Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 491: All of the following are used for treating 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. **Why Beta-blockers are the correct answer:** Beta-blockers are generally **contraindicated** in PAH. They possess negative inotropic and chronotropic effects, which can decrease cardiac output and potentially worsen right heart failure—the leading cause of death in PAH patients. Furthermore, blocking $\beta_2$ receptors can lead to unwanted bronchoconstriction and peripheral vasoconstriction, further compromising hemodynamics. **Why the other options are used:** * **Endothelin Receptor Antagonists (ERAs):** Drugs like **Bosentan** (non-selective) and **Ambrisentan** (selective $ET_A$) block the potent vasoconstrictive effects of endothelin-1, a peptide elevated in PAH patients. * **Phosphodiesterase-5 (PDE-5) Inhibitors:** **Sildenafil** and **Tadalafil** increase levels of cGMP, leading to nitric oxide-mediated vasodilation of the pulmonary vasculature. * **Calcium Channel Blockers (CCBs):** High-dose CCBs (e.g., **Nifedipine, Diltiazem**) are used in a specific subset of patients who show a positive "Vasoreactivity Test" during right heart catheterization. **High-Yield Clinical Pearls for NEET-PG:** 1. **Drug of choice for Vasoreactive patients:** Long-acting CCBs. 2. **Prostacyclin Analogs:** **Epoprostenol** (IV) is the drug of choice for severe (NYHA Class IV) PAH. 3. **Soluble Guanylate Cyclase Stimulator:** **Riociguat** is used for chronic thromboembolic pulmonary hypertension (CTEPH). 4. **Bosentan Side Effect:** It is hepatotoxic (requires monthly LFTs) and highly teratogenic.

Question 492: Alirocumab and Evolocumab are classified as which of the following?

A. NPGL1 inhibitors
B. Microsomal transport protein inhibitors
C. PCSK-9 inhibitors (Correct Answer)
D. Lipoprotein lipase inhibitors

Explanation: ### Explanation **Correct Option: C. PCSK-9 inhibitors** Alirocumab and Evolocumab are monoclonal antibodies that inhibit **Proprotein Convertase Subtilisin/Kexin type 9 (PCSK-9)**. * **Mechanism:** Normally, PCSK-9 binds to LDL receptors (LDLR) on the surface of hepatocytes and promotes their degradation. By inhibiting PCSK-9, these drugs increase the recycling and density of LDL receptors on the liver cell surface. * **Result:** Increased LDLRs lead to enhanced clearance of LDL-cholesterol from the plasma, resulting in a significant reduction (up to 60%) in LDL levels. **Why other options are incorrect:** * **A. NPGL1 inhibitors:** This likely refers to **Ezetimibe**, which inhibits the Niemann-Pick C1-Like 1 (NPC1L1) protein. It acts by blocking the intestinal absorption of dietary and biliary cholesterol. * **B. Microsomal transport protein (MTP) inhibitors:** The prototype drug is **Lomitapide**. It prevents the assembly of apoB-containing lipoproteins (VLDL and chylomicrons) in the liver and intestine. * **D. Lipoprotein lipase (LPL) inhibitors:** This is physiologically counterproductive for treating lipid disorders. Drugs like **Fibrates** actually *stimulate* LPL activity to enhance the clearance of triglyceride-rich lipoproteins. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Administration:** These are administered as **subcutaneous injections** once every 2–4 weeks. * **Indications:** Used in patients with **Familial Hypercholesterolemia** or clinical atherosclerotic cardiovascular disease (ASCVD) who require additional LDL lowering despite maximally tolerated statin therapy. * **Side Effects:** Generally well-tolerated; most common side effects are injection site reactions and nasopharyngitis. * **Bempedoic Acid (Newer Drug):** Often tested alongside these; it inhibits **ATP citrate lyase**, acting upstream of HMG-CoA reductase.

Question 493: Which drug is commonly used in the management of heart failure?

