Cardiovascular Drugs — MCQs
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An intravenous injection of a test drug is given to a healthy adult subject. Both blood pressure and total peripheral resistance rise promptly. This is followed immediately by a reduction of heart rate. In repeated experiments, the vasopressor response is not affected by pretreatment with prazosin, but pretreatment with atropine prevents the cardiac chronotropic response. The test drug was most likely which of the following?
What is true about propranolol?
Which drug may aggravate renovascular hypertension?
Which of the following short-acting selective beta-blocker drugs is used in the management of arrhythmia?
All are true about the staging of beta-blocker therapy in a case of Congestive Heart Failure except?
ACE inhibitors should not be used with which of the following drug classes?
Which antihypertensive drugs are beneficial or have a neutral role in lipid metabolism?
A 60-year-old man with rheumatic mitral stenosis and atrial fibrillation is being treated for a fast ventricular rate. While on treatment, he develops a regular pulse of 64 beats/min. Which of the following is the probable drug that the patient is receiving?
Which drug is most useful in cardiogenic shock?
Which of the following anti-arrhythmic agents does not belong to class Ic?
Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs
Question 441: An intravenous injection of a test drug is given to a healthy adult subject. Both blood pressure and total peripheral resistance rise promptly. This is followed immediately by a reduction of heart rate. In repeated experiments, the vasopressor response is not affected by pretreatment with prazosin, but pretreatment with atropine prevents the cardiac chronotropic response. The test drug was most likely which of the following?
- A. Angiotensin II (Correct Answer)
- B. Isoproterenol
- C. Norepinephrine
- D. Epinephrine
Explanation: ### Explanation **1. Analysis of the Correct Answer: Angiotensin II** The drug described causes a prompt rise in blood pressure (BP) and total peripheral resistance (TPR), followed by a decrease in heart rate (HR). This indicates a **reflex bradycardia** triggered by the baroreceptor reflex in response to vasoconstriction. * **Prazosin Resistance:** Prazosin is an $\alpha_1$-blocker. Since the vasopressor response is *not* affected by prazosin, the drug is not acting on $\alpha_1$ receptors. Angiotensin II (AII) causes potent vasoconstriction via **AT1 receptors**, making it independent of adrenergic blockade. * **Atropine Effect:** Atropine blocks the vagus nerve (parasympathetic). Since atropine prevents the drop in HR, it confirms that the bradycardia was a secondary reflex (vagal) rather than a direct drug effect. **2. Why Other Options are Incorrect:** * **B. Isoproterenol:** A potent $\beta_1$ and $\beta_2$ agonist. It decreases TPR (vasodilation) and increases HR (direct $\beta_1$ effect). This contradicts the prompt's findings. * **C. Norepinephrine:** While it causes reflex bradycardia and increases TPR, its vasopressor effect is mediated by $\alpha_1$ receptors. Therefore, the response **would be blocked** or significantly reduced by prazosin. * **D. Epinephrine:** At high doses, it increases BP and TPR. However, like norepinephrine, its vasoconstrictive action is mediated by $\alpha_1$ receptors and would be inhibited by prazosin. **3. High-Yield Clinical Pearls for NEET-PG:** * **Reflex Bradycardia Rule:** Any drug that causes significant vasoconstriction without stimulating $\beta_1$ receptors (e.g., Phenylephrine, Angiotensin II) will cause a reflex decrease in HR. * **Vagal Blockade:** Pretreatment with Atropine or Ganglionic blockers (like Hexamethonium) is the standard experimental method to prove that a change in HR is a reflex rather than a direct effect. * **AT1 Receptor:** Angiotensin II is the most potent endogenous vasoconstrictor; it also stimulates aldosterone release from the adrenal cortex.
Question 442: What is true about propranolol?
- A. Metabolism of propranolol is not dependent on the hepatic blood flow.
- B. Undergoes extensive first pass metabolism. (Correct Answer)
- C. Hydroxylated product of propranolol has alpha blocking property.
- D. Propranolol is lipophobic.
