Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 711: Which of the following is not a first-line antihypertensive medication?

A. Enalapril
B. Hydrochlorothiazide
C. Amlodipine
D. Atenolol (Correct Answer)

Explanation: The correct answer is **Atenolol**. According to current clinical guidelines (JNC 8 and AHA/ACC), **Beta-blockers** are no longer considered first-line agents for the management of primary hypertension in the absence of specific compelling indications (like post-MI or heart failure) [1, 2]. **Why Atenolol is the correct answer:** Clinical trials (such as the ASCOT-BPLA) demonstrated that Beta-blockers, particularly Atenolol, are less effective than other classes in preventing stroke and cardiovascular mortality [2]. They are also associated with an increased risk of new-onset diabetes and are less effective at reducing central aortic pressure compared to peripheral blood pressure. **Why the other options are incorrect:** * **Enalapril (ACE Inhibitor):** ACE inhibitors are first-line agents, especially beneficial in patients with diabetes or chronic kidney disease due to their renoprotective effects. * **Hydrochlorothiazide (Thiazide Diuretic):** Thiazides have long been a cornerstone of first-line therapy, proven to reduce cardiovascular morbidity and mortality effectively [3]. * **Amlodipine (Calcium Channel Blocker):** Dihydropyridine CCBs are highly effective first-line agents, particularly recommended for elderly patients and those of African descent. **High-Yield Clinical Pearls for NEET-PG:** * **First-line ABCD:** **A**CEIs/ARBs, **B**-blockers (only if compelling indications), **C**CBs, and **D**iuretics. * **Compelling Indications for Beta-blockers:** Stable angina, post-Myocardial Infarction, and Heart Failure with reduced Ejection Fraction (HFrEF) [2]. * **Side Effect Note:** Avoid Thiazides in patients with gout (hyperuricemia) and ACEIs in pregnancy (teratogenic).

Question 712: Ivabradine is used for the management of which condition?

A. Stable angina (Correct Answer)
B. Pre-renal azotemia
C. Alzheimer's disease
D. Smoking cessation

Explanation: **Explanation:** **Ivabradine** is a novel anti-anginal drug that acts as a selective and specific inhibitor of the **hyperpolarization-activated cyclic nucleotide-gated (HCN) channels** in the Sinoatrial (SA) node. These channels are responsible for the **cardiac pacemaker current ($I_f$ or "funny" current)**, which determines the slope of spontaneous diastolic depolarization. 1. **Why Stable Angina is Correct:** By inhibiting the $I_f$ current, Ivabradine slows the firing rate of the SA node, leading to a **reduction in heart rate** without affecting myocardial contractility (inotropic state) or systemic blood pressure. This decrease in heart rate reduces myocardial oxygen demand, making it an effective treatment for chronic stable angina in patients who have a contraindication to or intolerance of beta-blockers, or in combination with beta-blockers in patients whose heart rate is inadequately controlled. 2. **Why Other Options are Incorrect:** * **Pre-renal azotemia:** This is a kidney dysfunction caused by decreased blood flow to the kidneys (e.g., dehydration). Ivabradine has no role in renal perfusion. * **Alzheimer’s disease:** Managed with acetylcholinesterase inhibitors (Donepezil) or NMDA antagonists (Memantine). * **Smoking cessation:** Managed with Varenicline, Bupropion, or Nicotine Replacement Therapy (NRT). **High-Yield Clinical Pearls for NEET-PG:** * **Pure Chronotrope:** Unlike beta-blockers, Ivabradine is a "pure" heart rate reducer; it does not cause bronchospasm or mask hypoglycemia. * **Visual Side Effects:** A unique side effect is **luminous phenomena (phosphenes)**—enhanced brightness in a limited area of the visual field—caused by inhibition of $I_h$ channels in the retina. * **Indication in Heart Failure:** It is also used in chronic heart failure (HFrEF) with EF ≤35% and a resting heart rate ≥70 bpm. * **Contraindication:** It is ineffective in patients with **Atrial Fibrillation** because the heart rate is not controlled by the SA node in this condition.

Question 713: All of the following drugs are useful in detrusor instability except?

