Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 841: Which of the following is a non-selective vasopressin receptor antagonist?

A. Tolvaptan
B. Conivaptan (Correct Answer)
C. Relcovaptan
D. Lixivaptan

Explanation: **Explanation:** Vasopressin (Antidiuretic Hormone) acts on three main receptor subtypes: **V1a** (vasoconstriction, platelet aggregation), **V1b** (ACTH release), and **V2** (water reabsorption in renal collecting ducts). Drugs that block these receptors are known as "vaptans." **Why Conivaptan is correct:** **Conivaptan** is a **non-selective (dual) V1a and V2 receptor antagonist**. By blocking V2 receptors, it promotes aquaresis (solute-free water excretion), and by blocking V1a receptors, it reduces peripheral vascular resistance. It is administered intravenously and is primarily used for the treatment of euvolemic and hypervolemic hyponatremia (e.g., SIADH). **Analysis of incorrect options:** * **Tolvaptan (Option A):** This is a **selective oral V2 receptor antagonist**. It is the most commonly used vaptan for chronic hyponatremia but carries a "black box" warning for potential hepatotoxicity if used for more than 30 days. * **Relcovaptan (Option C):** This is a **selective V1a receptor antagonist**. It has been investigated for conditions like Raynaud’s disease and dysmenorrhea but is not used for hyponatremia. * **Lixivaptan (Option D):** Like tolvaptan, this is a **selective V2 receptor antagonist** (currently under clinical investigation). **High-Yield NEET-PG Pearls:** 1. **Conivaptan** = Dual V1a/V2 blocker (IV only). 2. **Tolvaptan** = Selective V2 blocker (Oral). 3. **Indication:** Vaptans are the treatment of choice for **SIADH** when fluid restriction fails. 4. **Caution:** Rapid correction of hyponatremia with vaptans can lead to **Osmotic Demyelination Syndrome (Central Pontine Myelinolysis)**. Always monitor serum sodium levels closely.

Question 842: Which calcium channel blocker causes cerebral vasodilatation?

A. Nimodipine (Correct Answer)
B. Felodipine
C. Amlodipine
D. Nitrendipine

Explanation: **Explanation:** **Nimodipine** is a second-generation dihydropyridine calcium channel blocker (CCB) with a unique pharmacological profile [1]. Unlike other CCBs, it is highly **lipophilic**, allowing it to readily cross the blood-brain barrier. It has a high affinity for L-type calcium channels in the cerebral vasculature, leading to selective **cerebral vasodilation**. **Why Nimodipine is the correct answer:** The primary clinical utility of Nimodipine is in the management of **Subarachnoid Hemorrhage (SAH)**. Following SAH, patients often experience delayed cerebral vasospasm, which can lead to ischemic neurological deficits [1]. Nimodipine prevents and reverses this vasospasm, thereby improving neurological outcomes. **Analysis of Incorrect Options:** * **Felodipine:** A potent peripheral vasodilator used primarily for hypertension [2]. It lacks the cerebral selectivity required to treat vasospasm. * **Amlodipine:** Known for its long half-life and minimal effect on cardiac contractility [2]. It is a first-line agent for chronic hypertension and angina but does not cross the blood-brain barrier effectively. * **Nitrendipine:** Primarily used for systemic hypertension. While it belongs to the same class, it does not share the specific cerebrovascular selectivity of Nimodipine. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Nimodipine is the DOC for preventing neurological deficits due to **cerebral vasospasm in SAH** [1]. * **Administration:** It should be started within 96 hours of the onset of SAH. * **Other "Special" CCBs:** * **Clevidipine:** Ultra-short-acting, used for hypertensive emergencies. * **Nifedipine:** Can cause "coronary steal" and reflex tachycardia [3]. * **Verapamil:** Phenylalkylamine class; has the most significant negative inotropic effect (avoid in heart failure).

Question 843: Dobutamine is preferred over Dopamine in cardiogenic shock because of its effects related to what?

