Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 461: Which vitamin is given in Type 2B Familial Hyperlipidemia?

A. Pantothenic acid
B. Riboflavin
C. Nicotinic acid (Correct Answer)
D. Thiamine

Explanation: **Explanation:** **Nicotinic Acid (Vitamin B3/Niacin)** is the correct answer because it is a potent lipid-lowering agent [1]. In **Type 2B Familial Hyperlipidemia** (Combined Hyperlipidemia), there is an elevation of both LDL and VLDL (and consequently, triglycerides). **Mechanism of Action:** Niacin acts by inhibiting the enzyme **hormone-sensitive lipase** in adipose tissue. This reduces the breakdown of triglycerides into free fatty acids (FFA). Since the liver uses FFA to synthesize VLDL, a decrease in FFA leads to: 1. Decreased VLDL synthesis. 2. Decreased LDL levels (as LDL is a metabolic product of VLDL). 3. Increased HDL levels (by decreasing its clearance) [1]. This makes it highly effective for Type 2B, where both cholesterol and triglycerides are elevated [2]. **Why other options are incorrect:** * **Pantothenic acid (B5), Riboflavin (B2), and Thiamine (B1):** While these are essential water-soluble vitamins acting as co-factors in various metabolic pathways (e.g., Krebs cycle, decarboxylation), they do not possess significant lipid-lowering properties and have no therapeutic role in treating hyperlipidemias. **High-Yield Clinical Pearls for NEET-PG:** * **Most Potent:** Niacin is the most effective drug for **increasing HDL** levels. * **Side Effects:** The most common side effect is **cutaneous flushing** (mediated by Prostaglandin D2/E2; prevented by **Aspirin**). * **Metabolic Risks:** It can cause **hyperuricemia** (precipitating gout), **hyperglycemia** (caution in diabetics), and hepatotoxicity. * **Type 2B Phenotype:** Characterized by increased LDL + VLDL (Apo B-100 elevation).

Question 462: Digoxin is contraindicated in which of the following conditions?

A. Supraventricular tachycardia
B. Atrial fibrillation
C. Congestive heart failure
D. Hypertrophic obstructive cardiomyopathy (Correct Answer)

Explanation: **Explanation:** **Correct Option: D. Hypertrophic Obstructive Cardiomyopathy (HOCM)** Digoxin is a positive inotropic agent that increases the force of myocardial contraction. In HOCM, there is asymmetrical septal hypertrophy that creates a dynamic sub-aortic pressure gradient. By increasing the force of contraction (positive inotropy), Digoxin narrows the left ventricular outflow tract (LVOT) further, worsening the obstruction. Additionally, Digoxin can increase the heart rate and decrease ventricular volume, both of which exacerbate the outflow obstruction. Therefore, it is strictly contraindicated. **Analysis of Incorrect Options:** * **A & B (SVT and Atrial Fibrillation):** Digoxin is used in these conditions because of its **vagomimetic effect**. It increases vagal tone, which slows conduction through the AV node (negative dromotropy), thereby controlling the ventricular rate in supraventricular arrhythmias. * **C (Congestive Heart Failure):** Digoxin is indicated in chronic HFrEF (Heart Failure with reduced Ejection Fraction), especially when associated with atrial fibrillation. It improves symptoms and reduces the rate of hospitalization, though it does not decrease overall mortality. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Inhibits Na+/K+ ATPase pump $\rightarrow$ increases intracellular Na+ $\rightarrow$ decreases Na+/Ca2+ exchange $\rightarrow$ increases intracellular Ca2+ $\rightarrow$ increased contractility. * **ECG Changes:** Characterized by the "reverse tick" or "Sagging" ST-segment depression (Salvador Dali sign). * **Toxicity:** Hypokalemia predisposes to Digoxin toxicity (as K+ and Digoxin compete for the same binding site). The most common arrhythmia in toxicity is **Ventricular Bigeminy**, while the most characteristic is **Atrial Tachycardia with AV block**. * **Other Contraindications:** WPW Syndrome (can lead to VF), Ventricular Tachycardia, and Hypokalemia.

