Cardiovascular Drugs Practice Questions

Q: Ezetimibe acts by

Decreasing absorption of cholesterol. **Explanation:** **Ezetimibe** is a cholesterol absorption inhibitor that specifically targets the **Niemann-Pick C1-Like 1 (NPC1L1)** transport protein located on the brush border of enterocytes in the small intestine. By inhibiting this transporter, it reduces the delivery of dietary and biliary cholesterol to the liver. This leads to an upregulation of LDL receptors on hepatocytes, subsequently decreasing circulating LDL-C levels. **Analysis of Options:** * **Option A (Enhancing excretion of bile acids):** This is the mechanism of **Bile Acid Sequestrants** (e.g., Cholestyramine, Colestipol). They bind bile acids in the gut, preventing enterohepatic circulation and forcing the liver to use cholesterol to synthesize new bile acids. * **Option B (Correct):** Ezetimibe directly inhibits the intestinal absorption of cholesterol. * **Option C (Inhibiting HMG CoA reductase):** This is the mechanism of **Statins** (e.g., Atorvastatin). Statins inhibit the rate-limiting step of endogenous cholesterol synthesis. * **Option D (Inhibiting intracellular lipase):** This refers to the mechanism of **Fibrates** (which stimulate lipoprotein lipase) or **Niacin** (which inhibits hormone-sensitive lipase in adipose tissue). **High-Yield Clinical Pearls for NEET-PG:** * **Synergy:** Ezetimibe is frequently used as an "add-on" therapy to Statins. While Statins inhibit cholesterol *synthesis*, Ezetimibe inhibits cholesterol *absorption*, leading to a potent dual effect. * **Vytorin:** A fixed-dose combination of Ezetimibe + Simvastatin. * **Side Effects:** Generally well-tolerated; however, it may cause a mild increase in hepatic transaminases when used with statins. * **Key Target:** Always remember **NPC1L1** for Ezetimibe; it is a common "one-liner" question in PG exams.

Q: A 55-year-old male with a history of type 2 diabetes mellitus, managed with oral hypoglycemic agents, presents with a blood pressure reading of 164/102 mm Hg. What is the most suitable antihypertensive drug for this patient?

Enalapril. **Explanation:** **1. Why Enalapril is the Correct Choice:** In patients with **Diabetes Mellitus (DM)** and hypertension, **ACE inhibitors (like Enalapril)** or ARBs are the first-line agents of choice. The underlying medical concept is **renoprotection**. Diabetes is a leading cause of chronic kidney disease (Diabetic Nephropathy). ACE inhibitors dilate the efferent arterioles of the glomerulus more than the afferent arterioles, reducing intraglomerular pressure. This action slows the progression of albuminuria and preserves renal function, regardless of the blood pressure-lowering effect. **2. Why the Other Options are Incorrect:** * **Propranolol (Beta-blocker):** Generally avoided as a first-line agent in diabetics because it can mask the autonomic symptoms of hypoglycemia (like tachycardia and tremors) and may impair glucose tolerance by inhibiting insulin release. * **Clonidine (Centrally acting alpha-2 agonist):** This is not a first-line drug for essential hypertension. It is associated with side effects like sedation and dry mouth, and it offers no specific metabolic or renal benefits for diabetic patients. * **Hydrochlorothiazide (Thiazide Diuretic):** While effective, thiazides can cause hyperglycemia (by inhibiting insulin secretion and decreasing peripheral glucose utilization) and hyperlipidemia, making them less ideal than ACE inhibitors for diabetic patients. **Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** ACE inhibitors/ARBs are DOC for HTN in patients with DM, Proteinuria, CKD, and Heart Failure. * **Side Effect Profile:** A common side effect of Enalapril is a **dry cough** (due to increased bradykinin). If a patient develops a cough, switch them to an **ARB (e.g., Losartan)**. * **Contraindication:** ACE inhibitors are strictly **contraindicated in pregnancy** (teratogenic) and in patients with **bilateral renal artery stenosis**.

Q: Which of the following is a beta-blocker antagonist?

