Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 781: Which beta-blocker lacks local anesthetic effect?

A. Metoprolol
B. Pindolol
C. Atenolol (Correct Answer)
D. All of the above

Explanation: **Explanation:** The "local anesthetic effect" of beta-blockers is also known as **Membrane Stabilizing Activity (MSA)**. This property is due to the blockade of voltage-gated sodium channels, similar to the mechanism of lidocaine. Drugs with high MSA can cause decreased corneal sensitivity (when used topically) and are more toxic in overdose due to cardiac conduction delays. **1. Why Atenolol is correct:** Atenolol is a **hydrophilic (water-soluble)**, cardioselective beta-1 blocker. It completely lacks membrane stabilizing activity (MSA). Because it is hydrophilic, it also has poor CNS penetration, leading to fewer side effects like nightmares or depression. **2. Why the other options are incorrect:** * **Metoprolol:** This is a cardioselective beta-blocker that possesses **weak but present** membrane stabilizing activity. * **Pindolol:** This is a non-selective beta-blocker with **significant** membrane stabilizing activity. It is also notable for having Intrinsic Sympathomimetic Activity (ISA). **High-Yield Clinical Pearls for NEET-PG:** * **Strongest MSA:** **Propranolol** has the highest membrane stabilizing activity (making it dangerous in overdose due to QRS widening). * **Beta-blockers with MSA:** Propranolol, Pindolol, Acebutolol, Metoprolol, and Labetalol. * **Beta-blockers WITHOUT MSA:** **Atenolol**, Sotalol, Timolol, and Nadolol. * **Clinical Significance:** Beta-blockers with MSA (like Propranolol) should never be used as eye drops for glaucoma because they would anesthetize the cornea, leading to a loss of the protective blink reflex and potential corneal ulceration. **Timolol** is preferred in glaucoma because it lacks MSA.

Question 782: Ticagrelor is a type of:

A. Cyclooxygenase inhibitor
B. Phosphodiesterase inhibitor
C. Glycoprotein IIb/IIIa inhibitor
D. P2Y12 receptor blocker (Correct Answer)

Explanation: **Explanation:** **Ticagrelor** is a potent antiplatelet agent that acts as a **direct-acting, reversible P2Y12 receptor antagonist**. [1] It inhibits the binding of Adenosine Diphosphate (ADP) to the P2Y12 receptor on the platelet surface, preventing the activation of the GPIIb/IIIa complex and subsequent platelet aggregation. Unlike Clopidogrel and Prasugrel, Ticagrelor is a **cyclopentyl-triazolo-pyrimidine** (not a thienopyridine) and does not require metabolic activation (it is not a prodrug). [1] **Analysis of Incorrect Options:** * **A. Cyclooxygenase (COX) inhibitor:** This describes **Aspirin**, which irreversibly inhibits COX-1 to prevent the synthesis of Thromboxane A2. [4] * **B. Phosphodiesterase (PDE) inhibitor:** This describes drugs like **Dipyridamole** or **Cilostazol**, which increase intracellular cAMP levels to inhibit platelet aggregation. [3] * **C. Glycoprotein IIb/IIIa inhibitor:** This describes intravenous agents like **Abciximab, Eptifibatide, and Tirofiban**, which block the final common pathway of platelet aggregation (fibrinogen binding). [2] **High-Yield Clinical Pearls for NEET-PG:** * **Reversibility:** Ticagrelor is the only oral P2Y12 inhibitor that is **reversible**, allowing for faster recovery of platelet function compared to Clopidogrel. [1] * **Adverse Effects:** A unique and high-yield side effect of Ticagrelor is **Dyspnea** (due to inhibition of adenosine reuptake) and occasionally **Bradyarrhythmias/Ventricular pauses**. * **Metabolism:** It is metabolized by **CYP3A4**; therefore, strong CYP3A4 inhibitors/inducers can significantly alter its plasma levels. * **Clinical Use:** It is a preferred agent in **Acute Coronary Syndrome (ACS)** and during Percutaneous Coronary Intervention (PCI).