Explanation: **Explanation:** **Correct Answer: B. Undergoes extensive first pass metabolism.** Propranolol is a prototypical non-selective beta-blocker. It is highly lipid-soluble, leading to almost complete absorption ( >90%) from the gut. However, it undergoes **extensive first-pass metabolism** in the liver. Consequently, its systemic bioavailability is low (approximately 25%), and there is significant inter-individual variation in plasma concentrations. This explains why the oral dose of propranolol is much higher than the intravenous dose. **Analysis of Incorrect Options:** * **Option A:** Propranolol is a **high-extraction ratio drug**. Its clearance is highly dependent on **hepatic blood flow** (perfusion-limited elimination). Drugs like cimetidine, which reduce hepatic blood flow, can decrease propranolol clearance. * **Option C:** The primary active metabolite of propranolol is **4-hydroxypropranolol**. This metabolite possesses **beta-blocking activity** (similar to the parent drug), not alpha-blocking property. * **Option D:** Propranolol is highly **lipophilic** (lipid-soluble). This property allows it to readily cross the blood-brain barrier (BBB), leading to central nervous system side effects like sedation, depression, and vivid dreams/nightmares. **High-Yield Clinical Pearls for NEET-PG:** 1. **Membrane Stabilizing Activity (MSA):** Propranolol possesses significant local anesthetic activity (quinidine-like effect) due to sodium channel blockade at high doses. 2. **Thyroid Storm:** It is the drug of choice because it not only controls peripheral sympathetic symptoms but also **inhibits the peripheral conversion of T4 to T3**. 3. **Portal Hypertension:** It is used to prevent esophageal variceal bleeding by reducing portal pressure via splanchnic vasoconstriction (beta-2 blockade). 4. **Contraindications:** Avoid in patients with bronchial asthma, AV blocks, and Prinzmetal angina.
Question 443: Which drug may aggravate renovascular hypertension?
- A. ACE inhibitors (Correct Answer)
- B. Beta blockers
- C. Calcium channel blockers
- D. Thiazide diuretics
Explanation: ### Explanation **Correct Option: A. ACE inhibitors** **Mechanism of Action:** In patients with **Bilateral Renal Artery Stenosis (RAS)** or stenosis in a solitary functioning kidney, the glomerular filtration rate (GFR) is heavily dependent on the **Renin-Angiotensin-Aldosterone System (RAAS)**. Due to reduced renal perfusion pressure, the body compensates by producing Angiotensin II, which causes **vasoconstriction of the efferent arteriole**. This maintains the intraglomerular pressure necessary for filtration. ACE inhibitors (and ARBs) block the production/action of Angiotensin II, leading to **efferent arteriolar vasodilation**. This causes a precipitous drop in intraglomerular pressure, resulting in a sharp decline in GFR and potentially triggering **acute renal failure**. Thus, while they treat systemic hypertension, they aggravate the underlying renal functional status in renovascular disease. **Why other options are incorrect:** * **B. Beta-blockers:** These reduce blood pressure by decreasing cardiac output and renin release. While they are less effective in RAS, they do not acutely compromise the intraglomerular pressure dynamics. * **C. Calcium Channel Blockers (CCBs):** CCBs primarily cause afferent arteriolar dilation. They do not interfere with the efferent compensatory mechanism and are generally considered safe in renal artery stenosis. * **D. Thiazide Diuretics:** These reduce blood volume. While they may activate the RAAS further, they do not directly cause efferent vasodilation or the acute drop in GFR seen with ACE inhibitors. **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:** For **Unilateral RAS**, ACE inhibitors are often used (the healthy kidney compensates). For **Bilateral RAS**, CCBs are preferred. * **Auscultation:** A continuous abdominal bruit is a classic physical sign of renovascular hypertension.
Question 444: Which of the following short-acting selective beta-blocker drugs is used in the management of arrhythmia?
- A. Carvedilol
- B. Esmolol (Correct Answer)
- C. Celiprolol
- D. Bisoprolol
Explanation: **Explanation:** **Esmolol** is the correct answer because it is a **highly cardioselective (Beta-1)** blocker characterized by its **ultra-short duration of action**. It has a half-life of approximately **9 minutes** due to its rapid hydrolysis by **red blood cell esterases** (not plasma cholinesterase). This pharmacokinetic profile makes it the drug of choice for the emergency management of supraventricular tachyarrhythmias, perioperative tachycardia, and hypertensive emergencies where precise, minute-to-minute control is required. **Analysis of Incorrect Options:** * **Carvedilol (Option A):** A non-selective beta-blocker with additional **alpha-1 blocking** and antioxidant properties. It is primarily used in the long-term management of chronic heart failure and hypertension, not for acute arrhythmia control. * **Celiprolol (Option C):** A selective beta-1 blocker with **partial beta-2 agonist** activity (intrinsic sympathomimetic activity). It is unique because it also has vasodilator properties, but it is not short-acting. * **Bisoprolol (Option D):** A highly cardioselective beta-1 blocker with a long half-life. It is a mainstay in the management of stable chronic heart failure (as per the CIBIS trials) and hypertension, but it is not suitable for rapid-onset/offset emergency use. **High-Yield Pearls for NEET-PG:** * **Metabolism:** Esmolol is metabolized by **RBC esterases**; therefore, its action is independent of renal or hepatic function. * **Administration:** It is administered only via **intravenous (IV) infusion**. * **Clinical Use:** Preferred for controlling heart rate in **Atrial Fibrillation/Flutter** during surgery or in the ICU. * **Mnemonic:** Remember **"Esmolol is Extremely short-acting"** (9 minutes).
