NEET-PG 2012 - Pharmacology Practice Questions

Q: What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?

500 mg once weekly. ***500 mg once weekly*** - The recommended dosage for chloroquine chemoprophylaxis in malaria prevention is **500 mg salt** (or equivalent to 300 mg base) administered **once weekly**. - This regimen ensures adequate blood concentrations to prevent malarial infection in endemic areas. *500 mg/week* - While the 500 mg dose is correct, simply stating "500 mg/week" without specifying "once weekly" could be misinterpreted. - Chloroquine is generally taken as a **single weekly dose**, not divided doses. *400 mg once weekly* - A dosage of **400 mg** is **sub-therapeutic** for weekly chloroquine chemoprophylaxis. - This dose would likely not provide sufficient protection against malaria. *500 mg BD/week* - Taking chloroquine **twice weekly (BD/week)** at 500 mg is excessive for chemoprophylaxis. - This regimen can lead to increased side effects and toxicity without providing additional prophylactic benefit.

Q: Which of the following is a synthetic estrogen?

Diethylstilbestrol. ***Diethylstilbestrol*** - **Diethylstilbestrol (DES)** is a **synthetic non-steroidal estrogen** that was historically used as a medication, particularly to prevent miscarriage. - Its use was discontinued after being linked to various adverse effects, including **vaginal clear cell adenocarcinoma** in female offspring whose mothers took DES during pregnancy. *Estrone* - **Estrone** is one of the three major **naturally occurring endogenous estrogens** in humans. - It is the primary estrogen during **menopause** and is derived from androstenedione. *Estriol* - **Estriol** is another of the three major **naturally occurring estrogens**, predominantly produced during **pregnancy** by the placenta. - It is often used as a marker for fetal well-being. *Estradiol* - **Estradiol** is the **most potent and abundant naturally occurring estrogen** in women during their reproductive years. - It plays a crucial role in the development and maintenance of female reproductive tissues and secondary sexual characteristics.

Q: What is the primary therapeutic use of 5-HT1B/1D agonists?

Acute migraine treatment. ***Acute migraine treatment*** - 5-HT1B/1D agonists, such as **triptans**, primarily work by causing **vasoconstriction of intracranial blood vessels** and inhibiting the release of pro-inflammatory neuropeptides. - This action directly alleviates the pain and associated symptoms of **acute migraine attacks**. *Anti-anxiety medications* - Anti-anxiety medications typically target neurotransmitter systems like **GABA** (e.g., benzodiazepines) or **serotonin reuptake** (e.g., SSRIs), not the 5-HT1B/1D receptors in this context. - While serotonin plays a role in anxiety, specific 5-HT1B/1D agonism does not lead to anxiolytic effects. *Anti-nausea medications for chemotherapy* - Anti-nausea medications used for chemotherapy-induced nausea and vomiting often target **5-HT3 receptors** (e.g., ondansetron) to block their pro-emetic effects. - 5-HT1B/1D agonists do not have primary anti-emetic properties useful in this setting. *Drugs for gastroesophageal reflux disease (GERD)* - GERD medications primarily focus on reducing stomach acid production (e.g., **proton pump inhibitors**, H2 blockers) or neutralizing it (antacids). - 5-HT1B/1D agonists do not directly influence gastric acid secretion or esophageal motility in a way beneficial for GERD.

Q: Which of the following statements about dopamine is false?

Causes increase in GI Ischemia. ***Causes increase in GI Ischemia*** (FALSE Statement) - This statement is **incorrect and misleading** as dopamine does not primarily "cause increase in GI ischemia" - While dopamine at **higher doses** can cause **splanchnic vasoconstriction** via alpha-1 receptors, this is not characterized as "causing GI ischemia" in standard pharmacology - GI ischemia is a potential adverse effect in susceptible patients, but not a primary pharmacological effect or standard clinical description of dopamine *Positive inotropic* (TRUE Statement) - Dopamine is a **catecholamine** with dose-dependent effects; at **moderate doses (5-10 mcg/kg/min)**, it stimulates **beta-1 adrenergic receptors** in the heart - This beta-1 stimulation leads to increased **myocardial contractility** and **heart rate**, thus exerting a **positive inotropic effect** - This is a well-established therapeutic effect of dopamine *Improves renal perfusion* (TRUE Statement) - At **low doses (0.5-3 mcg/kg/min)**, dopamine selectively activates **dopamine-1 (D1) receptors** in the renal vasculature - This activation causes **renal vasodilation**, leading to increased **renal blood flow**, improved **glomerular filtration rate**, and enhanced **sodium excretion** - This "renal dose" effect is a classic pharmacological property of dopamine *Causes Vasoconstriction* (TRUE Statement) - At **high doses (>10 mcg/kg/min)**, dopamine primarily stimulates **alpha-1 adrenergic receptors** - This leads to generalized **vasoconstriction**, increasing **systemic vascular resistance** and **blood pressure** - This dose-dependent alpha effect is well-documented

Q: Which of the following is a centrally acting antihypertensive drug?

