Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 721: All of the following drugs can be used in hypertensive crisis except?

A. Labetalol
B. Pindolol (Correct Answer)
C. Nitroprusside
D. Nifedipine

Explanation: ### Explanation **1. Why Pindolol is the Correct Answer:** A hypertensive crisis (Emergency or Urgency) requires rapid, predictable reduction of blood pressure. **Pindolol** is a non-selective beta-blocker with **Intrinsic Sympathomimetic Activity (ISA)**. This means it acts as a partial agonist; while it blocks beta receptors, it also slightly stimulates them. In a hypertensive crisis, this partial agonism can prevent the necessary profound drop in BP and may even cause an unpredictable initial rise in heart rate or BP. Therefore, it is not used in acute hypertensive settings. **2. Analysis of Incorrect Options:** * **Labetalol (Option A):** A combined alpha and beta-blocker. It is a first-line agent for hypertensive emergencies (especially in pregnancy/eclampsia and aortic dissection) because it reduces peripheral resistance without causing reflex tachycardia. * **Nitroprusside (Option B):** A potent parenteral vasodilator (releases Nitric Oxide). It acts rapidly on both arterioles and venules. It was long considered the "gold standard" for hypertensive emergencies due to its titratability and immediate onset. * **Nifedipine (Option D):** A Dihydropyridine Calcium Channel Blocker (CCB). While *sublingual* nifedipine is now discouraged due to risks of precipitous hypotension, **oral nifedipine** is still a recognized option for hypertensive **urgency** (severe BP elevation without end-organ damage). **3. NEET-PG High-Yield Pearls:** * **Drug of Choice (DOC):** For most hypertensive emergencies, **Fenoldopam** (D1 agonist) or **Nicardipine** (IV CCB) are now preferred over Nitroprusside to avoid cyanide toxicity. * **Aortic Dissection:** The DOC is **Labetalol** or a combination of Esmolol + Nitroprusside (Beta-blocker must be given first to prevent reflex tachycardia). * **Pregnancy-Induced Hypertension (PIH):** Labetalol is the DOC; Hydralazine is an alternative. * **Neurological Emergencies:** Avoid rapid BP drops to prevent cerebral ischemia; aim for a 20-25% reduction in the first hour.

Question 722: All of the following are actions of beta-blockers in congestive heart failure except:

A. Decrease in mortality
B. Antagonism of vasoconstriction due to sympathetic overactivity (Correct Answer)
C. Prevention of pathological remodeling of ventricular myocardium
D. Prevention of dangerous cardiac arrhythmias

Explanation: **Explanation:** In Congestive Heart Failure (CHF), the body compensates for low cardiac output by increasing sympathetic activity. While beta-blockers are a cornerstone of CHF management, their primary therapeutic actions are mediated through the heart, not the peripheral vasculature. **1. Why Option B is the Correct Answer (The "Except"):** Beta-blockers (especially non-selective ones like Propranolol or $\beta_1$-selective ones like Metoprolol) do **not** antagonize vasoconstriction. In fact, by blocking $\beta_2$ receptors (which mediate vasodilation), they can theoretically cause "unopposed alpha-mediated vasoconstriction." While third-generation beta-blockers like **Carvedilol** have $\alpha_1$-blocking properties that cause vasodilation, this is not a universal property of the beta-blocker class used in CHF. **2. Analysis of Incorrect Options:** * **Option A (Decrease in mortality):** This is a proven benefit. Large trials (CIBIS-II, MERIT-HF, COPERNICUS) have shown that Bisoprolol, Metoprolol succinate, and Carvedilol significantly reduce mortality in stable CHF patients. * **Option C (Prevention of remodeling):** Chronic sympathetic stimulation leads to myocyte hypertrophy and fibrosis. Beta-blockers inhibit the cardiotoxic effects of catecholamines, preventing the progressive "thinning and stretching" of the ventricles. * **Option D (Prevention of arrhythmias):** By reducing heart rate and antagonizing the arrhythmogenic effects of adrenaline, beta-blockers raise the threshold for ventricular fibrillation and prevent sudden cardiac death. **High-Yield Clinical Pearls for NEET-PG:** * **The "Big Three" in CHF:** Only three beta-blockers are FDA-approved to reduce mortality in CHF: **Bisoprolol, Carvedilol, and Metoprolol succinate.** * **Start Low, Go Slow:** Beta-blockers should only be started in **stable** patients (NYHA Class II/III) and never during an acute decompensated state, as their initial negative inotropic effect can worsen failure. * **Carvedilol:** Unique for being a non-selective $\beta$ blocker + $\alpha_1$ blocker + antioxidant.