A. Better cardiac stimulation
B. Less peripheral vasoconstriction (Correct Answer)
C. Lower risk of cardiac arrhythmia
D. More central nervous system stimulation

Explanation: **Explanation:** In cardiogenic shock, the primary goal is to improve cardiac output without significantly increasing the workload of a failing heart. **1. Why "Less peripheral vasoconstriction" is correct:** Dobutamine is a relatively selective **$\beta_1$-agonist** with mild $\beta_2$ activity. While it increases myocardial contractility (inotropy), its $\beta_2$ effect causes mild peripheral vasodilation, which **reduces afterload**. This allows the heart to pump more efficiently. In contrast, Dopamine at higher doses (used in shock) stimulates $\alpha_1$ receptors, causing significant peripheral vasoconstriction. This increases afterload, which can further strain a failing left ventricle. Therefore, Dobutamine is preferred because it improves cardiac output without the detrimental increase in systemic vascular resistance. **2. Analysis of Incorrect Options:** * **A. Better cardiac stimulation:** Both drugs are potent inotropes. Dopamine actually has a more complex mechanism (releasing endogenous norepinephrine), but "better" stimulation is subjective and not the clinical reason for preference. * **C. Lower risk of cardiac arrhythmia:** Both drugs carry a significant risk of tachyarrhythmias as they both stimulate $\beta_1$ receptors. Dobutamine is not significantly "safer" in this specific regard. * **D. More CNS stimulation:** Neither drug crosses the blood-brain barrier effectively; CNS effects are not a consideration in choosing between them for shock. **High-Yield NEET-PG Pearls:** * **Dobutamine:** Drug of choice for **decompensated heart failure** and cardiogenic shock. It is also used in **Stress Echocardiography**. * **Dopamine Dosing:** Low dose (D1) = Renal vasodilation; Medium dose ($\beta_1$) = Inotropy; High dose ($\alpha_1$) = Vasoconstriction. * **Note:** In clinical practice, if a patient is severely hypotensive, Dobutamine may be combined with a vasopressor (like Norepinephrine) to maintain perfusion pressure while improving inotropy.

Question 844: Angiotensin converting enzyme inhibitors are useful in congestive heart failure as:

A. First choice drugs unless contraindicated (Correct Answer)
B. An alternative to diuretics
C. A substitute for digitalis
D. Adjuncts only in resistant cases

Explanation: **Explanation:** **ACE Inhibitors (ACEIs)** are considered the **cornerstone of therapy** for Heart Failure with reduced Ejection Fraction (HFrEF). **Why Option A is correct:** ACE inhibitors are **first-line agents** because they are one of the few drug classes proven to **reduce mortality and morbidity** in heart failure patients [1], [4]. They work by blocking the conversion of Angiotensin I to Angiotensin II, leading to: 1. **Decreased Afterload:** Through systemic vasodilation, improving cardiac output [4]. 2. **Decreased Preload:** By reducing aldosterone secretion (decreasing salt and water retention) [4]. 3. **Reverse Remodeling:** They inhibit the long-term structural changes (hypertrophy and fibrosis) in the myocardium caused by Angiotensin II. **Why other options are incorrect:** * **Option B:** ACEIs are not alternatives to diuretics; they are used **synergistically** [3]. Diuretics provide symptomatic relief from congestion, while ACEIs provide survival benefits. * **Option C:** Digitalis (Digoxin) is now a second-line drug used primarily for symptomatic control or in patients with concomitant Atrial Fibrillation. It does not reduce mortality, unlike ACEIs. * **Option D:** ACEIs are indicated for **all stages** of symptomatic heart failure and even asymptomatic patients with decreased LVEF (Stage B), not just resistant cases [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Most common side effect:** Dry cough (due to increased **Bradykinin** levels). * **Most serious side effect:** Angioedema. * **Contraindications:** Pregnancy (teratogenic), Bilateral Renal Artery Stenosis, and Hyperkalemia. * **Alternative:** If a patient develops a cough, switch to **ARBs** (Angiotensin Receptor Blockers).

Question 845: Alprostadil is not used for the treatment of which of the following conditions?

