Cardiovascular Drugs Practice Questions

Q: What is the most common side effect of dihydropyridine calcium channel blockers?

Headache. **Explanation:** Dihydropyridine (DHP) Calcium Channel Blockers (CCBs), such as **Amlodipine** and **Nifedipine**, act primarily by inhibiting L-type calcium channels in the vascular smooth muscle. This leads to potent **peripheral vasodilation**. **1. Why Headache is the correct answer:** The primary mechanism of DHP-CCBs is the relaxation of arterial smooth muscle. This causes significant vasodilation of the meningeal and cerebral vessels. The resulting increase in intracranial blood flow and stretching of vessel walls triggers sensory nerves, leading to **vasodilatory headaches**. This is the most frequently reported side effect, especially during the initiation of therapy. Other common side effects due to this same mechanism include **peripheral edema** (due to precapillary dilation) and **flushing**. **2. Why the other options are incorrect:** * **B. Constipation:** This is a classic side effect of **Verapamil** (a non-dihydropyridine CCB). Verapamil inhibits calcium channels in the gastrointestinal smooth muscle, leading to decreased motility. It is rarely seen with DHPs. * **C. Diarrhoea:** This is not a characteristic side effect of CCBs. In fact, CCBs are more likely to cause decreased bowel motility. * **D. Muscle cramps:** While occasionally reported, these are not a "most common" or "classic" side effect compared to the vascular symptoms of DHPs. **High-Yield Clinical Pearls for NEET-PG:** * **Peripheral Edema:** A highly characteristic side effect of Amlodipine; it is **not** due to fluid overload but due to increased capillary hydrostatic pressure (pre-capillary dilation). * **Reflex Tachycardia:** Common with short-acting DHPs (like Nifedipine) due to rapid vasodilation triggering the baroreceptor reflex. * **Gingival Hyperplasia:** A shared side effect of CCBs (especially Nifedipine), Phenytoin, and Cyclosporine.

Q: Aspirin is used for secondary prevention of ischemic heart disease because it:

Inhibits TXA2 synthesis by platelets. **Explanation:** Aspirin (Acetylsalicylic acid) is a mainstay in the secondary prevention of ischemic heart disease due to its role as an antiplatelet agent. **1. Why Option A is Correct:** Aspirin works by **irreversibly inhibiting the enzyme Cyclooxygenase-1 (COX-1)** via acetylation. In platelets, COX-1 is responsible for the synthesis of **Thromboxane A2 (TXA2)**, a potent vasoconstrictor and mediator of platelet aggregation. Since platelets are anuclear and cannot synthesize new enzymes, the inhibition lasts for the entire lifespan of the platelet (approx. 7–10 days). Reducing TXA2 levels prevents thrombus formation over atherosclerotic plaques, thereby reducing the risk of myocardial infarction. **2. Why Other Options are Incorrect:** * **Option B:** While aspirin can inhibit **Prostacyclin (PGI2)** synthesis in vascular endothelial cells, PGI2 is a vasodilator and anti-aggregatory agent. At low doses (75–150 mg), aspirin is "platelet-selective" because endothelial cells can regenerate COX enzymes, whereas platelets cannot. Inhibiting PGI2 is actually an unwanted effect. * **Option C & D:** Aspirin does not have a direct inhibitory effect on **Endothelium-Derived Relaxing Factor (EDRF/Nitric Oxide)** or **Endothelins**. These are regulated by different pathways (e.g., NO synthase and Endothelin-converting enzyme). **High-Yield Clinical Pearls for NEET-PG:** * **Low-dose Aspirin (75–150 mg/day):** Preferred for cardioprotection to achieve selective TXA2 inhibition while sparing PGI2. * **Irreversible Action:** Aspirin is the only NSAID that binds irreversibly to COX. * **Primary vs. Secondary Prevention:** Aspirin is strongly indicated for *secondary* prevention (post-MI/Stroke). Its use in *primary* prevention is now limited due to the increased risk of major GI bleeding. * **Aspirin Resistance:** Can be seen in patients with high platelet turnover or genetic polymorphisms.

Q: ACE inhibitors are contraindicated in:

