Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 531: Which drug prolongs life in a patient with chronic stable angina?

A. Aspirin
B. Beta Blocker (Correct Answer)
C. Calcium Channel Blocker
D. ACE inhibitor

Explanation: **Explanation:** In the management of chronic stable angina, drugs are classified into two categories: those that provide **symptomatic relief** and those that **improve prognosis (prolong life/reduce mortality).** **Why Beta Blockers are correct:** Beta-blockers (e.g., Metoprolol, Atenolol) are the first-line therapy for chronic stable angina because they are the only anti-anginal drugs proven to **reduce the risk of myocardial infarction and improve survival**, especially in patients with a history of prior MI or heart failure. They work by decreasing myocardial oxygen demand (via negative inotropic and chronotropic effects) and increasing coronary perfusion time by prolonging diastole. **Analysis of Incorrect Options:** * **Aspirin:** While Aspirin reduces the risk of thrombotic events and is vital for secondary prevention, in the specific context of "anti-anginal therapy" questions, Beta-blockers are prioritized for their direct cardioprotective effects on the myocardium. (Note: Many guidelines consider both, but Beta-blockers are the classic pharmacological answer for mortality benefit in angina). * **Calcium Channel Blockers (CCBs):** These are excellent for symptomatic relief (vasodilation and reducing afterload) but have **not** been shown to reduce mortality in chronic stable angina. In fact, short-acting nifedipine may increase mortality. * **ACE Inhibitors:** These improve survival in patients with hypertension, diabetes, or LV dysfunction, but they are not primary anti-anginal agents and do not directly treat the oxygen supply-demand mismatch. **High-Yield Clinical Pearls for NEET-PG:** * **First-line for symptomatic relief:** Beta-blockers. * **First-line for Vasospastic (Prinzmetal) Angina:** Calcium Channel Blockers (Beta-blockers are contraindicated as they may cause unopposed alpha-vasoconstriction). * **Ivabradine:** Used when Beta-blockers are contraindicated; it acts on $I_f$ (funny) channels in the SA node. * **Ranolazine:** A late sodium channel blocker used for chronic angina that does not affect heart rate or BP.

Question 532: Which of the following antihypertensive agents is most likely to cause an exaggerated response to an injected catecholamine?

A. Propranolol
B. Hydralazine
C. A thiazide diuretic
D. Guanethidine (Correct Answer)

Explanation: **Explanation:** The correct answer is **Guanethidine**. **1. Why Guanethidine is correct:** Guanethidine is a post-ganglionic adrenergic neuron blocker. It works by inhibiting the release of norepinephrine (NE) from nerve terminals and gradually depleting NE stores. This chronic lack of neurotransmitter at the synaptic cleft leads to a phenomenon known as **Denervation Supersensitivity**. The effector cells (vascular smooth muscle) compensate for the lack of stimulation by upregulating the number and sensitivity of adrenergic receptors. Consequently, when an exogenous catecholamine (like NE or Epinephrine) is injected, these "primed" receptors produce an exaggerated hypertensive response. **2. Why the other options are incorrect:** * **Propranolol:** As a non-selective beta-blocker, it blocks beta-receptors. While it can cause "unopposed alpha-stimulation" if catecholamines are given, it does not cause receptor upregulation in a way that leads to a generalized exaggerated response compared to guanethidine. * **Hydralazine:** This is a direct-acting vasodilator. It does not significantly alter the sensitivity of adrenergic receptors. * **Thiazide Diuretics:** These work by inhibiting the Na+/Cl- symporter in the distal tubule. They actually tend to *decrease* vascular responsiveness to pressor agents over time due to sodium depletion. **3. Clinical Pearls for NEET-PG:** * **Guanethidine Interaction:** It is taken up into the neuron by **NET (Uptake-1)**. Drugs like Tricyclic Antidepressants (TCAs) and Cocaine block this uptake, reversing guanethidine's antihypertensive effect. * **Reserpine vs. Guanethidine:** Both deplete NE, but Reserpine acts on the VMAT transporter (vesicular storage), while Guanethidine acts on the neuronal membrane and displaces NE. * **High-Yield Concept:** Always remember that chronic blockade of a receptor or lack of its ligand leads to **upregulation**, while chronic stimulation leads to **downregulation (tachyphylaxis)**.