A. ACE inhibitors (Correct Answer)
B. Hydralazine
C. Ca2+ channel blockers
D. Carvedilol

Explanation: **Explanation:** **ACE Inhibitors (ACEIs)** are considered the cornerstone of heart failure (HF) management. Their primary benefit lies in their ability to inhibit the Renin-Angiotensin-Aldosterone System (RAAS). By preventing the conversion of Angiotensin I to Angiotensin II, they reduce systemic vascular resistance (afterload) and decrease salt/water retention (preload). Most importantly, ACEIs inhibit **cardiac remodeling**, which significantly reduces mortality and morbidity in patients with Heart Failure with reduced Ejection Fraction (HFrEF). **Analysis of Options:** * **B. Hydralazine:** While used in HF, it is typically a second-line agent. It is usually combined with Isosorbide Dinitrate (BiDil) specifically for patients who cannot tolerate ACEIs/ARBs or as add-on therapy in African-American patients. * **C. Ca2+ channel blockers:** Most CCBs (especially non-dihydropyridines like Verapamil/Diltiazem) are generally **avoided** in HFrEF due to their negative inotropic effects, which can worsen heart failure. * **D. Carvedilol:** This is a tricky distractor. While Carvedilol (a non-selective beta-blocker) is indeed used in HF to reduce mortality, ACE inhibitors are traditionally established as the first-line "foundational" therapy initiated in almost all patients unless contraindicated. (Note: In modern guidelines, both are started, but ACEIs remain the classic "most common" answer in standardized exams). **High-Yield Clinical Pearls for NEET-PG:** * **Mortality Benefit:** ACEIs, Beta-blockers (Carvedilol, Metoprolol succinate, Bisoprolol), Spironolactone, and ARNIs (Sacubitril/Valsartan) all reduce mortality in HF. * **Side Effects:** The most common side effect of ACEIs is a **dry cough** (due to increased Bradykinin); the most serious is **angioedema**. * **Contraindications:** ACEIs are strictly contraindicated in **pregnancy** (teratogenic) and patients with **bilateral renal artery stenosis**.

Question 494: Low doses of aspirin therapy is advised for all of the following conditions except?

A. Systemic Lupus Erythematosus (SLE) (Correct Answer)
B. Intrauterine Growth Restriction (IUGR)
C. Post myocardial infarction
D. Pre-eclampsia

Explanation: ### Explanation **1. Why Systemic Lupus Erythematosus (SLE) is the Correct Answer:** Low-dose aspirin (75–150 mg) acts as an antiplatelet agent by irreversibly inhibiting **COX-1**, thereby blocking the synthesis of **Thromboxane A2 (TXA2)**. While SLE is an autoimmune condition, low-dose aspirin is **not** a standard primary therapy for the disease itself. SLE management typically involves hydroxychloroquine, corticosteroids, or immunosuppressants. Aspirin is only indicated in SLE patients if they have secondary **Antiphospholipid Syndrome (APS)** to prevent thrombosis; however, as a general rule for SLE alone, it is not a routine indication. **2. Analysis of Other Options:** * **Post-Myocardial Infarction:** Low-dose aspirin is the gold standard for secondary prevention. It prevents further coronary artery occlusion by inhibiting platelet aggregation at the site of atherosclerotic plaque rupture. * **Pre-eclampsia:** Low-dose aspirin (started before 16 weeks of gestation) is used in high-risk pregnancies to improve the balance between prostacyclin and thromboxane, thereby reducing the risk of placental ischemia and hypertension. * **Intrauterine Growth Restriction (IUGR):** In cases where IUGR is caused by placental insufficiency or pre-eclampsia, low-dose aspirin improves uteroplacental blood flow and fetal growth outcomes. **3. High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Aspirin is the only NSAID that inhibits COX **irreversibly** via acetylation. * **Dose-Dependent Effect:** * *Low dose (75-150 mg):* Antiplatelet (TXA2 inhibition). * *Intermediate dose (300-2400 mg):* Analgesic and Antipyretic. * *High dose (>4 g):* Anti-inflammatory (used in Rheumatic fever). * **Zero-Order Kinetics:** Aspirin follows zero-order elimination at high/toxic doses. * **Contraindication:** Avoid in children with viral infections to prevent **Reye’s Syndrome**.

Question 495: In which condition is Digoxin indicated for Congestive Heart Failure (CHF)?