Question 445: All are true about the staging of beta-blocker therapy in a case of Congestive Heart Failure except?
- A. They should be started with optimal doses. (Correct Answer)
- B. They should be gradually increased over weeks.
- C. Special precautions should be taken in cases of NYHA class III and IV.
- D. Carvedilol and Metoprolol are the preferred drugs.
Explanation: In Congestive Heart Failure (CHF), beta-blockers are essential for reducing mortality and improving remodeling. However, their initiation requires a specific "start low, go slow" approach. **Explanation of the Correct Answer (Option A):** Beta-blockers possess negative inotropic properties. In a failing heart already struggling with contractility, starting with **optimal (high) doses** can lead to acute decompensation and worsening of heart failure. Therefore, they must be started at **very low doses** (e.g., 3.125 mg of Carvedilol) once the patient is clinically stable and euvolemic. **Analysis of Other Options:** * **Option B:** Dose titration is critical. Doses should be **gradually increased** (doubled every 2–4 weeks) only if the patient tolerates the current dose without signs of worsening failure. * **Option C:** Patients in **NYHA Class III and IV** have low cardiac reserve. They require extreme caution, stabilization with diuretics/ACE inhibitors first, and closer monitoring during the "initiation phase" to prevent pulmonary edema. * **Option D:** Large clinical trials (MERIT-HF, COPERNICUS) have proven mortality benefits for specific beta-blockers: **Carvedilol** (non-selective + alpha-blocker), **Metoprolol succinate** (long-acting B1 selective), and **Bisoprolol**. **High-Yield Clinical Pearls for NEET-PG:** * **The "Beta-Blocker Paradox":** While they are contraindicated in *acute* decompensated HF, they are life-saving in *chronic* stable HF. * **Preferred Drugs (MCQ favorite):** Bisoprolol, Carvedilol, Metoprolol succinate, and Nebivolol (specifically in elderly). * **Mechanism:** They prevent "catecholamine toxicity," reduce heart rate (increasing diastolic filling), and inhibit the RAAS pathway.
Question 446: ACE inhibitors should not be used with which of the following drug classes?
- A. Amilorides (Correct Answer)
- B. Calcium channel blockers
- C. Chlorthalidone
- D. All of the above
Explanation: **Explanation:** The correct answer is **Amilorides (Option A)**. **1. Why Amilorides are contraindicated with ACE inhibitors:** ACE inhibitors (e.g., Enalapril, Lisinopril) inhibit the production of Angiotensin II, which leads to a decrease in Aldosterone secretion. Since Aldosterone is responsible for potassium excretion, ACE inhibitors cause potassium retention. **Amiloride** is a potassium-sparing diuretic that works by blocking ENaC channels in the distal tubule. Using these two classes together creates a synergistic effect that significantly increases the risk of **life-threatening hyperkalemia**. **2. Why other options are incorrect:** * **Calcium Channel Blockers (Option B):** Drugs like Amlodipine are frequently combined with ACE inhibitors (e.g., for hypertension management). This combination is beneficial as ACE inhibitors can reduce the peripheral edema often caused by CCBs. * **Chlorthalidone (Option C):** This is a thiazide-like diuretic. Thiazides cause potassium loss (hypokalemia). Combining them with ACE inhibitors is a common clinical practice because the potassium-retaining effect of the ACE inhibitor offsets the potassium-wasting effect of the diuretic, maintaining electrolyte balance. **High-Yield Clinical Pearls for NEET-PG:** * **The "K-Sparing" Rule:** Never combine ACE inhibitors, ARBs, or Direct Renin Inhibitors (Aliskiren) with potassium-sparing diuretics (Amiloride, Spironolactone, Triamterene) or potassium supplements without rigorous monitoring. * **Teratogenicity:** ACE inhibitors are strictly contraindicated in pregnancy (cause fetal renal dysgenesis and skull hypoplasia). * **Side Effect Profile:** 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 (bilateral) contraindication, **I**ncreased potassium (**Hyperkalemia**), **L**eukopenia.
