Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 301: A patient with cardiac disease should be advised to stop which of the following medications if experiencing a persistent cough?

A. Diltiazem
B. Aspirin
C. Enalapril (Correct Answer)
D. Clopidogrel

Explanation: **Explanation:** **Correct Option: C. Enalapril** Enalapril is an **ACE (Angiotensin-Converting Enzyme) inhibitor**. The most characteristic side effect of ACE inhibitors is a **dry, persistent, non-productive cough**, occurring in approximately 5–20% of patients. * **Mechanism:** ACE is identical to Kininase II, the enzyme responsible for breaking down **Bradykinin** and **Substance P**. By inhibiting this enzyme, ACE inhibitors lead to an accumulation of these pro-inflammatory autacoids in the lungs. This irritates the sensory afferent C-fibers in the airways, triggering the cough reflex. * **Clinical Action:** If a patient develops this cough, the medication should be discontinued and replaced with an **ARB (Angiotensin Receptor Blocker)** like Losartan, which does not interfere with bradykinin metabolism. **Incorrect Options:** * **A. Diltiazem:** A non-dihydropyridine calcium channel blocker (CCB). Common side effects include bradycardia, constipation, and peripheral edema, but not cough. * **B. Aspirin:** An antiplatelet agent. While it can trigger "Aspirin-Exacerbated Respiratory Disease" (bronchospasm/asthma) in sensitive individuals, it does not typically cause a persistent dry cough. * **D. Clopidogrel:** A P2Y12 receptor antagonist. Its primary side effects are bleeding and gastrointestinal upset; it has no association with a cough. **High-Yield Clinical Pearls for NEET-PG:** * **ACEi Side Effects (Mnemonic: CAPTOPRIL):** **C**ough, **A**ngioedema, **P**roteinuria/Potassium excess (Hyperkalemia), **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis contraindication, **I**ncreased renin, **L**eukopenia. * The cough usually starts within 1 week to 6 months of therapy and typically resolves within 1–4 weeks after stopping the drug. * **Switching:** ARBs are the best alternative for patients who develop an ACEi-induced cough.

Question 302: Arrange the following drugs according to their half-life in increasing order: Amiodarone, Adenosine, Esmolol, Omeprazole?

A. Adenosine, Esmolol, Omeprazole, Amiodarone (Correct Answer)
B. Adenosine, Esmolol, Amiodarone, Omeprazole
C. Esmolol, Adenosine, Omeprazole, Amiodarone
D. Adenosine, Omeprazole, Adenosine, Amiodarone

Explanation: This question tests your knowledge of clinical pharmacokinetics, specifically the half-lives ($t_{1/2}$) of commonly used drugs in emergency and cardiovascular medicine. ### **Explanation of the Correct Order** The correct sequence (Option A) is based on the following pharmacokinetic profiles: 1. **Adenosine ($t_{1/2} < 10$ seconds):** It has the shortest half-life in clinical medicine due to rapid uptake by erythrocytes and vascular endothelial cells, where it is metabolized by adenosine deaminase. 2. **Esmolol ($t_{1/2} \approx 9$ minutes):** An ultra-short-acting $\beta_1$-selective blocker. Its rapid offset is due to hydrolysis by **red blood cell esterases** (not liver enzymes). 3. **Omeprazole ($t_{1/2} \approx 1$–$1.5$ hours):** A Proton Pump Inhibitor (PPI) with a short plasma half-life but a long duration of action because it binds irreversibly to the $H^+/K^+$ ATPase pump. 4. **Amiodarone ($t_{1/2} \approx 25$–$60$ days):** A Class III antiarrhythmic with an exceptionally long half-life due to its high lipophilicity and extensive sequestration in tissues (adipose and muscle). ### **Analysis of Incorrect Options** * **Option B & C:** These are incorrect because they place Amiodarone or Omeprazole before Esmolol. Esmolol’s "minutes-long" half-life is significantly shorter than Omeprazole’s "hour-long" half-life. * **Option D:** This option is logically inconsistent as it repeats Adenosine twice and misplaces the sequence. ### **NEET-PG High-Yield Pearls** * **Adenosine:** Must be given as a **rapid IV bolus** followed by a saline flush (due to its <10s half-life) for the treatment of PSVT. * **Esmolol:** Ideal for intraoperative tachycardia/hypertension or aortic dissection because its effects can be "switched off" quickly. * **Amiodarone:** Because of its long half-life, a **loading dose** is mandatory, and side effects (pulmonary fibrosis, thyroid dysfunction) can persist long after discontinuation. * **Shortest half-life drug:** Adenosine. * **Longest half-life drug:** Amiodarone (among common cardiovascular drugs).

