Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 331: Which hypolipidemic drug can exacerbate the symptoms of gout?

A. Ezetimibe
B. Gemfibrozil
C. Niacin (Correct Answer)
D. Simvastatin

Explanation: **Explanation:** **Niacin (Nicotinic Acid)** is the correct answer because it competes with uric acid for the same organic acid secretory carrier in the proximal convoluted tubules of the kidney. This competition leads to decreased renal excretion of uric acid, resulting in **hyperuricemia**. In susceptible individuals, this elevated serum uric acid can precipitate an acute attack of **gout**. **Analysis of Options:** * **Ezetimibe (A):** A cholesterol absorption inhibitor that acts on the NPC1L1 transporter in the intestine. It does not affect renal tubular secretion or uric acid levels. * **Gemfibrozil (B):** A Fibrate that activates PPAR-α. While fibrates can occasionally cause muscle toxicity, they do not typically cause hyperuricemia. In fact, Fenofibrate (another fibrate) actually has a mild uricosuric effect (lowers uric acid). * **Simvastatin (D):** An HMG-CoA reductase inhibitor. The primary side effects of statins are hepatotoxicity and myopathy (rhabdomyolysis); they do not interfere with uric acid metabolism. **NEET-PG High-Yield Pearls:** * **Niacin Side Effects:** The most common side effect is **cutaneous flushing** (mediated by Prostaglandin $D_2$ and $E_2$; prevented by Aspirin). The most serious side effects are **hepatotoxicity** and **hyperglycemia** (caution in diabetics). * **Clinical Contraindications:** Niacin should be avoided in patients with active peptic ulcer disease, gout, and uncontrolled diabetes. * **Lipid Profile:** Niacin is the most effective drug for **increasing HDL levels** and is also useful for lowering Triglycerides and LDL.

Question 332: Which drug is primarily used for the treatment of hypertriglyceridemia?

A. Cholestyramine
B. Nicotinic acid
C. Gemfibrozil (Correct Answer)
D. Resins

Explanation: **Explanation:** **Gemfibrozil** is the correct answer because it belongs to the **Fibrates** class of drugs, which are the first-line agents for treating isolated hypertriglyceridemia. **Mechanism of Action:** Fibrates act as agonists at the **PPAR-α (Peroxisome Proliferator-Activated Receptor-alpha)** receptors. Activation of these receptors increases the expression of **Lipoprotein Lipase (LPL)**, which enhances the clearance of triglyceride-rich lipoproteins (VLDL and chylomicrons). They also decrease the hepatic synthesis of VLDL. **Analysis of Incorrect Options:** * **Cholestyramine & Resins (Options A & D):** These are Bile Acid Sequestrants. They primarily lower LDL cholesterol by preventing bile acid reabsorption. Crucially, they can actually **increase triglyceride levels** in some patients; therefore, they are contraindicated in severe hypertriglyceridemia. * **Nicotinic Acid (Option B):** While Niacin can lower triglycerides and raise HDL, it is no longer a first-line treatment due to its side effect profile (flushing, glucose intolerance, hyperuricemia) and is generally reserved for refractory cases. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** Fibrates (e.g., Gemfibrozil, Fenofibrate) are the drugs of choice when triglycerides are >500 mg/dL to prevent **acute pancreatitis**. * **Drug Interaction:** Combining Gemfibrozil with Statins significantly increases the risk of **myopathy and rhabdomyolysis** because Gemfibrozil inhibits the glucuronidation (metabolism) of statins. * **Fenofibrate** is preferred over Gemfibrozil if a statin-fibrate combination is necessary, as it has a lower risk of causing myopathy.

Question 333: Which of the following intravenous drugs can be used in the management of hypertensive emergency?

