Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 691: Which is the longest-acting beta-blocker?

A. Nadolol (Correct Answer)
B. Esmolol
C. Carvedilol
D. Acebutolol

Explanation: **Explanation:** **Nadolol** is the correct answer because it has the longest half-life among all beta-blockers, typically ranging from **14 to 24 hours**. It is a non-selective beta-adrenergic antagonist that is not metabolized by the liver and is excreted unchanged by the kidneys. This prolonged duration of action allows for convenient once-daily dosing, which is particularly useful in the long-term management of hypertension and angina pectoris. **Analysis of Incorrect Options:** * **Esmolol:** This is the **shortest-acting** beta-blocker. It has an ultra-short half-life of approximately **9 minutes** due to rapid hydrolysis by red blood cell esterases. It is administered intravenously for acute situations like supraventricular tachycardia or intraoperative hypertension. * **Carvedilol:** A non-selective beta-blocker with alpha-1 blocking activity. Its half-life is approximately **7–10 hours**, making it intermediate-acting. It is primarily used in chronic heart failure. * **Acebutolol:** A cardioselective beta-blocker with intrinsic sympathomimetic activity (ISA). Its half-life is about **3–4 hours**, though its active metabolite (diacetolol) lasts longer (8–12 hours). **High-Yield Clinical Pearls for NEET-PG:** * **Longest Acting:** Nadolol (Half-life ~20 hours). * **Shortest Acting:** Esmolol (Half-life ~9 minutes). * **Lipid Solubility:** Propranolol is highly lipid-soluble (crosses BBB, causes vivid dreams); Nadolol and Atenolol are highly water-soluble (low CNS side effects). * **Intrinsic Sympathomimetic Activity (ISA):** Pindolol and Acebutolol (useful in patients with bradycardia who require beta-blockade). * **Drug of Choice for Aortic Dissection:** Esmolol (due to rapid titration) or Labetalol.

Question 692: Low doses of aspirin used in myocardial infarction act by which mechanism?

A. Inhibiting thromboxane synthetase
B. Inhibiting cyclooxygenase (Correct Answer)
C. Releasing endothelial-derived relaxing factor (EDRF)
D. High protein binding activity

Explanation: **Explanation:** Aspirin (Acetylsalicylic acid) is a cornerstone in the management of myocardial infarction. Its primary mechanism is the **irreversible inhibition of the enzyme Cyclooxygenase (COX-1)**. It achieves this by acetylating a serine residue at the active site of the enzyme. In low doses (75–150 mg), aspirin selectively inhibits COX-1 in platelets. This prevents the conversion of arachidonic acid into **Thromboxane A2 (TXA2)**, a potent vasoconstrictor and platelet aggregator. Because platelets are anuclear, they cannot synthesize new enzymes; thus, the inhibitory effect lasts for the entire lifespan of the platelet (8–11 days), providing a sustained antithrombotic effect. **Analysis of Incorrect Options:** * **Option A:** Aspirin inhibits the COX enzyme, which is upstream of **thromboxane synthetase**. While TXA2 levels drop, the drug does not directly bind to the synthetase enzyme. * **Option C:** EDRF (Nitric Oxide) causes vasodilation, but its release is not the primary mechanism by which low-dose aspirin prevents coronary thrombosis. * **Option D:** While aspirin does bind to plasma proteins (albumin), this is a pharmacokinetic property, not the pharmacodynamic mechanism of action for its antiplatelet effect. **High-Yield Clinical Pearls for NEET-PG:** * **Dose-Dependent Selectivity:** At low doses, aspirin inhibits TXA2 (pro-thrombotic) without significantly affecting **Prostacyclin (PGI2)** (anti-thrombotic) produced by vascular endothelium, as endothelial cells can regenerate COX enzymes. * **Primary/Secondary Prevention:** Low-dose aspirin is used for secondary prevention of MI and stroke. * **Zero-order Kinetics:** At high/toxic doses (salicylism), aspirin metabolism shifts from first-order to zero-order kinetics.

Question 693: Antihypertensives may act by blocking all of the following except?