Glucagon. ### Explanation **Correct Option: A. Glucagon** **Mechanism of Action:** Glucagon is considered the **specific antidote** for beta-blocker (BB) overdose. Beta-blockers work by inhibiting the $\beta_1$ receptors, which normally use the Gs-protein pathway to activate **adenylyl cyclase**, increasing intracellular cAMP and resulting in positive inotropic and chronotropic effects. In a BB overdose, this pathway is blocked. Glucagon bypasses the blocked beta-receptors by binding to its own specific **glucagon receptors** on the myocardium. These receptors are also coupled to Gs-proteins, which activate adenylyl cyclase independently of the beta-adrenergic system. This leads to an increase in **cAMP**, restoring heart rate and contractility despite the presence of the antagonist. **Why Incorrect Options are Wrong:** * **B & C (Neostigmine and Ambenonium):** These are **acetylcholinesterase inhibitors** used primarily in the treatment of Myasthenia Gravis. They increase the concentration of acetylcholine at the neuromuscular junction and muscarinic sites. Because they enhance parasympathetic activity, they would actually worsen the bradycardia associated with beta-blocker toxicity rather than reverse it. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** Glucagon is the first-line agent for symptomatic bradycardia and hypotension caused by beta-blocker toxicity. * **Other Treatments:** If glucagon fails, **High-dose Insulin Euglycemic Therapy (HIET)** and IV calcium gluconate are used. * **Side Effects of Glucagon:** High doses can cause significant vomiting; hence, airway protection is vital. * **Mnemonic:** "Glucagon bypasses the block" (it acts via a different receptor to achieve the same result as beta-agonists).

Q: Which of the following drugs acts as both an arteriolar and venodilator?

Sodium nitroprusside. **Explanation:** Sodium Nitroprusside (SNP) is the correct answer because it acts as a **balanced vasodilator**, affecting both resistance vessels (arterioles) and capacitance vessels (veins) [1, 3]. **Mechanism of Action:** SNP is a prodrug that reacts with hemoglobin to release **Nitric Oxide (NO)** [1]. NO activates guanylyl cyclase, increasing intracellular **cGMP**, which leads to dephosphorylation of myosin light chains and subsequent relaxation of smooth muscles in both arteries and veins. * **Arteriolar dilation** reduces Total Peripheral Resistance (Afterload). * **Venodilation** increases venous pooling and reduces venous return (Preload). **Analysis of Incorrect Options:** * **A. Hydralazine:** A direct-acting **pure arteriolar vasodilator** [1, 2]. It has minimal effect on veins, often leading to significant reflex tachycardia. * **C. Minoxidil:** A potent **arteriolar vasodilator** that works by opening ATP-sensitive $K^+$ channels, causing hyperpolarization of smooth muscle cells [1]. It does not affect veins. * **D. Captopril:** While ACE inhibitors do cause both arterial and venous dilation by reducing Angiotensin II and increasing Bradykinin, they are classified primarily as **balanced vasodilators in the context of chronic therapy**. In the specific context of "vasodilator pharmacology" questions, SNP is the classic prototype for immediate, direct-acting balanced dilation. **High-Yield Clinical Pearls for NEET-PG:** 1. **SNP Toxicity:** Prolonged infusion can lead to **Cyanide and Thiocyanate toxicity**. The antidote is **Sodium Thiosulfate** or **Hydroxocobalamin**. 2. **Drug of Choice:** SNP is used in hypertensive emergencies but must be protected from light (it is photosensitive). 3. **Steal Phenomenon:** SNP can cause "Coronary Steal," potentially worsening ischemia in patients with CAD. 4. **Minoxidil Side Effect:** Commonly causes **hypertrichosis** (used topically for alopecia) [1].