A. Solefenacin
B. Tolterodine
C. Flavoxate
D. Duloxetine (Correct Answer)

Explanation: **Explanation:** The question asks for the drug NOT used in **detrusor instability** (also known as **Overactive Bladder - OAB** or **Urge Incontinence**). **1. Why Duloxetine is the Correct Answer:** Duloxetine is a Serotonin-Norepinephrine Reuptake Inhibitor (SNRI) [4]. It is used in the management of **Stress Urinary Incontinence (SUI)**, not urge incontinence. It works by increasing the tone of the external urethral sphincter via stimulation of Onuf’s nucleus in the sacral spinal cord. In detrusor instability, the problem is an overactive bladder muscle; Duloxetine does not relax the detrusor. **2. Analysis of Incorrect Options:** * **Solifenacin & Tolterodine:** These are **M3-selective muscarinic antagonists** [1]. Since bladder contraction is mediated by M3 receptors, these drugs are the first-line pharmacological treatment for detrusor instability as they promote bladder relaxation and increase capacity [1], [2]. * **Flavoxate:** This is a tertiary amine with **antispasmodic** properties [3]. It exerts a direct relaxant effect on the smooth muscle of the urinary tract and is indicated for symptomatic relief of bladder spasms [3]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for OAB:** Oxybutynin (non-selective) or Darifenacin/Solifenacin (M3 selective) [2]. * **Mirabegron:** A **Beta-3 (β3) agonist** used for OAB; it relaxes the detrusor muscle during the storage phase. * **Stress Incontinence:** Characterized by leakage during coughing/sneezing. Treatment includes pelvic floor exercises (Kegel's) and Duloxetine. * **Urge Incontinence:** Characterized by a sudden, intense urge to void. Treatment focuses on anticholinergics [1].

Question 714: Which drug is contraindicated in bilateral renal artery stenosis?

A. Propranolol
B. Guanethidine
C. Captopril (Correct Answer)
D. Amlodipine

Explanation: **Explanation:** The correct answer is **Captopril (Option C)**. **Why Captopril is the correct answer:** In patients with **bilateral renal artery stenosis (RAS)**, the perfusion pressure to the kidneys is significantly reduced. To maintain an adequate Glomerular Filtration Rate (GFR), the body relies on the **Renin-Angiotensin-Aldosterone System (RAAS)**. Specifically, Angiotensin II causes **vasoconstriction of the efferent arteriole**, which creates the necessary back-pressure to maintain filtration. Captopril, an ACE inhibitor, prevents the formation of Angiotensin II. This leads to efferent arteriolar vasodilation, a sudden drop in intraglomerular pressure, and subsequent **acute renal failure**. Therefore, ACE inhibitors (and ARBs) are strictly contraindicated in bilateral RAS or RAS in a solitary functioning kidney. **Analysis of Incorrect Options:** * **A. Propranolol:** A non-selective beta-blocker. While it reduces renin release, it does not cause the acute hemodynamic collapse of GFR seen with ACE inhibitors. * **B. Guanethidine:** An older adrenergic neuron blocker. It lowers blood pressure by inhibiting norepinephrine release but does not specifically target the renal autoregulatory mechanism. * **D. Amlodipine:** A Calcium Channel Blocker (CCB). CCBs primarily dilate the *afferent* arteriole and are generally considered safe (and often preferred) in patients with renal artery stenosis. **High-Yield Clinical Pearls for NEET-PG:** * **Diagnostic Clue:** Suspect bilateral RAS if a patient’s serum creatinine rises by **>30%** after starting an ACE inhibitor or ARB. * **Drug of Choice:** CCBs or Beta-blockers are safer alternatives for hypertension in bilateral RAS. * **Teratogenicity:** ACE inhibitors are also contraindicated in pregnancy (Category X) due to fetal renal dysgenesis and skull hypoplasia.

Question 715: Sudden withdrawal of which of the following drugs could result in serious adverse cardiovascular changes in a patient taking the drug over a long time?