Question 463: Digoxin toxicity is precipitated by all except?

A. Electrolyte disturbance
B. Acute myocardial infarction
C. Hepatic disease (Correct Answer)
D. Renal disease

Explanation: **Explanation:** Digoxin is a cardiac glycoside with a narrow therapeutic index, meaning small changes in its metabolism or the body’s internal environment can easily lead to toxicity [3]. **Why Hepatic Disease is the Correct Answer:** Digoxin is primarily excreted **unchanged by the kidneys (approx. 60-80%)** [3]. It undergoes minimal hepatic metabolism. Therefore, hepatic impairment does not significantly affect digoxin levels and does not precipitate toxicity. In contrast, drugs like Digitoxin are metabolized by the liver and would be affected by hepatic disease [3]. **Analysis of Incorrect Options:** * **Electrolyte Disturbance:** This is the most common trigger. **Hypokalemia** is the classic precipitant because K+ and Digoxin compete for the same binding site on the Na+/K+ ATPase pump. Low K+ allows more Digoxin to bind. Hypomagnesemia and Hypercalcemia also increase toxicity risk. * **Acute Myocardial Infarction (MI):** Ischemic myocardium is more sensitive to the arrhythmogenic effects of Digoxin. The damaged tissue has altered electrical stability, lowering the threshold for Digoxin-induced arrhythmias. * **Renal Disease:** Since Digoxin is primarily cleared by the kidneys, any decrease in Glomerular Filtration Rate (GFR) leads to drug accumulation and toxicity [3]. Dose adjustment is mandatory in renal failure [3]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common ECG finding in toxicity:** Ventricular Bigeminy [2]. * **Most characteristic ECG finding:** Bidirectional Ventricular Tachycardia. * **Early signs of toxicity:** Gastrointestinal symptoms (anorexia, nausea, vomiting). * **Visual disturbance:** Xanthopsia (yellowish-green vision). * **Antidote:** Digoxin Immune Fab (Digibind). * **Drug Interactions:** Quinidine, Verapamil, and Amiodarone increase Digoxin levels by displacing it from tissue binding sites and reducing renal clearance [1].

Question 464: What is the drug of choice in paroxysmal supraventricular tachycardia?

A. Digoxin
B. Adenosine (Correct Answer)
C. Nifedipine
D. Esmolol

Explanation: ### Explanation **Correct Option: B. Adenosine** Adenosine is the **drug of choice (DOC)** for the acute termination of Paroxysmal Supraventricular Tachycardia (PSVT), specifically AV nodal re-entrant tachycardia (AVNRT). * **Mechanism of Action:** It acts on **A1 receptors** in the AV node, causing activation of Ach-sensitive $K^+$ channels and inhibition of $Ca^{2+}$ uptake. This results in intense hyperpolarization and a transient "chemical cardioversion" by blocking AV conduction. * **Pharmacokinetics:** It has an extremely short half-life (**<10 seconds**) due to rapid uptake by RBCs and endothelial cells. Therefore, it must be administered as a **rapid IV bolus** followed by a saline flush. **Why other options are incorrect:** * **A. Digoxin:** While it slows AV conduction, its onset of action is too slow (hours) for acute termination of PSVT. It is primarily used for rate control in chronic atrial fibrillation. * **C. Nifedipine:** This is a dihydropyridine calcium channel blocker (CCB) used for hypertension and angina. It has no significant anti-arrhythmic properties. (Note: *Verapamil*, a non-dihydropyridine CCB, is a second-line agent for PSVT). * **D. Esmolol:** This is an ultra-short-acting beta-blocker. While useful for rate control in atrial flutter/fibrillation or perioperative tachycardia, it is not the first-line agent for converting PSVT to sinus rhythm. **High-Yield Clinical Pearls for NEET-PG:** 1. **Side Effects:** Common side effects include flushing, dyspnea, and a transient feeling of "impending doom." 2. **Drug Interactions:** The dose must be **increased** in patients taking **Theophylline/Caffeine** (adenosine receptor antagonists) and **decreased** in those taking **Dipyridamole** (blocks adenosine uptake). 3. **Contraindications:** Avoid in patients with **Asthma** (may cause bronchospasm) and high-grade heart blocks. 4. **Wolff-Parkinson-White (WPW) Syndrome:** Adenosine is safe for narrow-complex PSVT but should be avoided in pre-excited atrial fibrillation.