Question 723: Which statin is not metabolized by CYP3A4?

A. Lovastatin
B. Simvastatin
C. Atorvastatin
D. Pravastatin (Correct Answer)

Explanation: ### Explanation Statins (HMG-CoA reductase inhibitors) are primarily metabolized by the hepatic cytochrome P450 (CYP) enzyme system. Understanding these metabolic pathways is crucial for predicting drug-drug interactions. **1. Why Pravastatin is the Correct Answer:** Pravastatin is a **hydrophilic** statin. Unlike most other statins, it is not metabolized by the CYP450 system to any significant extent. Instead, it undergoes enzymatic degradation in the cytosol and is excreted unchanged. This makes it a preferred choice in patients taking multiple medications (polypharmacy) or drugs that are potent CYP3A4 inhibitors (e.g., ketoconazole, clarithromycin, protease inhibitors), as it carries a lower risk of drug-induced myopathy. **2. Analysis of Incorrect Options:** * **A, B, and C (Lovastatin, Simvastatin, Atorvastatin):** These are **lipophilic** statins. They are primarily metabolized by the **CYP3A4** isoenzyme. Co-administration of these drugs with CYP3A4 inhibitors leads to increased plasma concentrations of the statin, significantly increasing the risk of skeletal muscle toxicity (rhabdomyolysis). **3. NEET-PG High-Yield Clinical Pearls:** * **CYP3A4 Metabolized:** Simvastatin, Lovastatin, Atorvastatin (Mnemonic: **SLA**p the 3A4). * **CYP2C9 Metabolized:** Rosuvastatin and Fluvastatin. * **Non-CYP Metabolized:** Pravastatin and Pitavastatin (Safest regarding CYP interactions). * **Potency:** Rosuvastatin is the most potent statin, followed by Atorvastatin. * **Prodrugs:** Lovastatin and Simvastatin are administered as inactive lactones (prodrugs); others are active. * **Timing:** Statins with short half-lives (Simvastatin, Pravastatin) should be taken at **bedtime** because cholesterol synthesis peaks between midnight and 2:00 AM. Atorvastatin and Rosuvastatin have long half-lives and can be taken any time.

Question 724: Which drug is known to prolong the QT interval?

A. Domperidone
B. Metoclopramide
C. Cisapride (Correct Answer)
D. Omeprazole

Explanation: **Cisapride** is a prokinetic agent that acts as a 5-HT4 receptor agonist [1]. The primary reason it causes **QT interval prolongation** is its ability to block the **hERG (human Ether-à-go-go-Related Gene) potassium channels** in the cardiac myocytes [1]. Blocking these channels delays ventricular repolarization, leading to a prolonged QT interval, which significantly increases the risk of life-threatening arrhythmias like **Torsades de Pointes (TdP)** [1]. Due to these serious cardiac side effects, Cisapride has been withdrawn or strictly restricted in many global markets [1]. **Analysis of Options:** * **Domperidone (Option A):** While Domperidone can also prolong the QT interval (especially at high doses or when given IV), it is less frequently associated with fatal arrhythmias compared to Cisapride. In the context of standard NEET-PG questions, Cisapride is the classic "textbook" example of a prokinetic causing this effect. * **Metoclopramide (Option B):** This is a D2 receptor antagonist. It does not significantly affect cardiac potassium channels and is generally considered safe regarding the QT interval. * **Omeprazole (Option D):** As a Proton Pump Inhibitor (PPI), it has no direct effect on cardiac conduction. **High-Yield Clinical Pearls for NEET-PG:** * **Drug Interactions:** The risk of QT prolongation with Cisapride is exponentially increased when co-administered with **CYP3A4 inhibitors** (e.g., Ketoconazole, Erythromycin, Clarithromycin) because they inhibit Cisapride metabolism [2]. * **Other QT Prolonging Drugs:** Remember the mnemonic **"ABCDE"**: **A**ntiarrhythmics (Class IA, III), **B**iotics (Macrolides, Fluoroquinolones), **C**ant Psychotics (Haloperidol), **D**epressants (TCAs), and **E**metics (Ondansetron).

