Cardiovascular Drugs Practice Questions

Q: Ouabain acts by inhibiting which of the following?

Na+/K+ ATPase. **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.

Q: Tolerance develops with which of the following drugs?

Nitrates. **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].

Q: Alteplase differs from streptokinase as it:

Activates plasminogen bound to fibrin. ### 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.

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

Acebutolol. **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.

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

Lupus erythematosis. **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**.

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

Ankle edema. **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].

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

All of the above. **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.

Q: Sildenafil (Viagra) is indicated for which condition?

Pulmonary hypertension. **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).

Question 1

Glucagon is most effective for which of the following conditions?

Accepted Answer

An elderly male with decreased blood pressure and decreased heart rate due to atenolol

Answer

Cocaine intake with a blood pressure of 180/110 mmHg

Answer

An elderly male with type 2 diabetes mellitus and no glipizide for 4 days

Answer

A female with lactic acidosis due to shock

Question 2

Ouabain acts by inhibiting which of the following?

Accepted Answer

Na+/K+ ATPase

Answer

Adenyl cyclase

Answer

Calcium channels

Answer

H+/K+ ATPase

Question 3

Tolerance develops with which of the following drugs?

Accepted Answer

Nitrates

Answer

Calcium channel blockers

Answer

ACE inhibitors

Answer

K channel openers

Question 4

Alteplase differs from streptokinase as it:

Accepted Answer

Activates plasminogen bound to fibrin

Answer

Is longer acting

Answer

Is derived from human kidney

Answer

Is cheap

Question 5

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

Accepted Answer

Acebutolol

Answer

Carvedilol

Answer

Atenolol

Answer

Metoprolol

Question 6

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

Accepted Answer

Lupus erythematosis

Answer

Gynaecomastia

Answer

Thrombocytopenia

Answer

Hemolytic anemia

Question 7

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

Accepted Answer

Ankle edema

Answer

Persistent cough

Answer

Taste alteration

Answer

Angioedema

Question 8

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

Accepted Answer

Produced in increased amounts in Pulmonary Arterial Hypertension

Answer

Used in hypertension treatment

Answer

Dilates vascular smooth muscle cells

Answer

Safely indicated in liver injury

Question 9

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

Accepted Answer

All of the above

Answer

Nesiritide

Answer

Digoxin

Answer

Spironolactone

Question 10

Sildenafil (Viagra) is indicated for which condition?

Accepted Answer

Pulmonary hypertension

Answer

Essential hypertension

Answer

Malignant hypertension

Answer

Hypertension in pregnancy

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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