Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 421: Which drug directly stimulates contraction of cardiac muscle?

A. Digitalis (Correct Answer)
B. ACE inhibitors
C. Nesiritide
D. Losartan

Explanation: **Explanation:** **1. Why Digitalis is Correct:** Digitalis (Digoxin) is a **positive inotropic agent**. Its primary mechanism involves the inhibition of the **Na⁺/K⁺-ATPase pump** on the cardiac myocyte membrane. This leads to an increase in intracellular sodium, which subsequently slows down the Na⁺/Ca²⁺ exchanger. The resulting increase in intracellular calcium levels allows for more calcium to be available for the contractile apparatus (actin-myosin interaction) during systole, thereby **directly stimulating cardiac muscle contraction**. **2. Why Other Options are Incorrect:** * **ACE Inhibitors (e.g., Enalapril):** These are vasodilators that reduce afterload and preload by inhibiting the conversion of Angiotensin I to Angiotensin II. They do not have a direct stimulatory effect on myocardial contractility. * **Nesiritide:** This is a recombinant B-type natriuretic peptide (BNP). It acts as a potent vasodilator and diuretic to reduce cardiac filling pressures in acute heart failure but does not stimulate contraction. * **Losartan:** An Angiotensin II Receptor Blocker (ARB) that works by blocking AT1 receptors. Like ACE inhibitors, its benefit in heart failure is through neurohormonal blockade and vasodilation, not direct inotropy. **3. NEET-PG High-Yield Pearls:** * **Electrolyte Interaction:** Hypokalemia increases the risk of Digitalis toxicity because K⁺ and Digoxin compete for the same binding site on the Na⁺/K⁺-ATPase pump. * **ECG Changes:** Digoxin typically causes a "reverse tick" or "hockey stick" appearance (ST-segment depression). * **Therapeutic Use:** It is the drug of choice for controlling ventricular rate in patients with **Atrial Fibrillation** who also have heart failure. * **Antidote:** Digibind (Digoxin-specific Fab fragments).

Question 422: All of the following drugs are non-selective beta-blockers with no pharmacological action on any other receptor, EXCEPT:

A. Propranolol
B. Timolol
C. Sotalol
D. Carvedilol (Correct Answer)

Explanation: ### Explanation The core concept tested here is the classification of beta-blockers based on their **generation** and **receptor selectivity**. **1. Why Carvedilol is the Correct Answer:** Carvedilol is a **third-generation non-selective beta-blocker**. Unlike traditional beta-blockers, it possesses **additional alpha-1 (α₁) blocking activity**. This dual action leads to peripheral vasodilation, making it highly effective in managing chronic heart failure and hypertension. Because it acts on α₁ receptors in addition to β₁ and β₂ receptors, it does not fit the criteria of having "no pharmacological action on any other receptor." **2. Analysis of Incorrect Options:** * **Propranolol:** The prototype **first-generation** non-selective beta-blocker. It blocks both β₁ and β₂ receptors equally but lacks action on alpha receptors or intrinsic sympathomimetic activity (ISA). * **Timolol:** A first-generation non-selective beta-blocker primarily used in the treatment of glaucoma (by reducing aqueous humor production). It has no significant action on other receptors. * **Sotalol:** A unique first-generation non-selective beta-blocker. While it also has Class III antiarrhythmic properties (potassium channel blockade), in the context of receptor-based classification, it is categorized as a pure beta-blocker without alpha-blocking activity. **3. NEET-PG High-Yield Pearls:** * **Mixed Antagonists (α + β blockers):** Remember the duo **Carvedilol** and **Labetalol**. * **Vasodilatory Beta-blockers:** These include Carvedilol (via α₁ block), Nebivolol (via Nitric Oxide release), and Celiprolol (via β₂ agonism). * **Heart Failure Trio:** Bisoprolol, Carvedilol, and Metoprolol succinate are the three beta-blockers proven to reduce mortality in chronic heart failure. * **Sotalol Warning:** It is notorious for causing **QT interval prolongation** and *Torsades de Pointes*.