Question 303: All of the following statements about digitalis are true except:

A. Excretion is mainly renal
B. Oral absorption is good
C. Actively metabolized in the liver (Correct Answer)
D. Lipid soluble

Explanation: **Explanation:** The question asks for the incorrect statement regarding **Digoxin** (the most commonly used digitalis glycoside). **Why Option C is the correct answer (The False Statement):** Digoxin is **not** actively metabolized in the liver. Approximately **60-80% of the drug is excreted unchanged in the urine** via glomerular filtration and tubular secretion (mediated by P-glycoprotein). Only a negligible amount (about 10-15%) undergoes hepatic metabolism. This is clinically significant because the dose must be adjusted in patients with renal impairment, not hepatic failure. **Analysis of Incorrect Options (True Statements):** * **Option A (Excretion is mainly renal):** This is true. Digoxin’s clearance is directly proportional to the Creatinine Clearance (CrCl). * **Option B (Oral absorption is good):** This is true. Digoxin has a high oral bioavailability (70-80% for tablets, up to 90-100% for capsules/elixirs). * **Option D (Lipid soluble):** This is true. Digoxin is moderately lipid-soluble, allowing it to be absorbed orally and distributed widely into tissues (especially skeletal muscle and heart), resulting in a large Volume of Distribution (Vd). **High-Yield NEET-PG Pearls:** 1. **Mechanism:** Inhibits Na+/K+ ATPase pump → increased intracellular Na+ → decreased Na+/Ca2+ exchange → increased intracellular Ca2+ → **Positive Inotropy**. 2. **Digitoxin vs. Digoxin:** Unlike Digoxin, **Digitoxin** is highly lipid-soluble, undergoes extensive hepatic metabolism, and is preferred in patients with renal failure (though it is rarely used now). 3. **Toxicity:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose to digitalis toxicity. 4. **ECG Changes:** The earliest sign of toxicity is often PVCs; the most characteristic sign is the "Reverse Tick" or "Sagging" ST-segment depression. 5. **Antidote:** Digibind (Digoxin-specific Fab fragments).

Question 304: Which of the following antiarrhythmic drugs does not cause Torsades de Pointes?

A. Quinidine
B. Disopyramide
C. Procainamide
D. Lidocaine (Correct Answer)

Explanation: **Explanation:** The risk of **Torsades de Pointes (TdP)** is directly linked to the prolongation of the **QT interval**. This occurs when a drug inhibits the outward potassium current ($I_K$), thereby delaying ventricular repolarization. **Why Lidocaine is the Correct Answer:** Lidocaine is a **Class IB antiarrhythmic**. Unlike other sodium channel blockers, Class IB drugs preferentially bind to sodium channels in the inactivated state and have a very rapid dissociation rate. Most importantly, Lidocaine **shortens the action potential duration (APD)** and the QT interval. Because it does not prolong repolarization, it carries a negligible risk of inducing Torsades de Pointes. **Why the Other Options are Incorrect:** * **Quinidine, Disopyramide, and Procainamide** are all **Class IA antiarrhythmics**. * The hallmark of Class IA drugs is that they block both fast sodium channels and **potassium channels**. * By blocking potassium channels, they significantly prolong the action potential duration and the **QT interval**. A prolonged QT interval creates a window of vulnerability for "early after-depolarizations" (EADs), which can trigger the polymorphic ventricular tachycardia known as Torsades de Pointes. **NEET-PG High-Yield Pearls:** * **Mnemonic for Class IA (QT prolongers):** "**Q**ueen **P**rom **D**isco" (**Q**uinidine, **P**rocainamide, **D**isopyramide). * **Class III drugs** (e.g., Sotalol, Ibutilide, Dofetilide) are also notorious for causing TdP due to potent potassium channel blockade. **Amiodarone** is a unique Class III drug that prolongs the QT interval but rarely causes TdP. * **Treatment of choice for TdP:** Intravenous **Magnesium Sulfate**, even if serum magnesium levels are normal.