A. Phenelzine (MAO inhibitor)
B. Enalapril (ACE inhibitor)
C. Clonidine (α2 agonist) (Correct Answer)
D. Fluoxetine (serotonin reuptake inhibitor)

Explanation: ### Explanation **Correct Option: C. Clonidine** **Mechanism of Withdrawal (Rebound Hypertension):** Clonidine is a centrally acting **$\alpha_2$-adrenergic agonist** that decreases sympathetic outflow from the vasomotor center in the brain. Long-term use leads to **downregulation (desensitization)** of these $\alpha_2$ receptors. When clonidine is suddenly discontinued, the inhibitory control over the sympathetic nervous system is lost. This results in a massive surge of catecholamines (norepinephrine), leading to **Rebound Hypertension**. Symptoms include severe tachycardia, tremors, headache, and anxiety. In extreme cases, this can lead to hypertensive encephalopathy or myocardial infarction. * **Management:** Re-administration of clonidine or treatment with both $\alpha$ and $\beta$ blockers (e.g., Phentolamine + Propranolol). --- ### Analysis of Incorrect Options: * **A. Phenelzine:** As an MAO inhibitor, its primary risk is a "hypertensive crisis" when combined with **tyramine-rich foods** (Cheese reaction), not typically a withdrawal syndrome involving cardiovascular collapse. * **B. Enalapril:** While stopping ACE inhibitors may lead to a gradual rise in blood pressure or worsening of heart failure symptoms, it does not cause an acute, life-threatening sympathetic surge like clonidine. * **D. Fluoxetine:** This SSRI has a very long half-life (due to its active metabolite norfluoxetine). Sudden withdrawal is less likely to cause "Discontinuation Syndrome" compared to shorter-acting SSRIs, and it does not typically manifest as acute cardiovascular instability. --- ### NEET-PG High-Yield Pearls: * **Other drugs causing Rebound Hypertension:** $\beta$-blockers (due to up-regulation of $\beta$-receptors during chronic blockade). * **Clonidine uses:** Hypertension, ADHD, opioid withdrawal, and prophylaxis of migraine. * **Test-taking tip:** If a question mentions "sudden withdrawal" and "cardiovascular changes," always look for **Clonidine** or **$\beta$-blockers** (like Propranolol) first.

Question 716: What is the biochemical mechanism of action of digitalis?

A. An increase in conduction from the atria to the ventricle
B. An increase in ATP synthesis
C. An increase in systolic intracellular calcium levels (Correct Answer)
D. A block of calcium channels

Explanation: Digitalis (Digoxin) is a cardiac glycoside primarily used in the management of congestive heart failure and certain supraventricular arrhythmias. ### **Mechanism of Action** The primary mechanism of digitalis is the **inhibition of the Na⁺/K⁺-ATPase pump** located on the myocardial cell membrane. 1. **Inhibition of the pump** leads to an accumulation of intracellular Sodium (Na⁺). 2. This increase in intracellular Na⁺ reduces the concentration gradient that drives the **Na⁺/Ca²⁺ exchanger (NCX)**. 3. Consequently, less Calcium (Ca²⁺) is extruded from the cell, and more is sequestered into the Sarcoplasmic Reticulum (SR). 4. During the next depolarization, a larger amount of Ca²⁺ is released from the SR, leading to an **increase in systolic intracellular calcium levels**, which enhances myocardial contractility (Positive Inotropy). ### **Analysis of Incorrect Options** * **Option A:** Digitalis actually **decreases** conduction velocity through the AV node (negative dromotropy) due to increased vagal tone. This is why it is used to control ventricular rate in Atrial Fibrillation. * **Option B:** Digitalis does not increase ATP synthesis; it inhibits an ATP-dependent enzyme (Na⁺/K⁺-ATPase). * **Option D:** Digitalis does not block calcium channels; it indirectly increases intracellular calcium availability. ### **NEET-PG High-Yield Pearls** * **Electrolyte sensitivity:** **Hypokalemia** increases digitalis binding to the Na⁺/K⁺-ATPase, predisposing patients to toxicity. Hypercalcemia and hypomagnesemia also worsen toxicity. * **ECG Changes:** The characteristic "reverse tick" or "hockey stick" appearance (ST-segment depression) is a sign of digitalis effect, not necessarily toxicity. * **Toxicity:** The most common symptom is GI upset (nausea/vomiting); the most specific arrhythmia is **Atrial Tachycardia with AV block**. * **Antidote:** Digoxin-specific antibody fragments (DigiFab).

