Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 581: What is the mechanism of action of Ezetimibe?

A. Interferes with absorption of bile acids
B. Inhibits CETP
C. Interferes with absorption of cholesterol by inhibiting NPC1L1 (Correct Answer)
D. Inhibitor of PPAR-α

Explanation: **Explanation:** **Correct Option: C (Interferes with absorption of cholesterol by inhibiting NPC1L1)** Ezetimibe is a lipid-lowering agent that selectively inhibits the **Niemann-Pick C1-Like 1 (NPC1L1)** protein. This transporter is located on the brush border of enterocytes in the small intestine and is responsible for the uptake of dietary and biliary cholesterol. By blocking this pathway, Ezetimibe reduces the delivery of intestinal cholesterol to the liver, leading to a reduction in hepatic cholesterol stores and a compensatory increase in the expression of LDL receptors on hepatocytes, which clears LDL from the blood. **Analysis of Incorrect Options:** * **Option A:** This describes **Bile Acid Sequestrants** (e.g., Cholestyramine, Colestipol). They bind bile acids in the gut, preventing their enterohepatic circulation. * **Option B:** **CETP (Cholesteryl Ester Transfer Protein) inhibitors** (e.g., Anacetrapib, Torcetrapib) aim to increase HDL levels by preventing the transfer of cholesterol from HDL to LDL/VLDL. * **Option D:** **PPAR-α (Peroxisome Proliferator-Activated Receptor-alpha) agonists** are the mechanism for **Fibrates** (e.g., Fenofibrate, Gemfibrozil), which primarily lower triglycerides. **High-Yield NEET-PG Pearls:** * **Synergy:** Ezetimibe is frequently used in combination with **Statins**. While statins inhibit cholesterol *synthesis*, Ezetimibe inhibits cholesterol *absorption*, leading to a synergistic reduction in LDL. * **Vytorin:** A fixed-dose combination of Ezetimibe + Simvastatin. * **Side Effects:** Generally well-tolerated; however, it may cause a reversible increase in hepatic transaminases when used with statins. * **Key Distinction:** Unlike bile acid sequestrants, Ezetimibe does not interfere with the absorption of fat-soluble vitamins or triglycerides.

Question 582: Lignocaine is useful for the treatment of which of the following conditions?

A. Atrial fibrillation
B. Paroxysmal supraventricular tachycardia
C. Digitalis-induced ventricular extrasystoles (Correct Answer)
D. All of the above

Explanation: **Explanation:** **Lignocaine (Lidocaine)** is a Class IB antiarrhythmic drug. Its primary mechanism involves blocking voltage-gated sodium channels in the **inactivated state**, with a high affinity for tissues that are depolarized or ischemic. 1. **Why Option C is Correct:** Lignocaine is highly effective for **ventricular arrhythmias**, particularly those arising from myocardial infarction or **digitalis toxicity**. In digitalis-induced toxicity, there is an overload of intracellular calcium leading to delayed after-depolarizations (DADs) and ventricular extrasystoles. Lignocaine suppresses these ectopic foci by shortening the action potential duration (APD) and decreasing automaticity in the Purkinje fibers without significantly affecting the SA node or atrial tissue. 2. **Why Options A and B are Incorrect:** Lignocaine has a very rapid "on-off" dissociation constant and binds preferentially to sodium channels in the ventricles. It has **minimal effect on atrial tissue** because the action potential duration in the atria is too short for the drug to bind effectively. Therefore, it is ineffective for supraventricular arrhythmias like **Atrial Fibrillation (AF)** or **PSVT**. These conditions are typically treated with Class II (Beta-blockers), Class IV (Calcium channel blockers), or Adenosine. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Administration:** Lignocaine undergoes extensive first-pass metabolism; hence, it is given only **intravenously** for arrhythmias. * **Drug of Choice:** While Lignocaine was previously the first line for post-MI ventricular tachycardia, **Amiodarone** is now preferred. However, Lignocaine remains a top choice for digitalis-induced ventricular arrhythmias. * **Toxicity:** Overdose primarily affects the CNS, causing tremors, seizures (treated with Diazepam), and blurred vision. * **Key Property:** It is the only sodium channel blocker that **shortens** the action potential duration (APD).