Question 725: Which of the following drugs acts as both a potassium channel opener and a nitric oxide donor?

A. Nicorandil (Correct Answer)
B. Diazoxide
C. Sodium nitroprusside
D. Minoxidil

Explanation: **Explanation:** **Nicorandil** is a unique anti-anginal agent characterized by a **dual mechanism of action**. It contains a nitrate moiety, allowing it to act as a **Nitric Oxide (NO) donor**, which increases cGMP levels leading to systemic venous dilation (preload reduction). Simultaneously, it acts as an **ATP-sensitive Potassium channel (K⁺$_{ATP}$) opener**, causing efflux of potassium, membrane hyperpolarization, and subsequent closure of voltage-gated calcium channels. This results in arterial dilation (afterload reduction). This balanced dilation of both epicardial coronary arteries and peripheral vessels makes it effective in stable angina. **Analysis of Incorrect Options:** * **B. Diazoxide:** This is a potent K⁺$_{ATP}$ channel opener used in hypertensive emergencies and insulinomas (as it inhibits insulin release). However, it lacks NO-donating properties. * **C. Sodium Nitroprusside:** A powerful vasodilator used in hypertensive crises. It acts solely as an NO donor (increasing cGMP) to dilate both arterioles and venules but does not affect potassium channels. * **D. Minoxidil:** A prodrug (converted to minoxidil sulfate) that acts strictly as a K⁺$_{ATP}$ channel opener. It is used for refractory hypertension and topically for alopecia. **High-Yield Clinical Pearls for NEET-PG:** * **Preconditioning:** Nicorandil mimics "ischemic preconditioning," protecting the myocardium during episodes of ischemia. * **Side Effects:** A highly specific and examiner-favorite side effect of Nicorandil is **perianal, oral, or mucosal ulceration**. * **Contraindication:** Like other nitrates, it should not be co-administered with PDE-5 inhibitors (e.g., Sildenafil) due to the risk of severe hypotension.

Question 726: Which of the following drugs can be used for the treatment of hypertension in a diabetic patient, EXCEPT?

A. Losartan
B. Captopril
C. Amlodipine
D. Hydrochlorothiazide (Correct Answer)

Explanation: **Explanation:** In diabetic patients with hypertension, the primary goal of therapy is not only blood pressure control but also **renoprotection** and **metabolic neutrality**. **Why Hydrochlorothiazide (HCTZ) is the correct answer:** Thiazide diuretics like Hydrochlorothiazide are generally avoided as first-line agents in diabetics because they can cause **hyperglycemia** and **dyslipidemia**. They inhibit insulin release from the pancreas and decrease peripheral glucose utilization, leading to worsened glycemic control. Additionally, they can cause hyperuricemia and hypokalemia. While they can be used in low doses as add-on therapy, they are the "least preferred" among the given options for a diabetic patient. **Analysis of other options:** * **Captopril (ACE Inhibitor) & Losartan (ARB):** These are the **drugs of choice** for hypertensive diabetics. They provide significant renoprotection by dilating the efferent arteriole, reducing intraglomerular pressure, and slowing the progression of diabetic nephropathy (reducing albuminuria). * **Amlodipine (Calcium Channel Blocker):** CCBs are metabolically neutral, meaning they do not affect blood glucose or lipid levels. They are excellent second-line agents or alternatives if ACE inhibitors are not tolerated. **NEET-PG High-Yield Pearls:** * **DOC for HTN with Diabetes:** ACE Inhibitors (e.g., Enalapril) or ARBs (e.g., Telmisartan). * **Metabolic effects of Thiazides:** Remember the mnemonic **"Hyper-GLUC"** (Hyper-Glycemia, Hyper-Lipidemia, Hyper-Uricemia, Hyper-Calcemia). * **Beta-blockers in Diabetes:** Use with caution as they can mask the tachycardia associated with hypoglycemia (except for non-selective ones like Propranolol, which can also delay recovery from hypoglycemia). Carvedilol/Nebivolol are preferred if a BB is necessary.