Question 783: Which antiglaucoma drug can be used in an asthmatic patient?

A. Timolol
B. Betaxolol (Correct Answer)
C. Propranolol
D. All

Explanation: **Explanation:** The primary concern when using beta-blockers for glaucoma in patients with respiratory comorbidities is **bronchoconstriction**. Beta-receptors are divided into $\beta_1$ (predominantly in the heart) and $\beta_2$ (predominantly in the bronchial smooth muscle). **Why Betaxolol is the correct answer:** Betaxolol is a **cardioselective ($\beta_1$ specific) blocker**. Because it lacks significant $\beta_2$ antagonist activity, it does not cause the bronchospasm typically associated with non-selective beta-blockers [1]. This makes it the safest beta-blocker option for patients with **Asthma or Chronic Obstructive Pulmonary Disease (COPD)** [3]. However, it should still be used with caution in severe cases. **Analysis of Incorrect Options:** * **Timolol:** This is a **non-selective beta-blocker** ($\beta_1 + \beta_2$). It is the gold standard for glaucoma but is strictly contraindicated in asthmatics because blocking $\beta_2$ receptors in the lungs leads to life-threatening bronchospasm [3]. * **Propranolol:** This is also a **non-selective beta-blocker** [1]. While it is the prototype of the class, it is not used topically for glaucoma and would be dangerous for an asthmatic patient. * **All:** This is incorrect as Timolol and Propranolol are contraindicated in asthma. **NEET-PG High-Yield Pearls:** * **Mechanism in Glaucoma:** Beta-blockers reduce intraocular pressure (IOP) by **decreasing the production of aqueous humor** from the ciliary body [2]. * **Side Effect Profile:** While Betaxolol is safer for the lungs, it is slightly **less efficacious** in lowering IOP compared to Timolol. * **Drug of Choice:** Currently, **Prostaglandin analogues (e.g., Latanoprost)** have replaced beta-blockers as the first-line treatment for Open-Angle Glaucoma due to better efficacy and fewer systemic side effects.

Question 784: Propranolol is useful for all of the following conditions except:

A. Angina
B. Familial tremor
C. Hypertension
D. Partial AV block (Correct Answer)

Explanation: **Explanation:** Propranolol is a non-selective beta-adrenergic antagonist ($\beta_1$ and $\beta_2$ blocker). Its primary cardiac effect is the inhibition of $\beta_1$ receptors in the SA and AV nodes, leading to decreased heart rate (negative chronotropy) and slowed conduction velocity (negative dromotropy). **Why Partial AV Block is the Correct Answer:** In **Partial AV block** (1st or 2nd degree), conduction through the AV node is already impaired. Propranolol further increases the refractory period of the AV node and slows conduction. Administering it can worsen the block, potentially progressing it to a **Complete (3rd degree) Heart Block**, which can lead to asystole or severe bradycardia. Therefore, it is strictly contraindicated. **Why the other options are incorrect:** * **Angina:** Propranolol reduces myocardial oxygen demand by decreasing heart rate and contractility, making it a first-line drug for chronic stable angina. * **Familial Tremor:** It is the drug of choice for essential/familial tremors. It works by blocking peripheral $\beta_2$ receptors in the skeletal muscles. * **Hypertension:** Although no longer first-line for uncomplicated hypertension, it is used to reduce cardiac output and inhibit renin release from the kidneys. **High-Yield Clinical Pearls for NEET-PG:** * **Membrane Stabilizing Activity (MSA):** Propranolol possesses significant local anesthetic activity (Quinidine-like effect). * **Lipophilicity:** It is highly lipid-soluble, allowing it to cross the BBB (useful for migraine prophylaxis) but also causing side effects like vivid dreams/nightmares. * **Contraindications:** Always remember the "ABCDE" contraindications for Beta-blockers: **A**sthma/COPD, **B**lock (Heart block), **C**onstrictive peripheral vascular disease (Raynaud's), **D**ecompensated heart failure, and **E**lderly (relative).

Question 785: Adenosine is used in which of the following conditions?

