Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 221: Which of the following plasminogen activators (fibrinolytics) can be administered as a bolus dose in patients with acute myocardial infarction?

A. Urokinase
B. Alteplase
C. Reteplase (Correct Answer)
D. None of the above

Explanation: **Explanation:** The correct answer is **Reteplase**. The primary factor determining whether a fibrinolytic can be given as a bolus dose is its **plasma half-life**. **Why Reteplase is correct:** Reteplase is a genetically engineered, non-glycosylated form of recombinant tissue plasminogen activator (rt-PA). It has a longer half-life (approximately 15–18 minutes) compared to native alteplase. This extended duration allows it to be administered as **two intravenous bolus injections** (10 units each, 30 minutes apart) rather than a continuous infusion. This simplifies administration in emergency settings like Acute Myocardial Infarction (AMI). **Why other options are incorrect:** * **Alteplase (rt-PA):** It has a very short half-life (3–5 minutes). Consequently, it requires a complex **"accelerated infusion"** regimen (a small initial bolus followed by a continuous IV infusion over 90 minutes) to maintain therapeutic levels. * **Urokinase:** It is a non-fibrin-specific activator with a short half-life (12–20 minutes) but is traditionally administered via **continuous intravenous infusion** for conditions like pulmonary embolism or peripheral arterial occlusion, rather than a rapid bolus for AMI. **High-Yield NEET-PG Pearls:** 1. **Tenecteplase (TNK-tPA):** This is the most fibrin-specific agent with the longest half-life. It is administered as a **single weight-based IV bolus**, making it the preferred agent for pre-hospital thrombolysis. 2. **Fibrin Specificity:** Alteplase, Reteplase, and Tenecteplase are fibrin-specific (clot-selective), whereas Streptokinase and Urokinase are non-specific (systemic lytic state). 3. **Antigenicity:** Streptokinase is the only highly antigenic agent; it can cause anaphylaxis and cannot be repeated within 6–12 months due to neutralizing antibodies.

Question 222: Which of the following is the drug of choice in treating suicidal overdose of digitoxin?

A. Digibind antibodies (Correct Answer)
B. Lignocaine
C. Magnesium
D. Potassium

Explanation: **Explanation:** **Correct Answer: A. Digibind antibodies** Digibind (Digoxin-specific antibody fragments or Fab) is the definitive antidote and **drug of choice** for life-threatening digitalis toxicity (both Digoxin and Digitoxin). These fragments bind to free glycoside molecules in the extracellular space, creating a complex that is excreted by the kidneys. This rapidly lowers the concentration of free drug, reversing toxic effects like life-threatening arrhythmias and hyperkalemia. **Why incorrect options are wrong:** * **B. Lignocaine:** While Lignocaine is the drug of choice for treating **digitalis-induced ventricular arrhythmias**, it does not treat the underlying toxicity or neutralize the drug. * **C. Magnesium:** Magnesium is useful for managing arrhythmias, especially in patients with low magnesium levels, but it is an adjunctive therapy, not the primary antidote. * **D. Potassium:** Potassium is used to treat digitalis toxicity because it competes with digitalis for the Na+/K+ ATPase pump. However, in **acute suicidal overdose**, patients often present with **hyperkalemia** (due to total pump inhibition). Giving more potassium in this scenario is contraindicated and potentially fatal. **High-Yield Clinical Pearls for NEET-PG:** 1. **Mechanism of Action:** Digitalis inhibits the Na+/K+ ATPase pump, leading to increased intracellular Na+ and subsequently increased intracellular Ca2+ via the Na+/Ca2+ exchanger. 2. **Earliest Symptom:** Anorexia, nausea, and vomiting. 3. **Most Common Arrhythmia:** Ventricular Bigeminy. 4. **Most Characteristic Arrhythmia:** Paroxysmal Atrial Tachycardia (PAT) with AV block. 5. **Visual Disturbance:** Xanthopsia (yellowish-green vision). 6. **Digitoxin vs. Digoxin:** Digitoxin has a longer half-life (~7 days) and is primarily metabolized by the liver, making it "safer" in renal failure compared to Digoxin.