Question 717: Triflusal is a:

A. Anti-inflammatory drug
B. Antibiotic
C. Anti-arthritic drug
D. Antiplatelet drug (Correct Answer)

Explanation: **Explanation:** **Triflusal** is a fluorinated salicylate derivative that acts as a potent **antiplatelet drug**. While it is structurally related to acetylsalicylic acid (Aspirin), its pharmacological profile is distinct. **Why Option D is correct:** Triflusal exerts its antiplatelet effect through two primary mechanisms: 1. **Irreversible inhibition of Cyclooxygenase-1 (COX-1):** This prevents the synthesis of Thromboxane A2 (TXA2), a potent platelet aggregator. 2. **Inhibition of Phosphodiesterase (PDE):** Unlike Aspirin, Triflusal inhibits the enzyme phosphodiesterase, leading to increased levels of cyclic AMP (cAMP) in platelets. This further inhibits platelet activation and promotes vasodilation. Crucially, at therapeutic doses, Triflusal spares the synthesis of **Prostacyclin (PGI2)** in vascular endothelial cells, maintaining a favorable antithrombotic balance with a lower risk of bleeding compared to Aspirin. **Why other options are incorrect:** * **A & C (Anti-inflammatory/Anti-arthritic):** Although it is a salicylate, Triflusal is not used clinically for its anti-inflammatory or analgesic properties. Its use is strictly restricted to the prevention of thromboembolic events. * **B (Antibiotic):** Triflusal has no antimicrobial activity and does not target bacterial structures or protein synthesis. **High-Yield Clinical Pearls for NEET-PG:** * **Indication:** Used for secondary prevention of stroke, myocardial infarction, and unstable angina. * **Active Metabolite:** It is metabolized into **HTB** (2-hydroxy-4-trifluoromethylbenzoic acid), which also possesses antiplatelet activity and has a long half-life (approx. 35 hours). * **Safety Profile:** It is associated with a significantly **lower incidence of gastrointestinal complications** and hemorrhagic events compared to Aspirin, making it a preferred alternative in high-risk patients.

Question 718: Which of the following is NOT true about fibrates?

A. Drug of choice for type III hyperlipoproteinemia and severe hypertriglyceridemia
B. Activate PPAR-alpha to stimulate LPL
C. Absorption is delayed by a fatty meal (Correct Answer)
D. Side effects include rash, urticaria, myalgia, and impotence

Explanation: **Explanation:** Fibrates (e.g., Gemfibrozil, Fenofibrate) are a class of lipid-lowering agents primarily used to target high triglyceride levels. **1. Why Option C is the correct (False) statement:** Contrary to the statement, the absorption of most fibrates is actually **enhanced**, not delayed, by a fatty meal. Fenofibrate, in particular, shows significantly improved bioavailability when taken with food. This is a high-yield pharmacological detail often tested to differentiate it from other drugs where food might impair absorption. **2. Analysis of other options:** * **Option A (True):** Fibrates are the **Drug of Choice (DOC)** for **Type III Hyperlipoproteinemia** (Dysbetalipoproteinemia) and **Severe Hypertriglyceridemia** (TG >500 mg/dL) to prevent acute pancreatitis. * **Option B (True):** Their primary mechanism involves activating **PPAR-alpha** (Peroxisome Proliferator-Activated Receptor-alpha). This leads to increased expression of **Lipoprotein Lipase (LPL)**, which enhances the catabolism of VLDL and triglycerides. * **Option D (True):** Common side effects include GI upset, skin rashes, urticaria, and myalgia. **Impotence** is a documented, though less common, side effect of clofibrate and other members of this class. **Clinical Pearls for NEET-PG:** * **Risk of Myopathy:** The risk of rhabdomyolysis increases significantly when fibrates (especially Gemfibrozil) are combined with **Statins**, as gemfibrozil inhibits the glucuronidation of statins, increasing their plasma levels. * **Gallstones:** Fibrates increase biliary cholesterol excretion, leading to a higher risk of **cholelithiasis** (gallstones). * **Contraindications:** Avoid in patients with severe hepatic or renal dysfunction and gallbladder disease.

Question 719: Enalapril increases the levels of which of the following?