A. Atrial flutter
B. Atrial fibrillation
C. Paroxysmal supraventricular tachycardia (PSVT) (Correct Answer)
D. Ventricular tachycardia

Explanation: ### Explanation **Correct Answer: C. Paroxysmal supraventricular tachycardia (PSVT)** **Mechanism of Action:** Adenosine is the drug of choice for the acute termination of **Paroxysmal Supraventricular Tachycardia (PSVT)**, specifically those involving the AV node (AVNRT). It acts by stimulating **A1 receptors** coupled to Gi proteins, leading to the opening of potassium channels and inhibition of calcium current. This results in profound **hyperpolarization** and a transient suppression of nodal conduction, effectively "resetting" the heart's electrical system and breaking the re-entry circuit. **Analysis of Incorrect Options:** * **A & B (Atrial Flutter/Fibrillation):** Adenosine is generally ineffective in converting these rhythms to sinus rhythm because the pathology originates in the atria, not the AV node. However, it may be used diagnostically to transiently slow the ventricular rate to reveal underlying "flutter waves." * **D (Ventricular Tachycardia):** Adenosine primarily acts on the supraventricular tissue (AV node). It is not the treatment for VT (where Amiodarone or Lidocaine are preferred), though it may be used in stable, regular, wide-complex tachycardias to differentiate SVT with aberrancy from VT. **NEET-PG High-Yield Pearls:** * **Half-life:** Extremely short (<10 seconds) due to rapid uptake by RBCs and endothelial cells; must be given as a **rapid IV bolus** followed by a saline flush. * **Antidote/Interaction:** Its effects are antagonized by **Theophylline and Caffeine** (adenosine receptor blockers) and potentiated by **Dipyridamole**. * **Side Effects:** Common "transient" effects include chest pain, dyspnea, and a sense of "impending doom." * **Contraindications:** Avoid in **Asthma** (causes bronchoconstriction via A2B receptors) and **2nd/3rd-degree heart block**.

Question 786: Nitroglycerine causes which of the following 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. **Why "Hypotension and bradycardia" is the correct answer (The Exception):** Nitroglycerine acts as a nitric oxide donor, leading to smooth muscle relaxation. This causes significant peripheral vasodilation (venous > arterial), which results in a drop in blood pressure (**Hypotension**). In response to this drop in BP, the body’s baroreceptor reflex is triggered, leading to **reflex tachycardia**, not bradycardia. Therefore, the combination of hypotension and bradycardia is physiologically incorrect for NTG. **Analysis of Incorrect Options:** * **Vasodilation:** This is the primary mechanism of action. NTG increases cGMP levels, leading to dephosphorylation of the myosin light chain and subsequent relaxation of vascular smooth muscle. * **Hypotension and tachycardia:** This is the classic physiological response to NTG. The decrease in venous return (preload) and systemic vascular resistance leads to a compensatory increase in heart rate. * **Methemoglobinemia:** This is a known, though rare, side effect of high-dose or prolonged nitrate therapy. Nitrate ions can oxidize the ferrous iron ($Fe^{2+}$) in hemoglobin to ferric iron ($Fe^{3+}$), forming methemoglobin, which cannot bind oxygen. **Clinical Pearls for NEET-PG:** * **Monday Disease:** Workers in dynamite factories develop tolerance to nitrates during the week, losing it over the weekend, leading to headaches and tachycardia upon re-exposure on Mondays. * **Drug Interaction:** Nitrates are strictly contraindicated with **Sildenafil** (PDE-5 inhibitors) as they synergistically increase cGMP, causing life-threatening hypotension. * **Nitrate Holiday:** To prevent tolerance, a nitrate-free interval of 8–12 hours (usually at night) is recommended.

Question 787: What is the mechanism of action of digitalis?