A. Hypertrophic obstructive cardiomyopathy (HOCM)
B. High output failure
C. Atrial fibrillation with a high ventricular rate (Correct Answer)
D. All of the above

Explanation: **Explanation:** Digoxin is a cardiac glycoside that exerts two primary effects: **positive inotropy** (by inhibiting Na+/K+ ATPase) and **negative chronotropy/dromotropy** (via vagomimetic action on the AV node). **Why Option C is Correct:** In patients with Congestive Heart Failure (CHF) and concomitant **Atrial Fibrillation (AF)**, Digoxin is highly effective. Its vagomimetic action slows conduction through the Atrioventricular (AV) node, thereby reducing the ventricular rate. This allows for better diastolic filling and improved cardiac output, making it a preferred choice for rate control in heart failure patients. **Why Other Options are Incorrect:** * **A. Hypertrophic Obstructive Cardiomyopathy (HOCM):** Digoxin is **contraindicated**. Increasing contractility (positive inotropy) in HOCM worsens the outflow tract obstruction, potentially leading to sudden cardiac collapse. * **B. High Output Failure:** Conditions like anemia, thyrotoxicosis, or thiamine deficiency cause heart failure due to excessive demand rather than primary pump failure. Digoxin is generally ineffective here as the underlying cause is metabolic or systemic, not a lack of contractility. **High-Yield NEET-PG Pearls:** * **Mechanism:** Inhibits Na+/K+ ATPase → increased intracellular Na+ → decreased Na+/Ca2+ exchange → increased intracellular Ca2+ → increased contractility. * **ECG Changes:** Characterized by the "reverse tick" or "Salvador Dali mustache" sign (ST-segment depression). * **Toxicity:** Hypokalemia predisposes to Digoxin toxicity. The most common arrhythmia in toxicity is **Ventricular Bigeminy**, while the most characteristic is **Non-paroxysmal Atrial Tachycardia with AV block**. * **Antidote:** Digibind (Digoxin-specific Fab fragments).

Question 496: Amyl nitrate is used by which route?

A. Oral
B. Inhalation (Correct Answer)
C. Intravenous
D. Intramedullary

Explanation: **Explanation:** **Amyl Nitrite** is a highly volatile liquid vasodilator belonging to the organic nitrate class. The correct route of administration is **Inhalation** because the drug is supplied in thin glass ampoules (crushable "pearls") wrapped in protective fabric. When crushed, the liquid vaporizes instantly and is inhaled through the nostrils, leading to rapid absorption across the pulmonary alveolar-capillary membrane. **Why the other options are incorrect:** * **Oral:** Amyl nitrite undergoes extensive **first-pass metabolism** in the liver, making oral administration ineffective. Furthermore, its rapid onset of action (within 30 seconds) is required for its clinical uses, which oral ingestion cannot provide. * **Intravenous:** While other nitrates like Nitroglycerin can be given IV, Amyl nitrite is specifically formulated for inhalation. IV administration is not standard due to the difficulty in titrating its extremely rapid and short-lived effect. * **Intramedullary:** This route (into the bone marrow) is reserved for emergency fluid resuscitation when IV access is impossible; it has no role in nitrate therapy. **Clinical Pearls for NEET-PG:** 1. **Mechanism in Cyanide Poisoning:** Amyl nitrite is a rapid-acting inducer of **Methemoglobinemia**. Methemoglobin has a high affinity for cyanide, forming **Cyanmethemoglobin**, which prevents cyanide from binding to Cytochrome Oxidase. 2. **Diagnostic Use:** In cardiology, it is used to differentiate heart murmurs. It **increases** the intensity of the murmur in **HOCM** and Mitral Regurgitation (due to decreased afterload) but decreases the murmur of Aortic Stenosis. 3. **Side Effects:** The most common side effect is a "throbbing" headache and orthostatic hypotension.

