Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 91: What are the ECG changes seen in digitalis toxicity?

A. T wave inversion
B. Diminished T wave amplitude (Correct Answer)
C. Conduction block
D. ST depression

Explanation: **Explanation:** Digitalis (Digoxin) has a narrow therapeutic index, and its effects on the ECG are categorized into "Digitalis Effect" (therapeutic) and "Digitalis Toxicity" (toxic). **Why Option B is correct:** The earliest and most characteristic ECG change associated with digitalis is a **decrease in the amplitude of the T wave**. As digitalis shortens the action potential duration and accelerates repolarization, the T wave becomes flattened or even biphasic. While other changes occur, diminished T-wave amplitude is a classic early finding in the progression toward toxicity. **Analysis of Incorrect Options:** * **A. T wave inversion:** While T wave inversion can occur, it is less specific than the flattening/diminished amplitude and is often part of the "Salvador Dali" ST-segment sagging rather than an isolated finding of toxicity. * **C. Conduction block:** Although digitalis increases vagal tone and can cause AV blocks (a sign of toxicity), it is a later manifestation compared to the initial repolarization changes. * **D. ST depression:** Therapeutic digitalis use typically causes a characteristic "scooped" or "hockey stick" ST-segment depression (Salvador Dali appearance). While seen in toxicity, it is also a common finding at therapeutic levels, making it less specific for "toxicity" alone compared to the progression of T-wave changes. **High-Yield Clinical Pearls for NEET-PG:** * **Most common arrhythmia in toxicity:** Ventricular Bigeminy. * **Most characteristic/pathognomonic arrhythmia:** Atrial Tachycardia with AV block. * **Electrolyte triggers:** Hypokalemia, Hypomagnesemia, and Hypercalcemia predispose to toxicity. * **Visual disturbance:** Xanthopsia (yellow-green halos) is a classic non-cardiac symptom. * **Antidote:** Digoxin-specific antibody fragments (DigiFab).

Question 92: Which of the following antihypertensive medications can cause impotence?

A. ACE inhibitors, Propranolol, Atenolol
B. Propranolol, Atenolol, Nifedipine (Correct Answer)
C. ACE inhibitors, Atenolol
D. Propranolol, Nifedipine

Explanation: **Explanation:** The correct answer is **B (Propranolol, Atenolol, Nifedipine)**. Sexual dysfunction, specifically erectile dysfunction (impotence), is a well-documented side effect of several classes of antihypertensive drugs. **1. Why Option B is Correct:** * **Beta-Blockers (Propranolol, Atenolol):** These are the most common culprits. They cause impotence through multiple mechanisms: reducing central sympathetic outflow, causing peripheral vasoconstriction (via $\beta_2$ blockade), and potentially lowering testosterone levels. Non-selective blockers (Propranolol) generally have a higher incidence than cardioselective ones (Atenolol), but both are implicated. * **Calcium Channel Blockers (Nifedipine):** While less common than with beta-blockers or diuretics, dihydropyridine CCBs like Nifedipine have been associated with impotence in clinical practice and trials. **2. Analysis of Incorrect Options:** * **ACE Inhibitors (Options A & C):** These are considered "sexually neutral" or even beneficial. By blocking Angiotensin II (a vasoconstrictor), they may improve penile blood flow. Therefore, options containing ACE inhibitors are incorrect. * **Option D:** While both drugs cause impotence, this option is less comprehensive than Option B, which includes Atenolol—another major causative agent. **3. NEET-PG High-Yield Pearls:** * **Most Common Offenders:** Thiazide diuretics (e.g., Chlorthalidone) and Beta-blockers are the two classes most frequently associated with erectile dysfunction. * **The "Safe" Drugs:** ACE inhibitors, ARBs (especially **Losartan**, which may improve sexual function), and Nebivolol (a $\beta_1$ blocker that increases Nitric Oxide) are preferred in patients concerned about sexual side effects. * **Centrally Acting Drugs:** Clonidine and Methyldopa also have high rates of causing impotence due to their effect on the CNS.