Question 727: What is the mechanism by which aspirin is used in the treatment of myocardial infarction?

A. It inhibits thromboxanes. (Correct Answer)
B. It stimulates prostacyclins.
C. It is a vasodilator.
D. It helps in reducing inflammatory aggregates.

Explanation: ### Explanation **1. Why Option A is Correct:** Aspirin (Acetylsalicylic acid) acts as an **irreversible inhibitor** of the enzyme **Cyclooxygenase-1 (COX-1)** [2]. In platelets, this inhibition prevents the synthesis of **Thromboxane A2 (TXA2)**, a potent vasoconstrictor and inducer of platelet aggregation [2], [4]. Since platelets lack a nucleus, they cannot synthesize new enzymes; thus, the antiplatelet effect lasts for the entire lifespan of the platelet (7–10 days). In the context of Myocardial Infarction (MI), aspirin prevents the enlargement of the coronary thrombus, maintaining some degree of blood flow and reducing mortality [1], [3]. **2. Why Other Options are Incorrect:** * **Option B:** Aspirin does not stimulate prostacyclins (PGI2). In fact, at high doses, it inhibits PGI2 synthesis in vascular endothelium. However, at low doses, its effect is selective for platelet TXA2 [2]. * **Option C:** Aspirin is not a vasodilator. While some NSAIDs affect renal blood flow, aspirin’s primary benefit in MI is antithrombotic, not hemodynamic [1], [2]. * **Option D:** While aspirin has anti-inflammatory properties at high doses, its immediate life-saving benefit in acute MI is due to its **anti-aggregatory** effect on platelets, not the reduction of inflammatory aggregates [4]. **3. NEET-PG High-Yield Pearls:** * **Loading Dose:** In acute MI, a loading dose of **162–325 mg** is given. It should be **chewed** (not swallowed whole) to ensure rapid buccal absorption and faster onset of action. * **Selectivity:** Low-dose aspirin (75–150 mg) is more selective for COX-1 than COX-2 [2]. * **Primary vs. Secondary Prevention:** Aspirin is a cornerstone for secondary prevention of MI and stroke [3]. * **Aspirin Resistance:** Some patients may not respond to aspirin due to genetic polymorphisms or drug interactions (e.g., Ibuprofen can block the aspirin binding site on COX-1).

Question 728: All of the following are true about ACE inhibitors except?

A. Drug of choice for hypertension in Diabetes Mellitus and chronic kidney disease
B. They are contraindicated in Bilateral Renal Artery stenosis
C. Fosinopril is safe in renal failure
D. Captopril & lisinopril are prodrugs (Correct Answer)

Explanation: **Explanation:** The correct answer is **D** because it is a false statement. In pharmacology, most ACE inhibitors are **prodrugs** (e.g., Enalapril, Ramipril, Perindopril) that require hepatic conversion to their active "-at" forms (e.g., Enalaprilat). However, **Captopril and Lisinopril are the two major exceptions; they are active drugs** and do not require metabolism by the liver to exert their effect. **Analysis of other options:** * **Option A:** ACE inhibitors are the **drugs of choice** for HTN in patients with DM and CKD because they are **nephroprotective**. They dilate the efferent arteriole, reducing intraglomerular pressure and decreasing proteinuria. * **Option B:** They are **contraindicated in Bilateral Renal Artery Stenosis (RAS)**. In RAS, glomerular filtration rate (GFR) is maintained by Angiotensin II-mediated constriction of the efferent arteriole. ACE inhibitors block this mechanism, leading to a precipitous drop in GFR and acute renal failure. * **Option C:** Most ACE inhibitors are excreted renally. However, **Fosinopril** (and Spirapril) undergoes balanced hepatobiliary and renal excretion, making it safer in patients with renal impairment as the liver compensates for decreased renal clearance. **High-Yield Clinical Pearls for NEET-PG:** * **Teratogenicity:** ACE inhibitors are contraindicated in pregnancy (cause fetal renal dysgenesis 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 contraindication, **I**ncreased potassium (Hyperkalemia), **L**eukopenia. * **Lisinopril** is the only ACE inhibitor not bound to plasma proteins.

