Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 911: A patient suffering from thyrotoxicosis is given propranolol. Which of the following is not controlled by propranolol in this patient?

A. Anxiety
B. Tachycardia
C. Tremor
D. Oxygen consumption (Correct Answer)

Explanation: **Explanation:** In thyrotoxicosis, there is an over-expression of beta-adrenergic receptors and increased sensitivity to catecholamines. Propranolol, a non-selective beta-blocker, is the drug of choice for the symptomatic management of hyperthyroidism [1]. **1. Why "Oxygen Consumption" is the correct answer:** The increase in **Basal Metabolic Rate (BMR)** and oxygen consumption in thyrotoxicosis is a direct effect of thyroid hormones ($T_3$ and $T_4$) on the mitochondria and the $Na^+/K^+$ ATPase pump. Since this is a metabolic effect rather than a sympathomimetic one, beta-blockers like propranolol cannot reverse or control the increased oxygen consumption or the underlying hypermetabolic state. **2. Why the other options are incorrect:** * **Tachycardia & Palpitations:** These are mediated by $\beta_1$ receptors in the heart. Propranolol effectively reduces heart rate [2]. * **Tremors & Anxiety:** These are mediated by $\beta_2$ receptors (skeletal muscle) and central nervous system effects [1]. Propranolol is highly lipid-soluble, allowing it to cross the blood-brain barrier to reduce anxiety and peripheral tremors [2]. **Clinical Pearls for NEET-PG:** * **Peripheral Conversion:** Propranolol is unique among beta-blockers because, in high doses, it inhibits the enzyme **5'-deiodinase**, which prevents the peripheral conversion of $T_4$ to the more active $T_3$ [1]. * **Thyroid Storm:** Propranolol is a mainstay in treating thyroid storm to control life-threatening cardiovascular symptoms [1]. * **Alternative:** If a patient has asthma (contraindication for propranolol), **Diltiazem** (a Calcium Channel Blocker) can be used to control tachycardia.

Question 912: Calcium channel blockers are used in all except?

A. Angina
B. Arrhythmia
C. Congestive heart failure (Correct Answer)
D. Hypertension

Explanation: **Explanation:** The correct answer is **Congestive Heart Failure (CHF)**. **1. Why CCBs are generally avoided in CHF:** Calcium Channel Blockers (CCBs), particularly the non-dihydropyridines (Verapamil and Diltiazem), possess significant **negative inotropic effects**. In patients with systolic heart failure (reduced ejection fraction), these drugs can further depress myocardial contractility, leading to clinical worsening and increased mortality [1]. While certain long-acting dihydropyridines (like Amlodipine) are considered "neutral" and can be used for comorbid hypertension in CHF, they are not a primary treatment for the heart failure itself [1]. **2. Why the other options are incorrect:** * **Angina:** CCBs are first-line agents. They reduce myocardial oxygen demand by decreasing afterload (dihydropyridines) and heart rate (non-dihydropyridines), and increase oxygen supply by causing coronary vasodilation [2]. This is especially useful in **Prinzmetal/Variant angina** [2]. * **Arrhythmia:** Class IV antiarrhythmics (Verapamil and Diltiazem) are highly effective for supraventricular tachycardias (SVT) and rate control in Atrial Fibrillation by slowing conduction through the AV node [3]. * **Hypertension:** CCBs are one of the four primary classes of antihypertensives. They cause peripheral vasodilation, reducing systemic vascular resistance [3]. **Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** CCBs are the DOC for **Prinzmetal Angina** [2] and **Prophylaxis of Cluster Headaches** (Verapamil). * **Nimodipine:** Specifically used in **Subarachnoid Hemorrhage** to prevent cerebral vasospasm [1]. * **Side Effects:** Amlodipine frequently causes **ankle edema** (due to precapillary vasodilation), while Verapamil is notorious for causing **constipation** [4]. * **Contraindication:** Avoid non-dihydropyridines in patients with **Wolff-Parkinson-White (WPW) syndrome** with Atrial Fibrillation.

