FMGE 2023 - Pharmacology PYQs Practice Questions

Q: A 50-year-old woman was prescribed a diuretic by a doctor to manage hypertension. Which of the following diuretics acts on site 'A' as marked in the given image?

Hydrochlorothiazide. ***Hydrochlorothiazide*** - Hydrochlorothiazide is a **thiazide diuretic** that acts on the **Distal Convoluted Tubule (DCT)**, which is indicated by the letter 'A' in the provided diagram. - It works by inhibiting the **Na+/Cl- cotransporter** in the early DCT, leading to increased excretion of sodium and water, which helps lower blood pressure. *Furosemide* - Furosemide is a potent **loop diuretic** that acts on the **thick ascending limb of the loop of Henle** (labeled as 'G'). - It inhibits the **Na+/K+/2Cl- cotransporter**, causing a significant increase in sodium and water excretion, making it more powerful than thiazides. *Acetazolamide* - Acetazolamide is a **carbonic anhydrase inhibitor**, and its primary site of action is the **Proximal Convoluted Tubule (PCT)** (labeled as 'D'). - It is a weak diuretic and is more commonly used for glaucoma, metabolic alkalosis, or altitude sickness rather than as a primary agent for hypertension. *Mannitol* - Mannitol is an **osmotic diuretic** that exerts its effect primarily in the **Proximal Convoluted Tubule (PCT)** and the **descending limb of the loop of Henle**. - It is administered intravenously and is used to reduce intracranial or intraocular pressure, not for the chronic management of hypertension. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following diuretics primarily acts on the part labeled 'D' in the given diagram of a nephron?

Hydrochlorothiazide. ***Hydrochlorothiazide*** - The part labeled 'D' in the diagram is the **Distal Convoluted Tubule (DCT)**. **Thiazide diuretics**, such as hydrochlorothiazide, primarily act on this segment of the nephron. - They work by inhibiting the **Na+/Cl- cotransporter** in the DCT, which reduces the reabsorption of sodium and chloride from the tubular fluid, leading to increased water excretion. *Furosemide* - Furosemide is a **loop diuretic** that acts on the **thick ascending limb of the Loop of Henle** (part of B), not the DCT. - It is a more potent diuretic than thiazides because it inhibits the **Na+-K+-2Cl- cotransporter**, which is responsible for reabsorbing a significant portion of filtered sodium. *Acetazolamide* - Acetazolamide is a **carbonic anhydrase inhibitor** that primarily acts on the **Proximal Convoluted Tubule (PCT)** (labeled 'A'). - Its mechanism involves reducing the reabsorption of **bicarbonate (HCO3-)**, which leads to a mild diuretic effect and can cause metabolic acidosis. *Mannitol* - Mannitol is an **osmotic diuretic** that acts mainly in the **Proximal Convoluted Tubule (PCT)** and the **descending limb of the Loop of Henle**. - It is a pharmacologically inert substance that increases the **osmolarity** of the tubular fluid, thereby preventing water reabsorption. [Practice more Pharmacology PYQs on OnCourse]

Q: Which of the following statement is correct regarding the mechanism of action of labetalol?

Blocks both alpha and beta-adrenergic receptors.. ***Blocks both alpha and beta-adrenergic receptors*** - Labetalol is a unique **non-selective beta-blocker** (blocking $\beta_1$ and $\beta_2$) that also possesses **selective $\alpha_1$-adrenergic blocking activity**. - This combined mechanism makes it effective for conditions like **hypertensive emergencies**, providing both reduced heart rate (via beta block) and peripheral vasodilation (via alpha block). *Directly acts as arterial vasodilator resulting in indirect effect tachycardia* - While labetalol causes **vasodilation** (due to $\alpha_1$ blockade), it also **blocks $\beta$-receptors**, preventing the typical **reflex tachycardia** that occurs with direct vasodilators like hydralazine. - Its primary mechanism is receptor blockade, not direct smooth muscle relaxation. *Primarily acts as a vasodilator with little effect on arterioles* - Labetalol acts as a potent **arteriolar vasodilator** (via $\alpha_1$ blockade), which is crucial for lowering systemic vascular resistance and blood pressure. - Its vasodilatory effect is significant and targeted at arterioles. *Decreases peripheral vascular resistance by directly acting as a relaxant for vascular smooth muscles* - Labetalol decreases **peripheral vascular resistance (PVR)** through **antagonism of $\alpha_1$ receptors** in vascular smooth muscles, preventing vasoconstriction. - It does not act as a direct smooth muscle relaxant like nitroprusside or hydralazine. [Practice more Pharmacology PYQs on OnCourse]

Q: A psychiatrist prescribes lithium for a patient who is diagnosed with bipolar disorder. Which of the following statements is incorrect regarding lithium?

