Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 381: Glucagon is most effective for which of the following conditions?

A. Cocaine intake with a blood pressure of 180/110 mmHg
B. An elderly male with decreased blood pressure and decreased heart rate due to atenolol (Correct Answer)
C. An elderly male with type 2 diabetes mellitus and no glipizide for 4 days
D. A female with lactic acidosis due to shock

Explanation: **Explanation:** **Correct Option: B (Beta-blocker overdose/toxicity)** Glucagon is the **drug of choice for Beta-blocker (e.g., Atenolol) toxicity**. In cases of overdose, beta-receptors are saturated, rendering traditional adrenergic agonists (like Adrenaline) ineffective. Glucagon acts by bypassing the blocked beta-receptors; it binds to specific **glucagon receptors** on the myocardium, which are coupled to Gs proteins. This stimulates **Adenylate Cyclase**, increasing intracellular **cAMP**. The result is a potent positive inotropic (increased contractility) and chronotropic (increased heart rate) effect, effectively reversing bradycardia and hypotension. **Incorrect Options:** * **Option A:** Cocaine toxicity causes a sympathomimetic surge. Treatment involves benzodiazepines or alpha-blockers (Phentolamine). Using Glucagon would worsen hypertension and tachycardia. * **Option C:** Glucagon is used to treat *hypoglycemia* (e.g., sulfonylurea overdose). A patient who hasn't taken their glipizide (an antidiabetic) for 4 days would likely be *hyperglycemic*; giving glucagon would further elevate blood glucose. * **Option D:** Lactic acidosis in shock requires fluid resuscitation and addressing the underlying cause. Glucagon has no role in correcting metabolic acidosis. **NEET-PG High-Yield Pearls:** * **Mechanism of Action:** Increases cAMP via non-adrenergic pathways (bypasses $\beta$-receptors). * **Antidote Checklist:** Glucagon is also used as an antidote for **Calcium Channel Blocker (CCB) toxicity**, though High-Dose Insulin Euglycemia (HIET) is often preferred. * **Diagnostic Use:** Glucagon is used during GI radiology to induce **bowel relaxation** (hypotonia). * **Side Effect:** Significant nausea and vomiting are common after bolus administration.

Question 382: Ouabain acts by inhibiting which of the following?

A. Adenyl cyclase
B. Calcium channels
C. H+/K+ ATPase
D. Na+/K+ ATPase (Correct Answer)

Explanation: **Explanation:** **Mechanism of Action (Why D is correct):** Ouabain is a rapidly acting **cardiac glycoside**, similar to Digoxin. It works by reversibly inhibiting the **Na+/K+ ATPase pump** (specifically the alpha subunit) located on the myocardial sarcolemma. 1. Inhibition of this pump leads to an increase in intracellular **Sodium (Na+)**. 2. This high intracellular Na+ reduces the concentration gradient required for the **Na+/Ca2+ exchanger (NCX)** to function. 3. Consequently, calcium extrusion from the cell is decreased, leading to increased intracellular **Calcium (Ca2+)** levels. 4. This excess calcium is taken up by the Sarcoplasmic Reticulum, resulting in increased calcium release during subsequent depolarizations, leading to a **positive inotropic effect** (increased force of contraction). **Analysis of Incorrect Options:** * **A. Adenyl cyclase:** This enzyme converts ATP to cAMP. Drugs like Beta-agonists (Dobutamine) act via this pathway, not cardiac glycosides. * **B. Calcium channels:** Calcium channel blockers (e.g., Verapamil) inhibit these channels. Ouabain actually increases intracellular calcium indirectly. * **C. H+/K+ ATPase:** This is the "proton pump" found in gastric parietal cells. It is inhibited by Proton Pump Inhibitors (PPIs) like Omeprazole. **NEET-PG High-Yield Pearls:** * **Source:** Ouabain is derived from the seeds of *Strophanthus gratus*. * **Pharmacokinetics:** Unlike Digoxin, Ouabain is highly polar, poorly absorbed orally, and must be given **intravenously**. It has the fastest onset of action among glycosides. * **Vagal Effect:** Like Digoxin, it increases vagal tone, making it useful for rate control in atrial fibrillation (negative dromotropic effect). * **Toxicity:** Hypokalemia predisposes to toxicity because K+ and cardiac glycosides compete for the same binding site on the Na+/K+ ATPase pump.