Question 423: Which one of the following drugs is contraindicated in acute myocardial infarction?

A. Morphine
B. Pentazocine (Correct Answer)
C. Nitroglycerin
D. Beta blockers

Explanation: **Explanation:** In the management of Acute Myocardial Infarction (AMI), the primary goal is to reduce myocardial oxygen demand and improve coronary perfusion. **Why Pentazocine is Contraindicated:** Pentazocine is an opioid agonist-antagonist. Unlike pure mu-agonists, it has significant **sympathomimetic effects**. It increases systemic vascular resistance (afterload), heart rate, and pulmonary artery pressure. These effects lead to an **increase in myocardial oxygen demand**, which can exacerbate ischemia and extend the size of the infarct. Therefore, it is strictly avoided in AMI. **Analysis of Incorrect Options:** * **Morphine:** This is the drug of choice for pain relief in AMI (especially STEMI). It provides potent analgesia and has beneficial hemodynamic effects, such as venodilation (reducing preload) and reducing sympathetic tone, which lowers myocardial oxygen demand. * **Nitroglycerin (NTG):** A potent vasodilator used to relieve ischemic chest pain. It reduces both preload and afterload, improving coronary blood flow. (Note: It is only contraindicated in right ventricular infarction or if the patient has recently used Sildenafil). * **Beta-blockers:** These are standard therapy in AMI (unless contraindicated by heart failure or bradycardia). They reduce heart rate and contractility, thereby decreasing oxygen consumption and reducing the risk of arrhythmias. **High-Yield Clinical Pearls for NEET-PG:** * **MONA regimen:** The classic mnemonic for AMI management: **M**orphine, **O**xygen, **N**itroglycerin, **A**spirin. * **Pentazocine & the Heart:** Always remember that Pentazocine "stresses" the heart, while Morphine "rests" the heart. * **Morphine Side Effect:** Be cautious of bradycardia and hypotension; the antidote is Naloxone.

Question 424: Which drug is not useful in a hypertensive emergency?

A. IV hydralazine
B. Indapamide (Correct Answer)
C. Sublingual nifedipine
D. Sodium nitroprusside

Explanation: **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, MI, pulmonary edema). The management requires immediate, controlled reduction of BP using **intravenous (IV)** medications with rapid onset and short duration of action. **Why Indapamide is the correct answer:** Indapamide is a **thiazide-like diuretic** administered **orally**. It has a slow onset of action and is primarily used for the long-term management of chronic hypertension. It lacks the potency and rapid onset required to address acute hypertensive crises, making it inappropriate for emergency settings. **Analysis of Incorrect Options:** * **IV Hydralazine:** A direct-acting vasodilator often used in hypertensive emergencies, particularly in **pregnancy-induced hypertension (Eclampsia/Pre-eclampsia)** due to its safety profile for the fetus. * **Sublingual Nifedipine:** Historically used for hypertensive urgencies; however, it is generally **avoided** now because it can cause an unpredictable, precipitous drop in BP, leading to reflex tachycardia or cerebral ischemia. Despite its declining use, it is still a drug that *can* lower BP acutely, unlike oral diuretics. * **Sodium Nitroprusside:** The **gold standard** for hypertensive emergencies. It is a potent venous and arterial vasodilator with an instantaneous onset and very short half-life, allowing for precise titration via IV infusion. **NEET-PG High-Yield Pearls:** 1. **Drug of Choice (DOC):** For most hypertensive emergencies, **Labetalol** or **Nicardipine** are preferred. **Sodium Nitroprusside** is the DOC for aortic dissection (with a beta-blocker). 2. **Nitroprusside Toxicity:** Prolonged use can lead to **Cyanide/Thiocyanate toxicity** (treated with Sodium Thiosulfate). 3. **BP Reduction Goal:** Reduce Mean Arterial Pressure (MAP) by no more than **25% within the first hour** to prevent ischemic stroke.

Question 425: Which of the following is a cardioselective beta-blocker?

