Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 431: Tadalafil is contraindicated in?

A. Pulmonary arterial hypertension
B. Chronic stable angina (acute episode) (Correct Answer)
C. Active infections
D. Hepatic dysfunction

Explanation: **Explanation:** **Tadalafil**, a selective Phosphodiesterase-5 (PDE-5) inhibitor, is contraindicated in patients experiencing an acute episode of **chronic stable angina** because the standard of care for acute anginal pain is **Nitroglycerin (Organic Nitrates)**. 1. **Mechanism of Contraindication:** PDE-5 inhibitors prevent the breakdown of cGMP, while Nitrates increase cGMP production via nitric oxide. When used together, they cause a synergistic accumulation of cGMP, leading to profound systemic vasodilation and **severe, life-threatening hypotension**, which can precipitate a myocardial infarction. 2. **Incorrect Options:** * **Pulmonary Arterial Hypertension (PAH):** This is actually a primary *indication* for Tadalafil (along with Sildenafil), as it promotes vasodilation in the pulmonary vasculature. * **Active Infections:** There is no direct contraindication for PDE-5 inhibitors in most infections, though caution is advised in severe sepsis due to baseline hypotension. * **Hepatic Dysfunction:** While dose adjustments are required in mild-to-moderate hepatic impairment, it is not an absolute contraindication unless the dysfunction is end-stage/severe. **High-Yield Clinical Pearls for NEET-PG:** * **The "Time Gap" Rule:** Nitrates should not be administered within **24 hours** of Sildenafil/Vardenafil or within **48 hours** of Tadalafil (due to its longer half-life of ~17.5 hours). * **Other Indications:** Tadalafil is also FDA-approved for **Erectile Dysfunction (ED)** and **Benign Prostatic Hyperplasia (BPH)**. * **Side Effects:** Common side effects include headache, flushing, and dyspepsia. A rare but serious side effect is **Non-arteritic Anterior Ischemic Optic Neuropathy (NAION)**.

Question 432: What is the drug of choice for paroxysmal supraventricular tachycardia?

A. Digoxin
B. Propranolol
C. Adenosine (Correct Answer)
D. Diltiazem

Explanation: ### Explanation **Correct Answer: C. Adenosine** **Why Adenosine is the Drug of Choice (DOC):** Adenosine is the first-line treatment for terminating acute episodes of **Paroxysmal Supraventricular Tachycardia (PSVT)**, specifically those involving the AV node (AVNRT) [1]. * **Mechanism of Action:** It acts on **A1 receptors** in the AV node, leading to the opening of potassium channels (hyperpolarization) [1] and inhibition of calcium current. This results in a transient, profound slowing of AV nodal conduction, effectively "breaking" the re-entry circuit. * **Pharmacokinetics:** It has an ultra-short half-life (**<10 seconds**), necessitating rapid IV push [1]. This rapid clearance minimizes prolonged systemic side effects. **Analysis of Incorrect Options:** * **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. * **B. Propranolol:** A beta-blocker that can be used for prophylaxis or rate control, but it is not the first-line agent for acute conversion due to a slower onset and risk of prolonged bradycardia/hypotension compared to Adenosine. * **D. Diltiazem:** A Calcium Channel Blocker (CCB) used as a second-line agent if Adenosine is ineffective or contraindicated (e.g., in asthma) [1]. It has a longer duration of action, which may cause persistent hypotension. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Must be given via a **large-bore peripheral IV** (usually antecubital) followed by a rapid saline flush (due to the short half-life). * **Contraindications:** Avoid in **Asthma/COPD** (causes bronchospasm via A2B receptors) and **2nd/3rd-degree Heart Block**. * **Drug Interactions:** **Theophylline/Caffeine** (antagonists) decrease its effect; **Dipyridamole** (uptake inhibitor) potentiates its effect. * **Side Effects:** Patients often experience a transient, distressing feeling of "impending doom," chest pain, or flushing [1].

Question 433: Which of the following Angiotensin II receptor blockers exhibits antiplatelet action?

