Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 161: Which of the following statements about fibrates is FALSE?

A. They increase lipoprotein lipase activity through PPAR alpha, leading to increased lipolysis of triglycerides.
B. They are better absorbed when taken on an empty stomach compared to when taken with food. (Correct Answer)
C. They can cause urticaria, rashes, alopecia, myopathy, and gastrointestinal distress.
D. They are first-line drugs for severe dysbetalipoproteinemias and hypertriglyceridemias.

Explanation: **Explanation** **1. Why Option B is the Correct Answer (The False Statement):** The absorption of most fibrates (especially **Fenofibrate**) is significantly **increased** when taken with food. Food enhances the solubility and bioavailability of these drugs. Therefore, the statement that they are better absorbed on an empty stomach is pharmacologically incorrect. *Note:* While newer micronized formulations of Fenofibrate have less food dependency, the classic pharmacological teaching remains that fibrates should be taken with meals to improve absorption and reduce GI side effects. **2. Analysis of Other Options:** * **Option A (Mechanism):** Fibrates are agonists of **PPAR-α** (Peroxisome Proliferator-Activated Receptor-alpha). Activation increases the expression of **Lipoprotein Lipase (LPL)** and decreases ApoC-III (an LPL inhibitor), leading to the rapid catabolism of VLDL and triglycerides. * **Option C (Side Effects):** Fibrates are generally well-tolerated but can cause GI upset, skin rashes, urticaria, and alopecia. Most importantly, they can cause **myopathy/rhabdomyolysis**, especially when combined with statins. * **Option D (Indications):** Fibrates are the **drugs of choice** for Type III Hyperlipoproteinemia (Dysbetalipoproteinemia) and severe Hypertriglyceridemia (to prevent pancreatitis). **3. NEET-PG High-Yield Pearls:** * **Gemfibrozil** is the fibrate most likely to interfere with statin metabolism (via inhibition of OATP1B1 and glucuronidation), significantly increasing the risk of **myopathy**. * Fibrates can increase the risk of **gallstones** (cholelithiasis) by increasing biliary cholesterol excretion. * They are contraindicated in patients with severe renal or hepatic dysfunction.

Question 162: Myocardial oxygen demand decreases by all EXCEPT?

A. Diltiazem
B. Metoprolol
C. Nitroglycerine
D. Amrinone (Correct Answer)

Explanation: **Explanation:** The myocardial oxygen demand ($MVO_2$) is primarily determined by four factors: **heart rate, contractility, intramyocardial wall tension (preload), and systemic vascular resistance (afterload).** To decrease oxygen demand, a drug must reduce one or more of these parameters. **Why Amrinone is the correct answer:** Amrinone (and Milrinone) is a **Phosphodiesterase-3 (PDE3) inhibitor**. It increases intracellular cAMP in cardiac myocytes, leading to **positive inotropy** (increased contractility) and **positive chronotropy** (increased heart rate). By forcing the heart to beat stronger and faster, it significantly **increases myocardial oxygen demand**. While it causes peripheral vasodilation ("inodilator"), the stimulatory effects on the heart override this, making it potentially hazardous in patients with active myocardial ischemia. **Analysis of incorrect options:** * **Diltiazem:** A Non-dihydropyridine Calcium Channel Blocker (CCB) that decreases $MVO_2$ by reducing heart rate and myocardial contractility. * **Metoprolol:** A Beta-1 selective blocker that decreases $MVO_2$ by reducing heart rate and contractility (negative inotropy/chronotropy). It also increases diastolic perfusion time. * **Nitroglycerine:** Primarily a venodilator. It decreases $MVO_2$ by reducing **preload** (venous return), which decreases ventricular wall tension (Laplace’s Law). **High-Yield Clinical Pearls for NEET-PG:** * **Inodilators:** Drugs like Amrinone and Milrinone increase contractility while decreasing afterload; they are used in acute heart failure but avoided in ischemic heart disease. * **Determinants of $MVO_2$:** Heart rate is the most important clinical determinant of oxygen demand. * **Nitrates vs. Beta-blockers:** Nitrates decrease preload; Beta-blockers decrease heart rate and contractility. Combining them is synergistic in treating angina.