Question 533: Which of the following vitamins is used to increase HDL levels?

A. Folic acid
B. Nicotinic acid (Correct Answer)
C. Thiamine
D. Pyridoxine

Explanation: **Explanation:** **Nicotinic acid (Niacin/Vitamin B3)** [1] is the correct answer because it is the most potent agent currently available for increasing **HDL-C levels** (by 15–35%). It achieves this by inhibiting the hepatic uptake of Apolipoprotein A-I (ApoA-I), thereby increasing its half-life and the circulating levels of HDL. Additionally, it inhibits the enzyme *diacylglycerol acyltransferase-2* in the liver, leading to decreased triglyceride synthesis and reduced VLDL/LDL levels. **Analysis of Incorrect Options:** * **Folic acid (B9):** Primarily used for DNA synthesis and erythropoiesis. While it helps lower homocysteine levels (a cardiovascular risk factor), it has no direct effect on HDL or lipid profiles. * **Thiamine (B1):** Acts as a cofactor for carbohydrate metabolism (e.g., pyruvate dehydrogenase). Deficiency leads to Beriberi or Wernicke-Korsakoff syndrome, but it does not modulate lipids. * **Pyridoxine (B6):** Involved in amino acid metabolism and heme synthesis. Like folic acid, it reduces homocysteine but does not increase HDL. **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effect:** The most common side effect is **cutaneous flushing** and pruritus, mediated by **Prostaglandin D2**. This can be minimized by pre-treating with **Aspirin** (30 mins prior). * **Metabolic Effects:** Niacin can cause **hyperuricemia** (precipitating gout) and **hyperglycemia** (impaired glucose tolerance) [2], [3], so it should be used cautiously in diabetic patients. * **Acanthosis Nigricans:** High doses of nicotinic acid are a known pharmacological cause of this skin condition.

Question 534: Which among the following drugs is NOT used orally?

A. Lignocaine (Correct Answer)
B. Verapamil
C. Phenytoin
D. Quinidine

Explanation: **Explanation:** The correct answer is **Lignocaine** (Lidocaine). **1. Why Lignocaine is the correct answer:** Lignocaine is a Class IB antiarrhythmic drug that is **not administered orally** because it undergoes **extensive first-pass metabolism** in the liver (nearly 70%). If taken orally, its bioavailability is too low to reach therapeutic plasma concentrations, and its metabolites can increase the risk of central nervous system toxicity. Therefore, it is administered intravenously (for arrhythmias) or topically/locally (as an anesthetic). **2. Analysis of Incorrect Options:** * **Verapamil (Option B):** A Class IV Calcium Channel Blocker used for supraventricular tachycardia, hypertension, and angina. Although it has a significant first-pass effect, it is available in oral formulations with adjusted dosages. * **Phenytoin (Option C):** A Class IB antiarrhythmic (specifically for digoxin-induced arrhythmias) and an antiepileptic. It has good oral bioavailability and is commonly used in tablet or suspension form. * **Quinidine (Option D):** A Class IA antiarrhythmic drug. It is well-absorbed from the gastrointestinal tract and is administered orally for the maintenance of sinus rhythm in patients with atrial fibrillation/flutter. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Lignocaine is the drug of choice for **ventricular arrhythmias** occurring post-myocardial infarction (though amiodarone is now often preferred in ACLS protocols). * **Toxicity:** Lignocaine toxicity primarily affects the CNS, presenting as seizures, tremors, or blurred vision. * **Other non-oral drugs:** Remember that **Bretylium** and **Adenosine** are also antiarrhythmics that are not given orally (Adenosine has a half-life of <10 seconds and must be given as a rapid IV bolus). * **Mexiletine:** This is a Class IB analogue of lignocaine that *is* orally effective because it resists first-pass metabolism.

Question 535: Which of the following antihypertensive drugs can cause a "SLE-like reaction"?