Question 465: What effect does digitalis have when given in atrial flutter?

A. Atrial fibrillation (Correct Answer)
B. Atrial tachycardia
C. Atrial asystole
D. Atrial bigeminy

Explanation: Digitalis (Digoxin) is a unique anti-arrhythmic agent that exerts its effects primarily through the enhancement of vagal tone (parasympathomimetic effect). **Why Atrial Fibrillation is the Correct Answer:** In **Atrial Flutter**, the atria beat at a rapid, organized rate (typically 250–350 bpm). Digitalis acts by **shortening the atrial refractory period** and increasing the conduction velocity in the atrial muscle [1]. This "pro-arrhythmic" effect on the atria tends to convert the organized, large-circuit reentry of flutter into the disorganized, multiple-micro-reentry circuits characteristic of **Atrial Fibrillation (AF)** [1, 2]. While this might seem counterintuitive, converting flutter to AF is often clinically acceptable because Digitalis simultaneously **increases the refractory period of the AV node** [1]. This slows the ventricular rate, protecting the ventricles from the rapid atrial impulses and providing symptomatic relief. **Analysis of Incorrect Options:** * **B. Atrial Tachycardia:** Digitalis is used to treat certain supraventricular tachycardias; it does not typically convert flutter into a simple tachycardia. * **C. Atrial Asystole:** Digitalis does not cause the atria to stop beating entirely; its effect is to change the rhythm, not induce standstill. * **D. Atrial Bigeminy:** While Digitalis toxicity can cause ventricular bigeminy (due to increased automaticity), it is not the characteristic outcome of treating atrial flutter. **High-Yield NEET-PG Pearls:** * **Mechanism:** Digoxin inhibits the Na+/K+ ATPase pump, but its anti-arrhythmic effect is via **vagal stimulation**. * **ECG Changes:** Look for the "reverse tick" or "Sagging ST segment" (Digitalis effect). * **Toxicity:** The most common arrhythmia in Digoxin toxicity is **PVCs**, but the most characteristic/pathognomonic is **PAT with AV block**. * **Electrolytes:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose to Digoxin toxicity.

Question 466: Fenoldopam is an?

A. D2
B. D1 Agonist
C. D2 Antagonist
D. D1 Agonist (Correct Answer)

Explanation: **Explanation:** **Fenoldopam** is a rapid-acting vasodilator used primarily in the management of hypertensive emergencies. **Why D1 Agonist is Correct:** Fenoldopam is a **selective post-synaptic Dopamine-1 (D1) receptor agonist**. Activation of D1 receptors leads to the stimulation of adenylyl cyclase, increasing intracellular cAMP. This results in potent arteriolar vasodilation. A unique and high-yield feature of Fenoldopam is its ability to cause **renal vasodilation**, which increases renal blood flow and promotes natriuresis (sodium excretion) and diuresis. This makes it particularly useful in hypertensive patients with renal impairment. **Why other options are incorrect:** * **D2 Agonist:** D2 receptors are primarily located in the CNS and presynaptic nerve terminals. Agonists (like Bromocriptine) are used in Parkinson’s disease or hyperprolactinemia, not for acute blood pressure control. * **D2 Antagonist:** These drugs (like Metoclopramide or Haloperidol) are used as anti-emetics or antipsychotics and can actually cause side effects like extrapyramidal symptoms or hyperprolactinemia. * **D1 Antagonist:** Blocking D1 receptors would inhibit vasodilation and decrease renal perfusion, which is the opposite of the desired effect in a hypertensive crisis. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Hypertensive emergencies, especially in patients with **acute kidney injury (AKI)** or renal insufficiency. * **Route:** Administered via continuous **IV infusion** due to a very short half-life (~5–10 minutes). * **Side Effects:** Reflex tachycardia, headache, flushing, and a dose-dependent **increase in intraocular pressure** (use with caution in glaucoma). * **Comparison:** Unlike Sodium Nitroprusside, Fenoldopam does not carry the risk of cyanide or thiocyanate toxicity.