A. Alpha adrenoceptors
B. ATP dependent potassium channels (Correct Answer)
C. Noradrenaline release
D. Beta adrenoceptors

Explanation: To understand this question, one must distinguish between **blocking** a channel/receptor and **activating** it to achieve a therapeutic effect. ### 1. Why Option B is Correct (The Concept) Antihypertensives do not work by *blocking* ATP-dependent potassium ($K_{ATP}$) channels; instead, they act as **Potassium Channel Openers** [2]. * **Mechanism:** Drugs like **Minoxidil, Diazoxide, and Nicorandil** open these channels, leading to an efflux of $K^+$ ions [2]. * **Result:** This causes membrane hyperpolarization, which prevents the opening of voltage-gated calcium channels, leading to smooth muscle relaxation and potent vasodilation. * **Note:** Blocking these channels (e.g., by Sulfonylureas) actually leads to depolarization and is used in treating Diabetes Mellitus, not hypertension. ### 2. Why Other Options are Incorrect * **Alpha adrenoceptors (A):** Drugs like **Prazosin and Phenoxybenzamine** block $\alpha_1$ receptors, preventing vasoconstriction and lowering peripheral resistance [1], [5]. * **Noradrenaline release (C):** Adrenergic neuron blockers like **Guanethidine and Reserpine** act by inhibiting the release or storage of noradrenaline, thereby reducing sympathetic tone [3]. * **Beta adrenoceptors (D):** Drugs like **Propranolol and Atenolol** block $\beta_1$ receptors in the heart (reducing cardiac output) and the kidney (reducing renin release) [1], [5]. ### 3. High-Yield Clinical Pearls for NEET-PG * **Minoxidil Side Effect:** Can cause **hypertrichosis** (excessive hair growth), hence its use in topical formulations for alopecia. * **Diazoxide Side Effect:** Can cause **hyperglycemia** because opening $K_{ATP}$ channels in pancreatic beta cells inhibits insulin release. * **Drug of Choice:** For hypertensive emergencies in pregnancy, **Labetalol** (alpha + beta blocker) is preferred; for aortic dissection, **Esmolol** is often used [4].

Question 694: Which of the following is NOT a true statement about clonidine?

A. It increases parasympathetic outflow.
B. It decreases sympathetic outflow by blocking central alpha receptors.
C. It is used in the management of hypertension.
D. Prazosin is used to antagonize its side effects. (Correct Answer)

Explanation: **Explanation** **Clonidine** is a centrally acting **$\alpha_2$-adrenergic agonist**. Its primary mechanism involves stimulating $\alpha_2$ receptors in the vasomotor center of the medulla, which leads to a decrease in sympathetic outflow and a compensatory increase in parasympathetic (vagal) tone. **Why Option D is the Correct Answer (The False Statement):** Prazosin is a selective **$\alpha_1$-blocker**. It does not antagonize the side effects of clonidine. In fact, if clonidine is abruptly withdrawn, it causes a "rebound hypertension" crisis due to a massive surge in catecholamines. While $\alpha$-blockers (like phentolamine) are used to manage this withdrawal, prazosin is not the specific antidote for clonidine's general side effects (such as sedation or xerostomia). Furthermore, combining these drugs can lead to complex hemodynamic interactions rather than simple antagonism. **Analysis of Incorrect Options:** * **Option A:** True. By reducing sympathetic drive, clonidine shifts the autonomic balance, leading to an increase in parasympathetic (vagal) outflow, which contributes to bradycardia. * **Option B:** True. Clonidine acts as an agonist at central $\alpha_2$ receptors (presynaptic), which inhibits the release of norepinephrine, thereby decreasing sympathetic outflow. * **Option C:** True. Clonidine is a well-established antihypertensive agent, though now primarily used as a second-line treatment or in resistant hypertension. **High-Yield Clinical Pearls for NEET-PG:** * **Rebound Hypertension:** Sudden cessation of clonidine causes a hypertensive crisis. It must be tapered slowly. * **Other Uses:** Management of opioid withdrawal, ADHD, nicotine cessation, and prophylaxis for migraine. * **Side Effects:** Dry mouth (xerostomia), sedation, and mental depression are the most common limiting factors. * **Diagnostic Test:** The **Clonidine Suppression Test** is used to diagnose Pheochromocytoma (clonidine fails to suppress plasma catecholamines in these patients).

