Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 111: Pulsus Bigeminus is a potential side effect of which class of medications?

A. Cardiac glycosides (Correct Answer)
B. Beta-adrenergic blockers
C. Angiotensin-converting enzyme inhibitors
D. Calcium channel blockers

Explanation: **Explanation:** **Pulsus Bigeminus** is a clinical finding where heartbeats occur in pairs—a normal sinus beat followed closely by a premature ventricular contraction (PVC), followed by a compensatory pause. **Why Cardiac Glycosides (e.g., Digoxin) are correct:** Digoxin toxicity is the most common cause of Pulsus Bigeminus. Digoxin inhibits the **Na+/K+ ATPase pump**, leading to an increase in intracellular sodium and, subsequently, intracellular calcium via the Na+/Ca2+ exchanger. While this increases contractility (positive inotropy), excessive calcium levels cause **delayed after-depolarizations (DADs)**. These DADs trigger premature ventricular beats, resulting in the characteristic bigeminal rhythm. **Why other options are incorrect:** * **Beta-adrenergic blockers:** These typically cause bradycardia or heart blocks (AV block) by slowing conduction through the AV node, but they do not typically trigger ectopic ventricular beats. * **ACE Inhibitors:** These primarily affect the renin-angiotensin system to lower blood pressure and do not have direct arrhythmogenic effects on the cardiac conduction system. * **Calcium Channel Blockers (CCBs):** Verapamil and Diltiazem slow the heart rate and can cause AV block, but they are actually used to *treat* certain arrhythmias rather than causing bigeminy. **High-Yield Clinical Pearls for NEET-PG:** * **Earliest sign of Digoxin toxicity:** Anorexia, nausea, and vomiting. * **Most common arrhythmia in Digoxin toxicity:** Ventricular Bigeminy. * **Most characteristic/specific arrhythmia:** Paroxysmal Atrial Tachycardia (PAT) with AV block. * **Electrolyte triggers:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose a patient to digoxin toxicity. * **Visual disturbance:** Xanthopsia (yellow-green halos around lights) is a classic board-style symptom of toxicity.

Question 112: Which of the following is NOT an adverse effect of Losartan?

A. Angioedema
B. Cough (Correct Answer)
C. Hyperkalemia
D. Headache

Explanation: **Explanation:** **Losartan** is an Angiotensin II Receptor Blocker (ARB) that selectively antagonizes the $AT_1$ receptor. **Why "Cough" is the correct answer:** Dry cough is a classic side effect of **ACE Inhibitors** (e.g., Enalapril), not ARBs. ACE inhibitors prevent the breakdown of **bradykinin** and **Substance P** in the lungs; the accumulation of these pro-inflammatory autacoids irritates the bronchial mucosa, leading to a persistent dry cough. Since Losartan acts downstream of ACE and does not interfere with bradykinin metabolism, it is characteristically "cough-neutral" and is the preferred alternative for patients who develop a cough on ACE inhibitors. **Analysis of incorrect options:** * **Angioedema:** While much rarer than with ACE inhibitors, angioedema can still occur with ARBs (likely due to $AT_2$ receptor overstimulation or indirect effects on the kinin system). * **Hyperkalemia:** Both ACE inhibitors and ARBs decrease Aldosterone secretion. Reduced aldosterone leads to potassium retention, making hyperkalemia a significant risk, especially in patients with renal impairment or those on K-sparing diuretics. * **Headache:** This is one of the most commonly reported non-specific side effects of Losartan, along with dizziness and fatigue. **High-Yield NEET-PG Pearls:** 1. **Teratogenicity:** Like ACE inhibitors, Losartan is **contraindicated in pregnancy** (causes fetal renal dysgenesis and skull hypoplasia). 2. **Uricosuric Effect:** Losartan is unique among ARBs as it inhibits the URAT1 transporter, increasing uric acid excretion. It is the drug of choice for hypertensive patients with **Gout**. 3. **First-pass metabolism:** Losartan undergoes significant metabolism to its active metabolite, **EXP3174**, which is a more potent non-competitive antagonist than the parent drug.

Question 113: Which of the following is not a common side effect for ACE inhibitors and Angiotensin receptor blockers?

