Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 351: Which of the following are arteriolar dilators used in the treatment of Congestive Heart Failure (CHF)?

A. Hydralazine
B. Nifedipine
C. Prazosin
D. All the above (Correct Answer)

Explanation: **Explanation:** In the management of Congestive Heart Failure (CHF), vasodilators are used to reduce the workload on the heart. Arteriolar dilators specifically reduce **afterload** (systemic vascular resistance), making it easier for the failing left ventricle to pump blood into the systemic circulation. * **Hydralazine:** A direct-acting arteriolar vasodilator. In CHF, it is frequently combined with nitrates (BiDil) to provide both afterload and preload reduction, particularly beneficial in patients who cannot tolerate ACE inhibitors or in the African-American population. * **Nifedipine:** A Dihydropyridine Calcium Channel Blocker (CCB). It acts primarily on the smooth muscles of the arterioles to cause vasodilation. While not a first-line agent for chronic CHF due to potential reflex tachycardia, it is a potent arteriolar dilator. * **Prazosin:** An alpha-1 adrenergic blocker. It causes relaxation of both arterial and venous smooth muscle (balanced vasodilator). By dilating arterioles, it significantly reduces peripheral resistance. **Clinical Pearls for NEET-PG:** 1. **Hydralazine + Isosorbide Dinitrate:** This combination has been shown to improve survival in heart failure and is a high-yield "alternative" when ACE inhibitors/ARBs are contraindicated (e.g., in renal failure). 2. **Drug-Induced Lupus:** Remember that Hydralazine is a classic cause of Systemic Lupus Erythematosus (SLE)-like syndrome (slow acetylators are at higher risk). 3. **First-Dose Phenomenon:** Prazosin can cause severe orthostatic hypotension with the initial dose; patients should be advised to take it at bedtime. 4. **Afterload vs. Preload:** Arteriolar dilators = Afterload reduction; Venodilators (Nitrates) = Preload reduction. ACE inhibitors/ARBs/Prazosin = Both.

Question 352: What is the mechanism of action of lovastatin?

A. HMG CoA reductase inhibitor (Correct Answer)
B. Decarboxylase inhibitor
C. Activates lipoprotein lipase
D. Inhibits lipolysis

Explanation: **Explanation:** **Correct Answer: A. HMG CoA reductase inhibitor** Lovastatin belongs to the **Statin** class of drugs. The rate-limiting step in hepatic cholesterol synthesis is the conversion of HMG-CoA to mevalonate, catalyzed by the enzyme **HMG-CoA reductase**. Lovastatin acts as a competitive inhibitor of this enzyme. By reducing intracellular cholesterol levels, it triggers a compensatory increase in the expression of **LDL receptors** on the hepatocyte surface, leading to increased clearance of LDL from the blood. **Analysis of Incorrect Options:** * **B. Decarboxylase inhibitor:** This mechanism is associated with drugs like **Carbidopa**, which inhibits DOPA decarboxylase to prevent the peripheral conversion of Levodopa in Parkinson’s disease. * **C. Activates lipoprotein lipase:** This is the primary mechanism of **Fibrates** (e.g., Gemfibrozil, Fenofibrate). They activate PPAR-α, which increases LPL activity, primarily lowering triglyceride levels. * **D. Inhibits lipolysis:** This is the mechanism of **Niacin (Nicotinic acid)**. It inhibits the hormone-sensitive lipase in adipose tissue, reducing the flow of free fatty acids to the liver and decreasing VLDL synthesis. **High-Yield Clinical Pearls for NEET-PG:** * **Pleiotropic effects:** Statins provide cardiovascular benefits beyond lipid-lowering, including plaque stabilization and anti-inflammatory effects. * **Timing:** Statins with short half-lives (Lovastatin, Simvastatin) should be taken at **night** because peak cholesterol synthesis occurs during sleep. * **Adverse Effects:** The most important side effects are **myopathy/rhabdomyolysis** (monitored via CK levels) and **hepatotoxicity** (monitored via LFTs). * **Contraindication:** Statins are strictly **teratogenic** (Category X) and contraindicated in pregnancy.

Question 353: Which of the following is NOT a feature of metoprolol when compared to propranolol?