Hemodialysis is not useful in lithium overdose. ***Correct Answer: Hemodialysis is not useful in lithium overdose*** - This statement is **INCORRECT** (making it the right answer to this negation question) - **Hemodialysis IS actually very useful** in severe lithium toxicity - Lithium has low molecular weight (~7 Da), minimal protein binding, and small volume of distribution, making it effectively removed by hemodialysis - **Indications for hemodialysis in lithium toxicity:** Lithium levels >4 mEq/L, severe clinical toxicity (seizures, altered consciousness), or renal failure *Incorrect Option: Lithium is teratogenic if given to pregnant females* - This statement is TRUE, so it's not the answer - Lithium causes **Ebstein's anomaly** (downward displacement of tricuspid valve) when given in first trimester - Risk is 1-2% (20x higher than general population) - FDA pregnancy category D *Incorrect Option: Lithium toxicity is exacerbated with thiazide* - This statement is TRUE, so it's not the answer - Thiazide diuretics decrease renal lithium clearance by promoting sodium depletion - This leads to **compensatory increase in proximal tubular reabsorption** of both sodium and lithium - NSAIDs and ACE inhibitors also increase lithium levels similarly *Incorrect Option: Lithium can decrease thyroid hormone levels* - This statement is TRUE, so it's not the answer - Lithium inhibits thyroid hormone synthesis and release, causing **hypothyroidism in 5-35%** of patients - Mechanism: Inhibits iodine uptake and blocks thyroid hormone release - Requires regular thyroid function monitoring (TSH, T3, T4) during lithium therapy [Practice more Pharmacology PYQs on OnCourse]

Q: Which of these drugs stimulates PPAR-alpha (Peroxisome proliferator-activated receptor alpha)?

Gemfibrozil. ***Gemfibrozil***- It belongs to the **fibrate class** of lipid-lowering drugs, and its primary mechanism is activating the **Peroxisome Proliferator-Activated Receptor alpha (PPAR-alpha)**.- PPAR-alpha activation leads to increased synthesis of **lipoprotein lipase (LPL)**, enhancing the catabolism of **VLDL** and chylomicrons, which effectively lowers **triglyceride** levels.*Ezetimibe*- This drug selectively inhibits the absorption of dietary and biliary cholesterol by blocking the **NPC1L1 (Niemann-Pick C1-Like 1)** transporter protein located on the brush border of the small intestine enterocytes.- It does not interact with PPAR-alpha but is typically used to reduce **LDL cholesterol**, often in combination with statins.*Colestipol*- It is a **bile acid sequestrant** (resin) that binds negatively charged bile acids in the intestinal lumen, forming a non-absorbable complex that is excreted in stool.- The loss of bile acids forces the liver to increase the synthesis of new bile acids from cholesterol, thereby upregulating hepatic **LDL receptors** and reducing plasma LDL levels.*Simvastatin*- This drug is an HMG-CoA reductase inhibitor (**statin**), which is the rate-limiting enzyme in hepatic cholesterol synthesis.- By reducing intracellular cholesterol synthesis, it causes upregulation of surface **LDL receptors** on hepatocytes, increasing LDL clearance from the blood. [Practice more Pharmacology PYQs on OnCourse]

Question 1

A 50-year-old woman was prescribed a diuretic by a doctor to manage hypertension. Which of the following diuretics acts on site 'A' as marked in the given image?

Accepted Answer

Hydrochlorothiazide

Answer

Acetazolamide

Answer

Mannitol

Answer

Furosemide

Question 2

Which of the following diuretics primarily acts on the part labeled 'D' in the given diagram of a nephron?

Accepted Answer

Hydrochlorothiazide

Answer

Acetazolamide

Answer

Mannitol

Answer

Furosemide

Question 3

Which of the following statement is correct regarding the mechanism of action of labetalol?

Accepted Answer

Blocks both alpha and beta-adrenergic receptors.

Answer

Primarily acts as a vasodilator with little effect on arterioles

Answer

Decreases peripheral vascular resistance by directly acting as a relaxant for vascular smooth muscles.

Answer

Directly acts as arterial vasodilator resulting in indirect effect tachycardia.

Question 4

A psychiatrist prescribes lithium for a patient who is diagnosed with bipolar disorder. Which of the following statements is incorrect regarding lithium?

Accepted Answer

Hemodialysis is not useful in lithium overdose

Answer

Lithium is teratogenic if given to pregnant females

Answer

Lithium toxicity is exacerbated with thiazide

Answer

Lithium can decrease thyroid hormone levels

Question 5

Which of these drugs stimulates PPAR-alpha (Peroxisome proliferator-activated receptor alpha)?

Accepted Answer

Gemfibrozil

Answer

Ezetimibe

Answer

Colestipol

Answer

Simvastatin

Question 6

Which drug is most appropriate for treating diarrhea in a patient treated for colorectal carcinoma with 5-fluorouracil?

Accepted Answer

Loperamide

Answer

Ciprofloxacin

Answer

Atropine

Answer

Ornidazole

Question 7

Which of the following drugs are used to treat chemotherapy-induced nausea and vomiting?

Accepted Answer

Granisetron + dexamethasone + aprepitant

Answer

Doxylamine + domperidone + aprepitant

Answer

Prochlorperazine + metoclopramide + domperidone

Answer

Dexamethasone + metoclopramide + domperidone

Question 8

A patient on anti-cancer therapy developed an infection. Blood analysis revealed neutropenia. Which of the following drugs is likely to be effective in this patient?

Accepted Answer

Filgrastim

Answer

Epoetin alfa

Answer

Oprelvekin

Answer

Romiplostim

Question 9

A 38-year-old professor with depression requests you to prescribe an antidepressant that would be least likely to cause sexual dysfunction. Which of the following drugs would you prescribe?

Accepted Answer

Bupropion

Answer

Venlafaxine

Answer

Fluoxetine

Answer

Escitalopram

Question 10

A 50-year-old factory worker was brought to the emergency room with complaints of headache, vomiting, and blurring of vision after he consumed local spirit. Which of the following is used for the treatment of his condition?

Accepted Answer

Fomepizole

Answer

Flumazenil

Answer

N-acetyl cysteine

Answer

Naloxone

FMGE 2023 — Pharmacology