Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 401: What is the most effective method of treatment for Digitalis toxicity?

A. Hemodialysis
B. Cardioversion
C. Digoxin Antibody (Correct Answer)
D. Atropine

Explanation: **Explanation:** **Digoxin-specific antibody fragments (Digibind/Digifab)** are the definitive and most effective treatment for life-threatening digitalis toxicity. These are Fab fragments derived from ovine (sheep) antibodies that have a high affinity for digoxin. Once administered, they bind to free digoxin in the extracellular space, creating a complex that is excreted by the kidneys. This shifts the equilibrium, pulling digoxin away from its binding sites on the Na+/K+ ATPase pump, rapidly reversing toxicity. **Analysis of Incorrect Options:** * **Hemodialysis (A):** Digoxin has a very large volume of distribution ($V_d$) and is sequestered in tissues (like skeletal muscle). Therefore, it is not effectively removed by dialysis or hemoperfusion. * **Cardioversion (B):** DC cardioversion is generally **contraindicated** in digitalis toxicity because the myocardium is electrically unstable. It can precipitate fatal ventricular fibrillation or asystole. * **Atropine (D):** While Atropine is used to treat digitalis-induced bradycardia or AV blocks, it only manages the symptom, not the underlying cause (the toxic levels of digoxin). **High-Yield Clinical Pearls for NEET-PG:** * **Indications for Digibind:** Severe hyperkalemia ($K^+ > 5.0$ mEq/L), life-threatening arrhythmias (VT/VF), or ingestion of >10 mg in adults. * **Electrolyte Warning:** The earliest sign of toxicity is often GI upset (nausea/vomiting), but the most common ECG finding is **PVCs**. The most specific ECG finding is **Bidirectional Ventricular Tachycardia**. * **Hypokalemia** predisposes a patient to digoxin toxicity, but **Hyperkalemia** is a marker of acute severe toxicity (due to inhibition of Na+/K+ pumps).

Question 402: All of the following can worsen angina except?

A. Dipyridamole
B. Oxyphedrine (Correct Answer)
C. Thyroxine
D. Sumatriptan

Explanation: **Explanation:** The core concept behind worsening angina is an imbalance between myocardial oxygen supply and demand. **Why Oxyphedrine is the Correct Answer:** Oxyphedrine is a unique **partial $\beta$-agonist** used specifically in the treatment of chronic angina. Unlike pure stimulants, it acts as a "myocardial enhancer." It improves coronary blood flow and myocardial metabolism without significantly increasing heart rate or oxygen consumption. Because it is used to *treat* angina rather than provoke it, it is the correct exception. **Why the Other Options Worsen Angina:** * **Dipyridamole:** It causes **Coronary Steal Phenomenon**. It dilates healthy coronary arterioles, diverting blood flow away from the already maximally dilated, ischemic vessels in stenosed areas, thus worsening ischemia. * **Thyroxine:** It increases the metabolic rate and expression of $\beta$-receptors in the heart. This leads to increased heart rate (tachycardia) and force of contraction, significantly raising myocardial oxygen demand. * **Sumatriptan:** As a 5-HT$_{1B/1D}$ receptor agonist used for migraines, it can cause **coronary vasospasm**. It is strictly contraindicated in patients with known ischemic heart disease (Prinzmetal or stable angina). **High-Yield Clinical Pearls for NEET-PG:** * **Coronary Steal Syndrome:** Classically associated with Dipyridamole and Adenosine; used clinically during pharmacological stress testing. * **Drugs causing Coronary Vasospasm:** Sumatriptan, Ergotamine, and Cocaine. * **Oxyphedrine vs. Ephedrine:** Do not confuse the two. Ephedrine is a sympathomimetic that *increases* BP/HR and would worsen angina, whereas Oxyphedrine is a vasodilator used in its management.

Question 403: Which of the following drugs is not a blocker of L-type calcium channels?