Q: All of the following statements about the use of spironolactone in CHF are true EXCEPT:

It affords rapid symptomatic relief in CHF patients.. ### Explanation **Spironolactone** is a potassium-sparing diuretic and a Mineralocorticoid Receptor Antagonist (MRA). In Chronic Heart Failure (CHF), its primary role is not acute diuresis, but rather long-term neurohormonal modulation. **1. Why Option D is the Correct Answer (The False Statement):** Spironolactone is a **weak diuretic**. It acts on the distal part of the nephron where only a small fraction of sodium is reabsorbed. Unlike loop diuretics (e.g., Furosemide), it does not produce rapid diuresis or immediate symptomatic relief from pulmonary edema. Its benefits in CHF are primarily due to its ability to prevent myocardial fibrosis and remodeling, which takes weeks to months to manifest. **2. Analysis of Other Options:** * **Option A:** Spironolactone carries a significant risk of **hyperkalemia**, especially when combined with ACE inhibitors. Therefore, it is initiated at low doses (e.g., 12.5–25 mg/day) with close monitoring of serum potassium and creatinine. * **Option B:** Large-scale trials like **RALES** have proven that adding low-dose spironolactone to standard therapy (ACE inhibitors + Digoxin) significantly reduces mortality and morbidity in patients with NYHA Class III and IV heart failure. This is known as "Aldosterone Escape" blockade. * **Option C:** In cases of "diuretic resistance," adding spironolactone can help overcome refractoriness to thiazides or loop diuretics by blocking the compensatory distal sodium reabsorption. **Clinical Pearls for NEET-PG:** * **Mechanism:** Competitive antagonist of aldosterone at the Mineralocorticoid Receptor (MR) in the late distal tubule/collecting duct. * **Side Effects:** Hyperkalemia and **Gynecomastia** (due to non-specific binding to androgen and progesterone receptors). **Eplerenone** is a more selective MRA with fewer endocrine side effects. * **Key Trial:** RALES trial (Spironolactone); EMPHASIS-HF trial (Eplerenone).

Question 1

Ezetimibe acts by

Accepted Answer

Decreasing absorption of cholesterol

Answer

Enhancing excretion of bile acids

Answer

Inhibiting HMG CoA reductase

Answer

Inhibiting intracellular lipase

Question 2

Thrombolytic therapy with streptokinase is contraindicated in all of the following conditions EXCEPT?

Accepted Answer

Supraventricular tachycardia

Answer

Recent trauma

Answer

Recent cerebral bleeding

Answer

Recent surgery

Question 3

A 55-year-old male with a history of type 2 diabetes mellitus, managed with oral hypoglycemic agents, presents with a blood pressure reading of 164/102 mm Hg. What is the most suitable antihypertensive drug for this patient?

Accepted Answer

Enalapril

Answer

Propranolol

Answer

Clonidine

Answer

Hydrochlorothiazide

Question 4

Which of the following drugs will decrease heart rate in a patient with a normal heart rate but will have little effect on heart rate in a cardiac transplant recipient?

Accepted Answer

Phenylephrine

Answer

Adrenaline

Answer

Noradrenaline

Answer

Isoproterenol

Question 5

ACE inhibitors should not be used concurrently with which of the following agents?

Accepted Answer

Spironolactone

Answer

Amiloride

Answer

Calcium Channel Blockers (CCB)

Answer

Thiazides

Question 6

Which of the following is a beta-blocker antagonist?

Accepted Answer

Glucagon

Answer

Neostigmine

Answer

Ambenonium

Answer

All of the above

Question 7

Which of the following drugs acts as both an arteriolar and venodilator?

Accepted Answer

Sodium nitroprusside

Answer

Hydralazine

Answer

Minoxidil

Answer

Captopril

Question 8

All of the following statements about the use of spironolactone in CHF are true EXCEPT:

Accepted Answer

It affords rapid symptomatic relief in CHF patients.

Answer

It should be administered in low doses to prevent hyperkalemia.

Answer

It affords prognostic benefit in severe heart failure over and above that afforded by ACE inhibitors.

Answer

It helps to overcome the refractoriness to thiazides.

Question 9

Which of the following is true about dobutamine?

Accepted Answer

Half-life is about 2 minutes

Answer

Selective beta-1 receptor agonist

Answer

Increases ventricular filling pressure

Answer

Dopamine receptor agonist

Question 10

Which of the following is a Class Ib antiarrhythmic drug?

Accepted Answer

Lidocaine

Answer

Encainide

Answer

Flecainide

Answer

Moricizine

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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