticholinergic agent** used to treat **acute extrapyramidal symptoms** but does not prevent or treat **tardive dyskinesia**. - Can actually **worsen tardive dyskinesia** by further disrupting the **dopamine-acetylcholine balance** in the brain. *Milnacipran* - **SNRI antidepressant** that inhibits **serotonin and norepinephrine reuptake** without affecting dopamine receptors. - Has **no association** with tardive dyskinesia as it doesn't interfere with **dopaminergic pathways** in the basal ganglia.

Q: The secretion of which of the following hormones increases with chlorpromazine therapy?

Prolactin. **Explanation:** The correct answer is **Prolactin**. **Mechanism of Action:** Chlorpromazine is a typical (first-generation) antipsychotic that acts primarily by blocking **Dopamine (D2) receptors**. In the brain, dopamine is the primary physiological inhibitor of prolactin secretion from the anterior pituitary (acting via the **tuberoinfundibular pathway**). By blocking D2 receptors in this pathway, chlorpromazine removes the "inhibitory brake" on lactotrophs, leading to hyperprolactinemia. **Analysis of Incorrect Options:** * **B. Gonadotropin (FSH/LH):** High prolactin levels exert negative feedback on the hypothalamus, inhibiting the release of Gonadotropin-Releasing Hormone (GnRH). This leads to a **decrease** in FSH and LH, often resulting in amenorrhea or infertility. * **C. Corticotropin (ACTH):** Chlorpromazine generally suppresses the hypothalamic-pituitary-adrenal (HPA) axis, leading to a potential **decrease** in ACTH secretion, rather than an increase. * **D. Antidiuretic hormone (ADH):** While some psychotropic drugs can cause SIADH, chlorpromazine does not typically increase ADH as a primary endocrine side effect. **NEET-PG High-Yield Pearls:** * **Clinical Manifestations:** Hyperprolactinemia presents as galactorrhea, gynecomastia, and sexual dysfunction. * **Pathway Specificity:** Antipsychotic efficacy (positive symptoms) is due to D2 blockade in the **mesolimbic** pathway; extrapyramidal side effects (EPS) are due to blockade in the **nigrostriatal** pathway. * **Exceptions:** **Clozapine** and **Quetiapine** have a lower risk of increasing prolactin compared to typical antipsychotics and Risperidone. * **Growth Hormone:** Chlorpromazine also tends to **decrease** Growth Hormone secretion (dopamine normally stimulates GH in healthy individuals).

Q: Which antipsychotic drug has the least extrapyramidal side effect?

Thioridazine. **Explanation:** The occurrence of **Extrapyramidal Side Effects (EPS)** in antipsychotic therapy is determined by the balance between **Dopaminergic (D2) blockade** and **Antimuscarinic (M1) activity** in the nigrostriatal pathway. **Why Thioridazine is correct:** Thioridazine is a low-potency typical antipsychotic. It possesses **inherent high central anticholinergic activity**. Since EPS results from a relative deficiency of dopamine and an excess of acetylcholine in the basal ganglia, the strong anticholinergic property of Thioridazine "self-neutralizes" the dopaminergic blockade, leading to the **lowest incidence of EPS** among typical antipsychotics. **Analysis of Incorrect Options:** * **Triflupromazine & Trifluoperazine:** These are high-potency piperazine phenothiazines. They have strong D2 receptor affinity but very weak anticholinergic properties, making them highly likely to cause severe EPS (dystonias, parkinsonism). * **Pimozide:** This is a potent diphenylbutylpiperidine used primarily for Tourette’s syndrome. Like other high-potency agents, it has a high propensity for inducing EPS. **High-Yield Clinical Pearls for NEET-PG:** * **The "Thio" Rule:** Thioridazine has the *least* EPS but is associated with unique side effects: **Retinal pigmentation** (at doses >800mg/day) and significant **QTc prolongation** (cardiotoxicity). * **Most EPS:** Haloperidol and Fluphenazine (High potency). * **Atypical Antipsychotics:** Among all antipsychotics (including atypicals), **Clozapine** has the absolute lowest risk of EPS. * **Mechanism:** EPS occurs when D2 receptor occupancy in the striatum exceeds **80%**.

Q: A woman treated with lithium during pregnancy, the fetus should be tested for which of the following?