A. Diltiazem
B. Amlodipine
C. Ethosuximide (Correct Answer)
D. Verapamil

Explanation: The core concept tested here is the classification of calcium channel blockers (CCBs) based on their specific channel targets and clinical applications. **1. Why Ethosuximide is the correct answer:** Ethosuximide is a primary anti-epileptic drug used for **Absence seizures (Petit mal)**. Its mechanism of action involves the selective blockade of **T-type (Transient) calcium calcium channels** in thalamic neurons. It does not inhibit L-type (Long-lasting) channels, which are predominantly found in vascular smooth muscle and cardiac tissue. **2. Why the other options are incorrect:** Options A, B, and D are all classic **L-type Calcium Channel Blockers**, categorized into two chemical classes [1]: * **Amlodipine (Option B):** A Dihydropyridine (DHP) [2]. It selectively blocks L-type channels in vascular smooth muscle, causing vasodilation [3]. It is used for hypertension and angina. * **Verapamil (Option D) & Diltiazem (Option A):** Non-Dihydropyridines. They block L-type channels in both the myocardium and specialized conduction tissue (SA/AV nodes) [1], [3]. They are used for arrhythmias (Rate control), angina, and hypertension. **3. NEET-PG High-Yield Pearls:** * **L-type channels:** "L" stands for **L**ong-lasting/Large current. Target for CVS drugs (HTN, Angina, Arrhythmia) [1]. * **T-type channels:** "T" stands for **T**ransient/Tiny current. Target for Ethosuximide and Valproate (in the thalamus) and Mibefradil (cardiac). * **N-type channels:** "N" stands for **N**euronal. Blocked by **Ziconotide** (used for chronic pain). * **Drug of Choice (DOC):** Ethosuximide is the DOC for Absence seizures in children; however, if generalized tonic-clonic seizures (GTCS) coexist, Valproate is preferred.

Question 404: A 75-year-old, obese female is admitted with acute myocardial infarction and congestive heart failure, then has an episode of ventricular tachycardia. She is prescribed multiple medications and soon develops confusion and slurred speech. What is the most likely cause of this confusion?

A. Captopril
B. Digoxin
C. Furosemide
D. Lidocaine (Correct Answer)

Explanation: **Explanation:** The correct answer is **Lidocaine**. Lidocaine is a Class IB antiarrhythmic used for ventricular arrhythmias, especially in the setting of acute myocardial infarction (MI). Unlike other antiarrhythmics, Lidocaine toxicity primarily manifests as **Central Nervous System (CNS) side effects**. Early signs include confusion, slurred speech, tremors, and paresthesia, which can progress to seizures and coma. In this patient, two factors increase the risk of toxicity: 1. **Congestive Heart Failure (CHF):** Lidocaine is metabolized by the liver. In CHF, reduced hepatic blood flow leads to decreased clearance and toxic accumulation of the drug. 2. **Age:** Elderly patients often have reduced metabolic capacity. **Why the other options are incorrect:** * **Captopril (ACE Inhibitor):** Common side effects include dry cough, hyperkalemia, and angioedema. It does not typically cause acute confusion or slurred speech. * **Digoxin:** Toxicity usually presents with gastrointestinal symptoms (nausea/vomiting), visual disturbances (xanthopsia/yellow-green halos), and cardiac arrhythmias (e.g., PVCs, AV block). * **Furosemide:** A loop diuretic that causes electrolyte imbalances (hypokalemia, hyponatremia) and dehydration. While severe hyponatremia can cause confusion, it is less likely to present acutely with slurred speech immediately following VT treatment. **NEET-PG High-Yield Pearls:** * **Lidocaine Metabolism:** It has a high first-pass metabolism; hence, it is given only IV. * **Drug of Choice:** While Lidocaine was historically the first choice for post-MI VT, **Amiodarone** is now preferred due to a better safety profile. * **CNS Toxicity Sequence:** "SAMS" (Slurred speech, Altered mental status, Muscle twitching, Seizures).