Question 93: What is the primary route of administration for glyceryl trinitrate for acute angina relief?

A. Oral
B. Submucosal
C. Rectal
D. Sublingual (Correct Answer)

Explanation: Explanation: 1. Why Sublingual is Correct: Glyceryl Trinitrate (GTN) is the drug of choice for the immediate relief of an acute anginal attack. The sublingual route is preferred because the oral mucosa is highly vascular, allowing the drug to bypass the portal circulation [1]. This avoids the extensive first-pass metabolism (nearly 90%) that occurs in the liver [1]. It ensures a rapid onset of action (1–3 minutes), providing quick vasodilation of coronary arteries and peripheral veins, which reduces cardiac preload and myocardial oxygen demand [2]. 2. Why Other Options are Incorrect: * Oral: GTN has very low bioavailability when swallowed due to significant hepatic first-pass metabolism [1]. While sustained-release oral nitrates exist for prophylaxis, they are ineffective for acute relief. * Submucosal: While similar to sublingual, it is not the standard clinical practice for GTN administration. Sublingual placement (under the tongue) offers the most rapid absorption surface. * Rectal: Although this route bypasses some first-pass metabolism, it is clinically impractical, socially unacceptable for this indication, and has a much slower absorption rate compared to the sublingual route. 3. High-Yield Clinical Pearls for NEET-PG: * Storage: GTN is volatile and light-sensitive; it must be stored in dark-colored glass bottles with tight metal caps. * Patient Counseling: Patients should be told to sit down before taking the dose to avoid orthostatic hypotension and syncope. * Tolerance: To prevent "nitrate tolerance," a nitrate-free interval of 8–12 hours (usually at night) is required [2]. * Contraindication: Never co-administer with Sildenafil (PDE-5 inhibitors) as it can lead to life-threatening hypotension.

Question 94: What is the treatment of hypertensive crisis in pheochromocytoma?

A. Phentolamine (Correct Answer)
B. Hydralazine
C. Guanethidine
D. Salmeterol

Explanation: **Explanation:** **1. Why Phentolamine is Correct:** Pheochromocytoma is a catecholamine-secreting tumor (epinephrine and norepinephrine) that causes severe hypertension via massive stimulation of **alpha-1 receptors**. **Phentolamine** is a potent, non-selective, competitive **alpha-adrenergic blocker**. It directly antagonizes the effects of circulating catecholamines on blood vessels, leading to rapid vasodilation and a decrease in blood pressure. It is the drug of choice for managing hypertensive crises during surgery or whenever catecholamine excess is suspected. **2. Why the Other Options are Incorrect:** * **Hydralazine:** While it is a direct vasodilator used in hypertensive emergencies (especially in pregnancy), it does not address the underlying catecholamine surge in pheochromocytoma and can cause reflex tachycardia. * **Guanethidine:** This is a post-ganglionic adrenergic neuron blocker. It is contraindicated because it initially causes a release of stored norepinephrine, which would dangerously worsen a pheochromocytoma crisis. * **Salmeterol:** This is a long-acting beta-2 agonist (LABA) used for asthma and COPD. It has no role in blood pressure management and could potentially worsen tachycardia. **3. NEET-PG High-Yield Pearls:** * **The "Alpha-First" Rule:** In pheochromocytoma, **always** give an alpha-blocker (e.g., Phenoxybenzamine for long-term, Phentolamine for crisis) *before* a beta-blocker. Giving a beta-blocker first leads to "unopposed alpha stimulation," causing a catastrophic rise in blood pressure. * **Phenoxybenzamine:** The preferred drug for preoperative management (irreversible alpha-blocker). * **Diagnosis:** Best initial screening test is urinary or plasma **metanephrines**.

Question 95: What is the drug of choice for bradycardia due to beta-blocker overdose?