Question 383: Tolerance develops with which of the following drugs?

A. Calcium channel blockers
B. ACE inhibitors
C. Nitrates (Correct Answer)
D. K channel openers

Explanation: **Explanation:** **Nitrates (Option C)** are classic examples of drugs that exhibit **tachyphylaxis** (rapidly developing tolerance). The primary mechanism behind nitrate tolerance is the **depletion of free sulfhydryl (-SH) groups** (specifically glutathione), which are essential for the conversion of nitrates into Nitric Oxide (NO) [1]. Other contributing factors include "pseudotolerance" (activation of the renin-angiotensin-aldosterone system due to vasodilation) [1] and increased production of free radicals (oxidative stress) which neutralize NO [1]. **Why other options are incorrect:** * **Calcium Channel Blockers (Option A):** These drugs do not show tolerance; their efficacy remains consistent with chronic dosing in hypertension and angina. * **ACE Inhibitors (Option B):** These do not exhibit tolerance. In fact, they are often used to *counteract* the pseudotolerance (fluid retention) caused by other vasodilators. * **K+ Channel Openers (Option D):** While drugs like Minoxidil or Nicorandil can cause reflex tachycardia, they do not typically demonstrate the biochemical tolerance seen with nitrates. **High-Yield Clinical Pearls for NEET-PG:** * **Nitrate-Free Interval:** To prevent tolerance, a "drug-free period" of **8–12 hours** (usually at night) is mandatory to allow the regeneration of sulfhydryl groups [1]. * **Monday Disease:** Industrial workers exposed to nitrates lose tolerance over the weekend, leading to severe headaches and tachycardia upon re-exposure on Mondays. * **Drug of Choice:** Nitrates remain the DOC for acute anginal attacks, but due to tolerance, they are not used as monotherapy for long-term prophylaxis without dosing gaps [1].

Question 384: Alteplase differs from streptokinase as it:

A. Is longer acting
B. Is derived from human kidney
C. Is cheap
D. Activates plasminogen bound to fibrin (Correct Answer)

Explanation: ### Explanation The core difference between Alteplase and Streptokinase lies in their **fibrin specificity**. **1. Why Option D is Correct:** Alteplase is a recombinant **Tissue Plasminogen Activator (t-PA)**. It is "fibrin-selective," meaning it has a high affinity for plasminogen that is already bound to a fibrin clot. It converts this bound plasminogen into plasmin directly on the clot surface. This localized action minimizes "systemic lytic state," unlike Streptokinase, which activates circulating plasminogen indiscriminately, leading to a higher risk of systemic bleeding. **2. Why the Other Options are Incorrect:** * **Option A (Longer acting):** Incorrect. Alteplase has a very short half-life (~5 minutes) and usually requires a bolus followed by an infusion. Streptokinase has a longer half-life (~20 minutes). * **Option B (Derived from human kidney):** Incorrect. **Urokinase** is the agent traditionally derived from human urine or kidney cultures. Alteplase is produced using **recombinant DNA technology**. * **Option C (Is cheap):** Incorrect. Streptokinase is a bacterial product (from *Streptococcus*) and is significantly cheaper. Alteplase is expensive due to the complex recombinant manufacturing process. **3. NEET-PG High-Yield Pearls:** * **Antigenicity:** Streptokinase is antigenic (derived from bacteria) and can cause anaphylaxis or resistance if reused. Alteplase is human-derived (recombinant) and **non-antigenic**. * **Mechanism:** Streptokinase is not an enzyme; it forms a complex with plasminogen to activate it. Alteplase is a direct-acting protease. * **Third-generation t-PAs:** **Tenecteplase** and **Reteplase** are more fibrin-specific than Alteplase and have longer half-lives, allowing for convenient single-bolus dosing.