A. Increase in heart rate with increase in oxygen consumption
B. Increase in heart rate without increase in oxygen consumption
C. Decrease in heart rate with increase in oxygen consumption
D. Decrease in heart rate with decrease in oxygen consumption (Correct Answer)

Explanation: **Mechanism of Action of Digitalis (Digoxin)** The therapeutic effect of digitalis in heart failure is unique because it increases cardiac output while simultaneously reducing the workload of the heart. **Why Option D is Correct:** 1. **Decrease in Heart Rate:** Digitalis exerts a **vagomimetic effect** (parasympathetic activation) and slows conduction through the AV node. This increases the diastolic filling time, leading to a decrease in heart rate (negative chronotropy). 2. **Decrease in Oxygen Consumption ($MVO_2$):** Although digitalis is a positive inotrope (it increases force of contraction by inhibiting the $Na^+/K^+$ ATPase pump), in a failing heart, it significantly **reduces ventricular wall tension** and heart size (Laplace’s Law). The reduction in heart rate and wall tension outweighs the energy cost of increased contractility, leading to a net **decrease** in myocardial oxygen demand. **Analysis of Incorrect Options:** * **Options A & B:** These are incorrect because digitalis is a **negative chronotrope**. It decreases heart rate, making it useful in controlling ventricular rate in atrial fibrillation. * **Option C:** While digitalis does decrease heart rate, it does not increase oxygen consumption in a failing heart. Drugs that increase both contractility and oxygen consumption (like Dobutamine) can worsen ischemia, whereas digitalis is more "oxygen-efficient" in the context of heart failure. **NEET-PG High-Yield Pearls:** * **Molecular Target:** Reversible inhibition of the **$Na^+/K^+$ ATPase pump** on the sarcolemma. * **ECG Changes:** Characterized by the **"Reverse Tick"** or "Sagging" ST-segment depression (Salvador Dali mustache sign). * **Electrolyte Interaction:** **Hypokalemia** predisposes to digitalis toxicity because $K^+$ and Digoxin compete for the same binding site on the ATPase pump. * **Antidote:** Digoxin-specific antibody fragments (**DigiFab**).

Question 788: Oral sacubitril is approved for the treatment of which condition?

A. Congestive cardiac failure (Correct Answer)
B. IBS with diarrhea predominance
C. Unstable angina
D. Vitamin K deficiency

Explanation: **Explanation:** **Sacubitril** is a first-in-class **Neprilysin inhibitor**. It is primarily used in combination with Valsartan (an Angiotensin Receptor Blocker) as an **ARNI** (Angiotensin Receptor-Neprilysin Inhibitor) for the management of **Congestive Cardiac Failure (CCF)**, specifically Heart Failure with reduced Ejection Fraction (HFrEF). * **Mechanism of Action:** Neprilysin is an enzyme responsible for the degradation of beneficial endogenous vasoactive peptides, such as **Atrial Natriuretic Peptide (ANP)** and **B-type Natriuretic Peptide (BNP)**. By inhibiting neprilysin, sacubitril increases the levels of these peptides, leading to vasodilation, natriuresis (sodium excretion), and diuresis, while reducing sympathetic tone and cardiac fibrosis. * **Why Valsartan is added:** Neprilysin also degrades Angiotensin II. Therefore, inhibiting neprilysin alone would increase Angiotensin II levels. Adding Valsartan counteracts this effect, providing a synergistic benefit in heart failure patients. **Analysis of Incorrect Options:** * **B. IBS with diarrhea:** Sacubitril has no role here. Eluxadoline or Alosetron are drugs used in IBS-D. * **C. Unstable Angina:** Treatment involves antiplatelets, anticoagulants, and nitrates. Sacubitril is not indicated for acute coronary syndromes. * **D. Vitamin K deficiency:** This is managed with Vitamin K1 (Phytonadione) supplementation. **High-Yield Clinical Pearls for NEET-PG:** * **PARADIGM-HF Trial:** The landmark study that established ARNI superiority over Enalapril in reducing mortality in HFrEF. * **Washout Period:** When switching from an ACE inhibitor to Sacubitril/Valsartan, a **36-hour washout period** is mandatory to prevent the risk of **angioedema** (as both drugs increase bradykinin). * **Contraindication:** Do not use in patients with a history of angioedema related to previous ACEI/ARB therapy.