Question 695: What is the preferred drug for the treatment of a 48-year-old man with uncomplicated grade 2 hypertension without any associated comorbidity?

A. Chlorthalidone (Correct Answer)
B. Triamterene
C. Spironolactone
D. Furosemide

Explanation: **Explanation:** The management of uncomplicated Grade 2 hypertension (BP ≥160/100 mmHg) in a patient without comorbidities follows the JNC-8 and AHA/ACC guidelines. The first-line pharmacological agents include **Thiazide-type diuretics**, ACE inhibitors, ARBs, or Calcium Channel Blockers (CCBs). **Why Chlorthalidone is correct:** Among diuretics, **Chlorthalidone** is the preferred agent over Hydrochlorothiazide (HCTZ). It is a "thiazide-like" diuretic with a significantly longer half-life (40–60 hours) and higher potency. Clinical trials (like ALLHAT) have demonstrated its superior efficacy in providing 24-hour blood pressure control and reducing cardiovascular morbidity and mortality. **Analysis of Incorrect Options:** * **B. Triamterene:** This is a potassium-sparing diuretic. It has weak antihypertensive efficacy when used alone and is typically used in combination with thiazides to prevent hypokalemia. * **C. Spironolactone:** An aldosterone antagonist used primarily in resistant hypertension, heart failure, or primary aldosteronism. It is not a first-line agent for uncomplicated hypertension due to side effects like gynecomastia. * **D. Furosemide:** A loop diuretic. While potent for fluid overload (edema, heart failure), it has a short duration of action and is less effective than thiazides for sustained blood pressure control in patients with normal renal function. **High-Yield Clinical Pearls for NEET-PG:** * **Thiazide Side Effects:** Remember the "Hyper" mnemonic: **Hyper**glycemia, **Hyper**lipidemia, **Hyper**uricemia, and **Hyper**calcemia. Conversely, they cause **Hypo**kalemia and **Hypo**natremia. * **Renal Function:** Thiazides lose efficacy when GFR is <30 mL/min (except Metolazone and Indapamide); in such cases, Loop diuretics are preferred. * **Drug of Choice:** For hypertension with **Osteoporosis**, thiazides are ideal because they decrease urinary calcium excretion.

Question 696: Why is Clopidogrel preferred over Ticlopidine?

A. Cost
B. Drug interaction
C. Side effect (Correct Answer)
D. Efficacy

Explanation: **Explanation:** Clopidogrel and Ticlopidine are both **P2Y12 receptor antagonists** (thienopyridines) that inhibit ADP-induced platelet aggregation. While they share a similar mechanism of action, **Clopidogrel is preferred primarily due to its superior safety profile.** **1. Why "Side effect" is the correct answer:** Ticlopidine is associated with severe, potentially life-threatening hematological toxicities, most notably **neutropenia** (occurring in ~1% of patients), agranulocytosis, and **Thrombotic Thrombocytopenic Purpura (TTP)**. Because of these risks, patients on Ticlopidine require frequent blood count monitoring (CBC) every two weeks for the first three months. Clopidogrel, a second-generation thienopyridine, has a much lower incidence of these bone marrow suppressive effects and TTP, making it safer for long-term clinical use. **2. Why other options are incorrect:** * **Cost:** Clopidogrel was historically more expensive, though both are now available as generics. Cost is rarely the deciding factor for clinical preference in standard guidelines. * **Drug Interaction:** Clopidogrel actually has significant drug interactions (e.g., with **Omeprazole**, which inhibits CYP2C19, the enzyme required to activate Clopidogrel). This is a disadvantage, not a reason for its preference. * **Efficacy:** Both drugs have comparable antiplatelet efficacy, but the toxicity of Ticlopidine limits its utility. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Both are **irreversible** inhibitors of the P2Y12 ADP receptor. * **Prodrug Status:** Both are prodrugs requiring hepatic activation via the Cytochrome P450 system (specifically **CYP2C19** for Clopidogrel). * **Prasugrel:** A third-generation thienopyridine that is more potent and has a faster onset than Clopidogrel. * **Ticagrelor:** A **reversible** P2Y12 inhibitor (not a thienopyridine) that does not require metabolic activation.