Question 583: In congestive cardiac failure, which of the following is NOT used?

A. Spironolactone
B. Nitrates
C. Nesiritide
D. Trimetazidine (Correct Answer)

Explanation: **Explanation:** The management of Congestive Cardiac Failure (CCF) focuses on reducing preload, afterload, and inhibiting maladaptive neurohumoral remodeling. **Why Trimetazidine is the correct answer:** Trimetazidine is a **pFOX (partial fatty acid oxidation) inhibitor**. It shifts myocardial metabolism from fatty acid oxidation to glucose oxidation, which requires less oxygen to produce ATP. While it is an effective anti-anginal agent used in stable coronary artery disease, it is **not** a standard treatment for the acute or chronic management of cardiac failure itself. It does not provide the hemodynamic benefits (like diuresis or vasodilation) required in CCF. **Analysis of Incorrect Options:** * **Spironolactone:** An aldosterone antagonist (MRA) that is a cornerstone in CCF management (NYHA Class II-IV). It prevents myocardial fibrosis and reduces mortality. * **Nitrates:** These are venodilators that reduce **preload**. They are particularly useful in acute heart failure and in combination with Hydralazine (especially in African American populations) to reduce mortality. * **Nesiritide:** A recombinant **B-type Natriuretic Peptide (BNP)**. It causes vasodilation and natriuresis, used primarily in the management of acutely decompensated heart failure. **High-Yield Clinical Pearls for NEET-PG:** * **Drugs reducing mortality in CCF:** ACE inhibitors/ARBs, Beta-blockers (Carvedilol, Metoprolol succinate, Bisoprolol), Spironolactone, and ARNIs (Sacubitril/Valsartan). * **Digoxin:** Improves symptoms and reduces hospitalization but does **not** reduce mortality in CCF. * **Trimetazidine Side Effect:** Can cause or worsen **Parkinsonian symptoms** (tremors, rigidity) due to its effect on the nigrostriatal pathway.

Question 584: All of the following are complications of streptokinase, except?

A. Joint pain (Correct Answer)
B. Intracranial bleed
C. Fever
D. Anaphylaxis

Explanation: **Explanation:** Streptokinase is a first-generation fibrinolytic agent derived from **Group C β-hemolytic Streptococci**. Because it is a bacterial protein, it is highly **antigenic** and associated with specific immune-mediated side effects. **1. Why "Joint Pain" is the correct answer:** While streptokinase can cause systemic allergic reactions, **isolated joint pain (arthralgia)** is not a recognized or common complication of its administration. In contrast, other systemic symptoms like fever and rashes are frequently documented. **2. Analysis of Incorrect Options:** * **Intracranial Bleed (B):** This is the most dreaded complication of all thrombolytic agents (Streptokinase, Alteplase, Tenecteplase). By activating plasminogen to plasmin, these drugs dissolve not just the pathological thrombus but also protective hemostatic plugs, leading to hemorrhagic strokes. * **Fever (C):** As a foreign bacterial protein, streptokinase is pyrogenic. Mild to moderate elevations in temperature are common post-administration due to the immune response. * **Anaphylaxis (D):** Due to its exogenous nature, streptokinase can trigger Type I hypersensitivity reactions. This ranges from mild urticaria to life-threatening anaphylactic shock. Because of this antigenicity, it should **not be repeated** within 6–12 months of the first dose due to the presence of neutralizing antibodies. **Clinical Pearls for NEET-PG:** * **Mechanism:** It is a non-specific plasminogen activator; it binds to plasminogen to form an active complex, unlike Alteplase which is fibrin-specific. * **Hypotension:** Rapid infusion of streptokinase can cause a transient drop in blood pressure. * **Antidote:** In cases of severe bleeding due to thrombolytics, **Epsilon-aminocaproic acid (EACA)** or **Tranexamic acid** can be used as antidotes. * **Trend:** In modern practice, streptokinase is largely replaced by fibrin-specific agents (Tenecteplase) which have lower bleeding risks and no antigenicity.