Question 223: Which antihypertensive agent is most commonly associated with causing impotence?

A. Calcium channel blocker
B. ACE inhibitors
C. Angiotensin II receptor antagonists
D. Beta-blockers (Correct Answer)

Explanation: ### Explanation **Correct Option: D. Beta-blockers** **Mechanism of Action:** Beta-blockers (especially non-selective ones like Propranolol) are the antihypertensive class most frequently associated with erectile dysfunction (ED) and decreased libido. The underlying medical concept involves several factors: 1. **Hemodynamics:** By reducing systemic blood pressure and cardiac output, they can decrease the perfusion pressure required for penile tumescence. 2. **Sympathetic Inhibition:** Beta-2 blockade can lead to vasoconstriction of the penile arteries (unopposed alpha-1 activity). 3. **Central Effects:** They may interfere with the central nervous system pathways that mediate sexual arousal. **Analysis of Incorrect Options:** * **A. Calcium Channel Blockers (CCBs):** These are generally considered "neutral" regarding sexual function. While rare cases of ED are reported, they are significantly less common than with beta-blockers or diuretics. * **B. ACE Inhibitors:** These are also considered sexually neutral. By inhibiting Angiotensin II (a vasoconstrictor), they may actually help maintain peripheral blood flow. * **C. Angiotensin II Receptor Antagonists (ARBs):** Interestingly, ARBs (like Losartan) have been shown in some studies to **improve** sexual function and are often the preferred choice for hypertensive patients concerned about impotence. **High-Yield Clinical Pearls for NEET-PG:** * **The "Two Big Culprits":** Among all antihypertensives, **Thiazide diuretics** and **Beta-blockers** are the most common causes of drug-induced impotence. * **Nebivolol Exception:** Unlike older beta-blockers, **Nebivolol** (a highly selective Beta-1 blocker) increases **Nitric Oxide (NO)** release, which causes vasodilation. It is the only beta-blocker that does *not* typically cause ED and may even improve it. * **Management:** If a patient develops ED on a beta-blocker, switching to an **ARB** or **ACE inhibitor** is the standard clinical recommendation.

Question 224: Which calcium channel blocker is used in the treatment of hypertension?

A. Prazosin
B. Lidoflazine
C. Captopril
D. Nifedipine (Correct Answer)

Explanation: ### Explanation **Correct Answer: D. Nifedipine** **Mechanism and Rationale:** Calcium Channel Blockers (CCBs) inhibit the entry of calcium ions through **L-type voltage-gated calcium channels** in vascular smooth muscle and myocardium. **Nifedipine** belongs to the **Dihydropyridine (DHP)** class of CCBs. Its primary action is potent peripheral vasodilation, which reduces total peripheral resistance (TPR), thereby lowering blood pressure. It is a first-line agent for managing chronic hypertension and is also used in Raynaud’s phenomenon. **Analysis of Incorrect Options:** * **A. Prazosin:** This is a selective **alpha-1 ($\alpha_1$) adrenergic blocker**. While it is used for hypertension and Benign Prostatic Hyperplasia (BPH), it is not a calcium channel blocker. * **B. Lidoflazine:** This is a piperazine derivative classified as a calcium channel blocker, but it was historically used as a **coronary vasodilator** for angina, not for the routine treatment of hypertension. It is largely obsolete due to its potential for QT prolongation. * **C. Captopril:** This is an **ACE (Angiotensin-Converting Enzyme) Inhibitor**. It lowers blood pressure by preventing the conversion of Angiotensin I to Angiotensin II, a potent vasoconstrictor. **High-Yield Clinical Pearls for NEET-PG:** * **DHP vs. Non-DHP:** DHPs (Nifedipine, Amlodipine) are potent vasodilators. Non-DHPs (Verapamil, Diltiazem) have significant negative inotropic and chronotropic effects (act on the heart). * **Side Effects:** A common side effect of Nifedipine/Amlodipine is **ankle edema** (due to precapillary vasodilation) and reflex tachycardia. * **Drug of Choice:** CCBs are preferred antihypertensives in elderly patients and those of African descent. * **Nimodipine:** A DHP CCB specifically used to prevent cerebral vasospasm in **Subarachnoid Hemorrhage (SAH)**.