Renal artery stenosis. **Explanation:** **Why Renal Artery Stenosis (RAS) is the Correct Answer:** In patients with bilateral renal artery stenosis (or stenosis in a solitary kidney), renal perfusion pressure is significantly reduced. To maintain the **Glomerular Filtration Rate (GFR)**, the body relies on Angiotensin II to cause **vasoconstriction of the efferent arteriole**. ACE inhibitors block the production of Angiotensin II, leading to efferent arteriolar vasodilation. This causes a sharp drop in intraglomerular pressure, resulting in acute renal failure. Therefore, ACE inhibitors are strictly contraindicated in these patients. **Why Other Options are Incorrect:** * **A. Hypertension:** ACE inhibitors are first-line agents for hypertension, especially in patients with diabetes or proteinuric kidney disease. * **B. Myocardial Infarction (MI):** They are standard of care post-MI to prevent "ventricular remodeling" and reduce mortality. * **D. Left Ventricular Dysfunction:** ACE inhibitors are the cornerstone of treatment for Heart Failure with Reduced Ejection Fraction (HFrEF) as they reduce both preload and afterload. **High-Yield NEET-PG Pearls:** * **Teratogenicity:** ACE inhibitors are contraindicated in **pregnancy** (cause fetal renal dysgenesis and skull hypoplasia). * **Side Effects:** The most common side effect is a **dry cough** (due to increased Bradykinin); the most serious is **angioedema**. * **Monitoring:** Always monitor serum creatinine and potassium levels. A minor rise in creatinine (up to 30%) is acceptable, but **hyperkalemia** is a known contraindication. * **Drug of Choice:** ACE inhibitors are the DOC for **Diabetic Nephropathy** because they are renoprotective (reduce proteinuria).

Q: Which of the following is a beta-blocker with a beta-2 receptor agonist action?

Celiprolol. **Explanation:** The correct answer is **Celiprolol**. **1. Why Celiprolol is correct:** Celiprolol is a unique, third-generation beta-blocker. Its pharmacological profile is characterized by **selective $\beta_1$ antagonism** (cardioselective) combined with **partial $\beta_2$ receptor agonism** (Intrinsic Sympathomimetic Activity - ISA) [1]. This $\beta_2$ agonist action leads to peripheral vasodilation and bronchodilation, which helps counteract the typical side effects of beta-blockers, such as cold extremities or bronchospasm. It also possesses weak $\alpha_2$ blocking and nitric oxide-modulating properties. **2. Analysis of Incorrect Options:** * **A. Labetalol:** This is a non-selective $\beta$ blocker with additional **$\alpha_1$ blocking** activity. It does not have $\beta_2$ agonist action. It is a drug of choice in pregnancy-induced hypertension. * **B. Carvedilol:** This is a non-selective $\beta$ blocker with **$\alpha_1$ blocking** and potent antioxidant properties. It is widely used in chronic heart failure but lacks $\beta_2$ agonism. * **C. Tilisolol:** This is a non-selective beta-blocker used primarily in Japan. It is unique because it has **potassium channel opening** properties (vasodilation), but it does not act as a $\beta_2$ agonist [1]. **3. High-Yield Clinical Pearls for NEET-PG:** * **Vasodilatory Beta-blockers:** Remember them by the mechanism [1]: * **$\alpha_1$ blockade:** Labetalol, Carvedilol. * **$\beta_2$ agonism:** Celiprolol, Carteolol. * **NO (Nitric Oxide) release:** Nebivolol (most cardioselective), Nipradilol. * **$K^+$ channel opening:** Tilisolol. * **Celiprolol** is particularly useful in hypertensive patients with asthma or peripheral vascular disease due to its $\beta_2$ agonist-mediated bronchodilation and vasodilation.

Q: Lipid-lowering agents, statins, act in all the following ways except:

Decreased LDL receptors. ### Explanation Statins (HMG-CoA reductase inhibitors) are the first-line agents for hypercholesterolemia. The core mechanism involves the competitive inhibition of the rate-limiting enzyme in cholesterol biosynthesis. **Why "Decreased LDL receptors" is the correct answer (the exception):** Statins actually **increase** the expression of LDL receptors. When statins inhibit hepatic cholesterol synthesis, the intracellular pool of cholesterol drops. To compensate, the liver upregulates the synthesis of LDL receptors on the hepatocyte surface. These receptors then clear more LDL and VLDL remnants from the circulation, leading to a significant drop in plasma LDL levels. Therefore, saying statins *decrease* these receptors is physiologically incorrect. **Analysis of Incorrect Options:** * **A & C (Inhibiting HMG CoA reductase / Decreased hepatic synthesis):** These are the primary actions of statins. By mimicking the substrate HMG-CoA, they block the conversion of HMG-CoA to mevalonate, directly halting endogenous cholesterol production. * **D (Decreasing VLDL):** Since VLDL is a precursor to LDL and requires cholesterol for its assembly, the reduction in hepatic cholesterol availability leads to a secondary decrease in VLDL secretion. **High-Yield Clinical Pearls for NEET-PG:** * **Pleiotropic Effects:** Statins have "extra" benefits beyond lipid lowering, including plaque stabilization, anti-inflammatory properties, and improved endothelial function. * **Timing:** Most statins (except Atorvastatin and Rosuvastatin) should be taken at **bedtime** because peak cholesterol synthesis occurs during the night. * **Side Effects:** Monitor for **myopathy** (elevated CPK) and hepatotoxicity. Risk increases when combined with Fibrates or Cytochrome P450 inhibitors. * **Contraindication:** Statins are strictly **Teratogenic** (Category X).