Question 385: Which beta-adrenergic blocker possesses cardioselectivity, intrinsic sympathomimetic activity, and membrane-stabilizing properties?

A. Carvedilol
B. Atenolol
C. Acebutolol (Correct Answer)
D. Metoprolol

Explanation: **Explanation:** The correct answer is **Acebutolol**. This question tests the classification of beta-blockers based on their pharmacological profile. **1. Why Acebutolol is correct:** Acebutolol is a unique second-generation beta-blocker that possesses a "triple profile": * **Cardioselectivity ($\beta_1$ selective):** It preferentially blocks $\beta_1$ receptors, making it safer for patients with mild reactive airway disease. * **Intrinsic Sympathomimetic Activity (ISA):** It acts as a partial agonist. It provides a low level of stimulation at rest (preventing excessive bradycardia) while blocking the effects of high catecholamine levels during exercise. * **Membrane Stabilizing Activity (MSA):** It possesses a quinidine-like local anesthetic effect on the cardiac action potential. **2. Why the other options are incorrect:** * **Carvedilol:** A non-selective beta-blocker that also blocks $\alpha_1$ receptors (vasodilatory beta-blocker). It lacks ISA. * **Atenolol:** A cardioselective ($\beta_1$) blocker but lacks both ISA and MSA. It is highly hydrophilic and excreted via kidneys. * **Metoprolol:** A cardioselective ($\beta_1$) blocker with some MSA, but it **lacks ISA**. It is the prototype cardioselective blocker used in post-MI and heart failure. **NEET-PG High-Yield Pearls:** * **Mnemonic for ISA:** "**P**apa **P**en **A**ce" (**P**indolol, **P**enbutolol, **A**cebutolol). Pindolol is the most potent ISA agent. * **Mnemonic for MSA:** "**P**roperly **M**ake **A**ll **L**iquid" (**P**ropranolol, **M**etoprolol, **A**cebutolol, **L**abetalol). Propranolol has the highest MSA. * **Esmolol:** Shortest-acting beta-blocker (T½ ≈ 9 mins) due to metabolism by RBC esterases; used in hypertensive emergencies.

Question 386: Prolonged use of hydralazine for the treatment of hypertension is likely to cause:

A. Gynaecomastia
B. Thrombocytopenia
C. Hemolytic anemia
D. Lupus erythematosis (Correct Answer)

Explanation: **Explanation:** **Hydralazine** is a direct-acting arterial vasodilator used in hypertensive emergencies and chronic heart failure. The correct answer is **Lupus erythematosus**, specifically **Drug-Induced Lupus Erythematosus (DILE)**. 1. **Why D is correct:** Hydralazine is metabolized in the liver via **N-acetylation**. In individuals who are **"slow acetylators"** (genetically deficient in N-acetyltransferase), the drug or its metabolites can accumulate and bind to nuclear proteins. This triggers the formation of antinuclear antibodies (ANA), leading to a clinical syndrome resembling Systemic Lupus Erythematosus (SLE), characterized by arthralgia, fever, and pleuritis. Notably, unlike idiopathic SLE, DILE rarely involves the kidneys or CNS and typically resolves upon drug discontinuation. 2. **Why other options are incorrect:** * **A. Gynaecomastia:** Commonly associated with Spironolactone, Digoxin, Cimetidine, or Ketoconazole ("DISCO" mnemonic), but not Hydralazine. * **B. Thrombocytopenia:** While many drugs cause marrow suppression, it is not a classic or high-yield side effect of Hydralazine. * **C. Hemolytic anemia:** Classically associated with **Methyldopa** (Coombs-positive hemolytic anemia), not Hydralazine. **High-Yield Clinical Pearls for NEET-PG:** * **DILE Markers:** The most specific screening marker for DILE is **Anti-histone antibodies** (positive in >95% of cases). * **Common Culprits of DILE:** Remember the mnemonic **"SHIP"**: **S**ulfonamides/Sulfasalazine, **H**ydralazine, **I**soniazid, and **P**rocainamide (Procainamide has the highest risk). * **Reflex Tachycardia:** Hydralazine causes significant reflex tachycardia and fluid retention; therefore, it is almost always co-administered with a **Beta-blocker** and a **Diuretic**.