Question 913: Propranolol is useful in all except?

A. Atrial flutter
B. Parkinsonian tremor (Correct Answer)
C. Thyrotoxicosis
D. Hypertrophic obstructive cardiomyopathy (HOCM)

Explanation: **Explanation:** The correct answer is **B. Parkinsonian tremor**. **1. Why Parkinsonian tremor is the correct answer:** Propranolol is a non-selective beta-blocker. While it is the drug of choice for **Essential tremor** (which is a postural/action tremor), it is ineffective for **Parkinsonian tremor**. Parkinsonian tremor is a "resting tremor" caused by a dopamine-acetylcholine imbalance in the basal ganglia. It requires dopaminergic agents (like Levodopa) or anticholinergics (like Trihexyphenidyl), not beta-blockade. **2. Analysis of incorrect options:** * **Atrial flutter:** Propranolol is a Class II antiarrhythmic. It decreases the ventricular rate by slowing conduction through the AV node, making it useful in supraventricular tachycardias. * **Thyrotoxicosis:** Propranolol is used to control symptoms (tachycardia, palpitations, tremors) and uniquely inhibits the peripheral conversion of T4 to the more active T3. * **HOCM:** Beta-blockers are first-line therapy. They increase ventricular filling time (by slowing heart rate) and reduce the outflow gradient by decreasing the force of contraction (negative inotropy), thereby relieving symptoms. **3. High-Yield Clinical Pearls for NEET-PG:** * **Essential Tremor:** Propranolol is the gold standard treatment. * **Performance Anxiety:** Propranolol is used to prevent the physical symptoms of stage fright. * **Portal Hypertension:** Propranolol is used for the primary prophylaxis of esophageal variceal bleeding. * **Contraindications:** Always remember the "ABCDE" contraindications for Propranolol: **A**sthma/COPD, **B**lock (Heart block), **C**onstrictive peripheral vascular disease (Raynaud's), **D**iabetes (masks hypoglycemia), and **E**lectrolyte imbalances (specifically hyperkalemia).

Question 914: Which drug is indicated in the management of subarachnoid hemorrhage?

A. Nimodipine (Correct Answer)
B. Amlodipine
C. Diltiazem
D. Verapamil

Explanation: **Explanation:** **Nimodipine** is the drug of choice for the management of subarachnoid hemorrhage (SAH). The primary rationale for its use is the prevention and treatment of **delayed cerebral ischemia (DCI)** caused by secondary vasospasm, which typically occurs 4–14 days after the initial bleed. * **Mechanism:** Nimodipine is a second-generation dihydropyridine calcium channel blocker (CCB). It is highly **lipophilic**, allowing it to readily cross the blood-brain barrier. It has a high affinity for cerebral blood vessels, where it prevents the influx of calcium into vascular smooth muscle, thereby reducing vasospasm and providing neuroprotection. **Why other options are incorrect:** * **Amlodipine:** While also a dihydropyridine, it is primarily used for systemic hypertension and chronic stable angina. It lacks the specific cerebrovascular selectivity and lipophilicity required to effectively manage SAH. * **Diltiazem & Verapamil:** These are non-dihydropyridine CCBs. They have significant negative inotropic and chronotropic effects on the heart. While they cause some vasodilation, they are not indicated for SAH and are primarily used for arrhythmias (SVT) and angina. **High-Yield Clinical Pearls for NEET-PG:** * **Route & Timing:** Nimodipine should be started within 96 hours of SAH onset and continued for 21 days. * **Administration:** It is ideally given **orally**. If given IV, it requires central line monitoring to avoid severe hypotension. * **The "Triple H" Therapy:** Historically, SAH was managed with Hypervolemia, Hypertension, and Hemodilution; however, Nimodipine remains the pharmacological mainstay for improving neurological outcomes. * **Side Effect:** The most common side effect to monitor is systemic hypotension.

Question 915: Which of the following is NOT a hypolipidemic drug?