Question 225: Beta-blockers are used in all of the following conditions except?

A. Essential tremors
B. AV block (Correct Answer)
C. Angina pectoris
D. Migraine prophylaxis

Explanation: **Explanation:** The correct answer is **AV block** because beta-blockers are strictly contraindicated in this condition. **1. Why AV block is the correct answer:** Beta-blockers exert **negative dromotropic** effects, meaning they slow down conduction through the Atrioventricular (AV) node by blocking $\beta_1$ receptors. In a patient already suffering from AV block (especially 2nd or 3rd degree), beta-blockers can further depress conduction, potentially leading to complete heart block, severe bradycardia, or asystole. **2. Why other options are incorrect:** * **Essential Tremors:** Propranolol (a non-selective beta-blocker) is the drug of choice. It acts on peripheral $\beta_2$ receptors in the skeletal muscles to reduce the amplitude of tremors. * **Angina Pectoris:** Beta-blockers are first-line agents. They reduce myocardial oxygen demand by decreasing heart rate (negative chronotropy) and contractility (negative inotropy). * **Migraine Prophylaxis:** Propranolol is a first-line agent for preventing migraine attacks (though it does not treat acute attacks). Its mechanism likely involves stabilizing vascular tone and reducing cortical excitability. **Clinical Pearls for NEET-PG:** * **Contraindications (ABCDE):** **A**sthma/COPD, **B**lock (Heart block), **C**onfused states (Depression), **D**iabetes mellitus (masks hypoglycemia), **E**lectrolyte imbalance (Hyperkalemia). * **Drug of Choice:** Propranolol is the DOC for **Performance Anxiety** and **Thyroid Storm** (it inhibits peripheral conversion of T4 to T3). * **Cardioselective Beta-blockers (A to M):** **A**tenolol, **B**isoprolol, **E**smolol (shortest acting), **M**etoprolol. These are preferred in patients with mild COPD or Diabetes.

Question 226: Captopril can cause all of the following except:

A. Decrease in K+ concentration (Correct Answer)
B. Decrease in afterload
C. Proteinuria
D. Blood dyscrasia

Explanation: **Explanation:** **Captopril** is an ACE (Angiotensin-Converting Enzyme) inhibitor. To understand its side effects, one must look at the Renin-Angiotensin-Aldosterone System (RAAS) blockade. **1. Why "Decrease in K+ concentration" is the correct answer:** ACE inhibitors block the conversion of Angiotensin I to Angiotensin II. Since Angiotensin II normally stimulates the adrenal cortex to release **aldosterone**, its inhibition leads to a decrease in aldosterone levels. Aldosterone is responsible for sodium reabsorption and potassium excretion in the distal tubule. Therefore, a decrease in aldosterone results in **potassium retention (Hyperkalemia)**, not a decrease in K+ concentration. **2. Analysis of incorrect options:** * **Decrease in afterload:** Angiotensin II is a potent vasoconstrictor. By blocking its production, ACE inhibitors cause systemic vasodilation, which directly reduces Total Peripheral Resistance (TPR) and afterload. * **Proteinuria:** While ACE inhibitors are generally nephroprotective in diabetics, Captopril (specifically due to its sulfhydryl group) has been associated with membranous glomerulopathy and proteinuria, especially at high doses. * **Blood dyscrasia:** Captopril can rarely cause neutropenia or agranulocytosis, particularly in patients with renal impairment or collagen vascular diseases. **High-Yield Clinical Pearls for NEET-PG:** * **Mnemonic for ACEI side effects (CAPTOPRIL):** **C**ough (due to Bradykinin), **A**ngioedema, **P**roteinuria/ **P**otassium excess, **T**aste changes (dysgeusia), **O**rthostatic hypotension, **P**regnancy contraindicated (Teratogenic), **R**enal artery stenosis (contraindicated), **I**ncreased renin, **L**eukopenia. * **First-dose hypotension** is a common phenomenon with ACE inhibitors. * Captopril is unique among ACE inhibitors because it contains a **sulfhydryl group**, which is linked to the higher incidence of skin rashes and taste disturbances.