Cardiac malformations. **Explanation:** Lithium is a well-known teratogen, and its use during the first trimester of pregnancy is specifically associated with an increased risk of **cardiac malformations**. The most characteristic defect is **Ebstein’s Anomaly**, which involves the apical displacement of the tricuspid valve leaflets, leading to "atrialization" of the right ventricle and severe tricuspid regurgitation. While the absolute risk is lower than previously thought (approx. 1-2 per 1000), it remains significantly higher than the general population. **Analysis of Incorrect Options:** * **Neural Tube Defects (NTDs):** These are primarily associated with **Valproate** and **Carbamazepine** due to interference with folate metabolism. * **Urogenital Abnormalities:** These are not typically associated with Lithium. Examples include hypospadias, which can be seen with certain anti-androgens or environmental factors. * **Scalp Defects (Aplasia Cutis Congenita):** This is a classic side effect associated with the use of **Methimazole** (anti-thyroid drug) during the first trimester. **High-Yield Clinical Pearls for NEET-PG:** * **Ebstein’s Anomaly:** Look for "atrialization of the right ventricle" in the question stem. * **Lithium in Pregnancy:** If used near term, it can cause **"Floppy Infant Syndrome"** (cyanosis, hypotonia, and poor suckling). * **Monitoring:** Fetal echocardiography is recommended at 18–20 weeks of gestation for mothers taking Lithium. * **Breastfeeding:** Lithium is generally avoided during breastfeeding as it is excreted in milk and can cause neonatal toxicity.

Q: What is the drug of choice in phenothiazine-induced dystonia?

Benztropine. **Explanation:** Phenothiazines (like Chlorpromazine) are typical antipsychotics that block dopamine ($D_2$) receptors in the nigrostriatal pathway. This creates a chemical imbalance where **cholinergic (acetylcholine) activity becomes relatively overactive** compared to dopamine, leading to Extrapyramidal Side Effects (EPS), such as acute dystonia. **1. Why Benztropine is Correct:** To treat acute dystonia, the goal is to restore the dopamine-acetylcholine balance. **Benztropine** is a potent **centrally-acting anticholinergic** drug. By blocking muscarinic receptors in the basal ganglia, it rapidly suppresses the cholinergic overactivity, providing quick relief from muscle spasms. It is considered the gold standard for drug-induced EPS. **2. Analysis of Incorrect Options:** * **Diphenhydramine:** While this is an antihistamine with significant anticholinergic properties and *can* be used as an alternative, Benztropine is more specific and preferred in clinical guidelines for dystonia. * **Metoclopramide:** This is a $D_2$ receptor antagonist used as an antiemetic. It actually **causes** dystonia rather than treating it. * **Trifluperamide:** This is an antipsychotic itself. Adding more antipsychotics would worsen the dopamine blockade and exacerbate the dystonia. **High-Yield Clinical Pearls for NEET-PG:** * **Acute Dystonia:** Usually occurs within hours to days of starting antipsychotics (e.g., torticollis, grimacing). * **Drug of Choice (DOC):** Central anticholinergics like **Benztropine** or **Trihexyphenidyl (PACANE)**. * **Route:** For acute crises, parenteral (IV/IM) administration is preferred for rapid onset. * **Prophylaxis:** If a patient is prone to EPS, oral anticholinergics are often co-prescribed with high-potency neuroleptics.

Q: Incidence of hyperprolactinemia is highest with which of the following medications?

Risperidone. **Explanation:** The correct answer is **Risperidone**. **Mechanism of Hyperprolactinemia:** Prolactin secretion is regulated by the **tuberoinfundibular pathway**, where dopamine acts as a prolactin-inhibiting factor. Antipsychotics block D2 receptors in this pathway, removing the inhibition and leading to hyperprolactinemia. While most first-generation antipsychotics (FGAs) cause this, **Risperidone** (a second-generation antipsychotic) is notorious for having the highest incidence, often exceeding that of FGAs. This is because Risperidone crosses the blood-brain barrier poorly and binds very strongly to D2 receptors in the pituitary gland, which lies outside the blood-brain barrier. **Analysis of Options:** * **Aripiprazole:** It is a **D2 partial agonist**. It can actually lower prolactin levels and is often used to treat antipsychotic-induced hyperprolactinemia. * **Clozapine:** Known as "prolactin-sparing." It has low affinity for D2 receptors and rapid dissociation, resulting in minimal to no effect on prolactin. * **Olanzapine:** While it can cause mild, transient elevations in prolactin, the effect is significantly less frequent and less severe than with Risperidone. **Clinical Pearls for NEET-PG:** * **Highest risk of hyperprolactinemia:** Risperidone and Paliperidone (its metabolite). * **Lowest risk/Prolactin sparing:** Aripiprazole, Clozapine, and Quetiapine. * **Clinical manifestations:** Galactorrhea, amenorrhea, gynecomastia, and long-term risk of osteoporosis. * **Management:** If symptomatic, switch to a prolactin-sparing agent (like Aripiprazole) or add a low dose of Aripiprazole to the current regimen.