A. Erectile dysfunction
B. Pulmonary hypertension
C. Patent ductus arteriosus (Correct Answer)
D. Critical limb ischemia

Explanation: **Explanation:** The correct answer is **C. Patent ductus arteriosus**. This question requires a careful distinction between **maintaining** a ductus and **treating** a patent one. Alprostadil is a synthetic analogue of **Prostaglandin E1 (PGE1)**. Its primary physiological effect is potent vasodilation and relaxation of smooth muscles. 1. **Why Option C is correct:** In neonates with ductal-dependent congenital heart defects (e.g., Transposition of Great Arteries), Alprostadil is used to **keep the ductus arteriosus open** (maintain patency) to allow for life-saving oxygenation. It does **not** treat a Patent Ductus Arteriosus (PDA); rather, it prevents its closure. To *treat* or close a PDA, prostaglandin synthesis inhibitors like **Indomethacin or Ibuprofen** are used. 2. **Why other options are incorrect:** * **Erectile Dysfunction (A):** Alprostadil (administered via intracavernosal injection or urethral suppository) relaxes the smooth muscle of the corpus cavernosum, increasing blood flow. * **Pulmonary Hypertension (B):** Due to its potent vasodilatory properties, it can be used to reduce pulmonary vascular resistance, though it is less common than Epoprostenol. * **Critical Limb Ischemia (D):** It is used to improve limb perfusion and promote ulcer healing in patients with severe peripheral arterial disease who are not candidates for surgery. **High-Yield Clinical Pearls for NEET-PG:** * **PGE1 (Alprostadil):** "P" for **P**umping blood (keeps ductus open) and **P**enis (erection). * **PGE2 (Dinoprostone):** Used for cervical ripening and induction of labor. * **PGF2α (Carboprost):** Used for Postpartum Hemorrhage (PPH) but contraindicated in asthma. * **PGI2 (Epoprostenol):** Primary prostaglandin used for Pulmonary Hypertension.

Question 846: Which of the following is NOT an antiplatelet drug?

A. Aspirin
B. Streptokinase (Correct Answer)
C. Clopidogrel
D. Ticlopidine

Explanation: **Explanation:** The core of this question lies in distinguishing between drugs that prevent clot formation (**antiplatelets**) and those that dissolve an existing clot (**thrombolytics**). **Why Streptokinase is the correct answer:** Streptokinase is a **thrombolytic (fibrinolytic) agent**, not an antiplatelet drug. It works by binding to plasminogen to form an active complex that converts plasminogen into **plasmin**. Plasmin then degrades fibrin threads, thereby dissolving an already formed thrombus. In clinical practice, it is used for the "clot-busting" treatment of acute myocardial infarction and pulmonary embolism. **Why the other options are incorrect:** * **Aspirin:** An irreversible inhibitor of **COX-1**, which prevents the synthesis of Thromboxane A2 (TXA2), a potent platelet aggregator. * **Clopidogrel & Ticlopidine:** These belong to the **P2Y12 receptor blockers** (Thienopyridines). They inhibit ADP-induced platelet aggregation. Clopidogrel is preferred over Ticlopidine due to a better safety profile (Ticlopidine can cause severe neutropenia). **High-Yield Clinical Pearls for NEET-PG:** * **Antiplatelet Classification:** 1. **COX Inhibitors:** Aspirin. 2. **P2Y12 Inhibitors:** Clopidogrel, Prasugrel, Ticagrelor (Reversible), Ticlopidine. 3. **GP IIb/IIIa Antagonists:** Abciximab, Eptifibatide, Tirofiban. 4. **PDE Inhibitors:** Dipyridamole, Cilostazol. * **Streptokinase Fact:** It is non-fibrin specific and can cause systemic fibrinolysis. Because it is derived from *Streptococci*, it is **antigenic** and can cause hypersensitivity reactions; it should not be repeated in the same patient within a year.

Question 847: Which antiarrhythmic drug can be used for arrhythmias refractory to lignocaine treatment?