Question 585: What effect does a lower dose of dopamine have on a patient in cardiogenic shock?

A. Cardiac output
B. Urine output (Correct Answer)
C. Heart rate
D. Blood pressure

Explanation: ### Explanation Dopamine is a unique catecholamine because its effects are strictly **dose-dependent**. Understanding these dose ranges is a high-yield concept for NEET-PG. **1. Why "Urine Output" is correct:** At **low doses (0.5–2 µg/kg/min)**, dopamine primarily acts on **D1 receptors** located in the renal, mesenteric, and coronary vascular beds. Activation of D1 receptors causes vasodilation, specifically increasing renal blood flow and the glomerular filtration rate (GFR). This results in increased **urine output** (diuresis) and sodium excretion (natriuresis). This is often referred to as the "renal dose" of dopamine. **2. Analysis of Incorrect Options:** * **Cardiac Output (Option A):** This is the primary effect of **medium doses (2–10 µg/kg/min)**. At this range, dopamine stimulates **β1-adrenergic receptors** in the heart, increasing myocardial contractility (inotropy) and stroke volume. * **Heart Rate (Option C):** While β1 stimulation at medium doses can increase heart rate (chronotropy), it is not the specific effect of a *low* dose. Tachycardia is often a limiting side effect at higher doses. * **Blood Pressure (Option D):** Significant increases in blood pressure occur at **high doses (>10 µg/kg/min)**. At this level, dopamine stimulates **α1-adrenergic receptors**, leading to systemic vasoconstriction and increased peripheral resistance. **3. Clinical Pearls for NEET-PG:** * **The "D-B-A" Rule:** Remember the sequence of receptor activation as dose increases: **D**opaminergic (Low) → **B**eta (Medium) → **A**lpha (High). * **Fenoldopam:** A selective D1 agonist used in hypertensive emergencies to maintain renal perfusion. * **Current Status:** While "renal dose" dopamine increases urine output, clinical trials (like the SOAP II trial) have shown it does not necessarily prevent acute renal failure or improve mortality, leading to a preference for Norepinephrine in many shock scenarios.

Question 586: A patient developed acute congestive heart failure and was put on digitalis therapy. ECG of this patient revealed the presence of ventricular extrasystoles. Which of the following drugs can be administered safely to this patient in order to counteract this arrhythmia?

A. Lignocaine (Correct Answer)
B. Quinidine
C. Atropine
D. Amiodarone

Explanation: **Explanation:** Digitalis (Digoxin) toxicity commonly manifests as cardiac arrhythmias, with **ventricular extrasystoles** (premature ventricular contractions) being one of the earliest and most frequent signs. This occurs due to increased intracellular calcium leading to delayed after-depolarizations (DADs). **Why Lignocaine is the Correct Choice:** Lignocaine (Lidocaine) is a **Class IB anti-arrhythmic** drug and is the drug of choice for digitalis-induced ventricular arrhythmias. It works by blocking activated and inactivated sodium channels, effectively suppressing ventricular ectopic foci without significantly depressing AV conduction or myocardial contractility. It has a high degree of safety in the setting of digitalis toxicity. **Why Other Options are Incorrect:** * **Quinidine (Option B):** It is strictly contraindicated. Quinidine reduces the renal and biliary clearance of Digoxin and displaces it from tissue binding sites, leading to a dangerous rise (doubling) in plasma Digoxin levels, worsening the toxicity. * **Atropine (Option C):** While Atropine is used to treat digitalis-induced bradycardia or AV block, it has no role in managing ventricular extrasystoles. * **Amiodarone (Option D):** Like Quinidine, Amiodarone can increase Digoxin levels by interfering with its excretion and is generally avoided in acute digitalis-induced ventricular arrhythmias. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice for Digitalis Toxicity:** Digoxin-specific Fab fragments (Digibind) is the definitive antidote. * **Electrolyte Imbalance:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose a patient to digitalis toxicity. * **ECG Sign of Toxicity:** Bigeminy (ventricular extrasystoles occurring every second beat) is a classic sign. * **ECG Sign of Digitalis Effect (Not Toxicity):** "Hockey stick" appearance or sagging ST-segment depression.