A. Bradykynin (Correct Answer)
B. Interferon
C. Platelet-activating factor (PAF)
D. Tumor necrosis factor (TNF)

Explanation: **Enalapril** is an Angiotensin-Converting Enzyme (ACE) inhibitor. To understand why it increases bradykinin, one must understand the dual role of the ACE enzyme (also known as Kininase II) [2].1. **Mechanism of Action:** In the body, the ACE enzyme has two primary functions: it converts Angiotensin I to Angiotensin II (a potent vasoconstrictor) and it **degrades bradykinin** into inactive metabolites [1]. By inhibiting this enzyme, Enalapril prevents the breakdown of bradykinin, leading to its accumulation in the tissues and blood [1].2. **Clinical Significance:** Increased levels of bradykinin promote vasodilation (via nitric oxide release), contributing to the drug's antihypertensive effect. However, bradykinin accumulation in the lungs is also responsible for the most common side effect of ACE inhibitors: a **dry, persistent cough**, and the more serious (though rare) **angioedema** [1].**Analysis of Incorrect Options:** * **B, C, and D:** Interferon, Platelet-activating factor (PAF), and Tumor necrosis factor (TNF) are inflammatory mediators and cytokines. ACE inhibitors do not have a direct biosynthetic or degradative pathway linked to these substances. While ACE inhibitors may have indirect anti-inflammatory effects over long-term use in heart failure, they do not acutely increase the levels of these specific markers.**NEET-PG High-Yield Pearls:** * **Drug of Choice:** ACE inhibitors are the first-line treatment for hypertension in patients with **Diabetes Mellitus** (due to nephroprotective effects) and **Heart Failure** (due to reversal of ventricular remodeling). * **Side Effects Mnemonic (CAPTOPRIL):** **C**ough, **A**ngioedema, **P**roteinuria, **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis (bilateral) contraindication, **I**ncreased potassium (Hyperkalemia), **L**eukopenia. * **Switching Therapy:** If a patient develops a bradykinin-induced cough, they should be switched to an **ARB (Angiotensin Receptor Blocker)** like Losartan, which does not affect ACE and thus does not increase bradykinin.

Question 720: Which of the following is an indication for the use of eptifibatide?

A. Angina (Correct Answer)
B. HIV
C. Congestive Cardiac Failure
D. Hypertension

Explanation: **Explanation:** **Eptifibatide** is a potent **Glycoprotein (GP) IIb/IIIa receptor antagonist**. It works by reversibly inhibiting the final common pathway of platelet aggregation—the binding of fibrinogen to the GP IIb/IIIa receptors on activated platelets. **Why Angina is Correct:** Eptifibatide is primarily indicated for the management of **Acute Coronary Syndromes (ACS)**, which includes **Unstable Angina** and Non-ST-elevation myocardial infarction (NSTEMI). It is also used in patients undergoing Percutaneous Coronary Intervention (PCI) to prevent thrombotic complications. By preventing platelet thrombus formation, it maintains coronary artery patency and reduces the risk of ischemic events. **Why Other Options are Incorrect:** * **HIV:** This is a viral infection treated with Antiretroviral Therapy (ART), such as Protease Inhibitors or Reverse Transcriptase Inhibitors. Eptifibatide has no antiviral properties. * **Congestive Cardiac Failure (CCF):** CCF is managed with diuretics, ACE inhibitors, beta-blockers, and inotropes. While ACS can lead to CCF, eptifibatide is not a treatment for the heart failure state itself. * **Hypertension:** Hypertension is managed with antihypertensives like CCBs, ACE inhibitors, or Thiazides. Eptifibatide does not lower blood pressure. **NEET-PG High-Yield Pearls:** * **Mechanism:** It is a cyclic heptapeptide derived from rattlesnake venom (Sistrurus miliarius barbouri). * **Classmates:** Other GP IIb/IIIa inhibitors include **Abciximab** (monoclonal antibody - irreversible) and **Tirofiban** (non-peptide - reversible). * **Route:** Administered only via the **intravenous** route. * **Side Effect:** The most significant adverse effect is **bleeding** and occasionally thrombocytopenia. * **Excretion:** It is primarily cleared by the kidneys; dose adjustment is required in renal impairment.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

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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

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