Q: Which of the following is a use of NDRI?

All of the above. The correct answer is **D. All of the above**. **Mechanism of Action:** NDRIs (**Norepinephrine-Dopamine Reuptake Inhibitors**), primarily represented by **Bupropion**, work by inhibiting the neuronal reuptake of dopamine and norepinephrine [1], [2]. Unlike SSRIs, they have no significant effect on serotonin, which accounts for their unique clinical profile and lack of sexual side effects. **Breakdown of Uses:** 1. **Hypoactive Sexual Desire Disorder (HSDD):** Bupropion is frequently used off-label (and as a component in newer formulations) to treat HSDD. Because it increases dopamine levels in the reward pathway and lacks serotonergic activity (which usually inhibits sexual desire), it can actually improve libido and arousal. 2. **Smoking Cessation:** Bupropion is an FDA-approved non-nicotine aid for smoking cessation [1]. It mimics the effect of nicotine by increasing dopamine in the nucleus accumbens, thereby reducing withdrawal symptoms and the "craving" associated with quitting [1]. 3. **ADHD:** By increasing norepinephrine and dopamine in the prefrontal cortex, NDRIs help improve focus and impulse control. Bupropion is considered a second-line, non-stimulant treatment for ADHD, especially in adults or patients with comorbid depression. **Clinical Pearls for NEET-PG:** * **Seizure Risk:** The most significant side effect of Bupropion is a dose-dependent increase in seizure risk. It is strictly **contraindicated** in patients with epilepsy, eating disorders (bulimia/anorexia), or those undergoing alcohol withdrawal [1]. * **Weight Neutrality:** Unlike many antidepressants, Bupropion is associated with weight loss rather than weight gain [1]. * **The "Happy-Horny-Skinny" Pill:** A common mnemonic to remember that Bupropion treats depression without causing sexual dysfunction or weight gain.

Question 1

Which of the following is a primary use of 5-HT1 agonists?

Accepted Answer

Anti-anxiety drugs

Answer

Antipsychotic drugs

Answer

Gastroesophageal reflux disease (GERD)

Answer

Chemotherapy-induced vomiting

Question 2

All of the following are side effects of Lithium except?

Accepted Answer

Leucopenia

Answer

Hypothyroidism

Answer

Diabetes Insipidus

Answer

Hypercalcemia

Question 3

Which of the following drugs is associated with the stated adverse drug reaction?

Accepted Answer

Haloperidol

Answer

Aripiprazole

Answer

Benztropine

Answer

Milnacipran

Question 4

The secretion of which of the following hormones increases with chlorpromazine therapy?

Accepted Answer

Prolactin

Answer

Gonadotropin

Answer

Corticotropin

Answer

Antidiuretic hormone

Question 5

Which antipsychotic drug has the least extrapyramidal side effect?

Accepted Answer

Thioridazine

Answer

Triflupromazine

Answer

Pimozide

Answer

Trifluoperazine

Question 6

A woman treated with lithium during pregnancy, the fetus should be tested for which of the following?

Accepted Answer

Cardiac malformations

Answer

Neural tube defects

Answer

Urogenital abnormalities

Answer

Scalp defects

Question 7

What is the drug of choice in phenothiazine-induced dystonia?

Accepted Answer

Benztropine

Answer

Diphenhydramine

Answer

Metoclopramide

Answer

Trifluperamide

Question 8

Incidence of hyperprolactinemia is highest with which of the following medications?

Accepted Answer

Risperidone

Answer

Aripiprazole

Answer

Olanzapine

Answer

Clozapine

Question 9

Which of the following is a use of NDRI?

Accepted Answer

All of the above

Answer

Hypoactive sexual desire

Answer

Smoking cessation

Answer

ADHD

Question 10

What are the common side effects of fluoxetine?

Accepted Answer

Urinary retention

Answer

Weight gain

Answer

Sweating

Answer

Diarrhoea

Drugs in Psychiatric Disorders — MCQs

Drugs in Psychiatric Disorders — MCQs

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