Question 447: Which antihypertensive drugs are beneficial or have a neutral role in lipid metabolism?
- A. Prazosin and Losartan (Correct Answer)
- B. Prazosin and Chlorthiazide
- C. Propranolol
- D. Furosemide
Explanation: **Explanation:** The impact of antihypertensive drugs on lipid profiles is a high-yield topic for NEET-PG, as clinicians must choose metabolic-friendly drugs for patients with co-existing dyslipidemia or diabetes. **1. Why Option A is Correct:** * **Prazosin (Alpha-1 Blockers):** These are unique among antihypertensives because they actually **improve** the lipid profile. They decrease LDL and triglycerides while increasing HDL (the "good" cholesterol). They also improve insulin sensitivity. * **Losartan (ARBs):** Angiotensin Receptor Blockers (ARBs) and ACE inhibitors are considered **metabolically neutral**. They do not adversely affect lipid levels or glucose tolerance, making them first-line choices in patients with metabolic syndrome. **2. Why Other Options are Incorrect:** * **Option B (Chlorthiazide):** Thiazide diuretics are notorious for causing **metabolic derangements**, including hyperlipidemia (increased LDL and VLDL) and hyperglycemia (impaired glucose tolerance). * **Option C (Propranolol):** Non-selective Beta-blockers (like Propranolol) generally have a negative impact on lipids. They can **increase triglycerides** and **decrease HDL** levels by inhibiting lipoprotein lipase. * **Option D (Furosemide):** Like Thiazides, Loop diuretics can cause a transient increase in serum cholesterol and triglycerides, although their effect is generally less pronounced than Thiazides. **Clinical Pearls for NEET-PG:** * **Lipid-Friendly:** Alpha-blockers (Prazosin), Calcium Channel Blockers (Amlodipine), and ACEIs/ARBs. * **Lipid-Unfriendly:** Thiazides and older Beta-blockers (Propranolol, Atenolol). * **Exception:** Vasodilating beta-blockers like **Carvedilol** and **Nebivolol** are generally metabolically neutral compared to Propranolol. * **Mnemonic:** "ACEs and ARBs are neutral; Alphas are beneficial."
Question 448: A 60-year-old man with rheumatic mitral stenosis and atrial fibrillation is being treated for a fast ventricular rate. While on treatment, he develops a regular pulse of 64 beats/min. Which of the following is the probable drug that the patient is receiving?
- A. Verapamil
- B. Digoxin (Correct Answer)
- C. Carvedilol
- D. Propranolol
Explanation: ### Explanation The correct answer is **Digoxin (Option B)**. **Mechanism and Clinical Reasoning:** In a patient with **Atrial Fibrillation (AF)**, the pulse is characteristically "irregularly irregular" because the AV node is bombarded by disorganized atrial impulses. When a patient on treatment for AF develops a **regular pulse**, it is a classic sign of **Digoxin Toxicity**. Digoxin increases vagal tone, slowing AV conduction to control the ventricular rate. However, at toxic levels, it can cause high-grade AV block (leading to a slow rate) combined with increased automaticity of the junctional or ventricular pacemakers. This results in a **regularized rhythm** (e.g., Junctional Tachycardia or accelerated idioventricular rhythm) despite the underlying AF. This phenomenon is often referred to as "regularization of the pulse" in AF. **Why Other Options are Incorrect:** * **Verapamil (CCB), Carvedilol, and Propranolol (Beta-blockers):** These drugs are used for rate control in AF by increasing the refractory period of the AV node. While they slow the heart rate, the rhythm remains **irregularly irregular** because they do not typically induce the junctional escape rhythms or complete heart block seen in digoxin toxicity. **High-Yield Clinical Pearls for NEET-PG:** * **ECG in Digoxin Toxicity:** The most common arrhythmia is **PVCs** (Bigeminy); the most characteristic/specific is **Atrial Tachycardia with AV block**. * **Electrolyte Triggers:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose to digoxin toxicity. * **Drug Interactions:** Quinidine, Verapamil, and Amiodarone increase digoxin levels by displacing it from tissue binding sites or reducing renal clearance. * **Visual Side Effect:** Xanthopsia (yellowish-green vision).