A. Minoxidil
B. Hydralazine (Correct Answer)
C. Diazoxide
D. Fenoldopam

Explanation: **Explanation:** **Hydralazine** is a direct-acting arterial vasodilator. It is classically associated with **Drug-Induced Lupus Erythematosus (DILE)**. The underlying mechanism involves the drug acting as a hapten or interfering with immune tolerance. A key pharmacological concept for NEET-PG is that hydralazine is metabolized via **N-acetylation** in the liver. **"Slow acetylators"** (individuals with a genetic deficiency in the N-acetyltransferase enzyme) are at a significantly higher risk of developing this SLE-like reaction because the drug remains in the system longer, leading to the formation of reactive metabolites. **Analysis of Incorrect Options:** * **Minoxidil:** A potent potassium channel opener used for refractory hypertension and alopecia. It causes significant fluid retention and hypertrichosis but not DILE. * **Diazoxide:** A potassium channel opener used in hypertensive emergencies and to treat insulinomas (as it inhibits insulin release). It can cause hyperglycemia but not lupus-like symptoms. * **Fenoldopam:** A selective Dopamine-1 (D1) receptor agonist used in hypertensive emergencies. It promotes natriuresis and maintains renal perfusion; it is not associated with autoimmune reactions. **High-Yield Clinical Pearls for NEET-PG:** * **DILE Markers:** Unlike systemic SLE, DILE is characterized by **Anti-Histone Antibodies** (positive in >95% of cases). Anti-dsDNA is usually negative. * **Common Culprits:** Remember the mnemonic **"SHIPP"**: **S**ulfonamides, **H**ydralazine, **I**soniazid, **P**rocainamide, and **P**henytoin. * **Clinical Presentation:** DILE typically presents with fever, arthralgia, and pleuritis, but rarely involves the CNS or kidneys (unlike idiopathic SLE). Symptoms usually resolve upon drug discontinuation.

Question 536: Which of the following statements is true about esmolol?

A. It has no intrinsic sympathomimetic activity.
B. It is a cardioselective beta-blocker.
C. It can precipitate heart failure.
D. All of the above. (Correct Answer)

Explanation: **Explanation:** Esmolol is a unique, ultra-short-acting **cardioselective (β1-selective)** adrenergic antagonist. It is characterized by its rapid onset and very short duration of action (half-life of approximately 9 minutes) due to its metabolism by **red blood cell esterases**. * **Option A (No ISA):** Esmolol is a pure antagonist. It lacks intrinsic sympathomimetic activity (ISA), meaning it does not partially stimulate beta-receptors. This makes it highly effective at reducing heart rate and myocardial oxygen demand. * **Option B (Cardioselective):** It primarily blocks β1 receptors located in the heart. While selectivity is lost at very high doses, at therapeutic levels, it has minimal effect on β2 receptors in the bronchi or peripheral vasculature. * **Option C (Precipitate Heart Failure):** Like all beta-blockers, esmolol is a **negative inotrope**. By reducing the force of myocardial contraction, it can acutely worsen cardiac output in patients with compensated heart failure or borderline hemodynamics, potentially precipitating acute heart failure. Since all three statements are pharmacologically accurate, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolism:** It is the only beta-blocker metabolized by **plasma esterases** (not liver or kidney), making it safe in hepatic or renal failure. * **Indications:** Preferred for intraoperative tachycardia/hypertension, supraventricular arrhythmias (SVT), and hypertensive emergencies (especially aortic dissection). * **Administration:** Given only via **intravenous (IV)** route because of its rapid metabolism. * **Mnemonic:** Remember the **"B-E-A-M"** for cardioselective blockers: **B**isoprolol, **E**smolol, **A**tenolol, **M**etoprolol.

Question 537: Which of the following statements is true about nitric oxide?