Question 697: All of the given drugs are positive inotropes EXCEPT?

A. Dopamine
B. Dobutamine
C. Digoxin
D. Doxepin (Correct Answer)

Explanation: The correct answer is **Doxepin**. This question tests your ability to distinguish between cardiovascular drugs and psychotropic medications with similar-sounding names. **1. Why Doxepin is the correct answer:** Doxepin is a **Tricyclic Antidepressant (TCA)**, not a cardiovascular drug [4]. It primarily acts by inhibiting the reuptake of norepinephrine and serotonin in the CNS [4]. Unlike the other options, it does not have a primary role as a positive inotrope. In fact, in toxic doses, TCAs like doxepin are known for their **cardiotoxic effects**, including sodium channel blockade which can lead to arrhythmias and myocardial depression. **2. Why the other options are incorrect:** * **Dopamine:** An endogenous catecholamine that acts on $\beta_1$ receptors (at moderate doses) to increase myocardial contractility (positive inotropy) and on $\alpha_1$ receptors (at high doses) for vasoconstriction. * **Dobutamine:** A synthetic catecholamine and a relatively selective **$\beta_1$ agonist**. It is the drug of choice for cardiogenic shock due to its potent positive inotropic effect with less chronotropic (heart rate) increase compared to dopamine. * **Digoxin:** A cardiac glycoside that inhibits the **$Na^+/K^+$ ATPase pump** [1]. This leads to an increase in intracellular calcium, resulting in a powerful positive inotropic effect used in heart failure and atrial fibrillation [1], [2]. **Clinical Pearls for NEET-PG:** * **Inotropic Mechanism:** Remember that Dopamine/Dobutamine work via **cAMP** elevation [3], while Digoxin works via **Sodium-Calcium exchange** inhibition [1], [2]. * **Dopamine Dosing:** Low dose (D1 receptors - renal vasodilation), Medium dose ($\beta_1$ - inotropy), High dose ($\alpha_1$ - vasoconstriction). * **Look-alike/Sound-alike (LASA):** Do not confuse **Doxepin** (TCA) with **Digoxin** (Inotrope) or **Doxazosin** ($\alpha_1$ blocker).

Question 698: Alteplase is a/an:

A. Anticoagulant
B. Antithrombotic
C. Fibrinolytic (Correct Answer)
D. Anti-fibrinolytic

Explanation: **Explanation:** **Alteplase** is a recombinant form of human **tissue Plasminogen Activator (t-PA)**. It is classified as a **Fibrinolytic** (or Thrombolytic) because it directly converts the inactive zymogen, plasminogen, into the active enzyme **plasmin**. Plasmin then degrades the fibrin meshwork of an existing clot into soluble fibrin degradation products (FDPs), effectively "dissolving" the thrombus. **Analysis of Options:** * **Option A (Anticoagulant):** These drugs (e.g., Heparin, Warfarin) prevent the *formation* of new clots by inhibiting the coagulation cascade. They cannot dissolve a clot that has already formed. * **Option B (Antithrombotic):** This is a broad umbrella term that includes both antiplatelets and anticoagulants. While fibrinolytics are technically antithrombotic, "Fibrinolytic" is the more specific and accurate pharmacological classification. * **Option D (Anti-fibrinolytic):** These drugs (e.g., Tranexamic acid, Epsilon-aminocaproic acid) *inhibit* plasminogen activation to prevent clot breakdown and are used to control bleeding. They have the opposite effect of Alteplase. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Alteplase is **clot-specific**; it preferentially activates plasminogen bound to fibrin, theoretically causing less systemic lytic state compared to Streptokinase. * **Indications:** Acute Ischemic Stroke (within 3–4.5 hours), ST-Elevation Myocardial Infarction (STEMI), and massive Pulmonary Embolism. * **Antidote:** In cases of severe bleeding due to Alteplase overdose, **Tranexamic acid** or **Aminocaproic acid** is used. * **Other Fibrinolytics:** Reteplase, Tenecteplase (longest half-life, given as a single bolus), and Streptokinase (non-specific, antigenic).