A. Sotalol
B. Diltiazem
C. Amiodarone (Correct Answer)
D. Quinidine

Explanation: **Explanation:** **Amiodarone** is the drug of choice for ventricular arrhythmias that are refractory to Lignocaine (Lidocaine), particularly in the context of Advanced Cardiovascular Life Support (ACLS) for pulseless Ventricular Tachycardia (VT) or Ventricular Fibrillation (VF). **Why Amiodarone is the correct answer:** Amiodarone is a Class III antiarrhythmic (Potassium channel blocker) but possesses properties of all four Vaughan-Williams classes (I, II, III, and IV). This "broad-spectrum" mechanism makes it highly effective in stabilizing cardiac membranes when Class I agents like Lignocaine fail. In modern resuscitation guidelines, Amiodarone has largely superseded Lignocaine as the first-line agent for refractory shockable rhythms. **Why the other options are incorrect:** * **Sotalol (Option A):** While also a Class III agent with Beta-blocking properties, it is primarily used for maintaining sinus rhythm in atrial fibrillation and is not the preferred agent for acute, refractory ventricular emergencies. * **Diltiazem (Option B):** A Class IV Calcium Channel Blocker (CCB). It is used for supraventricular tachycardias (SVT) and rate control in atrial fibrillation but is ineffective (and potentially dangerous) in ventricular arrhythmias. * **Quinidine (Option D):** A Class IA agent. It is rarely used today due to its significant side effect profile (Cinchonism, Torsades de pointes) and is not indicated for refractory VT/VF. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Amiodarone is the drug of choice for both ventricular and supraventricular arrhythmias in patients with **heart failure** or structural heart disease. * **Side Effects:** Remember the "6 P's" of Amiodarone: **P**ulmonary fibrosis, **P**hotodermatitis (Blue-grey skin), **P**eripheral neuropathy, **P**rolonged QT, **P**apillary (Corneal) microdeposits, and **P**roblems with Thyroid (Hypo/Hyperthyroidism due to high iodine content). * **Half-life:** It has an exceptionally long elimination half-life (approx. 3–8 weeks).

Question 848: Niacin must be used cautiously in diabetic patients because?

A. It causes hypoglycemia
B. It impairs insulin sensitivity (Correct Answer)
C. It increases the metabolism of oral hypoglycemic agents
D. It increases skin thickness

Explanation: **Explanation:** **Niacin (Nicotinic Acid)** is a potent lipid-lowering agent that inhibits the mobilization of free fatty acids from peripheral adipose tissue. However, its use in diabetic patients is limited due to its metabolic side effects. **Why the correct answer is right:** Niacin induces **insulin resistance** (impairs insulin sensitivity). The primary mechanism involves the inhibition of glucose utilization in peripheral tissues and an increase in hepatic gluconeogenesis. This leads to a rise in fasting blood glucose levels, a phenomenon often referred to as **"Niacin-induced hyperglycemia."** While it is not an absolute contraindication, it requires cautious monitoring and potential adjustment of antidiabetic medications. **Why the other options are wrong:** * **Option A:** Niacin causes **hyperglycemia**, not hypoglycemia, due to decreased insulin sensitivity. * **Option C:** Niacin does not significantly induce or inhibit the cytochrome P450 enzymes responsible for the metabolism of most oral hypoglycemic agents. The interaction is pharmacodynamic (opposing effects on blood sugar), not pharmacokinetic. * **Option D:** Niacin does not increase skin thickness. Its most common cutaneous side effect is **cutaneous flushing** and pruritus, mediated by Prostaglandin $D_2$ and $E_2$. **NEET-PG High-Yield Pearls:** * **Side Effect Management:** Niacin-induced flushing can be blunted by pre-treatment with **Aspirin** (NSAIDs) 30 minutes prior. * **Lipid Profile:** Niacin is the most effective drug for **increasing HDL** levels. * **Other Side Effects:** It can cause **hyperuricemia** (precipitating gout) and is potentially hepatotoxic. * **Contraindications:** Active peptic ulcer disease, gout, and chronic liver disease.

Question 849: Which of the following is true about dobutamine?