Question 163: All of the following are true about the mechanism of action of antihypertensive drugs EXCEPT:

A. Act by Na+ K+ ATPase inhibition (Correct Answer)
B. Thiazide Diuretics
C. Alpha adrenergic blockade
D. Beta adrenergic blockade

Explanation: **Explanation:** The question asks for the mechanism that is **NOT** typically used by standard antihypertensive drugs. [2] **1. Why "Act by Na+ K+ ATPase inhibition" is the Correct Answer:** Inhibition of the Na+/K+ ATPase pump is the primary mechanism of **Cardiac Glycosides (e.g., Digoxin)**, which are used to treat heart failure and atrial fibrillation. Inhibiting this pump increases intracellular sodium, which subsequently increases intracellular calcium via the Na+/Ca2+ exchanger, leading to positive inotropy (increased contractility). This mechanism actually has the potential to *increase* blood pressure or cause vasoconstriction, rather than lowering it. **2. Analysis of Incorrect Options:** * **Thiazide Diuretics:** These are first-line antihypertensives. They work by inhibiting the **Na+/Cl- symporter** in the distal convoluted tubule, leading to initial volume depletion and long-term reduction in peripheral vascular resistance. [3] * **Alpha-adrenergic blockade:** Drugs like Prazosin or Doxazosin block $\alpha_1$ receptors on vascular smooth muscle, leading to vasodilation and a decrease in total peripheral resistance. [1] * **Beta-adrenergic blockade:** Drugs like Atenolol or Metoprolol reduce blood pressure by decreasing cardiac output (via $\beta_1$ blockade) and inhibiting renin release from the juxtaglomerular apparatus. [1] **Clinical Pearls for NEET-PG:** * **Thiazides** are known to cause "Hyper-GLUC" (Hyperglycemia, Hyperlipidemia, Hyperuricemia, and Hypercalcemia). * **Beta-blockers** are generally avoided in patients with asthma or peripheral vascular disease (due to $\beta_2$ blockade). * **Digoxin Toxicity** is exacerbated by **Hypokalemia**, which is a common side effect of Thiazide and Loop diuretics. This is a high-yield drug interaction to remember.

Question 164: Ivabradine is indicated in the management of which condition?

A. Paroxysmal supraventricular tachycardia
B. Angina pectoris (Correct Answer)
C. Cardiomyopathy
D. Irritable bowel syndrome

Explanation: **Explanation:** **Ivabradine** is a novel heart-rate-lowering agent that acts by selectively and competitively inhibiting the **$I_f$ (funny) current** in the sinoatrial (SA) node. By blocking these hyperpolarization-activated cyclic nucleotide-gated (HCN) channels, it slows the diastolic depolarization slope, thereby reducing the heart rate without affecting myocardial contractility (inotropic state) or intracardiac conduction. **Why Angina Pectoris is Correct:** In chronic stable angina, the primary goal is to reduce myocardial oxygen demand. Ivabradine achieves this by lowering the heart rate, which prolongs diastole and improves coronary perfusion. It is specifically indicated for patients with stable angina who have a normal sinus rhythm but cannot tolerate or have contraindications to beta-blockers. **Analysis of Incorrect Options:** * **A. Paroxysmal Supraventricular Tachycardia (PSVT):** Ivabradine only acts on the SA node. It has no effect on AV nodal conduction or re-entrant circuits, making it ineffective for PSVT (where Adenosine or Calcium Channel Blockers are preferred). * **C. Cardiomyopathy:** While Ivabradine is used in **Heart Failure** (HFrEF) with HR >70 bpm to reduce hospitalization, it is not a primary treatment for the underlying structural pathology of cardiomyopathy itself. * **D. Irritable Bowel Syndrome:** There is no clinical indication for Ivabradine in gastrointestinal disorders. **High-Yield Clinical Pearls for NEET-PG:** * **Luminous Phenomena (Phosphenes):** The most characteristic side effect, caused by the blockade of $I_h$ channels in the retina (similar to $I_f$ channels in the heart). * **Requirement:** The patient must be in **Sinus Rhythm** for the drug to work. It is ineffective in Atrial Fibrillation. * **Benefit:** Unlike beta-blockers, it does not cause bronchospasm, making it safer in asthmatic patients with angina.