Q: A 60-year-old male with angina presents with severe chest pain unresponsive to sublingual nitroglycerin. An ECG shows ST segment elevation in the anterolateral leads, and thrombolytic therapy is initiated. If streptokinase is given to this patient, it may produce thrombolysis after binding to which of the following proteins?

Plasminogen. ### Explanation **Mechanism of Action (Why Option C is Correct):** Streptokinase is a first-generation thrombolytic agent derived from *beta-hemolytic streptococci*. Unlike tissue plasminogen activator (tPA), streptokinase is **not fibrin-specific**. It works by forming a stable **1:1 stoichiometric complex with plasminogen**. This streptokinase-plasminogen complex undergoes a conformational change that exposes an active site, which then enzymatically converts free circulating plasminogen into **plasmin**. Plasmin subsequently degrades fibrin clots, as well as fibrinogen and other clotting factors (factors V and VII). **Analysis of Incorrect Options:** * **A. Antithrombin III:** This is a natural anticoagulant that inhibits thrombin and Factor Xa. It is the site of action for **Heparin**, not thrombolytics. * **B. Fibrin:** While newer agents like Alteplase, Reteplase, and Tenecteplase are "fibrin-selective" (binding preferentially to plasminogen already bound to fibrin), **Streptokinase does not bind directly to fibrin**. It acts systemically on all circulating plasminogen. * **D. Protein C:** This is a vitamin K-dependent natural anticoagulant that inactivates Factors Va and VIIIa. It is not involved in the mechanism of streptokinase. **High-Yield NEET-PG Pearls:** * **Antigenicity:** Because it is a bacterial protein, streptokinase is antigenic. It can cause **hypersensitivity reactions** (anaphylaxis) and should not be repeated in the same patient within 6–12 months due to neutralizing antibodies. * **Side Effects:** The most common side effect is bleeding. Unlike tPA, streptokinase can also cause significant **hypotension**. * **Comparison:** Tenecteplase is currently the preferred thrombolytic in STEMI due to its high fibrin specificity, long half-life (bolus dose), and lower bleeding risk compared to streptokinase.

Question 1

A 42-year-old woman with a 20-year history of Type II diabetes has hypertension with a BP in the 150/94 mmHg range and mild proteinuria on urinalysis. Which drug would be the best to treat the hypertension in this individual?

Accepted Answer

Enalapril

Answer

Hydrochlorothiazide

Answer

Propranolol

Answer

Nifedipine

Question 2

What is the most common side effect of dihydropyridine calcium channel blockers?

Accepted Answer

Headache

Answer

Constipation

Answer

Diarrhoea

Answer

Muscle cramps

Question 3

Which of the following drugs can cause coronary steal phenomenon?

Accepted Answer

Hydralazine

Answer

Glyceryl trinitrate

Answer

Disopyramide

Answer

Diltiazem

Question 4

Aspirin is used for secondary prevention of ischemic heart disease because it:

Accepted Answer

Inhibits TXA2 synthesis by platelets

Answer

Inhibits prostacyclin synthesis

Answer

Inhibits the release of EDRF

Answer

Inhibits the synthesis of endothelins

Question 5

ACE inhibitors are contraindicated in:

Accepted Answer

Renal artery stenosis

Answer

Hypertension

Answer

Myocardial infarction

Answer

Left ventricular dysfunction

Question 6

Which of the following is a beta-blocker with a beta-2 receptor agonist action?

Accepted Answer

Celiprolol

Answer

Labetalol

Answer

Carvedilol

Answer

Tilisolol

Question 7

What is the most suitable antiarrhythmic drug for counteracting ventricular extrasystoles due to digoxin toxicity?

Accepted Answer

Lignocaine

Answer

Verapamil

Answer

Quinidine

Answer

Amiodarone

Question 8

Lipid-lowering agents, statins, act in all the following ways except:

Accepted Answer

Decreased LDL receptors

Answer

Decreased hepatic cholesterol synthesis

Answer

Inhibiting HMG CoA reductase

Answer

Decreasing VLDL

Question 9

What is the drug of choice in digitalis-induced ventricular arrhythmia?

Accepted Answer

IV Lignocaine

Answer

Phenytoin

Answer

Quinidine

Answer

Procainamide

Question 10

A 60-year-old male with angina presents with severe chest pain unresponsive to sublingual nitroglycerin. An ECG shows ST segment elevation in the anterolateral leads, and thrombolytic therapy is initiated. If streptokinase is given to this patient, it may produce thrombolysis after binding to which of the following proteins?

Accepted Answer

Plasminogen

Answer

Antithrombin III

Answer

Fibrin

Answer

Protein C

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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