A. Atropine (Correct Answer)
B. Dopamine
C. Adrenaline
D. Isoprenaline

Explanation: **Explanation:** **1. Why Atropine is the Correct Answer:** In the initial management of symptomatic bradycardia—regardless of the cause (including beta-blocker overdose)—**Atropine** is the first-line drug of choice. Atropine is a competitive muscarinic antagonist that blocks the parasympathetic (vagal) input to the SA and AV nodes. By inhibiting the vagus nerve, it increases the heart rate and improves conduction. In the context of beta-blocker toxicity, it serves as the immediate pharmacological intervention to stabilize the patient's heart rate. **2. Why Other Options are Incorrect:** * **Dopamine & Adrenaline:** These are vasopressors/inotropes used if the patient remains hypotensive or bradycardic *after* initial treatment with Atropine and fluids. They are not the first-line "drug of choice" for the bradycardia itself. * **Isoprenaline:** While it is a pure beta-agonist that can increase heart rate, its effects are often competitively blocked by the overdose of beta-blockers, making it less effective. It may also cause peripheral vasodilation, potentially worsening hypotension. **3. High-Yield Clinical Pearls for NEET-PG:** * **The Specific Antidote:** While Atropine is the first-line for *bradycardia*, the **specific antidote** for severe Beta-blocker toxicity (especially if refractory to Atropine) is **Glucagon**. Glucagon increases intracellular cAMP via non-adrenergic receptors, bypassing the blocked beta-receptors. * **Management Hierarchy:** 1. Atropine (Initial) 2. Glucagon (Specific Antidote) 3. High-dose Insulin Euglycemia Therapy (HIET) 4. Cardiac Pacing (if pharmacological therapy fails). * **Membrane Stabilizing Activity (MSA):** Propranolol overdose is particularly dangerous due to its sodium channel blocking effect, which can cause QRS widening (treated with Sodium Bicarbonate).

Question 96: Ivabradine is used in the treatment of which condition?

A. Ventricular arrhythmia
B. Angina (Correct Answer)
C. Atrial arrhythmia
D. Hypertension

Explanation: **Explanation:** **Ivabradine** is a unique cardiovascular drug that acts as a selective and specific inhibitor of the **cardiac pacemaker $I_f$ current** (the "funny" current) in the sinoatrial (SA) node. **1. Why Angina is Correct:** By inhibiting the $I_f$ current, Ivabradine slows the firing rate of the SA node, leading to a **dose-dependent reduction in heart rate**. Unlike beta-blockers, it reduces heart rate without affecting myocardial contractility (inotropy) or ventricular repolarization. In chronic stable angina, this reduction in heart rate decreases myocardial oxygen demand and increases diastolic perfusion time, effectively relieving ischemic symptoms. It is particularly useful in patients who have contraindications to beta-blockers (e.g., asthma). **2. Why Other Options are Incorrect:** * **Ventricular/Atrial Arrhythmias:** Ivabradine is not an anti-arrhythmic drug. It does not affect sodium, potassium, or calcium channels involved in tachyarrhythmias. In fact, it is ineffective in atrial fibrillation because the heart rate is not controlled by the SA node in that condition. * **Hypertension:** Ivabradine has no effect on peripheral vascular resistance or systemic blood pressure; therefore, it plays no role in treating hypertension. **3. High-Yield NEET-PG Pearls:** * **Mechanism:** Selective $I_f$ current inhibitor in the SA node. * **Clinical Use:** Chronic stable angina and Chronic Heart Failure (NYHA Class II-IV) with LVEF ≤ 35% in patients in sinus rhythm with a resting HR ≥ 70 bpm. * **Side Effects:** The most characteristic side effect is **luminous phenomena (phosphenes)**—enhanced brightness in limited areas of the visual field—caused by the inhibition of $I_h$ currents in the retina. * **Requirement:** The patient **must be in sinus rhythm** for the drug to be effective.

Question 97: What is the half-life of digoxin?