A. Timolol
B. Metoprolol (Correct Answer)
C. Carvedilol
D. Propranolol

Explanation: **Explanation:** **Beta-blockers** are classified based on their receptor selectivity. **Metoprolol** is a **cardioselective (Beta-1 selective)** blocker. These drugs primarily inhibit $\beta_1$ receptors located in the heart, leading to a decrease in heart rate, contractility, and AV conduction, while having minimal effect on $\beta_2$ receptors in the bronchi and peripheral vasculature at therapeutic doses. **Analysis of Options:** * **Metoprolol (Correct):** It belongs to the second generation of beta-blockers. Other common cardioselective agents include **A**tenolol, **B**isoprolol, **E**smolol, and **N**ebivolol (Mnemonic: **"A-B-E-M-N"**). * **Propranolol & Timolol (Incorrect):** These are **first-generation, non-selective** beta-blockers. They block both $\beta_1$ and $\beta_2$ receptors. Propranolol is highly lipid-soluble (crosses BBB), while Timolol is commonly used topically for glaucoma. * **Carvedilol (Incorrect):** This is a **third-generation, non-selective** beta-blocker that also possesses **alpha-1 ($\alpha_1$) blocking** properties. It is frequently used in chronic heart failure due to its vasodilatory and antioxidant effects. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nebivolol** is the most highly selective $\beta_1$ blocker and also stimulates Nitric Oxide (NO) release, causing vasodilation. 2. **Esmolol** has the shortest half-life (~9 minutes) and is administered IV for acute arrhythmias or aortic dissection. 3. **Cardioselectivity is dose-dependent:** At high doses, even selective blockers like Metoprolol can lose their selectivity and cause bronchoconstriction. 4. **Contraindication:** Non-selective beta-blockers (like Propranolol) are strictly contraindicated in patients with **Asthma/COPD** due to the risk of life-threatening bronchospasm.

Question 426: All of the following are used in atrial arrhythmia EXCEPT?

A. Digoxin
B. Verapamil
C. Quinidine
D. Lignocaine (Correct Answer)

Explanation: **Explanation:** The correct answer is **Lignocaine (Lidocaine)**. **Why Lignocaine is the correct answer:** Lignocaine is a **Class IB antiarrhythmic** agent. Its primary mechanism involves blocking activated and inactivated voltage-gated sodium channels, specifically in the **ventricular myocardium** and Purkinje fibers. It has a very fast "on-off" dissociation kinetics and a preference for tissues with long action potentials. Because the action potential duration (APD) in the atria is very short, Lignocaine does not have sufficient time to bind to sodium channels in atrial tissue. Consequently, it is **ineffective for atrial arrhythmias** and is used exclusively for ventricular arrhythmias (e.g., post-MI or digitalis-induced ventricular tachycardia). **Analysis of incorrect options:** * **Digoxin:** A cardiac glycoside that increases vagal tone, slowing conduction through the AV node. It is used for rate control in atrial fibrillation and flutter. * **Verapamil:** A Class IV antiarrhythmic (Calcium Channel Blocker). It slows AV nodal conduction and is a drug of choice for terminating Paroxysmal Supraventricular Tachycardia (PSVT). * **Quinidine:** A Class IA antiarrhythmic. It blocks sodium channels and has a moderate effect on potassium channels, increasing the refractory period in both atria and ventricles. It can be used to maintain sinus rhythm in atrial fibrillation. **High-Yield Clinical Pearls for NEET-PG:** * **Lignocaine** is the drug of choice for **emergency treatment of ventricular arrhythmias** (though Amiodarone is now often preferred in ACLS protocols). * **Side Effects of Lignocaine:** Primarily neurological (seizures, tremors, blurred vision) due to its ability to cross the blood-brain barrier. * **Class IB Mnemonic:** "Lidocaine, Mexiletine, Phenytoin" — **"L**earn **M**ore **P**harmacology" (Used for Ventricular arrhythmias only). * **Adenosine** is the drug of choice for acute termination of PSVT.

Question 427: Which antihypertensive medication is administered during pregnancy?