Question 587: Which drug is a potassium channel opener with anti-anginal activity?

A. Nicorandil (Correct Answer)
B. Dipyridamole
C. Dofetilide
D. Amiodarone

Explanation: **Explanation:** **Nicorandil (Option A)** is the correct answer because it possesses a unique dual mechanism of action. It acts as a **Potassium channel opener** (specifically ATP-sensitive $K^+$ channels) and a **Nitrate-like vasodilator**. By opening $K^+$ channels in vascular smooth muscle, it causes hyperpolarization, leading to arterial vasodilation (reducing afterload). Its nitrate moiety increases cGMP, causing venous vasodilation (reducing preload). This dual action improves coronary blood flow and reduces myocardial oxygen demand, making it effective in stable angina. **Incorrect Options:** * **Dipyridamole (Option B):** This is a phosphodiesterase inhibitor and adenosine uptake inhibitor. While it is a vasodilator, it is notorious for causing **"Coronary Steal Phenomenon"** and is primarily used in pharmacological stress testing or as an antiplatelet agent. * **Dofetilide (Option C):** This is a **Class III Antiarrhythmic** drug. It acts by *blocking* potassium channels (specifically the $I_{Kr}$ current) to prolong the action potential duration, rather than opening them. * **Amiodarone (Option D):** A broad-spectrum Class III Antiarrhythmic that blocks $K^+$, $Na^+$, and $Ca^{2+}$ channels, and has anti-adrenergic effects. Like Dofetilide, it is a $K^+$ channel **blocker**. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effect:** A highly specific side effect of Nicorandil is **painful mucosal ulcerations** (oral, anal, or GI ulcers). * **Preconditioning:** Nicorandil mimics "ischemic preconditioning," providing a cardioprotective effect during episodes of ischemia. * **Contraindication:** Avoid use with PDE-5 inhibitors (e.g., Sildenafil) due to the risk of severe hypotension.

Question 588: Aprindine is a ....... antiarrhythmic drug?

A. Class IA
B. Class IB (Correct Answer)
C. Class IC
D. Class IV

Explanation: **Explanation:** Antiarrhythmic drugs are categorized using the **Vaughan-Williams classification**, which is based on their primary mechanism of action on the cardiac action potential. **Why Class IB is correct:** **Aprindine** belongs to **Class IB** sodium channel blockers. Like Lidocaine and Mexiletine, Class IB drugs bind to sodium channels in the inactivated state. They are characterized by rapid onset and offset kinetics. They slightly shorten the action potential duration (APD) and the effective refractory period (ERP) in ventricular tissues, making them particularly useful for ventricular arrhythmias. **Why other options are incorrect:** * **Class IA (e.g., Quinidine, Procainamide):** These drugs moderately block sodium channels and also block potassium channels, leading to a prolonged action potential duration and QT interval. * **Class IC (e.g., Flecainide, Propafenone):** These are the most potent sodium channel blockers with slow dissociation kinetics. They significantly depress the rate of rise of the action potential (Phase 0) but have minimal effect on the duration of the action potential. * **Class IV (e.g., Verapamil, Diltiazem):** These are Calcium Channel Blockers (CCBs) that primarily act on the SA and AV nodes to slow conduction. **High-Yield NEET-PG Pearls:** * **Aprindine** has a narrow therapeutic index and is rarely used today due to side effects like agranulocytosis and neurological toxicity. * **Mnemonic for Class I:** **"Double Quarter Pounder"** (IA: Disopyramide, Quinidine, Procainamide), **"Lettuce, Mayo, Tomato, Apricot"** (IB: Lidocaine, Mexiletine, Tocainide, **Aprindine**), **"Fries Please"** (IC: Flecainide, Propafenone). * **Class IB** drugs are "selective" for ischemic or depolarized tissue, which is why they are effective post-MI.

Question 589: Which beta-blocker also possesses alpha-blocking activity?