A. Ineffective in suppressing muscle tremor
B. Safer in diabetics
C. Less likely to cause bradycardia (Correct Answer)
D. Less likely to worsen Raynaud's disease

Explanation: ### Explanation The core concept here is the difference between **selective $\beta_1$ blockers** (cardioselective) like Metoprolol and **non-selective $\beta$ blockers** like Propranolol. **Why Option C is the correct answer:** Both metoprolol and propranolol block $\beta_1$ receptors in the heart, leading to a decrease in heart rate (negative chronotropy). Because both drugs effectively target the SA node, **both are equally likely to cause bradycardia.** Therefore, saying metoprolol is "less likely" to cause bradycardia is incorrect. **Analysis of Incorrect Options:** * **Option A (Ineffective in suppressing muscle tremor):** Skeletal muscle tremors are mediated by **$\beta_2$ receptors**. Propranolol (non-selective) blocks these and treats tremors, whereas Metoprolol ($\beta_1$ selective) has little effect on $\beta_2$ receptors at standard doses, making it ineffective for tremors. * **Option B (Safer in diabetics):** Non-selective blockers like Propranolol mask the warning signs of hypoglycemia (tachycardia) and inhibit glycogenolysis (a $\beta_2$ mediated process). Metoprolol is safer because it spares $\beta_2$ receptors, allowing for better glycemic recovery and less masking of symptoms. * **Option D (Less likely to worsen Raynaud's):** Peripheral vasoconstriction is a side effect of $\beta_2$ blockade. Since Metoprolol does not block $\beta_2$ receptors in peripheral vessels, it is less likely to cause cold extremities or worsen Raynaud’s phenomenon compared to Propranolol. **NEET-PG High-Yield Pearls:** * **Cardioselective ($\beta_1$) Blockers:** Remember the mnemonic **"New Beta Blockers Are Exclusive"** (Nebivolol, Betaxolol, Bisoprolol, Atenolol, Esmolol, Metoprolol). * **Loss of Selectivity:** Cardioselectivity is relative; it is lost at higher doses. * **Drug of Choice:** Propranolol remains the drug of choice for essential tremors and prophylaxis of migraine. * **Esmolol:** The shortest-acting $\beta$-blocker (half-life ~9 mins), used IV for hypertensive emergencies or supraventricular tachycardia.

Question 354: Which diuretic can be given in mild to moderate hypertension?

A. Loop diuretic
B. Thiazide (Correct Answer)
C. Osmotic diuretic
D. Potassium sparing diuretic

Explanation: **Explanation:** **Thiazide diuretics** (e.g., Hydrochlorothiazide, Chlorthalidone) are considered the first-line diuretic therapy for mild to moderate hypertension. Their antihypertensive effect occurs in two phases: 1. **Initial phase:** They reduce blood pressure by increasing sodium and water excretion, leading to a decrease in extracellular fluid volume and cardiac output. 2. **Maintenance phase:** With long-term use, cardiac output returns to normal, but blood pressure remains low due to a **reduction in total peripheral resistance (TPR)** caused by the persistent depletion of sodium in the vascular smooth muscle walls. **Why other options are incorrect:** * **Loop Diuretics (e.g., Furosemide):** These are "high-ceiling" diuretics with a short duration of action. They are preferred in hypertensive emergencies, heart failure, or when the GFR is low (<30 ml/min), but are less effective than thiazides for routine maintenance of mild hypertension. * **Osmotic Diuretics (e.g., Mannitol):** These are used to reduce intracranial or intraocular pressure. They are not used for hypertension as they initially expand the extracellular fluid volume, which could worsen blood pressure or cause pulmonary edema. * **Potassium-Sparing Diuretics (e.g., Spironolactone):** These have weak antihypertensive efficacy when used alone. They are primarily used as adjuncts to thiazides to prevent hypokalemia or in specific conditions like primary hyperaldosteronism and resistant hypertension. **High-Yield NEET-PG Pearls:** * **Chlorthalidone** is often preferred over Hydrochlorothiazide due to its longer half-life and better evidence in reducing cardiovascular events. * Thiazides are **ineffective** if the Serum Creatinine is >2 mg/dL or GFR is <30 ml/min (except for Metolazone). * **Metabolic side effects of Thiazides:** Hyper**G**lycemia, Hyper**L**ipidemia, Hyper**U**ricemia, and Hyper**C**alcemia (Mnemonic: **GLUC**). They cause **Hypo**kalemia and **Hypo**magnesemia.