A. 24 hours
B. 40 hours (Correct Answer)
C. 48 hours
D. 60 hours

Explanation: **Explanation:** **Digoxin** is a cardiac glycoside used in the management of heart failure and atrial fibrillation. Its pharmacokinetic profile is a high-yield topic for NEET-PG. 1. **Why 40 hours is correct:** The average elimination half-life ($t_{1/2}$) of digoxin in a healthy individual with normal renal function is approximately **36 to 40 hours**. Because of this relatively long half-life, it takes about 5 to 7 days (4–5 half-lives) to reach a steady-state plasma concentration if a constant daily maintenance dose is started without a loading dose. 2. **Analysis of Incorrect Options:** * **24 hours (A):** This is too short for digoxin. However, it is closer to the half-life of *Digitoxin* in species with rapid metabolism, though in humans, Digitoxin lasts much longer (5–7 days). * **48 hours (C) & 60 hours (D):** While the half-life of digoxin can extend to 48–60 hours or more in patients with **renal impairment**, these are not the standard physiological values for a healthy adult. **High-Yield Clinical Pearls for NEET-PG:** * **Excretion:** Digoxin is primarily excreted **unchanged by the kidneys**. Therefore, the dose must be strictly reduced in patients with renal failure to prevent toxicity. * **Volume of Distribution:** It has a very high $V_d$ (approx. 6–7 L/kg) because it binds extensively to skeletal muscle (Na+/K+ ATPase). It is **not** removed by dialysis. * **Therapeutic Window:** It has a narrow therapeutic index (0.5–2 ng/mL). * **Toxicity Factors:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose a patient to digoxin toxicity. The most common initial symptom of toxicity is anorexia/nausea, while the most characteristic arrhythmia is **Non-paroxysmal AV junctional tachycardia** and the most common is **PVCs**.

Question 98: A 42-year-old man presents with dizziness on standing, and his systolic blood pressure falls by 50 mm Hg. What is the recommended initial management?

A. Gradual application of stockings and compression (Correct Answer)
B. Isoprenaline infusion
C. Fludrocortisone
D. Oral indomethacin

Explanation: The patient presents with Orthostatic (Postural) Hypotension, defined as a reduction in systolic blood pressure of at least 20 mm Hg or diastolic blood pressure of at least 10 mm Hg within 3 minutes of standing. A drop of 50 mm Hg is significant and requires immediate intervention.Why Option A is Correct:The initial management of orthostatic hypotension always begins with non-pharmacological measures. Gradual application of compression stockings and abdominal binders increases venous return (preload) by preventing peripheral pooling of blood in the lower extremities. Other first-line measures include increasing salt/fluid intake and rising slowly from a supine position.Analysis of Incorrect Options:* Option B (Isoprenaline): This is a non-selective beta-agonist used in bradycardia or heart block. It can actually worsen hypotension by causing beta-2 mediated vasodilation.* Option C (Fludrocortisone): This is a potent mineralocorticoid and the pharmacological drug of choice for chronic orthostatic hypotension. However, it is not the initial step; lifestyle and mechanical interventions must be tried first.* Option D (Oral Indomethacin): While NSAIDs can increase blood pressure by inhibiting prostaglandin-mediated vasodilation, they are not standard therapy and carry significant gastrointestinal and renal risks.NEET-PG High-Yield Pearls:* Midodrine (alpha-1 agonist) is an alternative pharmacological treatment if fludrocortisone is insufficient or contraindicated. Droxidopa, a synthetic precursor of norepinephrine, is recently approved for neurogenic orthostatic hypotension [1].* Common Causes: Autonomic neuropathy (Diabetes), drugs (alpha-blockers, diuretics, TCAs), and volume depletion.* Droxidopa: A synthetic precursor of norepinephrine recently approved for neurogenic orthostatic hypotension.

Question 99: Monday disease is associated with exposure to which of the following substances?