Question 467: Pancuronium differs from tubocurarine in that it:

A. Is a depolarizing blocker
B. Its action is not reversed by neostigmine
C. Can cause a rise in blood pressure on rapid intravenous injection (Correct Answer)
D. Causes marked histamine release

Explanation: **Explanation:** **Pancuronium** is a long-acting, non-depolarizing neuromuscular blocking agent (NMBA) belonging to the aminosteroid group. **Why Option C is correct:** Unlike many other NMBAs, Pancuronium has a distinct **vagolytic effect**. It blocks muscarinic receptors ($M_2$) in the heart and stimulates the release of norepinephrine from adrenergic nerve endings. This sympathomimetic activity leads to tachycardia and a **rise in blood pressure** (hypertension) upon rapid intravenous injection. This makes it useful in patients where maintaining heart rate and BP is desirable, but it should be used cautiously in patients with coronary artery disease. **Why other options are incorrect:** * **Option A:** Pancuronium is a **non-depolarizing** (competitive) blocker. Succinylcholine is the only commonly used depolarizing blocker. * **Option B:** As a competitive antagonist at the nicotinic receptors ($N_m$), its action **can be reversed** by acetylcholinesterase inhibitors like **Neostigmine**, which increase the concentration of acetylcholine at the neuromuscular junction. * **Option C:** Pancuronium is known for having **minimal to no histamine release**. In contrast, **Tubocurarine** (and Atracurium) causes significant histamine release, leading to hypotension and bronchospasm. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic:** "Pancuronium **P**umps the heart" (Tachycardia/Hypertension). * **Drug of choice in Renal Failure:** Cisatracurium (undergoes Hofmann elimination). * **Steroidal NMBAs:** Pancuronium, Vecuronium, Rocuronium (suffix "-curonium"). * **Vagolytic NMBAs:** Pancuronium and Gallamine. * **Rocuronium:** Fastest onset among non-depolarizing agents; used as an alternative to Succinylcholine for rapid sequence intubation.

Question 468: Which calcium channel sensitizer is approved for the treatment of congestive heart failure?

A. Levosimendan (Correct Answer)
B. Nesitritide
C. Vasopressin
D. Nitroprusside

Explanation: **Explanation:** **Levosimendan** is the correct answer because it is a unique "Inodilator" that acts primarily as a **calcium channel sensitizer**. It binds to cardiac troponin C in a calcium-dependent manner, increasing the sensitivity of the contractile apparatus to existing intracellular calcium. This enhances myocardial contractility (inotropy) without increasing intracellular calcium levels, thereby avoiding the risk of arrhythmias and increased myocardial oxygen demand associated with traditional inotropes like Dobutamine. Additionally, it opens ATP-sensitive potassium channels, leading to peripheral vasodilation. **Analysis of Incorrect Options:** * **Nesiritide:** This is a recombinant form of human B-type Natriuretic Peptide (BNP). It acts via cGMP to cause vasodilation and natriuresis but does not have calcium-sensitizing properties. * **Vasopressin:** An antidiuretic hormone (ADH) analogue used primarily as a vasoconstrictor in distributive shock; it would worsen heart failure by increasing afterload. * **Nitroprusside:** A potent vasodilator that acts by releasing Nitric Oxide (NO). It reduces both preload and afterload but has no direct effect on cardiac contractility or calcium sensitivity. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Levosimendan increases inotropy *without* increasing myocardial oxygen consumption ($MVO_2$). * **Dual Action:** It is an **Inodilator** (Inotrope + Vasodilator). * **Indication:** Short-term management of acutely decompensated severe chronic heart failure. * **Side Effects:** Hypotension (due to vasodilation) and headache. * **Comparison:** Unlike Milrinone (a PDE-3 inhibitor), Levosimendan does not significantly increase the risk of calcium-overload-induced arrhythmias.