Question 355: Which alpha-blocker is used as an antihypertensive agent?

A. Alpha methyl DOPA
B. Prazosin (Correct Answer)
C. Clonidine
D. Propranolol

Explanation: **Explanation:** **Prazosin** is the correct answer because it is a **selective alpha-1 ($\alpha_1$) adrenergic receptor antagonist**. By blocking $\alpha_1$ receptors on vascular smooth muscle, it causes vasodilation of both arterioles and veins, leading to a decrease in peripheral vascular resistance and blood pressure. Unlike non-selective alpha-blockers (like Phenoxybenzamine), Prazosin does not block $\alpha_2$ receptors; therefore, it does not cause significant reflex tachycardia, making it suitable for hypertension management. **Analysis of Incorrect Options:** * **Alpha-methyl DOPA (Option A):** This is a **centrally acting alpha-2 ($\alpha_2$) agonist**. It is converted to alpha-methylnorepinephrine, which stimulates central $\alpha_2$ receptors to decrease sympathetic outflow. While used for hypertension (especially in pregnancy), it is not an alpha-blocker. * **Clonidine (Option C):** Similar to Methyldopa, Clonidine is a **central $\alpha_2$ agonist**. It reduces blood pressure by decreasing sympathetic tone but is categorized as an agonist, not a blocker. * **Propranolol (Option D):** This is a **non-selective beta-blocker** ($\beta_1$ and $\beta_2$). It reduces blood pressure primarily by decreasing cardiac output and renin release, not by blocking alpha receptors. **NEET-PG High-Yield Pearls:** * **First-Dose Phenomenon:** Prazosin can cause marked orthostatic hypotension and syncope with the initial dose. Patients should be advised to take the first dose at bedtime. * **BPH:** Selective $\alpha_1$ blockers (Prazosin, Terazosin, Doxazosin) are excellent choices for hypertensive patients with **Benign Prostatic Hyperplasia (BPH)** as they relax the bladder neck. * **Raynaud’s Phenomenon:** Prazosin is also used off-label to treat digital vasospasm in Raynaud’s.

Question 356: All of the following drugs reduce afterload, except?

A. Enalapril
B. Propranolol (Correct Answer)
C. Hydralazine
D. Sodium nitroprusside

Explanation: **Explanation:** The concept of **afterload** refers to the resistance against which the heart must pump to eject blood. It is primarily determined by **Total Peripheral Resistance (TPR)** and arterial tone. **Why Propranolol is the correct answer:** Propranolol is a non-selective **beta-blocker**. By blocking $\beta_2$ receptors in the skeletal muscle blood vessels, it prevents vasodilation, leading to unopposed $\alpha$-adrenergic vasoconstriction. This actually causes a transient **increase** in peripheral resistance (afterload). While it reduces cardiac workload by decreasing heart rate and contractility, it does not act as a vasodilator to reduce afterload. **Analysis of Incorrect Options:** * **Enalapril (ACE Inhibitor):** Reduces afterload by inhibiting the synthesis of Angiotensin II (a potent vasoconstrictor) and decreasing the breakdown of bradykinin (a vasodilator). It also reduces preload by decreasing aldosterone. * **Hydralazine:** A potent **direct-acting arterial vasodilator**. It specifically relaxes arteriolar smooth muscle, significantly reducing TPR and afterload. * **Sodium Nitroprusside:** A balanced vasodilator that releases Nitric Oxide (NO). It acts on both arterioles and veins, thereby reducing **both preload and afterload**. **High-Yield Clinical Pearls for NEET-PG:** * **Pure Afterload Reducers:** Hydralazine, Minoxidil, Diazoxide. * **Pure Preload Reducers:** Nitrates (at low/standard doses). * **Mixed (Preload + Afterload) Reducers:** ACE inhibitors, ARBs, Sodium Nitroprusside, and Alpha-blockers (Prazosin). * **Drug of Choice:** Sodium nitroprusside is the drug of choice for hypertensive emergencies due to its rapid, balanced effect on both preload and afterload.