Question 497: In congestive cardiac failure, all of the following are used EXCEPT:

A. Spironolactone
B. Nitrates
C. Nesiritide
D. Trimetazidine (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Trimetazidine** **1. Why Trimetazidine is the correct answer:** Trimetazidine is a **metabolic modulator** that inhibits the enzyme **3-ketoacyl-CoA thiolase (3-KAT)**. This shifts myocardial metabolism from fatty acid oxidation to glucose oxidation, which is more oxygen-efficient. While it is an effective **anti-anginal drug** used for chronic stable angina, it has no established role in the standard management of Congestive Cardiac Failure (CCF). It does not improve hemodynamics or mortality in heart failure patients. **2. Why the other options are used in CCF:** * **A. Spironolactone:** An aldosterone antagonist (MRA) that is a cornerstone of heart failure therapy. It prevents myocardial fibrosis and remodeling, significantly reducing mortality in patients with HFrEF (NYHA Class II-IV). * **B. Nitrates:** These are vasodilators. In acute heart failure, they reduce **preload** (venous dilation), relieving pulmonary congestion. In chronic cases, they are often combined with Hydralazine to reduce mortality, especially in specific populations. * **C. Nesiritide:** A recombinant form of **B-type Natriuretic Peptide (BNP)**. It causes vasodilation and natriuresis, used primarily in acute decompensated heart failure to reduce dyspnea and wedge pressure. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drugs reducing mortality in CCF:** Beta-blockers (Carvedilol, Metoprolol, Bisoprolol), ACE inhibitors/ARBs, ARNIs (Sacubitril/Valsartan), Spironolactone, and SGLT2 inhibitors (Dapagliflozin). * **Trimetazidine Side Effect:** Can cause **Parkinsonian symptoms** (tremors, rigidity) and should be avoided in patients with Parkinson’s disease. * **Nesiritide** is contraindicated in patients with cardiogenic shock or systolic BP < 90 mmHg.

Question 498: Which of the following drugs reduces blood pressure primarily by directly decreasing heart rate?

A. Propranolol (Correct Answer)
B. Prazosin
C. Alpha methyl dopa
D. Nitroprusside sodium

Explanation: **Explanation:** **1. Why Propranolol is Correct:** Propranolol is a non-selective **beta-adrenergic antagonist (Beta-blocker)**. Its primary mechanism for lowering blood pressure involves blocking $\beta_1$ receptors in the heart, which leads to a **negative chronotropic effect** (decreased heart rate) and a **negative inotropic effect** (decreased myocardial contractility). By reducing the heart rate and stroke volume, it directly lowers **Cardiac Output (CO)**. Since Blood Pressure = Cardiac Output × Total Peripheral Resistance, the reduction in CO results in a decrease in BP. It also inhibits renin release from the juxtaglomerular apparatus, further aiding BP control. **2. Why the Other Options are Incorrect:** * **Prazosin:** This is a selective **$\alpha_1$-blocker**. It reduces BP by causing vasodilation (decreasing peripheral resistance), not by decreasing heart rate. In fact, it may cause compensatory reflex tachycardia. * **Alpha-methyl dopa:** A centrally acting **$\alpha_2$-agonist**. It reduces BP primarily by decreasing sympathetic outflow from the vasomotor center in the brain, leading to a decrease in systemic vascular resistance. * **Nitroprusside sodium:** A potent **direct vasodilator** (releasing NO) that acts on both arterioles and venules. It reduces BP by drastically decreasing peripheral resistance and is often associated with reflex tachycardia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Propranolol is the DOC for performance anxiety (stage fright) and essential tremors. * **Contraindication:** Avoid beta-blockers in patients with **Bronchial Asthma** (due to $\beta_2$ blockade causing bronchospasm) and **Prinzmetal Angina**. * **Metabolic Effect:** They can mask the warning symptoms of hypoglycemia (tachycardia) in diabetic patients. * **Lipid Solubility:** Propranolol is highly lipid-soluble, allowing it to cross the blood-brain barrier, which explains its efficacy in migraine prophylaxis but also its side effect of vivid dreams/nightmares.

Question 499: Tachycardia due to nitrates in a patient with angina pectoris is blocked by which of the following drug classes?