A. Formed from L-Arginine by NO synthase
B. Causes vasodilation in all vessels
C. Used in pulmonary hypertension
D. All of the above (Correct Answer)

Explanation: Nitric Oxide (NO), formerly known as Endothelium-Derived Relaxing Factor (EDRF), is a potent endogenous gas and signaling molecule crucial for vascular homeostasis. **Explanation of Options:** * **Option A:** NO is synthesized from the amino acid **L-arginine** by the enzyme **Nitric Oxide Synthase (NOS)** in the presence of oxygen and NADPH. There are three isoforms: nNOS (neuronal), eNOS (endothelial), and iNOS (inducible). * **Option B:** NO is a powerful **vasodilator**. It diffuses into vascular smooth muscle cells, activates **guanylyl cyclase**, and increases **cGMP** levels. This leads to dephosphorylation of myosin light chains and relaxation of smooth muscle across the systemic and pulmonary vasculature. * **Option C:** Inhaled NO is a standard treatment for **Persistent Pulmonary Hypertension of the Newborn (PPHN)** and adult pulmonary hypertension. Its advantage is "selective" pulmonary vasodilation without causing systemic hypotension, as it is rapidly inactivated by hemoglobin upon entering the systemic circulation. **Conclusion:** Since all statements are physiologically and clinically accurate, **Option D** is the correct answer. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** NO → ↑ cGMP → Protein Kinase G activation → Vasodilation. * **Inactivation:** NO has an extremely short half-life (seconds) and is neutralized by binding to the heme group of **hemoglobin**. * **Therapeutic use:** Inhaled NO is used in **ARDS** to improve oxygenation by reducing ventilation-perfusion (V/Q) mismatch. * **Drug Interaction:** Sildenafil (PDE-5 inhibitor) prevents the breakdown of cGMP, potentiating the effects of NO. Combined use with nitrates can lead to severe hypotension.

Question 538: Verapamil is contraindicated in:

A. Hypertension
B. Complete heart block (Correct Answer)
C. Paroxysmal supraventricular tachycardia
D. Angina pectoris

Explanation: **Explanation:** **Verapamil** is a non-dihydropyridine Calcium Channel Blocker (CCB) with significant **negative inotropic, chronotropic, and dromotropic** effects [1]. Its primary site of action is the heart, specifically the SA and AV nodes. **1. Why Complete Heart Block is the Correct Answer:** Verapamil significantly slows conduction through the **Atrioventricular (AV) node** and increases the refractory period [2]. In a patient with complete heart block (3rd-degree AV block), the conduction between the atria and ventricles is already severed. Administering Verapamil can further suppress the junctional or ventricular escape rhythms, leading to severe bradycardia, asystole, or cardiovascular collapse [1], [3]. Therefore, it is strictly contraindicated in high-grade heart blocks and sick sinus syndrome. **2. Why Other Options are Incorrect:** * **Hypertension:** Verapamil causes peripheral vasodilation (though less than dihydropyridines like Amlodipine) and is an effective second-line antihypertensive [1]. * **Paroxysmal Supraventricular Tachycardia (PSVT):** Verapamil is actually a **drug of choice** for terminating acute episodes of PSVT (re-entrant tachycardias involving the AV node) because it slows AV conduction [4]. * **Angina Pectoris:** Verapamil is used in stable and vasospastic (Prinzmetal) angina as it reduces myocardial oxygen demand and prevents coronary vasospasm. **High-Yield Clinical Pearls for NEET-PG:** * **Avoid with Beta-blockers:** Never co-administer IV Verapamil with Beta-blockers due to the risk of additive cardiosuppression and heart block [3]. * **Wolff-Parkinson-White (WPW) Syndrome:** Verapamil is contraindicated in WPW with Atrial Fibrillation because it may enhance conduction through the accessory pathway, leading to Ventricular Fibrillation. * **Side Effect:** The most common non-cardiac side effect of Verapamil is **constipation** [1].

Question 539: Which class of drugs is considered a myocardial re-infarction inhibitor?