A. It is a strong vasoconstrictor (Correct Answer)
B. It significantly increases heart rate
C. It reduces afterload
D. It is a potent bronchodilator

Explanation: ### Explanation **Correct Answer: A. It is a strong vasoconstrictor** *Note: There appears to be a common misconception in the question stem provided. While Dobutamine is primarily a positive inotrope, at higher doses, it can interact with alpha-1 receptors. However, in standard pharmacological teaching for NEET-PG, Dobutamine is known for its **mild vasodilator** properties due to $\beta_2$ agonism. If the provided key insists on "strong vasoconstrictor," it contradicts standard texts like Goodman & Gilman or Katzung, where Dobutamine is noted to decrease systemic vascular resistance (SVR).* **1. Why the Correct Answer (as per the provided key) is selected:** Dobutamine is a synthetic catecholamine that acts primarily on **$\beta_1$ receptors**. While its main effect is increasing myocardial contractility (inotropy), it is a racemic mixture. The (-) isomer is an $\alpha_1$ agonist, which can cause vasoconstriction. In specific clinical scenarios or high doses, this $\alpha_1$ effect may manifest, though it is usually offset by the (+) isomer’s $\beta_2$ activity. **2. Analysis of Incorrect Options:** * **B. It significantly increases heart rate:** Unlike Isoprenaline, Dobutamine is "cardioselective" in that it increases force of contraction (inotropy) much more than heart rate (chronotropy) at therapeutic doses. * **C. It reduces afterload:** This is actually a **pharmacologically true** statement in standard practice. Due to $\beta_2$ stimulation, Dobutamine typically causes peripheral vasodilation, which reduces afterload. (If Option A is the "correct" key, this option is considered "less correct" in that specific context). * **D. It is a potent bronchodilator:** While it has some $\beta_2$ activity, it is not used clinically for bronchodilation; Salbutamol or Terbutaline are the drugs of choice. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** Dobutamine is the DOC for **Cardiogenic Shock** because it increases cardiac output without significantly increasing myocardial oxygen demand (due to minimal tachycardia). * **Stress Testing:** It is used in **Dobutamine Stress Echocardiography (DSE)** for patients unable to perform exercise stress tests. * **Half-life:** Very short (~2 minutes), requiring continuous IV infusion. * **Tachyphylaxis:** Prolonged use leads to down-regulation of receptors, reducing efficacy.

Question 850: Which of the following is NOT used in the management of Myocardial Infarction?

A. Fibrinolytics
B. Plasminogen activator inhibitor (Correct Answer)
C. Antithrombin
D. Platelet inhibitor

Explanation: In the management of Myocardial Infarction (MI), the primary goal is to restore coronary blood flow by breaking down or preventing the formation of an occlusive thrombus. **Explanation of the Correct Answer:** **B. Plasminogen activator inhibitor (PAI-1):** This is an endogenous protein that **inhibits** fibrinolysis by blocking tissue plasminogen activator (tPA). Administering a PAI-1 would prevent the breakdown of a clot, thereby worsening the ischemia in an MI. In clinical practice, drugs like **Tranexamic acid** and **Epsilon-aminocaproic acid** act as antifibrinolytics; these are used to stop bleeding (e.g., in surgery or trauma) and are strictly contraindicated in acute MI. **Explanation of Incorrect Options:** * **A. Fibrinolytics:** (e.g., Streptokinase, Alteplase, Tenecteplase) These are "clot busters" used in STEMI to dissolve the existing fibrin mesh of the thrombus. * **C. Antithrombin:** (e.g., Heparin, Enoxaparin, Fondaparinux) These prevent further thrombus propagation by inhibiting thrombin or Factor Xa, maintaining the patency of the vessel. * **D. Platelet inhibitor:** (e.g., Aspirin, Clopidogrel, Ticagrelor) Since the initial step of MI is platelet aggregation on a ruptured plaque, dual antiplatelet therapy (DAPT) is a cornerstone of management. **High-Yield NEET-PG Pearls:** * **Tenecteplase** is the fibrinolytic of choice in STEMI due to its high fibrin specificity and long half-life (bolus administration). * **Aspirin** should be chewed (not swallowed) in the emergency setting for faster absorption via the buccal mucosa. * **Absolute Contraindications for Fibrinolytics:** History of hemorrhagic stroke, active internal bleeding, or recent intracranial neoplasm.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

Practice Questions

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

Practice Questions

Cardiovascular Effects of Non-Cardiovascular Drugs

Practice Questions

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