Question 227: Which of the following statements is NOT true about nesiritide?

A. It is a brain natriuretic peptide analogue.
B. It is used in acutely decompensated heart failure.
C. It has significant oral absorption. (Correct Answer)
D. It has a short half-life.

Explanation: ### Explanation **Nesiritide** is a recombinant form of human **B-type Natriuretic Peptide (BNP)**. Understanding its pharmacokinetic profile is crucial for NEET-PG. **Why Option C is the correct answer (The False Statement):** Nesiritide is a **polypeptide**. Like insulin or other protein-based drugs, it would be rapidly degraded by proteolytic enzymes in the gastrointestinal tract if taken orally. Therefore, it has **zero oral bioavailability** and must be administered exclusively via the **intravenous (IV)** route. **Analysis of Other Options:** * **Option A:** Nesiritide is indeed a recombinant B-type (Brain) Natriuretic Peptide analogue. It works by increasing intracellular cGMP, leading to smooth muscle relaxation. * **Option B:** Its primary clinical indication is **acutely decompensated heart failure (ADHF)** with dyspnea at rest. It provides "balanced" vasodilation (reducing both preload via venodilation and afterload via arteriodilation) and promotes natriuresis. * **Option D:** It has a very **short half-life** (approximately 18–20 minutes), necessitating administration as an IV bolus followed by a continuous infusion. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Binds to particulate guanylate cyclase receptor (NPR-A), increasing **cGMP**. * **Effects:** Vasodilation, natriuresis (sodium excretion), and diuresis; it lacks direct inotropic effects. * **Major Side Effect:** **Hypotension** is the most common dose-limiting adverse effect. Some studies also suggest a risk of worsening renal function. * **Mnemonic:** **N**esiritide = **N**atriuretic peptide for **N**ew (Acute) heart failure.

Question 228: Metoprolol is preferred over propranolol in some patients because it:

A. causes less cardiac depression
B. is less likely to cause bronchoconstriction (Correct Answer)
C. has both alpha- and beta-adrenoceptor blocking effects
D. is more effective as an antiarrhythmic

Explanation: ### Explanation The core concept behind this question is **β-receptor selectivity**. **1. Why Option B is Correct:** Propranolol is a **non-selective β-blocker**, meaning it blocks both $\beta_1$ (cardiac) and $\beta_2$ (bronchial, vascular, and metabolic) receptors [1]. Blocking $\beta_2$ receptors in the lungs leads to bronchoconstriction, which can be fatal in patients with asthma or COPD. **Metoprolol** is a **cardioselective ($\beta_1$-selective) blocker** [1]. It primarily targets the heart and has significantly less affinity for $\beta_2$ receptors in the airways. Therefore, it is safer (though still used with caution) in patients with reactive airway diseases. **2. Analysis of Incorrect Options:** * **Option A:** Both drugs decrease heart rate and contractility. Since both block $\beta_1$ receptors in the heart, they both cause cardiac depression; metoprolol does not inherently cause "less" depression at therapeutic doses. * **Option C:** Neither metoprolol nor propranolol has $\alpha$-blocking activity. Drugs with both $\alpha$ and $\beta$ blocking effects include **Labetalol** and **Carvedilol**. * **Option D:** Propranolol actually has a stronger membrane-stabilizing effect (quinidine-like action) than metoprolol, though this is clinically relevant only in toxic doses [2]. Metoprolol is not inherently "more effective" as an antiarrhythmic. ### High-Yield NEET-PG Pearls: * **Cardioselective ($\beta_1$) Blockers Mnemonic:** *"New Beta Blockers Act Exclusively At My Heart"* (Nebivolol, Betaxolol, Bisoprolol, Atenolol, Esmolol, Acebutolol, Metoprolol). * **Esmolol:** The shortest-acting $\beta$-blocker (half-life ~9 mins), administered IV for emergency arrhythmias. * **Propranolol:** Highly lipid-soluble, crosses the BBB (used for prophylaxis of migraine and performance anxiety), and inhibits the peripheral conversion of $T_4$ to $T_3$ (used in thyroid storm) [3]. * **Clinical Caution:** Even "selective" $\beta_1$ blockers lose their selectivity at high doses and can trigger bronchospasm.