A. Postural hypotension
B. Dry cough (Correct Answer)
C. Hyperkalemia
D. None of the above

Explanation: **Explanation:** The correct answer is **B. Dry cough**. **Why Dry Cough is the correct answer:** Dry cough is a classic side effect associated with **ACE inhibitors (ACEIs)**, occurring in 5–20% of patients, but it is **not** a common side effect of **Angiotensin Receptor Blockers (ARBs)**. * **Mechanism:** ACE (Angiotensin-Converting Enzyme) is also responsible for the degradation of **Bradykinin** and **Substance P** in the lungs. ACE inhibitors block this enzyme, leading to an accumulation of these pro-inflammatory peptides, which sensitize sensory nerve endings in the airway, triggering a dry, hacking cough. * **ARBs** act by blocking the $AT_1$ receptor directly and do not interfere with ACE; therefore, they do not increase bradykinin levels and are typically used as the alternative for patients who develop a cough on ACEIs. **Analysis of Incorrect Options:** * **A. Postural Hypotension:** Both ACEIs and ARBs can cause a "first-dose effect" leading to significant hypotension, especially in patients who are volume-depleted or on diuretics. * **C. Hyperkalemia:** Both drug classes inhibit the Renin-Angiotensin-Aldosterone System (RAAS). By reducing Angiotensin II (ACEIs) or its action (ARBs), they decrease **Aldosterone** secretion. Since aldosterone normally promotes potassium excretion, its suppression leads to potassium retention. **High-Yield NEET-PG Pearls:** 1. **Teratogenicity:** Both ACEIs and ARBs are strictly **contraindicated in pregnancy** (Category X) as they cause fetal renal dysgenesis and skull hypoplasia. 2. **Bilateral Renal Artery Stenosis:** Both are contraindicated because they cause efferent arteriolar vasodilation, leading to a precipitous drop in GFR and acute renal failure. 3. **Angioedema:** Like cough, this is more common with ACEIs due to bradykinin accumulation. 4. **Drug of Choice:** ACEIs/ARBs are the first-line antihypertensives for patients with **Diabetes Mellitus** (due to nephroprotective effects) and **Heart Failure**.

Question 114: Nitroglycerine causes all except:

A. Hypotension and bradycardia (Correct Answer)
B. Methemoglobinemia
C. Hypotension and tachycardia
D. Vasodilation

Explanation: **Explanation:** Nitroglycerine (NTG) is a potent vasodilator used primarily in the management of angina and heart failure. Understanding its hemodynamic effects is crucial for NEET-PG. **1. Why "Hypotension and bradycardia" is the correct answer (The Exception):** Nitroglycerine causes significant peripheral vasodilation (venodilation > arteriodilation), which leads to a decrease in blood pressure (**hypotension**). In response to this drop in BP, the body’s baroreceptor reflex is activated, leading to a compensatory **reflex tachycardia**, not bradycardia. Therefore, the combination of hypotension and bradycardia is physiologically inconsistent with the standard administration of NTG. **2. Analysis of Incorrect Options:** * **Methemoglobinemia (Option B):** High doses or prolonged infusions of nitrates can oxidize hemoglobin to methemoglobin. While rare, it is a known biochemical side effect. * **Hypotension and tachycardia (Option C):** This is the classic hemodynamic profile of NTG. Vasodilation reduces preload and afterload (hypotension), triggering the sympathetic nervous system (tachycardia). * **Vasodilation (Option D):** This is the primary mechanism of action. NTG is converted to Nitric Oxide (NO), which increases cGMP, leading to smooth muscle relaxation. **3. Clinical Pearls for NEET-PG:** * **The Bezold-Jarisch Reflex:** Occasionally, in the context of an inferior wall MI, NTG can trigger a paradoxical bradycardia via this reflex, but in general pharmacological terms, tachycardia is the expected rule. * **Monday Disease:** Workers in dynamite factories develop tolerance to nitrates during the week and lose it over the weekend, leading to "Monday morning headaches" due to sudden vasodilation. * **Contraindication:** Never co-administer NTG with Sildenafil (PDE-5 inhibitors) as it can cause life-threatening hypotension. * **Drug of Choice:** NTG is the drug of choice for Angina Pectoris and Acute Left Ventricular Failure.