Question 165: All of the following statements about digitalis action are true EXCEPT:

A. Increases cardiac contraction
B. Pumps sodium out of the cell (Correct Answer)
C. Increases intracellular calcium
D. Causes bradycardia

Explanation: The mechanism of action of Digitalis (Digoxin) involves the inhibition of the **Na⁺/K⁺-ATPase pump** (the sodium pump) located on the cardiac myocyte membrane [1]. 1. **Why Option B is the correct answer (The False Statement):** Digitalis **inhibits** the Na⁺/K⁺-ATPase pump. Normally, this pump moves 3 Na⁺ ions out of the cell and 2 K⁺ ions into the cell. By inhibiting it, digitalis causes **sodium to accumulate inside the cell** rather than pumping it out [1]. Therefore, the statement that it "pumps sodium out" is physiologically incorrect regarding its drug action. 2. **Analysis of Other Options:** * **Option A & C:** Due to the rise in intracellular Na⁺, the **Na⁺/Ca²⁺ exchanger (NCX)** is inhibited or reversed. This leads to an **increase in intracellular calcium** (Option C), which is then sequestered into the sarcoplasmic reticulum. Upon the next heartbeat, more calcium is released, leading to **increased cardiac contraction** (Positive Inotropy - Option A) [1, 2]. * **Option D:** Digitalis has potent **parasympathomimetic** (vagotonic) effects. It slows the heart rate by decreasing the firing of the SA node and slowing conduction through the AV node, resulting in **bradycardia** [2]. **High-Yield Clinical Pearls for NEET-PG:** * **ECG Changes:** The most characteristic ECG finding is the "reverse tick" sign or **Sagging ST-segment depression** [2]. * **Electrolyte Interactions:** **Hypokalemia** predisposes to digitalis toxicity because K⁺ and Digoxin compete for the same binding site on the Na⁺/K⁺-ATPase pump [1]. Conversely, **Hypercalcemia** and **Hypomagnesemia** also increase toxicity risk. * **Antidote:** Digoxin-specific antibody fragments (**DigiFab**). * **Therapeutic Range:** Narrow therapeutic index (0.5–2 ng/mL).

Question 166: A patient with hypertension was treated with propranolol. Although it controlled hypertension, it reduced the resting heart rate to 50/min. Which of the following beta-blockers can be used as an effective substitute that does not cause bradycardia?

A. Pindolol (Correct Answer)
B. Labetalol
C. Bisoprolol
D. Atenolol

Explanation: ### Explanation The correct answer is **Pindolol**. **1. Why Pindolol is correct:** The underlying medical concept here is **Intrinsic Sympathomimetic Activity (ISA)**, also known as partial agonist activity [1]. * **Mechanism:** Pindolol is a non-selective beta-blocker that acts as a partial agonist [1]. While it blocks the effects of endogenous catecholamines (lowering blood pressure), it simultaneously provides a low level of background stimulation to the beta-1 receptors. * **Clinical Effect:** This prevents the heart rate from dropping excessively during rest. Therefore, pindolol is the drug of choice for hypertensive patients who develop symptomatic bradycardia with pure beta-blockers. **2. Why the other options are incorrect:** * **Atenolol & Bisoprolol:** These are selective $\beta_1$ blockers (cardioselective). They lack ISA and are well-known for causing a significant reduction in heart rate (bradycardia) as a primary side effect [2], [3]. * **Labetalol:** This is a combined $\alpha_1$ and non-selective $\beta$ blocker [3]. While it is used in hypertensive emergencies and pregnancy, it does not possess ISA and can still cause a decrease in heart rate, though often less than pure beta-blockers due to its alpha-blocking vasodilatory effect. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for ISA:** "**P**alpitation **A**nd **C**ardiac **A**cceleration" (**P**indolol, **A**cebutolol, **C**artelol, **A**lprenolol). * **Avoid in Post-MI:** Beta-blockers with ISA (like Pindolol) are generally **avoided** in patients with a history of myocardial infarction or angina because they do not provide the same degree of "cardiac rest" as pure antagonists. * **Lipid Neutrality:** Beta-blockers with ISA have a more favorable profile on serum lipids compared to traditional beta-blockers.