A. Losartan (Correct Answer)
B. Valsartan
C. Irbesartan
D. Candesartan

Explanation: **Explanation:** **Losartan** is unique among Angiotensin II Receptor Blockers (ARBs) because it possesses a distinct pharmacological profile beyond AT1 receptor blockade. 1. **Why Losartan is correct:** Losartan and its active metabolite (E-3174) act as **competitive antagonists of the Thromboxane A2 (TXA2) receptor**. By blocking these receptors on the surface of platelets, Losartan inhibits platelet aggregation and reduces the risk of thrombus formation. Additionally, Losartan is the only ARB that exhibits **uricosuric activity** by inhibiting the URAT1 transporter in the proximal tubule, making it beneficial for hypertensive patients with gout. 2. **Why other options are incorrect:** * **Valsartan, Irbesartan, and Candesartan:** These are "pure" ARBs. While they are highly effective at blocking the AT1 receptor to cause vasodilation and reduce aldosterone secretion, they do not possess the specific molecular structure required to antagonize thromboxane receptors or inhibit uric acid reabsorption. Their primary clinical benefits are limited to blood pressure control, heart failure management, and nephroprotection in diabetes. **High-Yield Clinical Pearls for NEET-PG:** * **Uricosuric ARB:** Losartan (decreases serum uric acid). * **Longest-acting ARB:** Telmisartan (also acts as a partial agonist at PPAR-γ, improving insulin sensitivity). * **Highest affinity for AT1 receptor:** Candesartan. * **Prodrug ARBs:** Candesartan, Olmesartan, and Azilsartan. * **Common Side Effect:** ARBs do not cause a dry cough (unlike ACE inhibitors) because they do not increase bradykinin levels.

Question 434: Which beta-blocker is used in Congestive Heart Failure?

A. Timolol
B. Atenolol
C. Acebutalol
D. Carvedilol (Correct Answer)

Explanation: **Explanation:** In Congestive Heart Failure (CHF), chronic sympathetic overactivation leads to cardiac remodeling and worsening dysfunction. While beta-blockers were historically contraindicated in acute failure, specific agents are now a cornerstone of therapy to reduce mortality. **1. Why Carvedilol is Correct:** Carvedilol is a **non-selective beta-blocker (β1, β2) with additional alpha-1 (α1) blocking properties**. This dual action provides two benefits: * **Beta-blockade:** Protects the myocardium from the toxic effects of chronic catecholamine exposure and reduces heart rate. * **Alpha-1 blockade:** Causes peripheral vasodilation, which reduces **afterload**, making it easier for the failing heart to pump blood. * It also possesses antioxidant and anti-proliferative properties that inhibit cardiac remodeling. **2. Analysis of Incorrect Options:** * **Timolol (A):** A non-selective beta-blocker primarily used topically in glaucoma to reduce intraocular pressure. It is not a standard treatment for CHF. * **Atenolol (B):** A cardioselective (β1) blocker. While it reduces heart rate, it lacks the vasodilatory properties and robust clinical evidence for mortality benefit in CHF compared to the "Big Three" (Carvedilol, Metoprolol succinate, Bisoprolol). * **Acebutolol (C):** This drug has **Intrinsic Sympathomimetic Activity (ISA)**. Drugs with ISA act as partial agonists; they do not provide the necessary "complete rest" to the heart and may actually worsen CHF. **3. High-Yield Clinical Pearls for NEET-PG:** * **The "Big Three" in CHF:** Only three beta-blockers are proven to reduce mortality in chronic heart failure: **Carvedilol, Bisoprolol, and Metoprolol succinate.** (Note: Nebivolol is also used in elderly patients). * **Contraindication:** Beta-blockers should **never** be started during an *acute* decompensated phase of CHF; they are for stable, chronic management. * **Carvedilol Ratio:** It is more potent at blocking beta receptors than alpha receptors (approx. 10:1).

Question 435: Which is the longest-acting beta-blocker?

A. Nadolol (Correct Answer)
B. Esmolol
C. Carvedilol
D. Acebutolol

Explanation: **Explanation:** The duration of action of beta-blockers is primarily determined by their lipid solubility and metabolic pathway. **Nadolol** is a non-selective beta-blocker characterized by its high water solubility (hydrophilicity). Because it is not metabolized by the liver and is excreted unchanged by the kidneys, it possesses an exceptionally long plasma half-life (approximately 14 to 24 hours). This allows for once-daily dosing, making it the longest-acting conventional beta-blocker. **Analysis of Options:** * **B. Esmolol:** This is the **shortest-acting** beta-blocker. It is an ultra-short-acting $\beta_1$-selective antagonist with a half-life of only 9 minutes due to rapid hydrolysis by red blood cell esterases. It is administered via IV infusion for emergency situations. * **C. Carvedilol:** A combined $\alpha_1$ and non-selective $\beta$-blocker used in heart failure. It has a moderate half-life of about 6–10 hours. * **D. Acebutolol:** A cardioselective beta-blocker with Intrinsic Sympathomimetic Activity (ISA). Its half-life is roughly 3–4 hours, though its active metabolite (diacetolol) lasts longer (8–12 hours), it still does not exceed Nadolol. **NEET-PG High-Yield Pearls:** * **Longest acting:** Nadolol. * **Shortest acting:** Esmolol (used in supraventricular tachycardia and aortic dissection). * **Most lipid-soluble:** Propranolol (crosses BBB, used for tremors and prophylaxis of migraine). * **Least lipid-soluble:** Atenolol and Nadolol (low CNS side effects). * **Beta-blocker with longest half-life among "selective" agents:** Betaxolol.