A. Simvastatin
B. Fenofibrate
C. Somatostatin (Correct Answer)
D. Fluvastatin

Explanation: ### Explanation The correct answer is **C. Somatostatin**. **1. Why Somatostatin is the correct answer:** Somatostatin is a **regulatory peptide hormone**, not a lipid-lowering agent. It is produced in the hypothalamus, pancreas (delta cells), and GI tract. Its primary function is inhibitory; it inhibits the release of growth hormone (GH), thyroid-stimulating hormone (TSH), insulin, glucagon, and various gastrointestinal hormones. In clinical practice, synthetic analogs like **Octreotide** are used to treat acromegaly, carcinoid syndrome, and esophageal varices. It has no direct role in lowering serum cholesterol or triglycerides. **2. Analysis of incorrect options:** * **Simvastatin (A) and Fluvastatin (D):** These belong to the **HMG-CoA Reductase Inhibitors** class (Statins). They are the first-line drugs for hypercholesterolemia. They work by inhibiting the rate-limiting enzyme in cholesterol synthesis, leading to an increase in LDL-receptor expression on hepatocytes. * **Fenofibrate (B):** This is a **Fibric acid derivative (Fibrate)**. Fibrates act as agonists at the **PPAR-α** (Peroxisome Proliferator-Activated Receptor-alpha) receptor. They primarily lower triglycerides by increasing the activity of lipoprotein lipase (LPL). **3. High-Yield NEET-PG Pearls:** * **Statins:** Most common side effects include myalgia and increased liver enzymes. **Pitavastatin** is the most potent, while **Rosuvastatin** has the longest half-life. * **Fibrates:** Drug of choice for **severe hypertriglyceridemia** (to prevent pancreatitis). * **Ezetimibe:** Inhibits cholesterol absorption via the **NPC1L1** transporter in the intestine. * **PCSK9 Inhibitors (Evolocumab):** Monoclonal antibodies that significantly lower LDL by preventing LDL-receptor degradation.

Question 916: Hydroxyethyl starch is used as:

A. Plasma expander (Correct Answer)
B. Inotropic agent
C. Vasodilator
D. Type of dextran

Explanation: **Explanation:** **Hydroxyethyl starch (HES)** is a synthetic colloid derived from amylopectin. It is primarily used as a **plasma expander** to restore circulating blood volume in patients with hypovolemia, such as those suffering from acute hemorrhage, trauma, or major surgery. * **Why Option A is correct:** As a large molecular weight colloid, HES remains within the intravascular compartment for an extended period. It exerts **oncotic pressure**, drawing fluid from the interstitial space into the blood vessels, thereby increasing plasma volume more effectively and for a longer duration than crystalloids. * **Why Option B is incorrect:** Inotropic agents (e.g., Dobutamine, Digoxin) increase the force of myocardial contraction. HES increases preload via volume expansion but has no direct effect on cardiac contractility. * **Why Option C is incorrect:** Vasodilators (e.g., Nitroglycerin, Hydralazine) reduce peripheral resistance. HES does not act on vascular smooth muscle. * **Why Option D is incorrect:** While both are colloids, Dextran is a glucose polymer produced by bacteria (*Leuconostoc mesenteroides*), whereas HES is a modified starch. They have different chemical structures and side-effect profiles. **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effects:** The most significant side effects of HES include **nephrotoxicity** (acute kidney injury) and **coagulopathy** (by diluting clotting factors and interfering with von Willebrand factor/Factor VIII). * **Black Box Warning:** Due to the risk of kidney injury and mortality, HES is contraindicated in critically ill patients, including those with sepsis or pre-existing renal dysfunction. * **Pruritus:** Chronic use or high doses can lead to intractable itching due to starch deposition in the skin.

Question 917: A patient with asthma and glaucoma is to receive a beta-blocker. Regarding beta-blocking drugs, which of the following is true?