A. Hydralazine
B. Sodium nitroprusside
C. Esmolol
D. All of the above (Correct Answer)

Explanation: A **hypertensive emergency** is defined as a severe elevation in blood pressure (usually >180/120 mmHg) accompanied by evidence of **acute target organ damage** (e.g., encephalopathy, myocardial infarction, or acute kidney injury). Management requires immediate, controlled reduction of blood pressure using **intravenous (IV) medications** to prevent further damage [1].* **Sodium Nitroprusside (Option B):** Historically the gold standard, it is a potent balanced vasodilator (acting on both arterioles and veins) via nitric oxide release [2, 1]. It has an ultra-short duration of action, allowing for precise titration.* **Esmolol (Option C):** An ultra-short-acting cardioselective {1}-blocker. It is particularly useful in emergencies involving aortic dissection or perioperative hypertension where heart rate control is also vital.* **Hydralazine (Option A):** A direct-acting arteriolar vasodilator [3]. While less predictable than nitroprusside, it is a preferred agent in **pregnancy-induced hypertensive emergencies (Eclampsia/Pre-eclampsia)** due to its safety profile for the fetus.Since all three drugs are administered intravenously and are indicated for rapid BP reduction in specific emergency scenarios, **Option D** is the correct answer.**High-Yield Clinical Pearls for NEET-PG:*** **Drug of Choice (DOC):** **Labetalol** is often considered the first-line agent for most hypertensive emergencies (except acute heart failure).* **Aortic Dissection:** The goal is rapid reduction of SBP to <120 mmHg within 20 minutes. **Esmolol** is preferred to prevent reflex tachycardia.* **Nitroprusside Toxicity:** Prolonged infusion can lead to **Cyanide/Thiocyanate toxicity**. The antidote is Sodium Thiosulfate or Nitrites.* **Caution:** Avoid rapid BP lowering in ischemic stroke unless BP is >220/120 mmHg to maintain cerebral perfusion.

Question 334: Long-term ACE inhibitor therapy may retard the progression of which of the following conditions?

A. Diabetic retinopathy
B. Hypertensive nephropathy
C. Diabetic nephropathy
D. All of the above (Correct Answer)

Explanation: ACE inhibitors (ACEIs) are considered "organ-protective" agents due to their ability to reduce systemic blood pressure and, more importantly, inhibit the local effects of Angiotensin II in various tissues [1]. 1. **Diabetic Nephropathy (Option C):** This is the most classic indication [1]. ACEIs dilate the **efferent arteriole** more than the afferent arteriole, leading to a decrease in intraglomerular capillary pressure. This reduces albuminuria and slows the progression to end-stage renal disease (ESRD). 2. **Hypertensive Nephropathy (Option B):** By controlling systemic hypertension and reducing glomerular hyperfiltration, ACEIs prevent the development of hypertensive glomerulosclerosis [1]. 3. **Diabetic Retinopathy (Option A):** Emerging evidence and clinical trials (like the EUCLID study) suggest that ACEIs can reduce the progression of retinopathy. Angiotensin II is a pro-angiogenic factor; by inhibiting it, ACEIs reduce vascular endothelial growth factor (VEGF) expression and prevent pathological neovascularization in the retina. **Why "All of the above" is correct:** ACE inhibitors exert pleiotropic effects, including anti-inflammatory, anti-fibrotic, and anti-proliferative actions. These properties collectively protect the microvasculature in the kidneys and eyes, making them the drug of choice for hypertensive patients with diabetes [1]. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** ACEIs/ARBs are the first-line treatment for hypertension in patients with **Diabetes Mellitus** or **Chronic Kidney Disease (CKD)** with proteinuria [1]. * **The "Creatinine Rule":** A small rise in serum creatinine (up to 30%) is expected and acceptable after starting ACEIs. * **Contraindications:** Absolute contraindications include **pregnancy** (teratogenic) [1][2], **bilateral renal artery stenosis**, and a history of **angioedema**. * **Side Effect Mnemonic (CAPTOPRIL):** **C**ough (due to Bradykinin), **A**ngioedema, **P**roteinuria, **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication, **R**enal artery stenosis, **I**ncreased potassium (Hyperkalemia), **L**eukopenia.

Question 335: Which prostacyclin agonist is usually given orally?