Question 789: Which antihypertensive medication is safe to use in patients with renal disease?

A. Atenolol
B. Amlodipine (Correct Answer)
C. Thiazide
D. Methyldopa

Explanation: **Explanation:** **Amlodipine** is a long-acting Dihydropyridine Calcium Channel Blocker (CCB). It is considered safe and often preferred in patients with renal disease because it is primarily metabolized by the **liver** and does not require dose adjustment in renal impairment. Furthermore, CCBs do not adversely affect the Glomerular Filtration Rate (GFR) or electrolyte balance, unlike other antihypertensives. **Analysis of Incorrect Options:** * **Atenolol:** This is a hydrophilic beta-blocker that is primarily excreted unchanged by the **kidneys**. In patients with renal failure, it can accumulate, leading to severe bradycardia and toxicity. (Note: Metoprolol is preferred over Atenolol in renal disease as it is hepatically metabolized). * **Thiazides:** These diuretics lose their efficacy when the GFR falls below **30 mL/min**. In advanced renal disease, they are ineffective as antihypertensives (Loop diuretics like Furosemide are used instead). * **Methyldopa:** While used in pregnancy-induced hypertension, it is not a first-line drug for renal patients. Its metabolites are renally cleared, and it can cause significant sedation and central side effects in patients with uremia. **High-Yield Clinical Pearls for NEET-PG:** 1. **DOC for Hypertensive Diabetic Nephropathy:** ACE inhibitors (e.g., Enalapril) or ARBs (e.g., Losartan) are the drugs of choice due to their **renoprotective** effects (dilating the efferent arteriole), provided serum creatinine is <3 mg/dL. 2. **Safe Beta-blockers in Renal Failure:** Metoprolol, Propranolol, and Labetalol (Hepatic metabolism). 3. **Safe Statins in Renal Failure:** Atorvastatin (does not require dose adjustment). 4. **Avoid in Bilateral Renal Artery Stenosis:** ACE inhibitors/ARBs, as they can precipitate acute renal failure.

Question 790: Regarding lidocaine, all of the following are true EXCEPT:

A. Dose needs to be altered in renal failure (Correct Answer)
B. Loading dose is given before infusion
C. It is little affected by heat and pH
D. It prolongs the refractory period

Explanation: Lidocaine is a Class IB antiarrhythmic primarily used for ventricular arrhythmias, especially post-myocardial infarction. **Explanation of the Correct Answer (A):** Lidocaine is primarily metabolized by the **liver** via the CYP450 system (specifically CYP1A2 and CYP3A4) into active metabolites like monoethylglycinexylidide (MEGX). Its clearance is highly dependent on hepatic blood flow. Therefore, dose adjustments are crucial in **hepatic failure** or congestive heart failure (due to reduced liver perfusion), but **not in renal failure**, as the kidneys play a negligible role in its primary clearance. **Analysis of Other Options:** * **B. Loading dose is given before infusion:** Lidocaine has a short half-life (approx. 1.5–2 hours). To achieve rapid therapeutic plasma concentrations (1.5–5 µg/mL), a loading dose is mandatory before starting a continuous maintenance infusion. * **C. Little affected by heat and pH:** Lidocaine is a stable compound. Unlike some other local anesthetics, it is relatively resistant to heat (autoclavable) and maintains stability across a reasonable range of pH, though its lipid solubility (and thus onset) is influenced by tissue pH. * **D. It prolongs the refractory period:** While Class IB agents typically shorten the Action Potential Duration (APD) in healthy tissue, they **prolong the Effective Refractory Period (ERP) relative to the APD** in ischemic or depolarized myocardial tissue. This selective action helps suppress ectopic foci. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Lidocaine is no longer the first-line drug for stable VT (Amiodarone is preferred), but it remains an alternative in ACLS protocols. * **Toxicity:** CNS side effects are most common (dizziness, seizures, "Lidocaine crazies"). * **Route:** It undergoes extensive first-pass metabolism; hence, it is **never given orally**.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

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Antiarrhythmic Drugs

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Antianginal Agents

Practice Questions

Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

Practice Questions

Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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