Question 729: Which of the following drugs is used for the reversal of cerebral vasospasm and infarct following subarachnoid hemorrhage?

A. Nimodipine (Correct Answer)
B. Amlodipine
C. Diltiazem
D. Verapamil

Explanation: **Explanation:** **Nimodipine** is the drug of choice for preventing and treating delayed cerebral ischemia (DCI) caused by **cerebral vasospasm** following a subarachnoid hemorrhage (SAH). The underlying medical concept is its **high lipid solubility**, which allows it to cross the blood-brain barrier effectively. Unlike other Calcium Channel Blockers (CCBs), Nimodipine has a specific tropism for cerebral vasculature. It inhibits the influx of calcium into vascular smooth muscle cells, preventing the intense vasoconstriction (vasospasm) that typically occurs 4–14 days after a rupture of a berry aneurysm. **Analysis of Incorrect Options:** * **Amlodipine:** A long-acting dihydropyridine used primarily for systemic hypertension and chronic stable angina. It lacks the cerebrovascular specificity required for SAH. * **Diltiazem:** A benzothiazepine CCB that acts on both the heart and blood vessels. It is used for supraventricular tachycardia and angina but does not provide neuroprotection in SAH. * **Verapamil:** A phenylalkylamine with significant negative inotropic and dromotropic effects. While it can be used intra-arterially by neurosurgeons during procedures, it is not the standard oral prophylactic agent for post-SAH vasospasm. **High-Yield Clinical Pearls for NEET-PG:** * **Timing:** Nimodipine therapy should ideally be started within 96 hours of SAH onset. * **Route:** Usually administered orally (60 mg every 4 hours for 21 days). **Warning:** Never give the contents of the capsule intravenously, as it can cause fatal systemic hypotension. * **Other CCB uses:** Verapamil is the drug of choice for prophylaxis of **Cluster Headache** and **PSVT** (acute management).

Question 730: Which of the following drugs is NOT useful in the management of hypertension?

A. Calcium channel blockers
B. Alpha methyl dopa
C. Beta blockers
D. Pentoxifylline (Correct Answer)

Explanation: **Explanation:** The correct answer is **Pentoxifylline** because it is a hemorheological agent, not an antihypertensive drug. **1. Why Pentoxifylline is the correct answer:** Pentoxifylline is a methylxanthine derivative. Its primary mechanism involves increasing erythrocyte flexibility and reducing blood viscosity by inhibiting phosphodiesterase. It is clinically indicated for **intermittent claudication** in peripheral vascular disease (PVD) to improve blood flow to ischemic limbs. It does not possess significant vasodilatory or sympatholytic properties required to lower systemic blood pressure. **2. Why the other options are incorrect:** * **Calcium Channel Blockers (CCBs):** These are first-line antihypertensives (e.g., Amlodipine). They inhibit L-type calcium channels in vascular smooth muscle, leading to vasodilation and decreased peripheral resistance. * **Alpha Methyl Dopa:** This is a centrally acting sympatholytic. It is converted to alpha-methyl-norepinephrine, which stimulates central $\alpha_2$ receptors, decreasing sympathetic outflow. It is the **drug of choice for hypertension in pregnancy**. * **Beta Blockers:** Drugs like Atenolol or Metoprolol reduce blood pressure by decreasing cardiac output and inhibiting renin release from the juxtaglomerular apparatus. **High-Yield Clinical Pearls for NEET-PG:** * **Pentoxifylline** is also used off-label in severe alcoholic hepatitis to reduce the risk of hepatorenal syndrome (due to its anti-TNF-$\alpha$ effects). * **Cilostazol** (a PDE3 inhibitor) is now preferred over Pentoxifylline for intermittent claudication due to superior efficacy. * **Reserpine** is another historical antihypertensive that works by depleting catecholamine stores (VMAT inhibitor), but it is rarely used now due to the risk of severe depression.

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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