Question 167: Which of the following antihypertensives does not have any central action?

A. Propranolol
B. Methyldopa
C. Clonidine
D. Prazosin (Correct Answer)

Explanation: The question asks for an antihypertensive drug that lacks central action. The correct answer is **Prazosin**. **1. Why Prazosin is correct:** Prazosin is a **selective alpha-1 ($\alpha_1$) adrenergic blocker**. Its antihypertensive effect is mediated entirely in the **periphery** by blocking $\alpha_1$ receptors on vascular smooth muscle [4]. This leads to vasodilation and decreased peripheral resistance. It does not cross the blood-brain barrier in significant amounts to exert a central hypotensive effect, nor does it act on central vasomotor centers. **2. Why the other options are incorrect:** * **Methyldopa:** A classic **centrally acting** antihypertensive [1]. It is a prodrug converted to $\alpha$-methylnorepinephrine, which stimulates central $\alpha_2$ receptors in the nucleus tractus solitarius, reducing sympathetic outflow [2]. * **Clonidine:** A direct **central $\alpha_2$ agonist** [3]. It acts on the vasomotor center in the medulla to decrease sympathetic tone, leading to a fall in BP and heart rate. * **Propranolol:** While primarily a peripheral beta-blocker, Propranolol is highly **lipophilic** and readily crosses the blood-brain barrier. It exerts central actions contributing to its side effect profile (e.g., sedation, vivid dreams) and potentially its antihypertensive effect via central $\beta$-blockade. **Clinical Pearls for NEET-PG:** * **Prazosin** is notorious for the **"First Dose Phenomenon"** (marked orthostatic hypotension); advise patients to take the first dose at bedtime. * **Methyldopa** is the traditional drug of choice for **hypertension in pregnancy** [2]. * **Clonidine withdrawal** can cause a life-threatening hypertensive crisis due to a sympathetic "rebound." * **Selective $\alpha_1$ blockers** (Prazosin, Terazosin) are also useful in Benign Prostatic Hyperplasia (BPH) as they relax the bladder neck.

Question 168: All of the following are used in the treatment of pulmonary hypertension EXCEPT:

A. Endothelin receptor antagonists
B. Phosphodiesterase inhibitors
C. Calcium channel blockers
D. Beta blockers (Correct Answer)

Explanation: **Explanation:** The primary goal in treating Pulmonary Arterial Hypertension (PAH) is to reduce pulmonary vascular resistance (PVR) through vasodilation. **Beta-blockers (Option D)** are generally **contraindicated** or avoided in PAH. This is because they exert negative inotropic and chronotropic effects, which can decrease cardiac output and potentially worsen right heart failure—the leading cause of death in these patients. **Analysis of Options:** * **Endothelin Receptor Antagonists (Option A):** Drugs like **Bosentan** (non-selective) and **Ambrisentan** (ET-A selective) block endothelin-1, a potent vasoconstrictor and smooth muscle proliferator, making them a cornerstone of PAH therapy. * **Phosphodiesterase-5 (PDE-5) Inhibitors (Option B):** **Sildenafil** and **Tadalafil** increase cGMP levels, leading to nitric oxide-mediated vasodilation of the pulmonary vasculature. * **Calcium Channel Blockers (Option C):** High-dose CCBs (e.g., **Nifedipine, Diltiazem**) are used specifically in a subset of patients who show a positive "vasoreactivity test" during right heart catheterization. **Clinical Pearls for NEET-PG:** 1. **Prostacyclin Analogues:** Epoprostenol (IV), Treprostinil, and Iloprost are potent vasodilators used in advanced PAH. 2. **Soluble Guanylate Cyclase (sGC) Stimulator:** **Riociguat** is a high-yield drug used for both PAH and Chronic Thromboembolic Pulmonary Hypertension (CTEPH). 3. **Side Effects:** Bosentan is associated with **hepatotoxicity** (requires LFT monitoring) and is highly teratogenic. 4. **Drug of Choice:** For patients who are vasoreactive, CCBs are the initial choice; for others, ERA or PDE-5 inhibitors are preferred.