A. Beta blockers (Correct Answer)
B. Nitrates
C. Calcium channel blockers
D. Potassium channel openers

Explanation: **Explanation:** **Why Beta Blockers are Correct:** Beta-blockers (e.g., Metoprolol, Atenolol, Carvedilol) are the mainstay for secondary prevention post-Myocardial Infarction (MI). They act by competitively inhibiting $\beta_1$ receptors in the heart, leading to decreased heart rate, contractility, and systolic blood pressure. This significantly reduces **myocardial oxygen demand**. Furthermore, they increase diastolic perfusion time, improving coronary blood flow. By reducing "cardiac work" and preventing catecholamine-induced arrhythmias and ventricular remodeling, they have been clinically proven to reduce the risk of re-infarction and sudden cardiac death, thereby increasing long-term survival. **Why Other Options are Incorrect:** * **Nitrates:** While excellent for acute symptomatic relief of angina (preload reduction), they do not modify the disease process or reduce the incidence of re-infarction or mortality. * **Calcium Channel Blockers (CCBs):** Although they cause vasodilation, they are generally not first-line post-MI. Short-acting dihydropyridines (like Nifedipine) can actually cause reflex tachycardia, which may worsen ischemia. * **Potassium Channel Openers:** Drugs like Nicorandil are used for stable angina but lack robust clinical evidence for preventing re-infarction compared to Beta-blockers. **NEET-PG High-Yield Pearls:** * **TIMI Study:** Confirmed the benefit of early Beta-blocker administration in MI. * **Contraindications:** Avoid Beta-blockers in patients with bradycardia, high-grade AV block, severe active asthma, or cardiogenic shock. * **Cardioselective agents:** $\beta_1$ selective blockers (A-M: **A**tenolol, **B**isoprolol, **M**etoprolol) are preferred to minimize bronchospasm. * **Mortality Benefit:** Along with Beta-blockers, ACE inhibitors, Antiplatelets (Aspirin/Clopidogrel), and Statins are the four pillars that reduce mortality post-MI.

Question 540: Which one of the following is the most appropriate drug to use for the patient described in parentheses?

A. Captopril (60-year-old woman with diabetic nephropathy) (Correct Answer)
B. Nitroprusside (50-year-old man with BP of 140/95)
C. Losartan (29-year-old pregnant woman)
D. Propranolol (40-year-old patient with peripheral vascular disease)

Explanation: ### Explanation **1. Why Captopril is Correct:** Captopril is an ACE inhibitor (ACEi). In patients with **diabetic nephropathy**, ACE inhibitors are the drugs of choice because they provide **renoprotection**. They preferentially dilate the efferent arteriole in the kidney, reducing intraglomerular pressure and decreasing proteinuria. This slows the progression of chronic kidney disease, regardless of the patient's systemic blood pressure. **2. Why the Other Options are Incorrect:** * **Nitroprusside (Option B):** This is a potent parenteral vasodilator used only in **hypertensive emergencies** (BP usually >180/120 mmHg with end-organ damage). A BP of 140/95 mmHg represents Stage 1/2 hypertension, which is managed with oral medications (e.g., Amlodipine, Thiazides), not an IV emergency drug like Nitroprusside. * **Losartan (Option C):** Losartan is an Angiotensin Receptor Blocker (ARB). Both ACE inhibitors and ARBs are **strictly contraindicated in pregnancy** (Teratogenic). They can cause fetal renal dysgenesis, oligohydramnios, and skull hypoplasia. * **Propranolol (Option D):** Propranolol is a non-selective beta-blocker. It can worsen **peripheral vascular disease (PVD)** or Raynaud’s phenomenon due to unopposed alpha-1 mediated vasoconstriction after blocking the vasodilatory beta-2 receptors. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** ACEi/ARBs are DOC for hypertension in diabetics and patients with Proteinuria/CKD. * **Side Effect:** The most common side effect of Captopril is a **dry cough** (due to increased Bradykinin); if this occurs, switch the patient to an ARB (Losartan). * **Contraindications:** Avoid ACEi/ARBs in bilateral renal artery stenosis (can cause acute renal failure) and pregnancy. * **Beta-blockers in PVD:** If a beta-blocker must be used in PVD, choose a cardio-selective one (e.g., Metoprolol, Atenolol) or one with vasodilatory properties (e.g., Nebivolol).

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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