A. Verapamil
B. Nitroglycerine (Correct Answer)
C. Benzodiazepines
D. Propranolol

Explanation: **Explanation:** **Monday Disease** is a classic occupational phenomenon historically observed in workers in explosives and munitions factories who were chronically exposed to organic nitrates like **Nitroglycerine**. **1. Why Nitroglycerine is Correct:** The mechanism involves the development of **tachyphylaxis (rapid tolerance)**. Workers exposed to high concentrations of nitrates during the week experience systemic vasodilation, leading to headaches and dizziness. By Friday, they develop tolerance to these effects. However, after a weekend away from the factory (losing the exposure), the tolerance disappears. Upon returning to work on **Monday**, the re-exposure causes sudden, intense vasodilation, resulting in severe "Monday headaches" and tachycardia. Chronic exposure can also lead to "Monday morning sudden death" due to coronary artery spasms caused by compensatory vasoconstriction during withdrawal. **2. Why Incorrect Options are Wrong:** * **Verapamil:** A Calcium Channel Blocker (CCB) used for hypertension and arrhythmias. While it causes vasodilation, it is not associated with industrial exposure or the specific "Monday disease" cycle. * **Benzodiazepines:** These are sedative-hypnotics acting on GABA receptors. Withdrawal can cause rebound insomnia or anxiety, but it does not follow the nitrate-specific industrial pattern. * **Propranolol:** A non-selective Beta-blocker. Abrupt withdrawal can cause "Beta-blocker withdrawal syndrome" (rebound hypertension/tachycardia), but it is unrelated to the nitrate-induced Monday disease. **Clinical Pearls for NEET-PG:** * **Nitrate Tolerance:** To prevent tolerance in clinical practice, a **"Nitrate-free interval"** of 8–12 hours (usually at night) is mandatory. * **Mechanism:** Nitrates are prodrugs that release **Nitric Oxide (NO)**, which increases **cGMP**, leading to dephosphorylation of myosin light chains and vascular smooth muscle relaxation. * **Drug Interaction:** Never co-administer nitrates with **Sildenafil** (PDE-5 inhibitors) as it can lead to life-threatening hypotension.

Question 100: Which beta-blocker possesses antioxidant properties?

A. Celiprolol
B. Carvedilol (Correct Answer)
C. Betaxolol
D. Propranolol

Explanation: **Explanation:** **Carvedilol** is a unique, third-generation non-selective beta-blocker that also possesses alpha-1 ($\alpha_1$) blocking activity. Its **antioxidant properties** stem from its ability to scavenge free radicals and inhibit lipid peroxidation. This effect is attributed to its carbazole ring structure. By reducing oxidative stress and inhibiting the expression of adhesion molecules, carvedilol provides a "vasoprotective" effect, making it a cornerstone in the management of chronic heart failure (CHF) as it prevents remodeling. **Analysis of Incorrect Options:** * **A. Celiprolol:** A third-generation $\beta_1$-selective blocker with $\beta_2$-agonist and weak $\alpha_2$-blocking activity. It is known for its vasodilatory properties but lacks significant antioxidant effects. * **C. Betaxolol:** A cardioselective ($\beta_1$) blocker primarily used in glaucoma (topical) and hypertension. It does not possess antioxidant or vasodilatory properties. * **D. Propranolol:** A first-generation, non-selective beta-blocker. While it is highly lipid-soluble and has membrane-stabilizing activity, it does not have antioxidant capabilities. **High-Yield Clinical Pearls for NEET-PG:** * **Third-Generation Beta-Blockers:** Divided into Non-selective (Carvedilol, Labetalol) and $\beta_1$-selective (Nebivolol, Betaxolol, Celiprolol). * **Nebivolol:** Another third-generation blocker that causes vasodilation specifically via **Nitric Oxide (NO) release**. * **Heart Failure Trio:** The three beta-blockers proven to reduce mortality in CHF are **Carvedilol, Metoprolol succinate, and Bisoprolol.** * **Metabolic Profile:** Carvedilol is "metabolically neutral" or may improve insulin sensitivity, unlike older beta-blockers which can worsen glycemic control.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

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Antianginal Agents

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Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

Practice Questions

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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