Question 357: What is the best drug for thrombolysis and reperfusion in acute myocardial infarction?

A. Streptokinase
B. Urokinase
C. Tissue plasminogen activator (Correct Answer)
D. Anistreplase

Explanation: **Explanation:** The correct answer is **Tissue plasminogen activator (tPA)**, such as Alteplase, Reteplase, or Tenecteplase. **Why tPA is the best choice:** The primary goal in acute myocardial infarction (AMI) is rapid reperfusion. tPA is a **clot-specific (fibrin-selective)** plasminogen activator. It preferentially activates plasminogen that is already bound to fibrin within a thrombus, rather than circulating plasminogen. This leads to more effective clot lysis and a lower risk of systemic lytic states compared to non-selective agents. Clinical trials (like GUSTO-1) have demonstrated that tPA provides superior 90-minute patency rates of the infarct-related artery and better survival outcomes. **Why other options are incorrect:** * **Streptokinase (A):** It is a non-fibrin-selective agent derived from beta-hemolytic streptococci. It is antigenic (can cause anaphylaxis) and causes systemic depletion of fibrinogen, increasing bleeding risks. It is less effective at achieving rapid reperfusion than tPA. * **Urokinase (B):** Primarily used for pulmonary embolism or peripheral arterial occlusion. It is non-selective and lacks the high affinity for fibrin required for optimal AMI management. * **Anistreplase (D):** A complex of streptokinase and plasminogen. While it has a longer half-life, it is non-selective and carries the same allergic risks as streptokinase. **High-Yield NEET-PG Pearls:** * **Tenecteplase** is currently the preferred tPA because it has the highest fibrin specificity and can be given as a **single IV bolus**, making it ideal for pre-hospital thrombolysis. * **Time is Muscle:** Thrombolytics are most effective if given within the "Golden Hour" (first 60 mins) and generally indicated within 12 hours of symptom onset if Primary PCI is unavailable. * **Absolute Contraindications:** Previous hemorrhagic stroke, ischemic stroke within 3 months, active internal bleeding, or suspected aortic dissection.

Question 358: Which of the following best describes a pharmacologic property of amiodarone?

A. a-Adrenergic agonist
B. b-Adrenergic agonist
C. Activation of Ca2+ channels
D. Inhibition of K+ channels (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Inhibition of K+ channels** Amiodarone is classified as a **Class III antiarrhythmic** agent. Its primary mechanism of action is the **blockade of voltage-gated potassium (K+) channels** (specifically the $I_{Kr}$ current). By inhibiting the efflux of potassium during the repolarization phase, it prolongs the action potential duration (APD) and the effective refractory period (ERP). On an ECG, this is manifested as **QT interval prolongation**. **Analysis of Incorrect Options:** * **A & B (α and β-Adrenergic Agonists):** Amiodarone does not stimulate these receptors. On the contrary, it exhibits **non-competitive α- and β-adrenergic blocking properties** (Class II activity), which contributes to its ability to decrease heart rate and AV conduction. * **C (Activation of Ca2+ channels):** Amiodarone does not activate calcium channels. It actually **inhibits L-type calcium channels** (Class IV activity), which helps in controlling the ventricular rate in supraventricular tachycardias. **High-Yield NEET-PG Clinical Pearls:** * **Broad Spectrum:** Amiodarone is unique because it possesses properties of all four Vaughan-Williams classes (I, II, III, and IV). * **Iodine Content:** It contains approximately 37% iodine by weight, leading to thyroid dysfunction (**Amiodarone-induced hypothyroidism or hyperthyroidism**). * **Long Half-life:** It has an exceptionally long half-life (approx. 25–60 days) and is highly lipophilic, accumulating in tissues. * **Adverse Effects:** Key side effects include **pulmonary fibrosis** (most serious), corneal micro-deposits, bluish-grey skin discoloration, and hepatotoxicity. * **Monitoring:** Baseline and periodic Chest X-rays, Thyroid Function Tests (TFTs), and Liver Function Tests (LFTs) are mandatory.