Question 115: A patient with atherosclerosis requires prevention of stroke. Which of the following is the most beneficial drug for this purpose?

A. Aspirin (Correct Answer)
B. Warfarin
C. Low dose subcutaneous heparin
D. Digoxin

Explanation: ### Explanation **Correct Option: A. Aspirin** Aspirin is the drug of choice for the primary and secondary prevention of ischemic stroke in patients with atherosclerosis. Atherosclerosis leads to the formation of arterial plaques; when these plaques rupture, they trigger **platelet aggregation** and subsequent thrombus formation, leading to arterial occlusion. Aspirin acts as an **irreversible inhibitor of Cyclooxygenase-1 (COX-1)**, preventing the synthesis of **Thromboxane A2 (TXA2)**, a potent platelet aggregator and vasoconstrictor. By inhibiting platelet-rich "white clots" in the high-pressure arterial system, Aspirin significantly reduces the risk of cerebrovascular accidents (CVA). **Why other options are incorrect:** * **B. Warfarin:** This is an oral anticoagulant that inhibits Vitamin K Epoxide Reductase. It is primarily used to prevent embolic strokes originating from the heart (e.g., **Atrial Fibrillation** or prosthetic heart valves), rather than strokes caused by localized atherosclerosis. * **C. Low dose subcutaneous heparin:** This is typically used for the prophylaxis of **Deep Vein Thrombosis (DVT)** and pulmonary embolism in hospitalized, immobilized patients. It is not indicated for the long-term prevention of arterial stroke. * **D. Digoxin:** This is a cardiac glycoside used in the management of heart failure and rate control in atrial fibrillation. It has no antiplatelet or antithrombotic properties. **High-Yield NEET-PG Pearls:** * **Mechanism:** Aspirin causes irreversible acetylation of a serine residue in the active site of COX-1. * **Dose:** Low-dose aspirin (75–150 mg/day) is sufficient for antiplatelet effects because platelets are anucleated and cannot synthesize new enzymes. * **Primary Prevention:** In atherosclerosis, the goal is to prevent the transition from a stable plaque to an unstable, thrombogenic one. * **Dual Antiplatelet Therapy (DAPT):** Clopidogrel is often added to Aspirin following acute coronary syndromes or stenting.

Question 116: In the treatment of severe bradycardia, all of the following can be the best modality of treatment except?

A. Atropine
B. Pacing
C. Isoproterenol
D. Diltiazem (Correct Answer)

Explanation: **Explanation:** The goal in treating severe bradycardia is to increase the heart rate and improve cardiac output. **Diltiazem** is a non-dihydropyridine Calcium Channel Blocker (CCB) that acts as a negative chronotrope and negative dromotrope. It inhibits the influx of calcium ions into the sinoatrial (SA) and atrioventricular (AV) nodes, further slowing the heart rate and delaying conduction. Therefore, Diltiazem is **contraindicated** in bradycardia as it would worsen the condition and potentially lead to asystole. **Analysis of other options:** * **Atropine:** This is the **first-line drug** for symptomatic bradycardia. It is a muscarinic antagonist that blocks the vagal (parasympathetic) tone on the SA node, thereby increasing the heart rate. * **Pacing (Transcutaneous or Transvenous):** This is the **most definitive treatment** for severe, unstable bradycardia, especially if it is unresponsive to pharmacotherapy or caused by high-grade AV blocks (e.g., Mobitz II or 3rd-degree block). * **Isoproterenol:** This is a potent non-selective beta-adrenergic agonist ($\beta_1$ and $\beta_2$). By stimulating $\beta_1$ receptors in the heart, it exerts strong positive chronotropic and inotropic effects, making it a useful chemical "bridge" to pacing. **Clinical Pearls for NEET-PG:** * **Drug of choice for Bradycardia:** Atropine (0.5 mg IV, repeated up to 3 mg). * **Atropine Caution:** It may be ineffective or worsen bradycardia in patients with heart transplants (denervated heart) or high-grade AV blocks; pacing is preferred here. * **Diltiazem/Verapamil:** These are used for rate control in **Tachyarrhythmias** (like Atrial Fibrillation or PSVT), not bradycardia. * **Glucagon:** The specific antidote for bradycardia caused by Beta-blocker or CCB overdose.