Question 387: Which of the following is NOT an adverse effect of ACE inhibitors?

A. Persistent cough
B. Taste alteration
C. Angioedema
D. Ankle edema (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Ankle edema**. ACE inhibitors (ACEIs) prevent the conversion of Angiotensin I to Angiotensin II. While they have several characteristic side effects, **ankle edema** is not one of them. Instead, ankle edema is a classic adverse effect of **Dihydropyridine Calcium Channel Blockers (CCBs)** like Amlodipine, caused by preferential precapillary vasodilation leading to increased hydrostatic pressure. **Why the other options are incorrect:** * **A. Persistent cough:** This is the most common side effect of ACEIs (occurring in 5-20% of patients) [1]. It is caused by the accumulation of **Bradykinin** and **Substance P** in the lungs, which sensitizes cough receptors [1]. * **B. Taste alteration (Dysgeusia):** This is specifically associated with **Captopril**, likely due to the presence of a sulfhydryl group in its chemical structure. * **C. Angioedema:** A rare but life-threatening side effect. It is also mediated by increased levels of **Bradykinin**, leading to rapid swelling of the lips, tongue, and airway. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for ACEI side effects (CAPTOPRIL):** **C**ough, **A**ngioedema, **P**otassium excess (Hyperkalemia), **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis (contraindicated in bilateral), **I**ncreased renin, **L**eukopenia [1], [2]. * **Switching Therapy:** If a patient develops a cough on ACEIs, the next best step is to switch to an **Angiotensin Receptor Blocker (ARB)**, as ARBs do not affect bradykinin metabolism [1]. * **Teratogenicity:** ACEIs are contraindicated in pregnancy because they cause **fetal renal dysgenesis** and skull hypoplasia [2].

Question 388: Which of the following is a true statement about Endothelin-1, a potent vasoconstrictor?

A. Used in hypertension treatment
B. Produced in increased amounts in Pulmonary Arterial Hypertension (Correct Answer)
C. Dilates vascular smooth muscle cells
D. Safely indicated in liver injury

Explanation: **Explanation:** **Endothelin-1 (ET-1)** is the most potent endogenous vasoconstrictor discovered to date. It is synthesized by vascular endothelial cells and plays a critical role in the pathophysiology of various cardiovascular diseases. **1. Why Option B is Correct:** In **Pulmonary Arterial Hypertension (PAH)**, there is a significant imbalance between vasodilators (like Nitric Oxide and Prostacyclin) and vasoconstrictors. ET-1 levels are markedly **increased** in the plasma and lung tissue of PAH patients. This excess ET-1 leads to sustained vasoconstriction, smooth muscle hypertrophy, and vascular remodeling, which increases pulmonary vascular resistance. **2. Why the Other Options are Incorrect:** * **Option A:** ET-1 is a potent vasoconstrictor, not a treatment for hypertension. In fact, **Endothelin Receptor Antagonists (ERAs)** like Bosentan and Ambrisentan are used to *treat* PAH by blocking its effects. * **Option C:** ET-1 causes **contraction** (vasoconstriction) of vascular smooth muscle cells via $ET_A$ and $ET_B$ receptors. While $ET_B$ on endothelial cells can trigger NO release, the predominant effect of ET-1 is profound vasoconstriction. * **Option D:** ERAs (especially Bosentan) are associated with **hepatotoxicity** and elevation of liver transaminases. They are contraindicated in patients with significant liver injury. **High-Yield Clinical Pearls for NEET-PG:** * **Receptors:** $ET_A$ (mainly on smooth muscle, causes vasoconstriction); $ET_B$ (on both endothelium and smooth muscle). * **Drug Class (ERAs):** * **Bosentan:** Non-selective ($ET_A$ + $ET_B$) antagonist; requires monthly LFT monitoring. * **Ambrisentan:** Selective $ET_A$ antagonist. * **Macitentan:** Tissue-bound non-selective antagonist with better efficacy. * **Teratogenicity:** All ERAs are highly teratogenic (Category X) and require a negative pregnancy test before initiation.