Question 305: Which one of the following is NOT true in relation to angiotensin converting enzyme (ACE) inhibitors?

A. May cause hyperkalemia in diabetic patients
B. Contraindicated in pregnancy
C. Contraindicated in diabetic nephropathy (Correct Answer)
D. NSAIDs may impair its hypotensive effect

Explanation: **Explanation:** The correct answer is **C**. ACE inhibitors (ACEIs) are **not** contraindicated in diabetic nephropathy; in fact, they are the **drugs of choice** for this condition. **1. Why Option C is the correct answer (The False Statement):** ACE inhibitors provide significant **renoprotection** in diabetic patients. They preferentially dilate the efferent arteriole of the glomerulus, which reduces intraglomerular capillary pressure. This mechanism decreases albuminuria and slows the progression of chronic kidney disease (CKD). Therefore, stating they are contraindicated is medically incorrect. **2. Analysis of Incorrect Options (True Statements):** * **Option A (Hyperkalemia):** ACEIs reduce aldosterone secretion (which normally excretes potassium). Diabetic patients often have hyporeninemic hypoaldosteronism or are on other drugs that impair potassium balance, making them highly susceptible to hyperkalemia. * **Option B (Pregnancy):** ACEIs are absolute **teratogens** (Category X). They can cause fetal renal dysgenesis, oligohydramnios, and skull hypoplasia, especially during the 2nd and 3rd trimesters. * **Option D (NSAIDs interaction):** Hypotensive action of ACEIs is partly mediated by vasodilatory prostaglandins (like Bradykinin). NSAIDs inhibit prostaglandin synthesis, thereby antagonizing the blood pressure-lowering effect of ACEIs. **Clinical Pearls for NEET-PG:** * **Side Effects Mnemonic (CAPTOPRIL):** **C**ough (due to Bradykinin), **A**ngioedema, **P**regnancy contraindication, **T**aste changes, **O**thostatic hypotension, **P**otassium excess (Hyperkalemia), **R**enal artery stenosis contraindication, **I**tch (Rash), **L**eukopenia. * **Bilateral Renal Artery Stenosis:** ACEIs are strictly contraindicated here as they can precipitate acute renal failure by abolishing the efferent vasoconstriction needed to maintain GFR. * **First Dose Phenomenon:** Significant hypotension can occur with the first dose, especially in patients on diuretics.

Question 306: A sixteen-year-old girl is found to have paroxysmal attacks of rapid heart rate. What is the antiarrhythmic of choice in most cases of acute AV nodal tachycardia?

A. Adenosine (Correct Answer)
B. Amiodarone
C. Propranolol
D. Quinidine

Explanation: The clinical presentation of paroxysmal attacks of rapid heart rate in a young patient is highly suggestive of **Paroxysmal Supraventricular Tachycardia (PSVT)**, most commonly caused by **AV Nodal Reentrant Tachycardia (AVNRT)**. **Why Adenosine is the Correct Choice:** Adenosine is the **drug of choice** for the acute termination of PSVT/AVNRT. It works by stimulating A1 receptors on the AV node, leading to increased potassium efflux and inhibition of calcium influx. This results in profound hyperpolarization and a transient **AV nodal block**, which effectively "resets" the heart by breaking the re-entrant circuit. It has an ultra-short half-life (<10 seconds), making it ideal for rapid action and minimal systemic side effects. **Analysis of Incorrect Options:** * **B. Amiodarone:** A Class III antiarrhythmic used primarily for ventricular arrhythmias and rhythm control in atrial fibrillation. It is not the first-line agent for narrow-complex PSVT. * **C. Propranolol:** A non-selective beta-blocker. While it can slow the heart rate and be used for prophylaxis, it is slower in onset compared to Adenosine and is not the preferred agent for acute termination [1]. * **D. Quinidine:** A Class IA antiarrhythmic rarely used today due to its side effect profile (e.g., Cinchonism, Torsades de pointes). It is not indicated for acute AVNRT. **High-Yield Clinical Pearls for NEET-PG:** * **Administration:** Adenosine must be given as a **rapid IV bolus** (usually 6mg, followed by 12mg if needed) followed by a saline flush due to its rapid metabolism by erythrocytes and vascular endothelial cells. * **Contraindications:** Avoid in patients with **Asthma** (can cause bronchospasm) and **2nd/3rd-degree heart block** [1]. * **Drug Interactions:** Its effects are **antagonized by Theophylline/Caffeine** and **potentiated by Dipyridamole**. * **Common Side Effect:** Patients often experience a transient, distressing feeling of "impending doom" or chest heaviness during administration.