A. Teleprost
B. Iloprost
C. Riociguat
D. Selexipag (Correct Answer)

Explanation: **Explanation:** **Selexipag** is the correct answer because it is a selective, non-prostanoid **prostacyclin (IP) receptor agonist** specifically designed for **oral administration**. Unlike traditional prostacyclin analogs, Selexipag is a prodrug metabolized into its active form (ACT-333602), providing a longer half-life and making it suitable for twice-daily oral dosing in the management of Pulmonary Arterial Hypertension (PAH). **Analysis of Incorrect Options:** * **Iloprost:** This is a synthetic analog of PGI2. While it can be given intravenously, it is most commonly administered via **inhalation** (6–9 times daily) due to its very short half-life. * **Treprostinil (often confused with 'Teleprost'):** While Treprostinil has an oral formulation (Orenitram), it is more famously known for its subcutaneous or intravenous infusion and inhalation. (Note: "Teleprost" is likely a distractor or misspelling of Treprostinil). * **Riociguat:** This drug is used for PAH, but it is **not a prostacyclin agonist**. It is a **Soluble Guanylate Cyclase (sGC) stimulator** that works via the Nitric Oxide pathway. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Selexipag targets the IP receptor, leading to vasodilation and anti-proliferative effects on pulmonary vessels. * **PAH Treatment Hierarchy:** Oral agents like Selexipag or Endothelin receptor antagonists (Bosentan/Ambrisentan) are preferred for early-stage PAH (WHO Class II/III), whereas IV Epoprostenol remains the gold standard for severe, late-stage disease (Class IV). * **Side Effects:** Common to all prostacyclin pathways—headache, jaw pain, diarrhea, and flushing.

Question 336: A patient is prescribed a drug for treating hypertension that can cause tachycardia and marked fluid retention. Which of the following could be the prescribed drug?

A. Captopril
B. Guanethidine
C. Minoxidil (Correct Answer)
D. Metoprolol

Explanation: **Explanation:** The correct answer is **Minoxidil**. **Mechanism and Rationale:** Minoxidil is a potent **direct-acting peripheral vasodilator** that works by opening ATP-sensitive potassium channels in vascular smooth muscle, leading to hyperpolarization and relaxation of arterioles. This profound vasodilation significantly drops peripheral resistance, triggering two major compensatory homeostatic mechanisms: 1. **Reflex Tachycardia:** The drop in blood pressure activates the baroreceptor reflex, leading to increased sympathetic outflow. 2. **Fluid Retention:** Reduced renal perfusion and sympathetic activation trigger the Renin-Angiotensin-Aldosterone System (RAAS), causing significant sodium and water retention. To counteract these side effects, Minoxidil is almost always co-administered with a **beta-blocker** (to control heart rate) and a **loop diuretic** (to manage edema). **Analysis of Incorrect Options:** * **A. Captopril:** An ACE inhibitor. It typically causes a slight decrease in sympathetic activity and promotes sodium excretion (natriuresis), making it unlikely to cause tachycardia or fluid retention. * **B. Guanethidine:** An adrenergic neuron blocker. It prevents the release of norepinephrine, typically causing bradycardia and orthostatic hypotension, not tachycardia. * **D. Metoprolol:** A cardioselective beta-1 blocker. It decreases heart rate (bradycardia) and is used to treat tachycardia, not cause it. **NEET-PG High-Yield Pearls:** * **Hypertrichosis:** Minoxidil causes abnormal hair growth; it is used topically for androgenetic alopecia. * **Hydralazine:** Another direct vasodilator that causes similar reflex tachycardia and a lupus-like syndrome (slow acetylators). * **Clinical Use:** Minoxidil is reserved for **refractory hypertension** that does not respond to multidrug regimens.

Question 337: Which of the following is NOT an ADP inhibitor?