Question 117: What is the only FDA-approved therapeutic use of Endothelium-Derived Relaxing Factor?

A. Pulmonary hypertension in newborns (Correct Answer)
B. Primary pulmonary hypertension
C. Congestive cardiac failure
D. Essential hypertension in newborns

Explanation: **Explanation:** **Endothelium-Derived Relaxing Factor (EDRF)** is chemically identified as **Nitric Oxide (NO)**. It is a potent endogenous vasodilator that acts by stimulating soluble guanylyl cyclase, increasing intracellular cGMP, and leading to smooth muscle relaxation. **Why Option A is Correct:** The only FDA-approved clinical use for inhaled Nitric Oxide is **Persistent Pulmonary Hypertension of the Newborn (PPHN)**. In newborns with hypoxic respiratory failure, inhaled NO acts as a **selective pulmonary vasodilator**. Because it is rapidly inactivated by binding to hemoglobin upon entering the systemic circulation, it reduces pulmonary vascular resistance without causing systemic hypotension. **Why Other Options are Incorrect:** * **Option B (Primary Pulmonary Hypertension):** While NO can be used during "vasoreactivity testing" to identify responders in adults, it is not the primary FDA-approved therapeutic treatment. Drugs like Bosentan (Endothelin antagonist) or Sildenafil (PDE-5 inhibitor) are preferred for long-term management. * **Option C (Congestive Cardiac Failure):** NO is not used here as it does not address myocardial contractility and could potentially worsen left-sided heart failure by increasing pulmonary venous return. * **Option D (Essential Hypertension):** NO is administered via inhalation and has a very short half-life (seconds). It is impractical and ineffective for treating systemic (essential) hypertension. **High-Yield NEET-PG Pearls:** * **Mechanism:** NO → ↑ cGMP → Protein Kinase G → Vasodilation. * **Diagnostic Use:** Inhaled NO is used in the cardiac cath lab to differentiate reversible from irreversible pulmonary hypertension. * **Toxicity:** Monitor for **Methemoglobinemia** and Nitrogen Dioxide (NO₂) toxicity during administration. * **Synergy:** Sildenafil potentiates the effects of NO by inhibiting the breakdown of cGMP.

Question 118: Which of the following drugs releases Nitric oxide?

A. Hydralazine (Correct Answer)
B. Aminophylline
C. Amrinone
D. Sildenafil sulfate

Explanation: **Explanation:** **1. Why Hydralazine is Correct:** Hydralazine is a direct-acting peripheral arterial vasodilator. Its primary mechanism involves the release of **Nitric Oxide (NO)** from the vascular endothelium, which stimulates guanylyl cyclase to increase intracellular **cGMP**. This leads to smooth muscle relaxation and vasodilation. It also inhibits calcium release from the sarcoplasmic reticulum and hyperpolarizes the membrane. **2. Why the other options are incorrect:** * **Aminophylline:** This is a methylxanthine derivative (a complex of theophylline and ethylenediamine). It acts primarily as a **non-selective phosphodiesterase (PDE) inhibitor** and adenosine receptor antagonist, used mainly in asthma/COPD, not via NO release. * **Amrinone (Inamrinone):** This is a **PDE-3 inhibitor**. It increases cAMP levels in cardiac and vascular muscle, exerting positive inotropic and vasodilator effects (inodilator). * **Sildenafil sulfate:** This is a selective **PDE-5 inhibitor**. While it *potentiates* the action of Nitric Oxide by preventing the breakdown of cGMP, it does **not** release NO itself. **High-Yield Clinical Pearls for NEET-PG:** * **Drug-Induced Lupus Erythematosus (DILE):** Hydralazine is a classic cause, especially in "slow acetylators." * **Clinical Use:** It is a preferred drug for managing **hypertension in pregnancy** (along with Labetalol and Methyldopa). * **Reflex Tachycardia:** Because it causes significant arterial dilation, it often triggers compensatory tachycardia and fluid retention; thus, it is frequently co-administered with a Beta-blocker and a diuretic. * **Other NO donors:** Nitroglycerin, Sodium Nitroprusside (releases NO directly), and Minoxidil (though Minoxidil primarily acts via K+ channel opening).