Question 307: BNP is degraded by:

A. Neutral endopeptidase (Correct Answer)
B. Elastase
C. Ormapatrilat
D. ACE

Explanation: **Explanation:** **1. Why Neutral Endopeptidase (NEP) is the Correct Answer:** B-type Natriuretic Peptide (BNP), along with ANP and CNP, is primarily degraded by **Neutral Endopeptidase (NEP)**, also known as **Neprilysin**. NEP is a zinc-dependent metalloprotease found in various tissues, particularly the kidneys. It cleaves natriuretic peptides, rendering them inactive. Inhibiting this enzyme increases the levels of BNP, leading to beneficial effects like vasodilation, natriuresis, and diuresis, which is a key strategy in managing heart failure. **2. Analysis of Incorrect Options:** * **B. Elastase:** This is a protease that breaks down elastin in connective tissue. While involved in lung pathology (e.g., emphysema), it plays no role in the metabolic degradation of natriuretic peptides. * **C. Ormapatrilat:** This is a **Vasopeptidase Inhibitor** (inhibits both ACE and NEP). It is a drug that *prevents* the degradation of BNP rather than being the enzyme responsible for it. * **D. ACE (Angiotensin-Converting Enzyme):** ACE is primarily responsible for converting Angiotensin I to Angiotensin II and degrading Bradykinin. It does not significantly contribute to the breakdown of BNP. **3. High-Yield Clinical Pearls for NEET-PG:** * **ARNI (Angiotensin Receptor-Neprilysin Inhibitor):** **Sacubitril/Valsartan** is the prototype. Sacubitril inhibits Neprilysin to increase BNP levels, while Valsartan blocks the AT1 receptor. * **Nesiritide:** A recombinant form of human BNP used in acute decompensated heart failure. * **Dual Mechanism of BNP Clearance:** BNP is cleared via two pathways: 1) Enzymatic degradation by **Neprilysin** and 2) Binding to **Natriuretic Peptide Receptor-C (NPR-C)** followed by internalisation. * **Diagnostic Note:** When a patient is on Sacubitril, BNP levels will be falsely elevated. In these cases, **NT-proBNP** is used for diagnosis/monitoring as it is *not* a substrate for Neprilysin.

Question 308: Beta blockers are antiarrhythmic agents of which class?

A. Class I
B. Class II (Correct Answer)
C. Class III
D. Class IV

Explanation: The classification of antiarrhythmic drugs is based on the **Vaughan Williams classification**, which categorizes agents according to their primary mechanism of action on the cardiac action potential [1, 2]. **Why Class II is correct:** **Class II** agents are **Beta-blockers** (e.g., Propranolol, Metoprolol, Esmolol). They work by inhibiting sympathetic stimulation of the heart [3, 4]. Their primary effect is on the SA and AV nodes, where they decrease the slope of Phase 4 depolarization, thereby slowing the heart rate and increasing the refractory period of the AV node [3]. This makes them particularly effective for rate control in supraventricular tachycardias. **Analysis of Incorrect Options:** * **Class I:** These are **Sodium (Na+) channel blockers**. They primarily affect Phase 0 of the action potential [1]. Examples include Lidocaine (Ib), Flecainide (Ic), and Quinidine (Ia) [1]. * **Class III:** These are **Potassium (K+) channel blockers**. They prolong Phase 3 (repolarization), thereby increasing the action potential duration and effective refractory period [1]. Examples include Amiodarone, Sotalol, and Dofetilide [1]. * **Class IV:** These are **Calcium (Ca2+) channel blockers** (specifically non-dihydropyridines like Verapamil and Diltiazem). Like beta-blockers, they act primarily on the SA and AV nodes but by blocking L-type calcium channels [1]. **High-Yield NEET-PG Pearls:** * **Esmolol** is the shortest-acting beta-blocker (half-life ~9 minutes), administered IV for acute situations like aortic dissection or intraoperative arrhythmias. * **Sotalol** is unique as it exhibits both Class II (beta-blocking) and Class III (K+ channel blocking) properties. * Beta-blockers are the only antiarrhythmic drugs proven to **reduce mortality** in patients post-myocardial infarction.