Methyldopa. ***Methyldopa*** - **Methyldopa** is a **prodrug** that is converted to **alpha-methylnorepinephrine** in the brain, which then stimulates **alpha-2 adrenergic receptors** in the brainstem. - This stimulation reduces **sympathetic outflow** from the central nervous system, leading to decreased heart rate, stroke volume, and peripheral vascular resistance, thus lowering blood pressure. *Phenoxybenzamine* - **Phenoxybenzamine** is an **alpha-1 and alpha-2 adrenergic receptor antagonist** (non-selective alpha blocker) that primarily acts peripherally. - It causes **vasodilation** by blocking alpha-1 receptors on smooth muscle, which reduces peripheral vascular resistance. *Propranolol* - **Propranolol** is a **non-selective beta-blocker** that primarily acts on peripheral beta-adrenergic receptors. - It reduces heart rate and cardiac output by blocking **beta-1 receptors** in the heart and can also affect beta-2 receptors in the lungs and vasculature. *Prazosin* - **Prazosin** is a **selective alpha-1 adrenergic receptor antagonist** that acts primarily on peripheral blood vessels. - It causes **vasodilation** in both arteries and veins by blocking alpha-1 receptors, which reduces both preload and afterload, lowering blood pressure.

Q: Which of the following statements about Conivaptan is correct?

It is a vasopressin antagonist.. ***It is a vasopressin antagonist.*** * **Conivaptan** is a non-peptide, dual **vasopressin V1A and V2 receptor antagonist**, meaning it blocks the action of vasopressin. * By blocking vasopressin, it promotes **aquaresis** (excretion of solute-free water), which is beneficial in conditions like **hyponatremia**. * *It selectively acts on V2 receptors.* * **Conivaptan** is a **dual antagonist**, blocking both **V1A and V2 receptors**, not just V2. * **Tolvaptan**, in contrast, is a selective **V2 receptor antagonist**. * *It is administered orally.* * **Conivaptan** is typically administered intravenously, particularly in hospital settings for acute hyponatremia. * **Tolvaptan** is the orally administered vasopressin antagonist. * *All of the options.* * Since Conivaptan is not selectively acting on V2 receptors and is not administered orally, this option is incorrect.

Q: Which of the following potassium-sparing diuretics was the first to be shown to reduce cardiac mortality in chronic heart failure patients?

Spironolactone. ***Spironolactone*** - **Spironolactone** was the first potassium-sparing diuretic shown to reduce **cardiac mortality** in patients with **chronic heart failure** in the **RALES trial** (Randomized Aldactone Evaluation Study). - Its beneficial effects in heart failure are primarily attributed to its **aldosterone receptor antagonist** properties, which counteract the harmful effects of aldosterone on the myocardium and vasculature, rather than just its diuretic effect. *Amiloride* - **Amiloride** is a potassium-sparing diuretic that works by directly inhibiting **epithelial sodium channels (ENaC)** in the collecting duct. - While it helps in potassium conservation, it has not been shown to significantly reduce cardiac mortality in chronic heart failure patients in clinical trials. *Triamterene* - **Triamterene** is another potassium-sparing diuretic that also directly inhibits **ENaC** in the collecting duct, similar to amiloride. - Like amiloride, it is used to prevent hypokalemia but lacks evidence for significant **cardiac mortality reduction** in chronic heart failure. *Eplerenone* - **Eplerenone** is a selective **aldosterone receptor antagonist**, similar to spironolactone, with fewer hormonal side effects. - While it has been shown to reduce **cardiac mortality** in chronic heart failure (e.g., in the EMPHASIS-HF trial), it was introduced later than spironolactone and was not the *first* to demonstrate this benefit.

Q: Which medication is commonly used in heart failure that also has aldosterone antagonistic properties?

Spironolactone. ***Spironolactone*** - **Spironolactone** is a **potassium-sparing diuretic** that acts as a **competitive antagonist of aldosterone** receptors, primarily in the collecting ducts of the kidneys. - This action leads to increased excretion of sodium and water, and retention of potassium, which is beneficial in **heart failure** by reducing fluid overload and mitigating the detrimental effects of aldosterone on cardiac remodeling. *Carvedilol* - **Carvedilol** is a **beta-blocker** with additional **alpha-1 blocking** properties, commonly used in heart failure to reduce heart rate, blood pressure, and myocardial oxygen demand. - It does not possess significant aldosterone antagonistic properties. *Sacubitril/Valsartan* - **Sacubitril/Valsartan** is an **angiotensin receptor-neprilysin inhibitor (ARNI)**. Valsartan is an **angiotensin receptor blocker (ARB)**, and sacubitril inhibits neprilysin, an enzyme that degrades natriuretic peptides. - While it modulates the **renin-angiotensin-aldosterone system (RAAS)** and is highly effective in heart failure, it does not directly antagonize aldosterone receptors. *Abiraterone* - **Abiraterone** is an **androgen-biosynthesis inhibitor** used in the treatment of **prostate cancer**. - Its primary mechanism involves inhibiting **CYP17**, an enzyme critical for androgen production, and it has no role in the management of heart failure or aldosterone antagonism.