Question 405: A hypertensive patient with BP 160/90 mm Hg presents with an increased level of Lipoprotein A. Which hypolipidemic drug will you prescribe?

A. Fenofibrate
B. Pitavastatin
C. Niacin (Correct Answer)
D. Ezetimibe

Explanation: The correct answer is **Niacin (Nicotinic Acid)**. **1. Why Niacin is Correct:** Lipoprotein(a) [Lp(a)] is an independent genetic risk factor for atherosclerosis and cardiovascular disease. Most conventional lipid-lowering drugs (like statins and fibrates) have little to no effect on Lp(a) levels. **Niacin** is the most potent traditional hypolipidemic agent for reducing Lp(a) levels (by approximately 20-30%) [1]. It works by inhibiting the synthesis of apolipoprotein B-100 and reducing the assembly of VLDL, which subsequently lowers LDL and Lp(a). **2. Why Other Options are Incorrect:** * **Pitavastatin:** While statins are the first-line treatment for lowering LDL-C, they do not significantly reduce Lp(a) [1]. In some cases, statins may even cause a paradoxical slight increase in Lp(a) levels. * **Fenofibrate:** Fibrates primarily target triglycerides by activating PPAR-α. They have a negligible effect on Lp(a) concentrations [1]. * **Ezetimibe:** This drug inhibits cholesterol absorption in the small intestine. While it lowers LDL-C, it has no clinically significant effect on Lp(a) [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Most effective drug to increase HDL:** Niacin [1]. * **Most effective drug to lower Triglycerides:** Fibrates [1]. * **Most effective drug to lower LDL:** Statins (specifically Rosuvastatin/Atorvastatin) [1]. * **Niacin Side Effects:** Cutaneous flushing (mediated by Prostaglandin $D_2$; prevented by Aspirin), Hyperuricemia (can precipitate Gout), and Hyperglycemia (caution in Diabetics). * **Newer Agents for Lp(a):** PCSK9 inhibitors (Evolocumab) also reduce Lp(a), but Niacin remains the classic answer for this specific pharmacological property in exams.

Question 406: What is the antidote for digoxin toxicity?

A. Potassium
B. Lidocaine
C. Digoxin-specific antibody fragments (Fab) (Correct Answer)
D. Propranolol

Explanation: Correct Answer: C. Digoxin-specific antibody fragments (Fab)Digoxin-specific antibody fragments (Digibind/Digifab) are the **definitive antidote** for life-threatening digoxin toxicity. They work by binding to free intravascular digoxin, creating a complex that is excreted by the kidneys. This shifts the equilibrium, pulling digoxin away from its binding sites on the Na+/K+ ATPase pump, thereby reversing the toxic effects on the heart.Analysis of Incorrect Options:* **A. Potassium:** While hypokalemia predisposes a patient to digoxin toxicity, potassium is only used to treat toxicity if the patient is hypokalemic. In acute overdose, **hyperkalemia** is actually a common and dangerous finding (due to inhibition of the Na+/K+ pump); giving more potassium in such cases would be fatal.* **B. Lidocaine:** This is the drug of choice for treating digoxin-induced **ventricular arrhythmias** (tachyarrhythmias), but it does not reverse the underlying toxicity or the drug levels.* **D. Propranolol:** Beta-blockers are generally avoided in digoxin toxicity because they can worsen the bradycardia and AV block already caused by digoxin’s vagomimetic effects.High-Yield Clinical Pearls for NEET-PG:* **Mechanism of Action:** Digoxin inhibits the Na+/K+ ATPase pump, leading to increased intracellular Na+, which then decreases Ca2+ efflux via the Na+/Ca2+ exchanger, increasing intracellular Ca2+ (positive inotropy) [1].* **ECG Changes:** The most common arrhythmia is **PVCs**; the most characteristic is **Paroxysmal Atrial Tachycardia with AV block** [2].* **Visual Side Effect:** Xanthopsia (yellow-green halos around lights).* **Indications for Fab:** Serum K+ > 5.0 mEq/L, life-threatening arrhythmias [2], or ingestion of >10 mg in adults.