A. Metoprolol blocks beta-2 receptors selectively.
B. Esmolol's pharmacokinetics are compatible with chronic topical use.
C. Nadolol lacks beta-2 blocking action.
D. Timolol lacks the local anesthetic effects of propranolol. (Correct Answer)

Explanation: ### Explanation **1. Why Option D is Correct:** Timolol is a non-selective beta-blocker primarily used in the treatment of glaucoma. Unlike propranolol, it lacks **Membrane Stabilizing Activity (MSA)**, also known as a local anesthetic effect. This is clinically significant because drugs with MSA (like propranolol or pindolol) can cause corneal anesthesia when applied topically, leading to a loss of the protective blink reflex and potential corneal damage. Timolol’s lack of MSA makes it safe for long-term ophthalmic use. **2. Why the Other Options are Incorrect:** * **Option A:** Metoprolol is a **cardioselective beta-1 blocker**, not a beta-2 blocker. While selectivity is lost at high doses, its primary therapeutic action is on $\beta_1$ receptors. * **Option B:** Esmolol is an ultra-short-acting beta-blocker with a half-life of approximately **9 minutes** due to rapid hydrolysis by RBC esterases. It is administered via IV infusion for acute situations (e.g., supraventricular tachycardia) and is entirely unsuitable for chronic topical use. * **Option C:** Nadolol is a **non-selective** beta-blocker, meaning it blocks both $\beta_1$ and $\beta_2$ receptors. It is notable for having a very long half-life and being excreted unchanged by the kidneys. **3. NEET-PG High-Yield Pearls:** * **Asthma Contraindication:** Non-selective beta-blockers (like Timolol or Nadolol) are contraindicated in asthmatics as $\beta_2$ blockade causes bronchoconstriction. * **Glaucoma Choice:** **Betaxolol** is a $\beta_1$ selective blocker used topically in glaucoma; it is safer (though not absolute) for patients with mild respiratory issues compared to Timolol. * **MSA Mnemonic:** "P-P-L" (Propranolol, Pindolol, Labetalol) are drugs with significant Membrane Stabilizing Activity. * **Esmolol:** Always remember it is the "shortest-acting" beta-blocker, metabolized by **plasma esterases**.

Question 918: Which of the following agents is NOT recommended in the treatment of aortic dissection?

A. Beta blockers
B. Labetalol
C. Sodium nitroprusside
D. Diazoxide (Correct Answer)

Explanation: **Explanation:** The primary goal in managing aortic dissection is to reduce **shear stress** on the aortic wall. This is achieved by lowering both the systemic blood pressure and the rate of rise of the pressure pulse (**dP/dt**). **Why Diazoxide is NOT recommended:** Diazoxide is a potent arteriolar vasodilator. However, it causes **reflex tachycardia** and a compensatory increase in cardiac output and stroke volume. This increases the dP/dt (the force of ventricular contraction), which can worsen the intimal tear and propagate the dissection. Therefore, it is contraindicated. **Analysis of other options:** * **Beta-blockers (e.g., Esmolol):** These are the **first-line** agents. They decrease both heart rate and dP/dt, effectively reducing the shearing forces on the aorta. * **Labetalol:** This is a combined alpha and beta-blocker. It is highly effective as it reduces both systemic vascular resistance (via alpha-blockade) and the reflex tachycardia/contractility (via beta-blockade). * **Sodium Nitroprusside:** This is a potent vasodilator used to rapidly lower blood pressure. However, it must **always** be administered *after* or *concurrently* with a beta-blocker to prevent the reflex increase in dP/dt. **High-Yield Clinical Pearls for NEET-PG:** * **Target:** Aim for a systolic BP of 100–120 mmHg and a heart rate <60 bpm within 20 minutes. * **Sequence Matters:** Never give a pure vasodilator (like Nitroprusside or Hydralazine) alone; always ensure prior beta-blockade to protect the aorta from reflex sympathetic stimulation. * **Drug of Choice:** **IV Esmolol** is often preferred due to its short half-life, allowing for rapid titration.

Question 919: Coronary steal phenomenon is caused by which of the following drugs?