Question 389: Which of the following drugs are used in the management of Congestive Heart Failure (CHF)?

A. Nesiritide
B. Digoxin
C. Spironolactone
D. All of the above (Correct Answer)

Explanation: **Explanation:** Congestive Heart Failure (CHF) management involves a multi-faceted approach focusing on symptomatic relief, reducing cardiac workload, and improving long-term survival. * **Nesiritide:** This is a recombinant form of **human B-type Natriuretic Peptide (BNP)**. It increases cGMP, leading to potent vasodilation (reducing both preload and afterload) and promotes natriuresis. It is primarily used in acute decompensated heart failure. * **Digoxin:** A cardiac glycoside that inhibits the **Na+/K+ ATPase pump**, leading to increased intracellular calcium and positive inotropy. While it does not improve mortality, it is highly effective for symptomatic relief and reducing hospitalization rates, especially in patients with concomitant atrial fibrillation. * **Spironolactone:** An **Aldosterone Antagonist** (Mineralocorticoid Receptor Antagonist). Unlike digoxin, spironolactone is proven to **reduce mortality** and prevent myocardial fibrosis (cardiac remodeling) in patients with NYHA Class II-IV heart failure. Since all three drugs target different pathophysiological pathways of CHF, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mortality Benefit:** Drugs that improve survival in CHF include ACE inhibitors, ARBs, Beta-blockers (Carvedilol, Metoprolol succinate, Bisoprolol), Spironolactone, and SGLT2 inhibitors. 2. **Digoxin Toxicity:** The earliest symptom is usually anorexia/nausea; the most characteristic visual disturbance is **Xanthopsia** (yellowish vision); the most common arrhythmia is PVCs, but the most specific is **Atrial Tachycardia with AV block**. 3. **Sacubitril/Valsartan (ARNI):** Currently a first-line recommendation that replaces ACEIs/ARBs to further reduce mortality.

Question 390: Sildenafil (Viagra) is indicated for which condition?

A. Pulmonary hypertension (Correct Answer)
B. Essential hypertension
C. Malignant hypertension
D. Hypertension in pregnancy

Explanation: **Explanation:** **Mechanism of Action:** Sildenafil is a selective inhibitor of **Phosphodiesterase-5 (PDE-5)**. By inhibiting this enzyme, it prevents the breakdown of cyclic Guanosine Monophosphate (cGMP). Increased levels of cGMP lead to smooth muscle relaxation and vasodilation. While PDE-5 is found in the corpora cavernosa (treating erectile dysfunction), it is also highly expressed in the **pulmonary vasculature**. In Pulmonary Arterial Hypertension (PAH), Sildenafil reduces pulmonary vascular resistance and improves exercise capacity. **Analysis of Options:** * **Option A (Correct):** Sildenafil is FDA-approved for PAH (Group 1) to improve exercise ability and delay clinical worsening. * **Option B (Incorrect):** Essential hypertension is managed with first-line agents like ACE inhibitors, ARBs, Calcium Channel Blockers, or Thiazides. Sildenafil does not provide sufficient systemic blood pressure lowering for this use. * **Option C (Incorrect):** Malignant hypertension is a medical emergency requiring rapid-acting intravenous agents like Labetalol, Nicardipine, or Sodium Nitroprusside. * **Option D (Incorrect):** The drugs of choice for hypertension in pregnancy are Labetalol, Methyldopa, or Nifedipine. **High-Yield NEET-PG Pearls:** * **Contraindication:** Never co-administer Sildenafil with **Nitrates** (e.g., Nitroglycerin). This can cause a synergistic increase in cGMP, leading to life-threatening hypotension. * **Side Effects:** Headache, flushing, and **"Blue-tinted vision" (Cyanopsia)** due to weak inhibition of PDE-6 in the retina. * **Tadalafil:** Another PDE-5 inhibitor used for PAH; it has a longer half-life (36 hours) compared to Sildenafil (4 hours).

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

Practice Questions

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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