Cardiovascular Drugs Practice Questions

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

Conivaptan. **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.

Q: Which calcium channel blocker causes cerebral vasodilatation?

Nimodipine. **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).

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

First choice drugs unless contraindicated. **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).

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

Patent ductus arteriosus. **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.

Q: Which of the following is NOT an antiplatelet drug?

Streptokinase. **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.

Q: Niacin must be used cautiously in diabetic patients because?

It impairs insulin sensitivity. **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.

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

Plasminogen activator inhibitor. 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.

Question 1

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

Accepted Answer

Conivaptan

Answer

Tolvaptan

Answer

Relcovaptan

Answer

Lixivaptan

Question 2

Which calcium channel blocker causes cerebral vasodilatation?

Accepted Answer

Nimodipine

Answer

Felodipine

Answer

Amlodipine

Answer

Nitrendipine

Question 3

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

Accepted Answer

Less peripheral vasoconstriction

Answer

Better cardiac stimulation

Answer

Lower risk of cardiac arrhythmia

Answer

More central nervous system stimulation

Question 4

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

Accepted Answer

First choice drugs unless contraindicated

Answer

An alternative to diuretics

Answer

A substitute for digitalis

Answer

Adjuncts only in resistant cases

Question 5

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

Accepted Answer

Patent ductus arteriosus

Answer

Erectile dysfunction

Answer

Pulmonary hypertension

Answer

Critical limb ischemia

Question 6

Which of the following is NOT an antiplatelet drug?

Accepted Answer

Streptokinase

Answer

Aspirin

Answer

Clopidogrel

Answer

Ticlopidine

Question 7

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

Accepted Answer

Amiodarone

Answer

Sotalol

Answer

Diltiazem

Answer

Quinidine

Question 8

Niacin must be used cautiously in diabetic patients because?

Accepted Answer

It impairs insulin sensitivity

Answer

It causes hypoglycemia

Answer

It increases the metabolism of oral hypoglycemic agents

Answer

It increases skin thickness

Question 9

Which of the following is true about dobutamine?

Accepted Answer

It is a strong vasoconstrictor

Answer

It significantly increases heart rate

Answer

It reduces afterload

Answer

It is a potent bronchodilator

Question 10

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

Accepted Answer

Plasminogen activator inhibitor

Answer

Fibrinolytics

Answer

Antithrombin

Answer

Platelet inhibitor

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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