A. Dipyridamole (Correct Answer)
B. Diltiazem
C. Propranolol
D. Verapamil

Explanation: ### Explanation **Coronary Steal Phenomenon** occurs when blood flow is diverted away from ischemic (stenosed) myocardial areas toward non-ischemic areas. In a diseased heart, vessels supplying ischemic zones are already maximally dilated due to local metabolic factors. When a potent arteriolar vasodilator is administered, it dilates the vessels in the **non-ischemic** zones. This reduces resistance in healthy areas, "stealing" blood flow away from the pressure-dependent ischemic zones, potentially worsening myocardial ischemia. **Why Dipyridamole is the Correct Answer:** Dipyridamole is a potent coronary vasodilator that acts by inhibiting adenosine deaminase and phosphodiesterase, leading to increased levels of **adenosine**. Because it causes powerful generalized vasodilation of coronary arterioles, it is the classic drug associated with the coronary steal phenomenon. This property is actually utilized clinically in **Pharmacological Stress Testing** (e.g., Thallium scan) to identify areas of inducible ischemia. **Analysis of Incorrect Options:** * **Diltiazem & Verapamil:** These are Non-dihydropyridine Calcium Channel Blockers (CCBs). While they have some vasodilatory effects, their primary actions are negative inotropy and chronotropy. They do not cause the intense, selective arteriolar dilation required to trigger significant coronary steal. * **Propranolol:** This is a non-selective Beta-blocker. It reduces myocardial oxygen demand by decreasing heart rate and contractility. It is used to *treat* angina, not provoke it, and does not cause coronary vasodilation. **High-Yield Clinical Pearls for NEET-PG:** * **Other drugs causing Coronary Steal:** Hydralazine, Isoflurane, and Nitroprusside. * **Nitroglycerin** does **not** cause coronary steal because it primarily dilates large epicardial vessels and redistributes blood *toward* the ischemic subendocardium. * **Drug of choice for Dipyridamole overdose/reversal:** Aminophylline (adenosine antagonist).

Question 920: What is the mechanism of action of dipyridamole?

A. Adenosine reuptake inhibition (Correct Answer)
B. Increases phosphodiesterase activity
C. Inhibits cyclooxygenase
D. None of the above

Explanation: **Explanation:** Dipyridamole is a pyrimidine derivative that acts as a coronary vasodilator and an antiplatelet agent. **1. Why Option A is Correct:** The primary mechanism of dipyridamole involves the **inhibition of adenosine uptake** by erythrocytes and vascular endothelial cells. This leads to increased local concentrations of extracellular adenosine, which acts on $A_2$ receptors to stimulate adenylate cyclase, increasing intracellular **cAMP** levels. Elevated cAMP inhibits platelet aggregation and causes vasodilation. Additionally, dipyridamole directly inhibits **phosphodiesterase (PDE3 and PDE5)**, further preventing the breakdown of cAMP and cGMP. **2. Why Other Options are Incorrect:** * **Option B:** Dipyridamole **decreases** (inhibits) phosphodiesterase activity rather than increasing it. Increasing PDE activity would lead to lower cAMP levels and promote platelet aggregation. * **Option C:** Inhibition of cyclooxygenase (COX) is the mechanism of action for **Aspirin** and other NSAIDs, not dipyridamole. **3. Clinical Pearls for NEET-PG:** * **Coronary Steal Phenomenon:** Dipyridamole dilates healthy coronary arteries more than stenosed ones. This can divert blood flow away from ischemic areas, potentially worsening angina. * **Diagnostic Use:** Due to its vasodilatory properties, it is used in **pharmacological stress testing** (Thallium imaging) for patients unable to exercise. * **Therapeutic Use:** It is often combined with low-dose aspirin (Aggrenox) for **secondary stroke prevention** or used with warfarin for prophylaxis of thromboembolism in patients with **prosthetic heart valves**. * **Side Effects:** Headache (most common due to vasodilation) and dizziness.

Practice by Chapter

Antihypertensive Agents

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Drugs for Heart Failure

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Antiarrhythmic Drugs

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Antianginal Agents

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Lipid-Lowering Drugs

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Anticoagulants and Antiplatelet Drugs

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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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