Question 229: Bosentan is:

A. An endothelin receptor blocker (Correct Answer)
B. An ACE inhibitor
C. A IIb/IIIa receptor blocker
D. None of the above

Explanation: **Explanation:** **Bosentan** is a non-selective, competitive antagonist of **Endothelin-1 (ET-1)** receptors. It blocks both **$ET_A$** and **$ET_B$** receptors. Endothelin-1 is one of the most potent endogenous vasoconstrictors; by blocking its action, Bosentan decreases pulmonary vascular resistance. It is primarily used in the management of **Pulmonary Arterial Hypertension (PAH)** (WHO Group 1) to improve exercise capacity and decrease clinical worsening. **Analysis of Incorrect Options:** * **Option B (ACE Inhibitor):** Drugs in this class (e.g., Enalapril, Lisinopril) inhibit the Angiotensin-Converting Enzyme, preventing the conversion of Angiotensin I to Angiotensin II. They are used for systemic hypertension and heart failure, not pulmonary-specific vasoconstriction pathways. * **Option C (IIb/IIIa receptor blocker):** These are antiplatelet agents (e.g., Abciximab, Eptifibatide, Tirofiban) that block the Glycoprotein IIb/IIIa receptor on platelets, preventing fibrinogen binding and platelet aggregation. **High-Yield Clinical Pearls for NEET-PG:** * **Route:** It is administered orally. * **Adverse Effects:** The most significant side effect is **Hepatotoxicity** (elevation of serum transaminases); therefore, monthly Liver Function Tests (LFTs) are mandatory. * **Teratogenicity:** It is highly teratogenic (Category X) and contraindicated in pregnancy. * **Other Endothelin Antagonists:** * **Ambrisentan:** Selective $ET_A$ receptor antagonist (less hepatotoxic). * **Macitentan:** Tissue-targeting non-selective antagonist with a longer half-life.

Question 230: Propranolol is useful in the treatment of all of the following EXCEPT:

A. Angina
B. Partial atrioventricular block (Correct Answer)
C. Idiopathic hypertrophic subaortic stenosis
D. Familial tremor

Explanation: ### Explanation **Correct Answer: B. Partial atrioventricular block** **Why it is the correct answer:** Propranolol is a non-selective beta-blocker that acts on $\beta_1$ receptors in the heart to decrease heart rate (negative chronotropy) and slow conduction through the atrioventricular (AV) node (negative dromotropy). In patients with **Partial AV block**, the conduction between the atria and ventricles is already impaired. Administering Propranolol can further delay AV conduction, potentially converting a partial block into a **complete heart block** or causing severe bradycardia. Therefore, it is strictly contraindicated in such cases. **Analysis of Incorrect Options:** * **A. Angina:** Propranolol is a first-line drug for chronic stable angina. It reduces myocardial oxygen demand by decreasing heart rate and myocardial contractility. * **C. Idiopathic hypertrophic subaortic stenosis (IHSS/HOCM):** Beta-blockers are the drugs of choice here. By slowing the heart rate and reducing the force of contraction, they increase ventricular filling time and reduce the outflow tract gradient, relieving symptoms. * **D. Familial tremor:** Propranolol is highly effective for essential/familial tremors. It works by blocking peripheral $\beta_2$ receptors in the skeletal muscles that mediate the tremors. **NEET-PG High-Yield Pearls:** * **Membrane Stabilizing Activity (MSA):** Propranolol possesses significant MSA (local anesthetic effect), making it useful in certain arrhythmias but also contributing to its toxicity in overdose. * **Lipid Solubility:** It is highly lipophilic, allowing it to cross the blood-brain barrier (useful for migraine prophylaxis and performance anxiety) but also causing side effects like vivid dreams. * **Contraindications:** Always remember the "ABCDE" of beta-blocker contraindications: **A**sthma/COPD, **B**lock (Heart block), **C**HF (Acute/Decompensated), **D**iabetes (masks hypoglycemia), and **E**xtremity issues (Raynaud's phenomenon).

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

Want unlimited practice?

Get full access to all questions, explanations, and performance tracking.

Start For Free