Question 169: What is the initial drug of choice for a newly detected hypertension in a 42-year-old male with a history of calcium stones?

A. Furosemide
B. Losartan
C. Atenolol
D. Chlorthalidone (Correct Answer)

Explanation: **Explanation:** The correct answer is **Chlorthalidone**. This question tests the ability to select an antihypertensive based on comorbid conditions—a high-yield topic for NEET-PG. **Why Chlorthalidone is correct:** Thiazide and thiazide-like diuretics (such as Chlorthalidone and Hydrochlorothiazide) are unique because they **decrease urinary calcium excretion**. They act on the distal convoluted tubule to inhibit the Na+/Cl- symporter, which indirectly enhances Ca2+ reabsorption. In a patient with a history of calcium stones (nephrolithiasis), reducing the concentration of calcium in the urine prevents stone formation while simultaneously managing blood pressure. Chlorthalidone is often preferred over HCTZ due to its longer half-life and superior evidence in reducing cardiovascular events. **Why other options are incorrect:** * **Furosemide (Loop Diuretic):** Unlike thiazides, loop diuretics **increase** urinary calcium excretion ("Loops lose calcium"). This would increase the risk of stone formation in this patient. * **Losartan (ARB):** While an excellent first-line antihypertensive (especially in diabetics), it has no specific benefit for preventing calcium stones. * **Atenolol (Beta-blocker):** No longer considered first-line for uncomplicated hypertension unless there is a specific cardiac indication (e.g., post-MI or heart failure). **Clinical Pearls for NEET-PG:** * **Thiazides:** Cause Hyper**GLUC** (Hyper**G**lycemia, Hyper**L**ipidemia, Hyper**U**ricemia, Hyper**C**alcemia). * **Loop Diuretics:** Used for edema and acute heart failure; cause **hypo**calcemia. * **First-line HTN drugs (JNC-8):** Thiazides, ACE inhibitors, ARBs, or Calcium Channel Blockers. * **Drug of choice for HTN with Benign Prostatic Hyperplasia (BPH):** Prazosin (Alpha-1 blocker).

Question 170: Which of the following drugs hyperpolarizes AV nodal tissue, is used in PSVT, and has short-lasting adverse effects?

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

Explanation: ### Explanation **Correct Answer: C. Adenosine** **Mechanism and Rationale:** Adenosine is the drug of choice for the acute termination of Paroxysmal Supraventricular Tachycardia (PSVT). It acts by binding to **A1 receptors** on the AV node, which activates G protein-coupled inward-rectifying potassium channels (GIRK). This leads to an **efflux of Potassium (K+)**, causing **hyperpolarization** of the nodal tissue. Simultaneously, it decreases cAMP, inhibiting Calcium (Ca2+) influx. The result is a transient but potent suppression of AV nodal conduction, "resetting" the rhythm. **Why the other options are incorrect:** * **Verapamil (CCB):** While used for PSVT, it works by blocking L-type Calcium channels (decreasing the slope of Phase 0). It does not cause hyperpolarization and has a much longer half-life (hours) compared to Adenosine. * **Digoxin:** It increases vagal tone to slow the AV node but is primarily used for rate control in Atrial Fibrillation. It does not cause hyperpolarization; rather, it can increase intracellular Calcium. * **Propranolol (Beta-blocker):** It slows the heart rate by decreasing the Phase 4 depolarization slope in the SA node. It is used for prophylaxis rather than acute termination of PSVT and lacks the rapid "on-off" effect of Adenosine. **High-Yield Facts for NEET-PG:** * **Ultra-short half-life:** <10 seconds (due to rapid uptake by RBCs and endothelial cells). * **Administration:** Must be given as a **rapid IV bolus** followed by a saline flush, preferably through a central or large peripheral vein. * **Adverse Effects:** Flushing, chest pain, and dyspnea. These are distressing but **short-lasting** (seconds). * **Drug Interactions:** Effects are **potentiated by Dipyridamole** and **antagonized by Theophylline/Caffeine** (adenosine receptor blockers). * **Contraindication:** Bronchial asthma (can cause bronchospasm) and high-grade heart block.

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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