Question 407: Which of the following drugs commonly causes constipation?

A. Propranolol
B. Verapamil (Correct Answer)
C. Nitroglycerin
D. Captopril

Explanation: **Explanation:** **Verapamil** is a non-dihydropyridine Calcium Channel Blocker (CCB) that is notorious for causing **constipation** (seen in up to 25% of patients). The underlying mechanism involves the blockade of L-type calcium channels in the smooth muscles of the gastrointestinal tract. Calcium entry is essential for the contraction of colonic smooth muscle; by inhibiting this, Verapamil reduces intestinal motility and increases transit time, leading to constipation. **Analysis of Incorrect Options:** * **Propranolol (Beta-blocker):** More commonly associated with fatigue, bradycardia, and bronchospasm. While it can occasionally cause GI upset, it is not a classic cause of constipation. * **Nitroglycerin (Nitrate):** Its primary side effects are related to vasodilation, such as throbbing headaches, flushing, and orthostatic hypotension. * **Captopril (ACE Inhibitor):** Most famous for causing a dry cough (due to bradykinin accumulation), angioedema, and hyperkalemia. **High-Yield Clinical Pearls for NEET-PG:** * **Verapamil** is the CCB with the most significant negative inotropic effect; it is contraindicated in Heart Failure. * Among CCBs, constipation is most severe with Verapamil and least common with dihydropyridines like Amlodipine. * **Drug of Choice:** Verapamil is a drug of choice for Supraventricular Tachycardia (SVT) and prophylaxis of Cluster Headaches. * **Gingival Hyperplasia:** Along with Phenytoin and Cyclosporine, CCBs (especially Nifedipine and Verapamil) are common causes of gum enlargement.

Question 408: Which of the following beta-blockers can be used in renal failure, EXCEPT?

A. Propranolol
B. Pindolol
C. Sotalol (Correct Answer)
D. Oxprenolol

Explanation: ### Explanation The key to answering this question lies in understanding the **pharmacokinetics** of beta-blockers, specifically their route of elimination. **1. Why Sotalol is the Correct Answer:** Beta-blockers are broadly categorized based on their lipid solubility. **Sotalol** is a highly water-soluble (hydrophilic) beta-blocker. Unlike lipid-soluble drugs that are metabolized by the liver, hydrophilic drugs are primarily excreted **unchanged by the kidneys**. In patients with renal failure, the clearance of Sotalol is significantly reduced, leading to toxic accumulation and an increased risk of life-threatening arrhythmias (like Torsades de Pointes due to its Class III antiarrhythmic properties). Therefore, it must be avoided or strictly dose-adjusted in renal impairment. **2. Analysis of Incorrect Options:** * **Propranolol:** This is the prototype of highly lipid-soluble beta-blockers. it undergoes extensive hepatic metabolism. Since it does not rely on renal excretion, it is safe to use in renal failure. * **Pindolol and Oxprenolol:** These are moderately lipid-soluble drugs. They undergo significant hepatic metabolism and are generally considered safe for use in patients with decreased renal function without major dose adjustments. **3. NEET-PG High-Yield Pearls:** * **Lipid Soluble (Hepatic Clearance):** Propranolol, Metoprolol, Labetalol, Carvedilol. (Mnemonic: **L**ipid = **L**iver). Safe in renal failure. * **Water Soluble (Renal Clearance):** Atenolol, Sotalol, Nadolol. (Mnemonic: **S**afe **A**nswer **N**eeded for Kidney). Avoid/Adjust in renal failure. * **Esmolol:** Unique because it is metabolized by **RBC esterases**, giving it the shortest half-life (~9 minutes). * **Bisoprolol:** Undergoes balanced clearance (50% hepatic, 50% renal).