A. Carvedilol (Correct Answer)
B. Atenolol
C. Pindolol
D. Nadolol

Explanation: **Explanation:** The correct answer is **Carvedilol**. Beta-blockers are classified into three generations based on their receptor selectivity and additional properties [1]. Carvedilol is a **third-generation, non-selective beta-blocker** that also possesses **alpha-1 ($\alpha_1$) blocking activity** [2]. This dual action leads to peripheral vasodilation (via $\alpha_1$ blockade) alongside decreased heart rate and contractility (via $\beta$ blockade). This unique profile makes it particularly effective in managing chronic heart failure and hypertension, as it reduces afterload without causing reflex tachycardia [2]. **Analysis of Incorrect Options:** * **Atenolol:** A second-generation, **cardioselective ($\beta_1$)** blocker. It lacks $\alpha$-blocking activity and is primarily used for hypertension and angina. * **Pindolol:** A first-generation, non-selective beta-blocker characterized by **Intrinsic Sympathomimetic Activity (ISA)**. It acts as a partial agonist, causing less bradycardia at rest. * **Nadolol:** A first-generation, **non-selective** beta-blocker with a long half-life. It does not possess $\alpha$-blocking properties. **High-Yield Clinical Pearls for NEET-PG:** * **Mixed $\alpha$ and $\beta$ Blockers:** Remember the duo **Labetalol** and **Carvedilol** [2], [3]. Labetalol is the drug of choice for hypertension in pregnancy (preeclampsia) [3]. * **Third-Generation Blockers:** These are "vasodilatory" beta-blockers. Examples include **Carvedilol** ($\alpha_1$ block), **Labetalol** ($\alpha_1$ block), and **Nebivolol** (via Nitric Oxide release). * **Heart Failure Benefit:** Carvedilol, Metoprolol succinate, and Bisoprolol are the three beta-blockers proven to reduce mortality in chronic heart failure.

Question 590: Which of the following drugs are used in the management of heart failure?

A. ACE inhibitors
B. Hydralazine
C. Carvedilol (Correct Answer)
D. Chlorthalidone

Explanation: **Explanation:** **Correct Answer: C. Carvedilol** **Mechanism and Rationale:** In chronic heart failure (CHF), there is chronic overactivation of the sympathetic nervous system, leading to maladaptive cardiac remodeling, tachycardia, and increased oxygen demand. **Carvedilol** is a non-selective beta-blocker with additional alpha-1 blocking properties. It improves survival in CHF by reducing cardiac workload, preventing catecholamine-induced toxicity, and reversing ventricular remodeling. It is one of the three beta-blockers proven to reduce mortality in heart failure (alongside Metoprolol succinate and Bisoprolol). **Analysis of Incorrect Options:** * **A. ACE inhibitors:** While ACE inhibitors (e.g., Enalapril) are a cornerstone of heart failure management and reduce mortality, the question asks for the specific drug identified in the key. In many MCQ formats, if multiple drugs are used, the "most" characteristic or specific one indicated by the examiner must be chosen. However, in standard clinical practice, both A and C are correct. * **B. Hydralazine:** This is a potent vasodilator. It is generally used in heart failure only when combined with **Isosorbide Dinitrate** (BiDil), specifically in patients who cannot tolerate ACE inhibitors or in the African-American population. * **D. Chlorthalidone:** This is a thiazide-like diuretic primarily used for hypertension. In heart failure, **Loop diuretics** (like Furosemide) are preferred for symptomatic relief of congestion; thiazides have a limited role except in refractory cases. **High-Yield NEET-PG Pearls:** * **Mortality Benefit Drugs:** ACE inhibitors, ARBs, Beta-blockers (Carvedilol, Bisoprolol, Metoprolol succinate), Spironolactone/Eplerenone, and ARNI (Sacubitril/Valsartan). * **Beta-blocker Initiation:** Always start at a very low dose ("Start low, go slow") only when the patient is **hemodynamically stable** and euvolemic. They are contraindicated in acute decompensated heart failure. * **Digoxin:** Improves symptoms and reduces hospitalization but has **no effect on mortality**.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

Practice Questions

Lipid-Lowering Drugs

Practice Questions

Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

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Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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