Q: Which of the following drugs acts directly to induce an erection without the need for sexual stimulation?

Alprostadil. ***Alprostadil***- **Alprostadil** is a **prostaglandin E1** analog that can directly induce vasodilation in the penile arteries, leading to an erection without sexual stimulation [1].- It is typically administered via **intracavernosal injection** or as a **urethral suppository**.*Sildenafil*- **Sildenafil** is a **PDE5 inhibitor** that works by enhancing the effects of **nitric oxide**, which is released in response to sexual stimulation [2, 3].- It requires **sexual arousal** to be effective, as it doesn't directly initiate the erectile process [2, 3].*Tadalafil*- Similar to sildenafil, **tadalafil** is also a **PDE5 inhibitor** that works by increasing cGMP levels and promoting smooth muscle relaxation [2, 3].- Its action is dependent on the release of **nitric oxide** triggered by sexual stimulation [2, 3].*Testosterone*- **Testosterone** is a hormone involved in sex drive and overall erectile function over time, but it does not directly or acutely induce an erection.- Its primary role in erectile dysfunction is in cases of **hypogonadism**, and it requires sexual stimulation for its effects on erection.

Q: Which antilipidemic drug reduces cholesterol levels by inhibiting cholesterol absorption?

Ezetimibe. ***Ezetimibe*** - **Ezetimibe** selectively inhibits the **Niemann-Pick C1-Like 1 (NPC1L1) protein**, which is responsible for plant sterol and cholesterol absorption in the small intestine. - This action leads to a reduction in **LDL-C** levels by decreasing the amount of cholesterol available to the liver. *Orlistat* - **Orlistat** is a **lipase inhibitor** that prevents the absorption of dietary fats by inhibiting gastric and pancreatic lipases. - While it aids in weight loss and can indirectly improve lipid profiles, its primary mechanism is *not* direct inhibition of cholesterol absorption. *Cholestyramine* - **Cholestyramine** is a **bile acid sequestrant** that binds to bile acids in the intestine, preventing their reabsorption. - This increases the excretion of bile acids, prompting the liver to synthesize more bile acids from cholesterol, thereby lowering cholesterol levels, but it does *not* directly inhibit cholesterol absorption. *Statins* - **Statins** (HMG-CoA reductase inhibitors) are considered first-line agents for lowering cholesterol by inhibiting the **rate-limiting step in cholesterol synthesis** in the liver. - Their primary action is to reduce endogenous cholesterol production, not to block cholesterol absorption from the gut.

Question 1

What is the recommended dosage for chloroquine chemoprophylaxis in malaria prevention?

Accepted Answer

500 mg once weekly

Answer

500 mg/week

Answer

400 mg once weekly

Answer

500 mg BD/week

Question 2

Which of the following is a synthetic estrogen?

Accepted Answer

Diethylstilbestrol

Answer

Estrone

Answer

Estriol

Answer

Estradiol

Question 3

What is the primary therapeutic use of 5-HT1B/1D agonists?

Accepted Answer

Acute migraine treatment

Answer

Anti-anxiety medications

Answer

Anti-nausea medications for chemotherapy

Answer

Drugs for gastroesophageal reflux disease (GERD)

Question 4

Which of the following statements about dopamine is false?

Accepted Answer

Causes increase in GI Ischemia

Answer

Improves renal perfusion

Answer

Causes Vasoconstriction

Answer

Positive ionotropic

Question 5

Which of the following is a centrally acting antihypertensive drug?

Accepted Answer

Methyldopa

Answer

Phenoxybenzamine

Answer

Propranolol

Answer

Prazosin

Question 6

Which of the following statements about Conivaptan is correct?

Accepted Answer

It is a vasopressin antagonist.

Answer

It selectively acts on V2 receptors.

Answer

It is administered orally.

Answer

All of the options.

Question 7

Which of the following potassium-sparing diuretics was the first to be shown to reduce cardiac mortality in chronic heart failure patients?

Accepted Answer

Spironolactone

Answer

Amiloride

Answer

Triamterene

Answer

Eplerenone

Question 8

Which medication is commonly used in heart failure that also has aldosterone antagonistic properties?

Accepted Answer

Spironolactone

Answer

Carvedilol

Answer

Abiraterone

Answer

Sacubitril/Valsartan

Question 9

Which of the following drugs acts directly to induce an erection without the need for sexual stimulation?

Accepted Answer

Alprostadil

Answer

Sildenafil

Answer

Tadalafil

Answer

Testosterone

Question 10

Which antilipidemic drug reduces cholesterol levels by inhibiting cholesterol absorption?

Accepted Answer

Ezetimibe

Answer

Orlistat

Answer

Cholestyramine

Answer

Statins

NEET-PG 2012 — Pharmacology