Question 119: All of the following are indications for the use of ACE inhibitors, except?

A. Hypertension
B. Myocardial Infarction
C. Left Ventricular Dysfunction
D. Pheochromocytoma (Correct Answer)

Explanation: **Explanation:** The correct answer is **D. Pheochromocytoma**. **1. Why Pheochromocytoma is the correct answer:** Pheochromocytoma is a catecholamine-secreting tumor of the adrenal medulla. The resulting hypertension is driven by excessive stimulation of **alpha-1 adrenergic receptors** by norepinephrine and epinephrine. ACE inhibitors (ACEIs) target the Renin-Angiotensin-Aldosterone System (RAAS), which is not the primary pathophysiological driver in this condition. The definitive medical management for pheochromocytoma involves **alpha-blockers** (e.g., Phenoxybenzamine) followed by beta-blockers. Using ACEIs here is ineffective and clinically inappropriate. **2. Why the other options are incorrect:** * **Hypertension (A):** ACEIs are first-line agents for hypertension, especially in patients with co-morbidities like diabetes mellitus (due to nephroprotective effects). * **Myocardial Infarction (B):** ACEIs are started within 24 hours of an MI to improve survival rates and prevent adverse cardiac remodeling. * **Left Ventricular Dysfunction (C):** In heart failure and LV dysfunction, ACEIs reduce afterload and inhibit the compensatory RAAS activation that leads to progressive cardiac hypertrophy and fibrosis. They are proven to reduce mortality in these patients. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** ACEIs are the DOC for hypertension in **Diabetic Nephropathy** because they dilate the efferent arteriole, reducing intraglomerular pressure. * **Teratogenicity:** ACEIs are strictly contraindicated in pregnancy (cause fetal renal anomalies and skull hypoplasia). * **Side Effects:** Remember the mnemonic **CAPTOPRIL**: **C**ough (due to bradykinin), **A**ngioedema, **P**roteinuria, **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication, **R**enal artery stenosis (bilateral) contraindication, **I**ncreased potassium (Hyperkalemia), **L**eukopenia.

Question 120: Acute anginal attack can be terminated by:

A. Nitroglycerin (Correct Answer)
B. Digoxin
C. Lignocaine
D. Verapamil

Explanation: **Explanation:** **Nitroglycerin (Option A)** is the drug of choice for terminating an acute anginal attack. It acts as a prodrug that releases **Nitric Oxide (NO)**, which stimulates guanylyl cyclase to increase cGMP levels. This leads to dephosphorylation of myosin light chains, causing potent vascular smooth muscle relaxation. Its primary benefit in angina is **venodilation**, which reduces venous return (preload) and decreases myocardial oxygen demand. When administered **sublingually**, it bypasses first-pass metabolism, providing a rapid onset of action (1–3 minutes) essential for acute relief. **Why other options are incorrect:** * **Digoxin (Option B):** A cardiac glycoside used in heart failure and atrial fibrillation. It increases myocardial contractility (positive inotropy), which actually *increases* oxygen demand and could worsen angina. * **Lignocaine (Option C):** A Class IB antiarrhythmic used for ventricular arrhythmias, particularly post-MI. It has no role in relieving myocardial ischemia or anginal pain. * **Verapamil (Option D):** A non-dihydropyridine Calcium Channel Blocker. While used for *prophylaxis* of stable and variant angina, its oral onset is too slow for terminating an acute attack, and IV use is reserved for supraventricular tachycardias. **High-Yield NEET-PG Pearls:** * **Route of Choice:** Sublingual or buccal spray for acute attacks; transdermal patches for chronic prophylaxis. * **Storage:** Nitroglycerin is volatile and light-sensitive; it must be stored in dark glass containers. * **Tolerance:** A "nitrate-free interval" (8–12 hours) is required daily to prevent tachyphylaxis. * **Contraindication:** Never co-administer with **Sildenafil** (PDE-5 inhibitors) due to the risk of severe, fatal hypotension.

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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