A. Propranolol
B. Acebutalol
C. Metoprolol
D. Labetalol (Correct Answer)

Explanation: **Explanation:** **Labetalol** is the drug of choice for managing hypertension in pregnancy (including pre-eclampsia). It is a non-selective beta-blocker with additional **alpha-1 blocking activity**. This dual action reduces peripheral vascular resistance without causing significant reflex tachycardia or compromising uteroplacental blood flow. It has a proven safety profile and is not associated with significant teratogenicity. **Analysis of Options:** * **Propranolol (Option A):** While sometimes used for thyrotoxicosis in pregnancy, it is generally avoided for hypertension because it is associated with **intrauterine growth restriction (IUGR)**, neonatal hypoglycemia, and bradycardia due to its non-selective nature and lack of alpha-blocking activity. * **Acebutolol (Option B):** This is a cardioselective beta-blocker with intrinsic sympathomimetic activity (ISA). It is not a first-line agent in pregnancy due to limited safety data compared to Labetalol. * **Metoprolol (Option C):** Although it is a cardioselective beta-1 blocker and sometimes used in the second/third trimester, it is considered second-line to Labetalol and Methyldopa. **High-Yield Clinical Pearls for NEET-PG:** * **First-line drugs in Pregnancy:** Labetalol (DOC), Oral Methyldopa (safest long-term), and Nifedipine (long-acting). * **Hypertensive Emergency in Pregnancy:** Intravenous Labetalol or Hydralazine are preferred. * **Absolute Contraindications:** ACE inhibitors and ARBs are **teratogenic** (cause fetal renal dysgenesis and skull defects). Diuretics are generally avoided as they prevent the physiological expansion of plasma volume. * **Magnesium Sulfate (MgSO₄):** The drug of choice for preventing and treating seizures in eclampsia (not for blood pressure control).

Question 428: Digoxin is not affected in which of the following conditions?

A. Hepatic disease (Correct Answer)
B. Electrolyte disturbances
C. Renal failure
D. Myocardial infarction

Explanation: **Explanation:** The correct answer is **Hepatic disease** because of the specific pharmacokinetic profile of Digoxin. **1. Why Hepatic Disease is the correct answer:** Digoxin is a polar glycoside that is primarily excreted **unchanged by the kidneys** (approximately 60-80%) via glomerular filtration and tubular secretion (P-glycoprotein). It undergoes minimal hepatic metabolism. Therefore, its clearance and plasma concentration remain largely unaffected in patients with liver dysfunction, making dose adjustments unnecessary in hepatic disease. **2. Why the other options are incorrect:** * **Renal failure:** Since the kidneys are the primary route of elimination, renal impairment significantly decreases digoxin clearance, leading to toxicity. Doses must be calculated based on Creatinine Clearance. * **Electrolyte disturbances:** Digoxin toxicity is highly sensitive to electrolyte levels. **Hypokalemia**, hypomagnesemia, and hypercalcemia potentiate digoxin's effects and increase the risk of life-threatening arrhythmias. * **Myocardial infarction (MI):** In the acute phase of an MI, the myocardium becomes "irritable" and sensitized. Digoxin can further increase myocardial oxygen demand and lower the threshold for arrhythmias in ischemic tissue. **High-Yield Clinical Pearls for NEET-PG:** * **Digitoxin vs. Digoxin:** Unlike Digoxin, *Digitoxin* is primarily metabolized by the liver and is the drug of choice in renal failure (though rarely used now). * **Volume of Distribution:** Digoxin has a very high $V_d$ because it binds strongly to cardiac and skeletal muscle (Na+/K+ ATPase). It is **not** removed by dialysis. * **Antidote:** Digibind (Digoxin-specific Fab fragments) is the specific treatment for toxicity. * **Monitoring:** Therapeutic range is narrow (0.5–2 ng/mL). Toxicity typically presents with GI symptoms (earliest) and xanthopsia (yellow vision).

Question 429: Which drugs are used for cardiac remodeling in congestive heart failure?