A. Ticlopidine
B. Tirofiban (Correct Answer)
C. Clopidogrel
D. Prasugrel

Explanation: **Explanation:** The question asks to identify the drug that does not belong to the **ADP (P2Y12) receptor antagonist** class. **1. Why Tirofiban is the correct answer:** Tirofiban is a **Glycoprotein (GP) IIb/IIIa inhibitor**, not an ADP inhibitor. It works by blocking the final common pathway of platelet aggregation—the binding of fibrinogen to the GP IIb/IIIa receptors on the platelet surface [1], [2]. It is administered intravenously, primarily in the management of Acute Coronary Syndrome (ACS) and during Percutaneous Coronary Intervention (PCI). **2. Analysis of incorrect options (ADP Inhibitors):** * **Ticlopidine:** A first-generation thienopyridine ADP inhibitor. It is rarely used now due to side effects like severe neutropenia and TTP [1]. * **Clopidogrel:** A second-generation thienopyridine. It is a prodrug activated by CYP2C19 [3]. It irreversibly inhibits the P2Y12 receptor. * **Prasugrel:** A third-generation thienopyridine. It is more potent and has a faster onset than clopidogrel [3] but carries a higher risk of bleeding. **High-Yield Clinical Pearls for NEET-PG:** * **Classification of Antiplatelets:** * **COX Inhibitors:** Aspirin. * **ADP (P2Y12) Blockers:** Clopidogrel, Prasugrel, Ticlopidine (Irreversible); **Ticagrelor, Cangrelor** (Reversible) [3]. * **GP IIb/IIIa Inhibitors:** Abciximab, Eptifibatide, Tirofiban. * **PDE Inhibitors:** Dipyridamole, Cilostazol. * **Ticagrelor** is unique because it is a direct-acting (not a prodrug) and reversible P2Y12 inhibitor [3]. * **Cilostazol** is the drug of choice for intermittent claudication (Peripheral Vascular Disease).

Question 338: Aspirin is used in the prophylaxis of myocardial infarction because it results in:

A. Inhibition of thromboxane synthetase
B. Inhibition of cyclooxygenase (Correct Answer)
C. Decreased serum lipids
D. Coronary steal phenomenon

Explanation: ### Explanation **Correct Answer: B. Inhibition of cyclooxygenase** **Mechanism of Action:** Aspirin (Acetylsalicylic acid) is the only NSAID that **irreversibly** inhibits the enzyme **Cyclooxygenase-1 (COX-1)** by acetylating a specific serine residue. In platelets, COX-1 is responsible for converting arachidonic acid into **Thromboxane A2 (TXA2)**, a potent vasoconstrictor and platelet aggregator. Since platelets are anuclear and cannot synthesize new enzymes, the inhibition lasts for the entire lifespan of the platelet (approx. 7–10 days). This reduction in TXA2 shifts the balance toward Prostacyclin (PGI2), preventing thrombus formation in coronary arteries. **Analysis of Incorrect Options:** * **A. Inhibition of thromboxane synthetase:** Aspirin inhibits the *upstream* enzyme COX-1, not thromboxane synthetase. Specific thromboxane synthetase inhibitors (e.g., Dazoxiben) exist but are not the mechanism for aspirin. * **C. Decreased serum lipids:** Aspirin has no significant effect on lipid profiles. Statins are the primary class used for lipid-lowering in MI prophylaxis. * **D. Coronary steal phenomenon:** This occurs when a vasodilator (like Dipyridamole or Hydralazine) dilates healthy vessels, "stealing" blood away from ischemic areas. Aspirin does not cause this. **High-Yield Clinical Pearls for NEET-PG:** * **Low-dose Aspirin (75–150 mg):** Highly selective for COX-1 (anti-platelet effect). * **High-dose Aspirin:** Inhibits both COX-1 and COX-2 (analgesic/anti-inflammatory effect). * **Primary Prophylaxis:** Aspirin is used to prevent the first MI in high-risk patients. * **Secondary Prophylaxis:** Used in patients with a history of MI or stroke to prevent recurrence. * **Side Effect:** Gastric irritation and bleeding (due to inhibition of protective PGE2 in the stomach).

Question 339: What is the mechanism of action of sodium nitroprusside?