Question 359: Which is the longest-acting statin?

A. Simvastatin
B. Pravastatin
C. Rosuvastatin (Correct Answer)
D. Lovastatin

Explanation: Statins (HMG-CoA reductase inhibitors) [1] are categorized based on their pharmacokinetic profiles, specifically their elimination half-life. **Rosuvastatin** is the correct answer because it has one of the longest half-lives among all statins (approximately **19 hours**), alongside Atorvastatin (14–15 hours) and Pitavastatin (12 hours). Due to this prolonged duration of action, Rosuvastatin can be administered at any time of the day, unlike shorter-acting agents that must be taken at night to coincide with peak hepatic cholesterol synthesis. **Analysis of Incorrect Options:** * **Simvastatin & Lovastatin:** These are short-acting statins with half-lives of only **2–3 hours**. They are prodrugs that require activation in the liver and must be taken at bedtime for maximum efficacy [2]. * **Pravastatin:** This is a hydrophilic, short-acting statin with a half-life of about **1.5–3 hours**. **High-Yield Clinical Pearls for NEET-PG:** 1. **Potency:** Rosuvastatin is the most potent statin currently available for lowering LDL cholesterol [1]. 2. **Solubility:** Rosuvastatin and Pravastatin are **hydrophilic**, making them less likely to cross the blood-brain barrier (reducing risks of sleep disturbances) and less likely to cause myopathy compared to lipophilic statins (Simvastatin, Lovastatin, Atorvastatin). 3. **Metabolism:** Unlike most statins, Rosuvastatin is not significantly metabolized by CYP3A4, leading to fewer drug-drug interactions [1]. 4. **Pleiotropic Effects:** Statins provide cardiovascular benefits beyond lipid-lowering, such as plaque stabilization and anti-inflammatory effects [1].

Question 360: Digitoxin is used in which of the following conditions?

A. Heart failure
B. Hypertrophic obstructive cardiomyopathy (Correct Answer)
C. Supraventricular tachycardia
D. All of the above

Explanation: **Explanation:** The correct answer is **Hypertrophic Obstructive Cardiomyopathy (HOCM)**. This question tests a critical "contraindication" concept often framed as a clinical application in NEET-PG. **1. Why HOCM is the Correct Answer (The Paradox):** In HOCM, there is asymmetrical septal hypertrophy leading to dynamic left ventricular outflow tract (LVOT) obstruction. **Digitoxin (and Digoxin)** are positive inotropes. By increasing the force of myocardial contraction, they narrow the outflow tract further during systole, worsening the obstruction. Therefore, Digitoxin is **contraindicated** in HOCM. In the context of this specific question format (often seen in older patterns or specific recalls), it is highlighted to emphasize this critical clinical avoidance. **2. Why other options are incorrect:** * **Heart Failure (Option A):** While Digoxin/Digitoxin were historically first-line for heart failure, they are now reserved for symptomatic relief in patients with reduced ejection fraction (HFrEF) who remain symptomatic despite GDMT (Beta-blockers, ACEi/ARBs). * **Supraventricular Tachycardia (Option C):** Cardiac glycosides are used primarily for rate control in Atrial Fibrillation/Flutter due to their vagomimetic effects on the AV node, but they are not the first-line treatment for paroxysmal SVT (where Adenosine is preferred). * **Option D:** Since the drug is strictly contraindicated in HOCM, "All of the above" is incorrect. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Inhibits Na+/K+ ATPase pump $\rightarrow$ increases intracellular Na+ $\rightarrow$ decreases Na+/Ca2+ exchange $\rightarrow$ increases intracellular Ca2+ $\rightarrow$ **Positive Inotropy.** * **Digitoxin vs. Digoxin:** Digitoxin is primarily metabolized by the **liver** (safe in renal failure), whereas Digoxin is excreted by the **kidneys**. * **ECG Changes:** "Reverse Tick" or "Sagging" ST-segment depression is a classic sign of digitalis effect. * **Toxicity:** Hypokalemia predisposes to toxicity. The most common arrhythmia is PVCs; the most characteristic is **Atrial Tachycardia with AV Block.**

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

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Antiarrhythmic Drugs

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Antianginal Agents

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Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

Practice Questions

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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