Question 409: Fenoldopam is a selective agonist for which receptors?

A. D1 agonist
B. D1, α1, β1 agonist
C. D1, α2 agonist (Correct Answer)
D. D1, D2 agonist

Explanation: **Explanation:** Fenoldopam is a unique parenteral vasodilator used primarily in the management of **hypertensive emergencies**. **Why Option C is Correct:** Fenoldopam acts as a **selective post-synaptic Dopamine-1 (D1) receptor agonist** and a **moderate α2-adrenoceptor agonist**. * **D1 Agonism:** This leads to potent vasodilation in the coronary, renal, and mesenteric vascular beds via the activation of adenylyl cyclase and increased cAMP. * **α2 Agonism:** While its primary clinical effect is attributed to D1 stimulation, its affinity for α2 receptors is a recognized pharmacological property that distinguishes it from pure dopamine. **Analysis of Incorrect Options:** * **Option A:** While Fenoldopam is often simplified as a "selective D1 agonist" in basic texts, it possesses α2 activity, making Option C more precise in a competitive exam context. * **Option B:** Fenoldopam lacks significant activity at α1 or β1 receptors. This is a major clinical advantage over Dopamine, as it does not cause reflex tachycardia or vasoconstriction. * **Option D:** Fenoldopam has negligible affinity for D2 receptors, unlike Dopamine which stimulates both D1 and D2. **NEET-PG High-Yield Pearls:** 1. **Renal Benefit:** Fenoldopam is the only intravenous antihypertensive that **maintains or increases renal perfusion** while lowering blood pressure. It also promotes natriuresis (sodium excretion). 2. **Clinical Use:** It is a preferred agent for hypertensive emergencies in patients with **renal insufficiency**. 3. **Side Effects:** It can cause a dose-dependent increase in **intraocular pressure** (avoid in glaucoma) and may cause hypokalemia. 4. **Half-life:** It has a very short half-life (~5–10 minutes), requiring continuous IV infusion.

Question 410: High-density lipoprotein (HDL) levels are specifically increased by which of the following medications?

A. Lovastatin
B. Niacin (Correct Answer)
C. Gemfibrozil
D. Probucol

Explanation: **Explanation:** **Niacin (Vitamin B3)** is the correct answer because it is the most potent agent currently available for increasing **HDL-C levels** (typically by 15–35%). It achieves this primarily by inhibiting the surface expression of ATP synthase beta, which decreases the hepatic uptake and catabolism of HDL particles, thereby increasing their half-life in the circulation. Additionally, Niacin inhibits adipose tissue lipolysis, reducing the delivery of free fatty acids to the liver and subsequently lowering VLDL and LDL production. **Analysis of Incorrect Options:** * **Lovastatin (Statins):** Their primary mechanism is inhibiting HMG-CoA reductase. While they are the first-line drugs for lowering **LDL-C**, their effect on increasing HDL is modest (5–10%). * **Gemfibrozil (Fibrates):** These are PPAR-α agonists primarily used to lower **Triglycerides**. While they do increase HDL, their effect is generally less consistent and less potent than Niacin. * **Probucol:** This is an older lipid-lowering agent that is unique because it actually **decreases HDL levels** (by inhibiting CETP-like activity), making it the opposite of what the question asks. **NEET-PG High-Yield Pearls:** * **Side Effects of Niacin:** The most common side effect is **cutaneous flushing** (mediated by Prostaglandin D2/E2), which can be prevented by pre-treatment with **Aspirin**. It can also cause hyperuricemia (gout) and hyperglycemia (diabetes). * **Drug of Choice:** Statins are the DOC for hypercholesterolemia; Fibrates are the DOC for hypertriglyceridemia. * **Combination Therapy:** Combining Niacin with Statins increases the risk of **myopathy**, though less so than the Statin-Gemfibrozil combination.

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

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