A. Increased cAMP
B. Increased guanylate cyclase (Correct Answer)
C. Calcium channel blockage
D. IC channel opener

Explanation: **Mechanism of Action: Sodium Nitroprusside** **Explanation of the Correct Answer:** Sodium nitroprusside (SNP) is a potent, rapid-acting parenteral vasodilator. Unlike organic nitrates (like nitroglycerin) which require enzymatic bioactivation, SNP is a non-enzymatic nitric oxide (NO) donor. Once in the bloodstream, it spontaneously releases NO, which activates the enzyme **soluble guanylate cyclase**. This leads to an increase in intracellular **cyclic GMP (cGMP)**. Elevated cGMP levels activate protein kinase G, resulting in dephosphorylation of myosin light chains and sequestration of calcium, which causes profound relaxation of both **arteriolar and venous** smooth muscle. **Analysis of Incorrect Options:** * **A. Increased cAMP:** This is the mechanism for drugs like Beta-2 agonists (Salbutamol) or PDE-3 inhibitors (Milrinone), which cause vasodilation via the cAMP pathway, not NO. * **C. Calcium channel blockage:** This describes the mechanism of CCBs (e.g., Amlodipine, Verapamil), which inhibit the entry of calcium into the cell. * **D. K+ channel opener:** Drugs like Minoxidil, Diazoxide, and Nicorandil work by opening ATP-sensitive potassium channels, leading to hyperpolarization and vasodilation. **NEET-PG High-Yield Pearls:** * **Balanced Vasodilator:** SNP acts equally on veins (reducing preload) and arteries (reducing afterload). * **Clinical Use:** Drug of choice for **Hypertensive Emergencies** and controlled hypotension during surgery. * **Toxicity:** Metabolism of SNP releases **cyanide**. Chronic infusion or high doses can lead to cyanide and thiocyanate toxicity. * **Antidote:** Sodium thiosulfate or Hydroxocobalamin (Vitamin B12a) are used to treat SNP-induced cyanide poisoning. * **Light Sensitivity:** SNP is photosensitive; the infusion bottle must be covered with opaque foil.

Question 340: A 35-year-old woman presents with palpitations, and diagnostic tests confirm supraventricular tachycardia. Vagal maneuvers fail to provide an adequate response. What is the best therapy that can be advocated?

A. Amiodarone
B. Verapamil
C. Digoxin
D. Adenosine (Correct Answer)

Explanation: **Explanation:** The clinical presentation of a young patient with palpitations and confirmed **Supraventricular Tachycardia (SVT)**, specifically Paroxysmal SVT (PSVT), requires immediate pharmacological intervention when vagal maneuvers fail. **Why Adenosine is the Correct Answer:** Adenosine is the **drug of choice** for the acute termination of PSVT. It works by stimulating A1 receptors on the AV node, leading to increased K+ efflux and inhibition of Ca2+ influx. This causes profound hyperpolarization and a transient "chemical" AV block (lasting 10–15 seconds), which breaks the re-entry circuit. Its rapid onset and ultra-short half-life (<10 seconds) make it both effective and safe for emergency use. **Analysis of Incorrect Options:** * **Verapamil (Option B):** While it is an effective Class IV antiarrhythmic for SVT, it has a slower onset and a longer duration of action compared to Adenosine. It can also cause significant hypotension and is contraindicated in patients with heart failure or wide-complex tachycardias. * **Amiodarone (Option A):** This is a broad-spectrum antiarrhythmic primarily used for ventricular arrhythmias or rhythm control in atrial fibrillation. It is not the first-line agent for narrow-complex PSVT. * **Digoxin (Option C):** Digoxin is used for rate control in chronic atrial fibrillation. Its onset of action is too slow (hours) for the acute termination of an SVT paroxysm. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Adenosine must be given as a **rapid IV bolus** (usually 6mg, followed by 12mg) through a large-bore cannula in the antecubital vein, followed by a saline flush, due to its short half-life. * **Side Effects:** Patients often experience a transient sense of "impending doom," chest pain, or flushing. * **Contraindications:** Avoid in patients with **Asthma** (can cause bronchospasm) and **2nd/3rd-degree heart block**. * **Drug Interactions:** The dose should be **increased** in patients taking caffeine/theophylline (adenosine receptor antagonists) and **decreased** in those on dipyridamole (uptake inhibitor).

Practice by Chapter

Antihypertensive Agents

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Drugs for Heart Failure

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Antiarrhythmic Drugs

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Antianginal Agents

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Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

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Drugs Used in Pulmonary Hypertension

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Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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