A. Digoxin
B. Dobutamine
C. Beta blocker (Correct Answer)
D. Calcium channel blocker

Explanation: ### Explanation **Why Beta Blockers are the Correct Choice:** Nitrates are potent vasodilators. By dilating peripheral veins (reducing preload) and arteries (reducing afterload), they cause a drop in blood pressure. This triggers a **baroreceptor-mediated reflex increase in sympathetic activity**, leading to **reflex tachycardia**. In patients with angina, this tachycardia is detrimental because it increases myocardial oxygen demand and shortens diastolic filling time. **Beta-blockers** (e.g., Metoprolol, Atenolol) are the drugs of choice to counteract this because they directly block the $\beta_1$ receptors in the heart, preventing the reflex increase in heart rate and contractility. The combination of nitrates and beta-blockers is synergistic: nitrates reduce preload, while beta-blockers prevent reflex tachycardia. **Analysis of Incorrect Options:** * **A. Digoxin:** Primarily used for rate control in atrial fibrillation and in heart failure. It increases vagal tone but is not the standard treatment for nitrate-induced reflex tachycardia. * **B. Dobutamine:** A $\beta_1$ agonist that *increases* heart rate and contractility. Administering it would worsen tachycardia and myocardial oxygen demand. * **C. Calcium Channel Blockers (CCBs):** While non-dihydropyridines (Verapamil/Diltiazem) can decrease heart rate, the question asks for the standard class used to block reflex sympathetic activity. Furthermore, Dihydropyridines (like Nifedipine) can actually *cause* reflex tachycardia themselves, worsening the condition. **High-Yield Clinical Pearls for NEET-PG:** * **The "Monday Disease":** Chronic exposure to nitrates leads to tolerance; reflex tachycardia is most prominent during the initial doses. * **Synergistic Combination:** Nitrates + Beta-blockers is a classic "High-Yield" combination. Nitrates decrease preload/heart size, while Beta-blockers prevent the reflex tachycardia and increased contractility caused by nitrates. * **Contraindication:** Never give Nitrates to a patient on Sildenafil (PDE-5 inhibitor) due to the risk of severe, life-threatening hypotension.

Question 500: Prolonged administration of sodium nitroprusside can cause poisoning of which substance?

A. Cyanide (Correct Answer)
B. Methanol
C. Arsenic
D. Phenol

Explanation: Explanation: Sodium Nitroprusside (SNP) is a potent, rapid-acting vasodilator used in hypertensive emergencies [1]. Its chemical structure consists of a ferrous iron center surrounded by five cyanide (CN⁻) groups and one nitrosyl group. Why Cyanide is the correct answer: When SNP is administered intravenously, it reacts with hemoglobin and sulfhydryl groups in erythrocytes to release nitric oxide (the active vasodilator) and five cyanide ions. Normally, the liver enzyme rhodanese detoxifies cyanide by converting it into thiocyanate using sulfur donors (thiosulfate) [2]. However, with prolonged infusion (typically >24–48 hours) or high doses, the body’s thiosulfate stores are exhausted. This leads to cyanide accumulation, which inhibits mitochondrial cytochrome oxidase, causing cellular hypoxia and lactic acidosis. Why other options are incorrect: Methanol: Poisoning typically occurs via ingestion of adulterated alcohol, leading to formic acid accumulation. It is not a byproduct of SNP metabolism. Arsenic: A heavy metal toxin that inhibits pyruvate dehydrogenase; it is unrelated to vasodilator therapy. Phenol: Used as a disinfectant or chemical intermediate; it is not chemically related to the structure or metabolism of nitroprusside. High-Yield Clinical Pearls for NEET-PG: Early sign of toxicity: Metabolic acidosis (due to lactate) and an unexplained decrease in oxygen saturation (venous hyperoxemia). Management of SNP-induced Cyanide Poisoning: 1. Sodium Thiosulfate: Provides sulfur donors for rhodanese [2]. 2. Hydroxocobalamin (Vitamin B12a): Binds cyanide to form non-toxic cyanocobalamin (preferred first-line) [2]. 3. Amyl/Sodium Nitrite: Induces methemoglobinemia, which has a high affinity for cyanide [2]. Thiocyanate Toxicity: In patients with renal failure, the metabolite thiocyanate can accumulate, causing psychosis and seizures.

Practice by Chapter

Antihypertensive Agents

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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

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Thrombolytic Agents

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Drugs Used in Pulmonary Hypertension

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Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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