Question 436: Flushing with niacin is reduced by all of the following EXCEPT:

A. Laropiprant
B. Premedication with aspirin
C. Tachyphylaxis
D. PGD2 (Correct Answer)

Explanation: **Explanation:** Niacin (Nicotinic acid) induces cutaneous flushing primarily through the release of **Prostaglandin D2 (PGD2)** and **Prostaglandin E2 (PGE2)** in the skin. These prostaglandins act on DP1 receptors, causing intense vasodilation. Therefore, PGD2 is the **cause** of the flushing, not a factor that reduces it. **Why the other options are incorrect (Factors that REDUCE flushing):** * **Laropiprant:** This is a selective **DP1 receptor antagonist**. By blocking the receptor where PGD2 acts, it significantly reduces niacin-induced flushing. * **Premedication with Aspirin:** Aspirin is a COX inhibitor. Since flushing is mediated by prostaglandins, taking aspirin 30 minutes before niacin inhibits prostaglandin synthesis, thereby mitigating the side effect. * **Tachyphylaxis:** This refers to the rapid decrease in response to a drug after repeated doses. With continued use of niacin, the flushing response typically diminishes within 1–2 weeks as the skin cells become desensitized. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Niacin:** It inhibits adipose tissue lipolysis by acting on G protein-coupled receptors (HM74A), leading to decreased VLDL and LDL synthesis. * **Lipid Profile:** Niacin is the most effective agent for **increasing HDL levels**. * **Side Effects:** Apart from flushing, niacin can cause **hyperuricemia** (precipitating gout), **hyperglycemia** (caution in diabetics), and **acanthosis nigricans**. * **Pro-tip:** Taking niacin with meals or using sustained-release formulations also helps reduce the intensity of flushing.

Question 437: What is the most rapid method for relieving the symptoms of angina pectoris?

A. Oxygen
B. Ibuprofen
C. A barbiturate
D. Nitrates (Correct Answer)

Explanation: **Explanation:** **Nitrates** (specifically sublingual Nitroglycerin) are the treatment of choice for the immediate relief of acute angina pectoris. Their rapid onset of action (1–3 minutes) is due to their ability to act as prodrugs that release **Nitric Oxide (NO)**. NO activates guanylate cyclase, increasing cGMP, which leads to dephosphorylation of myosin light chains and subsequent vascular smooth muscle relaxation. The primary therapeutic effect is **venodilation**, which decreases venous return (preload), thereby reducing left ventricular end-diastolic pressure and myocardial oxygen demand. **Why other options are incorrect:** * **Oxygen:** While supplemental oxygen is indicated if the patient is hypoxemic (SpO2 <90%), it does not provide immediate relief of ischemic pain in a stable patient with normal oxygen saturation. * **Ibuprofen:** NSAIDs are generally avoided in ischemic heart disease as they can increase the risk of cardiovascular events and do not address the underlying pathophysiology of myocardial oxygen supply-demand mismatch. * **Barbiturates:** These are sedatives/hypnotics. While they may reduce anxiety, they have no direct effect on coronary blood flow or myocardial oxygen consumption. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Choice:** Sublingual administration bypasses **first-pass metabolism**, ensuring rapid systemic availability. * **Drug of Choice for Prinzmetal Angina:** Nitrates or Calcium Channel Blockers (CCBs). * **Contraindication:** Nitrates must never be given with **Sildenafil** (PDE-5 inhibitors) due to the risk of severe, life-threatening hypotension. * **Tolerance:** Continuous use leads to "Nitrate tolerance"; a 10–12 hour nitrate-free interval is required daily to maintain efficacy.

Question 438: Colesevelam is a:

A. HMG Co enzyme inhibitor
B. Insulin secretogogue
C. Bile acid sequestrant (Correct Answer)
D. Alpha glucosidase inhibitor

Explanation: **Explanation:** **Colesevelam** is a second-generation **Bile Acid Sequestrant** (also known as a bile acid-binding resin). **Mechanism of Action:** These drugs are large, non-absorbable polymers that bind to bile acids in the intestinal lumen, preventing their enterohepatic circulation. This forces the liver to synthesize new bile acids from endogenous cholesterol. To meet this demand, the liver increases the expression of **LDL receptors**, leading to a significant reduction in serum LDL-C levels. **Analysis of Incorrect Options:** * **Option A (HMG-CoA Reductase Inhibitors):** These are the **Statins** (e.g., Atorvastatin). They inhibit the rate-limiting enzyme in cholesterol synthesis. * **Option B (Insulin Secretagogues):** These include **Sulfonylureas** (e.g., Glipizide) and **Meglitinides**, which stimulate the pancreas to release insulin. * **Option D (Alpha-glucosidase Inhibitors):** These are drugs like **Acarbose** and **Voglibose** that delay carbohydrate absorption in the gut. **High-Yield Clinical Pearls for NEET-PG:** 1. **Unique Property:** Unlike older resins (Cholestyramine), Colesevelam has a higher affinity for bile acids, requires a lower dose, and causes fewer GI side effects. 2. **Dual Indication:** Colesevelam is the only bile acid sequestrant also FDA-approved for improving glycemic control in **Type 2 Diabetes Mellitus** (it reduces HbA1c by ~0.5%). 3. **Safety in Pregnancy:** Since they are not absorbed systemically, bile acid sequestrants are often considered the safest lipid-lowering drugs during pregnancy. 4. **Adverse Effect:** They can cause a compensatory rise in **Triglycerides**; therefore, they are contraindicated if baseline TG levels are >300 mg/dL.