A. Beta blockers
B. ACE inhibitors
C. Digoxin (Correct Answer)
D. Aldosterone antagonists

Explanation: **Explanation** In the management of Congestive Heart Failure (CHF), it is crucial to distinguish between drugs that provide symptomatic relief and those that modify the disease process (remodeling). **Why the Correct Answer is Digoxin:** The question asks which drug is **NOT** used for cardiac remodeling (or implies the exception based on standard pharmacology). **Note:** In standard medical teaching, Digoxin is the classic "exception." While it increases cardiac contractility and provides symptomatic relief, it has **no effect on cardiac remodeling** and does not reduce long-term mortality. It is primarily used for rate control in atrial fibrillation or for patients who remain symptomatic despite optimal medical therapy. **Analysis of Other Options (Disease-Modifying Drugs):** * **ACE Inhibitors (B):** These are the cornerstone of CHF therapy. By inhibiting Angiotensin II, they prevent pathological hypertrophy and fibrosis, significantly reducing mortality. * **Beta Blockers (A):** Drugs like Carvedilol, Metoprolol succinate, and Bisoprolol prevent catecholamine-induced cardiotoxicity and reverse remodeling, improving ejection fraction over time. * **Aldosterone Antagonists (D):** Spironolactone and Eplerenone block the fibrotic effects of aldosterone on the myocardium, reducing collagen deposition and mortality in NYHA Class II-IV heart failure. **High-Yield Clinical Pearls for NEET-PG:** * **Mortality-Reducing Drugs in CHF:** ACEIs/ARBs, Beta-blockers, Aldosterone antagonists, ARNI (Sacubitril/Valsartan), and SGLT2 inhibitors. * **Symptomatic Only:** Digoxin and Diuretics (Furosemide) improve symptoms but do **not** decrease mortality. * **Digoxin Toxicity:** Characterized by xanthopsia (yellow vision) and various arrhythmias; the most common is PVCs, while the most specific is Atrial Tachycardia with AV block.

Question 430: Which of the following agents does not worsen angina?

A. Sumatriptan
B. Oxyfedrine (Correct Answer)
C. Dipyrickuriole
D. Thyroxine

Explanation: **Explanation:** The correct answer is **Oxyfedrine**. **Why Oxyfedrine is correct:** Oxyfedrine is a unique **partial beta-agonist** used in the treatment of angina pectoris. Unlike most sympathomimetics, it has a dual mechanism: it improves myocardial metabolism and acts as a potent coronary vasodilator. Most importantly, it possesses **"positive inotropic"** effects without significantly increasing myocardial oxygen demand. It is considered a "myocardial nutritional agent" and is specifically indicated for chronic stable angina, as it does not cause coronary steal or worsen ischemia. **Analysis of Incorrect Options:** * **Sumatriptan (Option A):** This is a 5-HT$_{1B/1D}$ agonist used for migraines. It causes **coronary vasospasm** via 5-HT$_{1B}$ receptors. It is strictly contraindicated in patients with Ischemic Heart Disease (IHD) as it can precipitate myocardial infarction. * **Dipyridamole (Option C):** (Note: Likely "Dipyridamole" in the question). While it is a vasodilator, it causes **"Coronary Steal Phenomenon."** It dilates healthy vessels, diverting blood flow away from ischemic, maximally dilated collateral vessels, thereby worsening angina. * **Thyroxine (Option D):** Thyroxine increases the metabolic rate and upregulates beta-receptors in the heart. This leads to increased heart rate (tachycardia) and force of contraction, significantly **increasing myocardial oxygen demand**, which can precipitate or worsen angina. **High-Yield Clinical Pearls for NEET-PG:** * **Coronary Steal Phenomenon:** Classically associated with Dipyridamole and Hydralazine. * **Drugs contraindicated in Angina:** Sumatriptan, Ergotamine, Cocaine, and non-selective Beta-agonists (like Isoprenaline). * **Oxyfedrine** is often tested as an "exception" because it is a sympathomimetic that is actually *beneficial* in angina rather than harmful.

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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