Question 469: Monday disease is associated with exposure to which class of drugs?

A. Beta blockers
B. Nitrates (Correct Answer)
C. Calcium channel blockers
D. Potassium channel openers

Explanation: **Explanation:** **Monday Disease** is a classic phenomenon associated with industrial exposure to **Nitrates** (specifically nitroglycerin and ethylene glycol dinitrate) in explosives factories. **Why Nitrates are the correct answer:** Workers in these factories develop a high degree of **tolerance** to the vasodilatory effects of nitrates during the workweek. By the weekend, when they are away from the exposure, this tolerance is lost. Upon returning to work on **Monday**, the re-exposure causes sudden, intense vasodilation, leading to severe headaches (due to meningeal artery dilation), dizziness, and tachycardia. This cycle of losing and regaining tolerance is the hallmark of "Monday Disease." **Why other options are incorrect:** * **Beta blockers:** These drugs are used to manage heart rate and blood pressure; they do not cause industrial tolerance-withdrawal syndromes like nitrates. * **Calcium channel blockers (CCBs):** While CCBs cause vasodilation, they are not associated with the rapid tolerance and "weekend-reset" phenomenon seen in industrial nitrate exposure. * **Potassium channel openers:** Drugs like Minoxidil or Nicorandil cause vasodilation but are not used in the industrial manufacturing processes linked to this specific occupational hazard. **High-Yield Clinical Pearls for NEET-PG:** 1. **Tolerance Management:** To prevent nitrate tolerance in clinical practice, a **"Nitrate-free interval"** of 8–12 hours (usually at night) is mandatory. 2. **Mechanism:** Nitrates work by releasing **Nitric Oxide (NO)**, which increases **cGMP**, leading to dephosphorylation of myosin light chains and vascular smooth muscle relaxation. 3. **Drug Interaction:** Nitrates are strictly contraindicated with **Sildenafil** (PDE-5 inhibitors) as the combination can cause life-threatening hypotension.

Question 470: Which class of antihypertensive medications is primarily used in the management of angina pectoris?

A. Alpha blocker
B. Beta blocker (Correct Answer)
C. Diuretics
D. ACE inhibitors

Explanation: **Explanation:** **Why Beta Blockers are the Correct Choice:** Beta-blockers (e.g., Atenolol, Metoprolol) are the first-line antihypertensive agents for patients with comorbid stable angina. Their primary mechanism involves blocking $\beta_1$ receptors in the heart, leading to a decrease in heart rate (**negative chronotropy**) and myocardial contractility (**negative inotropy**). This significantly reduces **myocardial oxygen demand**. Additionally, by slowing the heart rate, they increase the duration of diastole, which improves coronary perfusion. **Analysis of Incorrect Options:** * **Alpha-blockers (A):** These cause peripheral vasodilation. While they lower blood pressure, they often trigger **reflex tachycardia**, which increases oxygen demand and can worsen anginal symptoms. * **Diuretics (C):** These reduce blood pressure by decreasing plasma volume. They have no direct effect on myocardial oxygen supply or demand and are not used for the management of angina. * **ACE Inhibitors (D):** These are excellent for hypertension, heart failure, and diabetic nephropathy. While they provide cardioprotection post-MI, they do not have direct anti-anginal properties (they don't reduce heart rate or contractility). **High-Yield Clinical Pearls for NEET-PG:** * **DOC for Angina:** Beta-blockers are the drugs of choice for the chronic prophylaxis of stable angina. * **Contraindication:** Avoid beta-blockers in **Prinzmetal (variant) angina**, as they can lead to unopposed alpha-mediated coronary vasospasm. * **Goal:** In angina patients, the dose should be titrated to maintain a resting heart rate of 55–60 bpm. * **Sudden Withdrawal:** Never stop beta-blockers abruptly; it can precipitate rebound hypertension or myocardial infarction due to receptor up-regulation.

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

Practice Questions

Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

Practice Questions

Cardiovascular Effects of Non-Cardiovascular Drugs

Practice Questions

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free