Question 449: Which drug is most useful in cardiogenic shock?
- A. Dopamine (Correct Answer)
- B. Dobutamine
- C. Noradrenaline
- D. Adrenaline
Explanation: **Explanation:** In the management of **cardiogenic shock**, the primary goal is to improve cardiac output and maintain vital organ perfusion (especially renal blood flow) without excessively increasing myocardial oxygen demand [4]. **Why Dopamine is the correct answer:** Dopamine is traditionally considered the drug of choice because of its **dose-dependent receptor activity**. At low doses (0.5–2 µg/kg/min), it acts on **D1 receptors**, causing renal and mesenteric vasodilation (improving renal perfusion) [3]. At moderate doses (2–10 µg/kg/min), it stimulates **β1 receptors**, exerting a potent positive inotropic effect that increases cardiac output. This dual action of increasing contractility while protecting renal function makes it highly effective in shock states. **Analysis of Incorrect Options:** * **Dobutamine:** While it is a potent inotrope (β1 agonist), it often causes peripheral vasodilation (β2 effect), which can lead to a further drop in blood pressure (hypotension) in an already shocked patient [2]. It is preferred in "cold and wet" heart failure where BP is stable [4]. * **Noradrenaline:** This is a potent α1 agonist used primarily in **septic shock** to increase systemic vascular resistance [1]. In cardiogenic shock, it is usually reserved for cases where dopamine fails to maintain MAP, as it increases afterload. * **Adrenaline:** Though it increases heart rate and contractility, it significantly increases myocardial oxygen consumption and the risk of arrhythmias, making it a second-line agent. **High-Yield Clinical Pearls for NEET-PG:** * **Dopamine Dose Rule:** Low (D1 - Renal), Medium (β1 - Heart), High (α1 - Vasoconstriction). * **Drug of Choice for Septic Shock:** Noradrenaline. * **Drug of Choice for Anaphylactic Shock:** Adrenaline (IM). * **Fenoldopam:** A selective D1 agonist used in hypertensive emergencies to maintain renal perfusion.
Question 450: Which of the following anti-arrhythmic agents does not belong to class Ic?
- A. Tocainide (Correct Answer)
- B. Encainide
- C. Flecainide
- D. Propafenone
Explanation: ### Explanation The classification of anti-arrhythmic drugs is based on the **Vaughan-Williams Classification**, which categorizes drugs according to their primary mechanism of action on the cardiac action potential. **1. Why Tocainide is the Correct Answer:** **Tocainide** belongs to **Class Ib** anti-arrhythmics. Class Ib agents are weak sodium channel blockers that decrease the duration of the action potential and shorten the refractory period. They specifically bind to sodium channels in the inactivated state and dissociate rapidly. Other drugs in this class include Lidocaine and Mexiletine. **2. Analysis of Incorrect Options (Class Ic Agents):** Class Ic drugs are the most potent sodium channel blockers. They significantly decrease the slope of Phase 0 depolarization and have little to no effect on the action potential duration. * **Encainide:** A classic Class Ic agent (though largely discontinued due to pro-arrhythmic risks). * **Flecainide:** A prototype Class Ic drug used for supraventricular tachycardias (SVT) and atrial fibrillation in patients without structural heart disease. * **Propafenone:** A Class Ic agent that also possesses weak beta-blocking activity. **3. High-Yield NEET-PG Clinical Pearls:** * **Mnemonic for Class I:** "**D**ouble **P**yramids **Q**uickly" (Ia: Disopyramide, Procainamide, Quinidine); "**L**etters **M**ake **T**ext" (Ib: Lidocaine, Mexiletine, Tocainide); "**F**ries **P**lease **E**at" (Ic: Flecainide, Propafenone, Encainide). * **CAST Trial Warning:** The Cardiac Arrhythmia Suppression Trial (CAST) showed that Class Ic drugs (Flecainide/Encainide) increase mortality in patients with a history of myocardial infarction or structural heart disease. * **Class Ib Specificity:** These drugs are most effective in **ischemic tissues** because they bind preferentially to depolarized/inactivated sodium channels.
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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