Question 309: Which of the following is a venodilator?

A. Hydralazine
B. Minoxidil
C. Nitroprusside (Correct Answer)
D. Nifedipine

Explanation: ### Explanation **Sodium Nitroprusside** is the correct answer because it is a **balanced vasodilator**, meaning it acts on both the arterial (resistance) and venous (capacitance) vessels. **Mechanism of Action:** Nitroprusside acts by releasing **Nitric Oxide (NO)**, which stimulates guanylyl cyclase to increase intracellular **cGMP**. This leads to dephosphorylation of myosin light chains and relaxation of smooth muscles in both arterioles and venules. By dilating veins, it increases venous capacitance, thereby reducing **preload** (venous return to the heart). **Analysis of Incorrect Options:** * **A. Hydralazine:** This is a selective **arteriolar dilator**. It has minimal to no effect on the venous system. It is commonly used in pregnancy-induced hypertension. * **B. Minoxidil:** A potent **arteriolar dilator** that works by opening ATP-sensitive $K^+$ channels, causing hyperpolarization of smooth muscle. It is associated with reflex tachycardia and hypertrichosis. * **C. Nifedipine:** A Dihydropyridine **Calcium Channel Blocker (CCB)** that acts predominantly on the L-type calcium channels in the **arterial** smooth muscle. It does not possess significant venodilating properties. **High-Yield Clinical Pearls for NEET-PG:** * **Preload vs. Afterload:** Pure venodilators (like Nitroglycerin at low doses) reduce preload; pure arteriolar dilators (like Hydralazine) reduce afterload. Nitroprusside reduces **both**. * **Toxicity:** Prolonged infusion of Nitroprusside can lead to **Cyanide and Thiocyanate toxicity**. The antidote is Sodium Thiosulfate or Hydroxocobalamin. * **Light Sensitivity:** Nitroprusside is unstable in light; hence, the infusion bottle must be covered with opaque foil. * **Drug of Choice:** It was traditionally the drug of choice for **Hypertensive Emergencies**, though it is now often replaced by Labetalol or Nicardipine due to its toxicity profile.

Question 310: Which one of the following is a contraindication to the use of ergot derivatives?

A. Migraine
B. Hyperprolactinemia
C. Obstructive vascular disease (Correct Answer)
D. Postpartum hemorrhage

Explanation: ### Explanation **Correct Option: C. Obstructive vascular disease** Ergot derivatives (such as Ergotamine and Ergonovine) act as **partial agonists at alpha-adrenergic and 5-HT receptors** [4]. Their primary hemodynamic effect is **potent, prolonged vasoconstriction** [3]. In patients with obstructive vascular diseases—such as Coronary Artery Disease (CAD), Raynaud’s phenomenon, or Buerger’s disease—this vasoconstriction can critically reduce blood flow, leading to myocardial infarction, gangrene, or severe tissue ischemia [2]. Therefore, any pre-existing compromise in vascular patency is a strict contraindication [2]. **Why the other options are incorrect:** * **A. Migraine:** Ergotamine and Dihydroergotamine (DHE) are established treatments for acute migraine attacks [1]. They work by constricting dilated cerebral vessels and inhibiting neurogenic inflammation. * **B. Hyperprolactinemia:** Bromocriptine and Cabergoline are ergot derivatives that act as **D2 receptor agonists** [4]. They inhibit prolactin release from the anterior pituitary and are the first-line treatment for prolactinomas. * **C. Postpartum hemorrhage (PPH):** Ergometrine (Ergonovine) is used to prevent and treat PPH [1]. It induces forceful, rhythmic contractions of the uterine smooth muscle (oxytocic effect), which compresses bleeding vessels at the placental site [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Ergotism (St. Anthony’s Fire):** Chronic poisoning characterized by intense burning pain and dry gangrene due to persistent vasoconstriction [3]. * **Drug Interaction:** Ergot derivatives should not be used within 24 hours of **Triptans** due to the risk of additive vasospasm. * **Specific Contraindications:** Pregnancy (due to fetal distress/abortion), uncontrolled hypertension, and sepsis [2]. * **Bromocriptine** is also used in Parkinson’s disease and Type 2 Diabetes (as a quick-release formulation) [4].

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

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

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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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