Question 699: Dysgeusia is a side effect of which of the following medications?

A. Captopril (Correct Answer)
B. Enalapril
C. Ramipril
D. Lisinopril

Explanation: **Explanation:** **Captopril** is the correct answer because it is the only ACE inhibitor in the options that contains a **sulfhydryl (-SH) group**. This chemical structure is directly responsible for specific side effects not commonly seen with other ACE inhibitors, most notably **dysgeusia** (distortion of taste) and skin rashes. The sulfhydryl group can interfere with taste bud function or lead to a metallic taste. **Analysis of Options:** * **A. Captopril (Correct):** As the prototype ACE inhibitor, its sulfhydryl group is the culprit for dysgeusia and occasionally neutropenia. * **B, C, and D (Enalapril, Ramipril, Lisinopril):** These are non-sulfhydryl-containing ACE inhibitors. While they share the class side effects (like dry cough and angioedema), they are significantly less likely to cause taste disturbances. Enalapril and Ramipril are prodrugs, whereas Captopril and Lisinopril are active drugs. **High-Yield Clinical Pearls for NEET-PG:** 1. **Captopril Unique Features:** It has the shortest half-life among ACE inhibitors (requires frequent dosing) and must be taken on an empty stomach as food decreases its bioavailability. 2. **Class Side Effects (Mnemonic: CAPTOPRIL):** **C**ough (due to bradykinin), **A**ngioedema, **P**roteinuria, **T**aste changes (Dysgeusia), **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis (contraindicated in bilateral), **I**ncreased Potassium (Hyperkalemia), **L**eukopenia. 3. **Drug of Choice:** ACE inhibitors are the first-line treatment for hypertension in patients with **Diabetes Mellitus** because they provide renoprotection by dilating the efferent arteriole.

Question 700: Which of the following drugs is a known cause of chronic cough?

A. Captopril (Correct Answer)
B. Domperidone
C. Cimetidine
D. Celecoxib

Explanation: **Explanation:** **Captopril** is an **ACE (Angiotensin-Converting Enzyme) Inhibitor**. The primary mechanism behind the chronic dry cough associated with ACE inhibitors involves the breakdown of kinins. ACE is identical to **Kininase II**, the enzyme responsible for degrading **Bradykinin** and **Substance P**. When ACE is inhibited, these inflammatory peptides accumulate in the upper respiratory tract and lungs, stimulating sensory C-fibers and inducing a persistent, non-productive cough. This side effect occurs in approximately 5–20% of patients and is a "class effect," though it is most classically associated with Captopril in exams. **Analysis of Incorrect Options:** * **Domperidone:** A peripheral dopamine (D2) receptor antagonist used as an antiemetic and prokinetic. It does not affect the respiratory system. * **Cimetidine:** An H2-receptor antagonist used for peptic ulcers. While it has many side effects (like gynecomastia due to anti-androgenic effects), chronic cough is not one of them. * **Celecoxib:** A selective COX-2 inhibitor (NSAID). While NSAIDs can occasionally trigger "aspirin-exacerbated respiratory disease" (bronchospasm) in sensitive individuals, they are not a standard cause of chronic dry cough. **NEET-PG High-Yield Pearls:** * **Management:** If a patient develops an ACEI-induced cough, the drug should be stopped. The cough typically resolves within 1–4 weeks. * **Alternative:** Switch the patient to an **ARB (Angiotensin Receptor Blocker)** like Losartan, as ARBs do not interfere with bradykinin metabolism. * **Other Side Effects of ACEIs:** Remember the mnemonic **CAPTOPRIL**: **C**ough, **A**ngioedema, **P**roteinuria/ **P**otassium excess (Hyperkalemia), **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis contraindication, **I**ncreased renin, **L**eukopenia.

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