Question 439: All of the following statements about amlodipine are true except?

A. It acts by conversion to an active metabolite in the liver. (Correct Answer)
B. It has a very large volume of distribution.
C. It undergoes very little first pass metabolism and possesses high and consistent oral bioavailability.
D. It has a very long elimination half life.

Explanation: ### Explanation **1. Why Option A is the correct answer (The False Statement):** Amlodipine is a **direct-acting drug**, not a prodrug. Unlike some other cardiovascular agents, it does not require hepatic conversion to an active metabolite to exert its pharmacological effects. It is extensively metabolized in the liver, but the resulting metabolites are **pharmacologically inactive**. Therefore, the statement that it acts via an active metabolite is incorrect. **2. Analysis of Incorrect Options (True Statements):** * **Option B:** Amlodipine is highly lipophilic and extensively tissue-bound, leading to a **very large volume of distribution (Vd ≈ 21 L/kg)**. This is a characteristic feature of long-acting dihydropyridines (DHPs). * **Option C:** Unlike nifedipine, which has high first-pass metabolism, amlodipine is absorbed slowly but completely. It has a **high and consistent oral bioavailability (60–65%)** because it escapes significant first-pass degradation. * **Option D:** Amlodipine has the **longest elimination half-life (35–50 hours)** among common Calcium Channel Blockers (CCBs). This allows for convenient once-daily dosing and provides a "smooth" antihypertensive effect with minimal reflex tachycardia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Blocks L-type voltage-gated calcium channels in vascular smooth muscle. * **Side Effects:** The most common side effect is **ankle edema** (due to precapillary vasodilation, not fluid overload). It does not cause significant pedal edema if combined with ACE inhibitors. * **Clinical Use:** It is a first-line drug for hypertension and chronic stable angina (Prinzmetal angina). * **Comparison:** Unlike Nifedipine (short-acting), Amlodipine does not cause "steal phenomenon" or precipitate acute MI.

Question 440: The antiarrhythmic classification into Class IA, IB, IC, II, III, IV, and V was proposed by whom?

A. Vaughan Williams (Correct Answer)
B. Ramnath Chopra
C. Oswald
D. David Sackett

Explanation: The classification of antiarrhythmic drugs is a fundamental concept in cardiovascular pharmacology. Explanation of the Correct Answer: The most widely used system for categorizing antiarrhythmic agents is the **Vaughan Williams classification**, proposed by Miles Vaughan Williams in 1970 and later modified by Singh and Harrison [1]. It organizes drugs based on their primary electrophysiological mechanism of action on the cardiac action potential [1, 2]: **Class I:** Sodium ($Na^+$) channel blockers (further divided into IA, IB, and IC based on their effect on the action potential duration) [1, 2]. **Class II:** Beta-blockers [1, 2]. **Class III:** Potassium ($K^+$) channel blockers (prolong repolarization) [1, 2]. **Class IV:** Calcium ($Ca^{2+}$) channel blockers [1, 2]. **Class V:** Miscellaneous agents (e.g., Adenosine, Digoxin, Magnesium) [2]. Analysis of Incorrect Options: Ramnath Chopra: Known as the "Father of Indian Pharmacology," he contributed significantly to the study of indigenous medicinal plants in India. Oswald Schmiedeberg: Often regarded as the "Father of Modern Pharmacology," he helped establish pharmacology as an independent scientific discipline in Germany. David Sackett: Known as the "Father of Evidence-Based Medicine (EBM)," his work focused on clinical epidemiology rather than drug classification. High-Yield Clinical Pearls for NEET-PG: **Class IA (Procainamide, Quinidine):** Increases Action Potential Duration (APD) and QT interval; risk of Torsades de pointes. **Class IB (Lidocaine, Mexiletine):** Decreases APD; most effective in ischemic arrhythmias (post-MI). **Class IC (Flecainide, Propafenide):** No effect on APD; contraindicated in structural heart disease or post-MI. **Class III (Amiodarone):** The "broad-spectrum" antiarrhythmic; despite being Class III, it exhibits properties of all four classes.

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

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