Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 31: Which of the following drugs has uricosuric action?

A. Nifedipine
B. Amlodipine (Correct Answer)
C. Atenolol
D. Carvedilol

Explanation: **Explanation:** The correct answer is **Amlodipine**. **1. Why Amlodipine is correct:** Amlodipine, a long-acting dihydropyridine Calcium Channel Blocker (CCB), is unique among antihypertensives for its **uricosuric effect**. It increases the renal excretion of uric acid by inhibiting the tubular reabsorption of urate. This property makes it particularly beneficial for hypertensive patients who also suffer from hyperuricemia or gout, as it helps lower serum uric acid levels. **2. Why the other options are incorrect:** * **Nifedipine (Option A):** While also a dihydropyridine CCB, Nifedipine does not possess significant uricosuric properties. In some clinical observations, it has even been associated with a slight increase in uric acid levels, unlike Amlodipine. * **Atenolol (Option C):** This is a cardioselective $\beta_1$ blocker. Beta-blockers generally have a neutral effect on uric acid, though some non-selective agents may slightly decrease renal blood flow, potentially leading to minor uric acid retention. * **Carvedilol (Option D):** A combined $\alpha$ and $\beta$ blocker. Like most beta-blockers, it does not have a documented uricosuric action. **3. NEET-PG High-Yield Pearls:** * **Losartan** is the most well-known antihypertensive with potent uricosuric action (via inhibition of the URAT1 transporter). * **Diuretics (Thiazides and Loops)** are notorious for causing **hyperuricemia** (by competing with uric acid for secretion in the proximal tubule) and can precipitate acute gouty arthritis. * In a patient with **Hypertension + Gout**, the preferred drugs are **Losartan** or **Amlodipine**. * **Atorvastatin** and **Fenofibrate** are other non-antihypertensive drugs that also exhibit uricosuric properties.

Question 32: Losartan is similar to enalapril in all of the following features except:

A. Anti-hypertensive efficacy
B. Potential to reverse left ventricular hypertrophy
C. Lack of effect on carbohydrate tolerance
D. Potential to induce cough in susceptible individuals (Correct Answer)

Explanation: **Explanation:** The core difference between **ACE Inhibitors (ACEIs)** like Enalapril and **Angiotensin Receptor Blockers (ARBs)** like Losartan lies in their mechanism of action regarding the kinin system. **1. Why Option D is correct:** ACE inhibitors (Enalapril) block the enzyme *Angiotensin Converting Enzyme*, which is also responsible for the degradation of **bradykinin** and **Substance P** [1]. Accumulation of these pro-inflammatory peptides in the lungs triggers the dry, irritating cough seen in 5-20% of patients [1]. In contrast, Losartan blocks the $AT_1$ receptor directly and has no effect on ACE; therefore, it does not lead to bradykinin accumulation and **does not induce cough** [2]. **2. Why the other options are incorrect:** * **Option A (Anti-hypertensive efficacy):** Both ACEIs and ARBs are equally effective first-line agents for managing hypertension [2]. * **Option B (Reversal of LVH):** Both drug classes effectively inhibit the trophic effects of Angiotensin II on the myocardium, promoting the regression of left ventricular hypertrophy (LVH) [2]. * **Option C (Carbohydrate tolerance):** Both classes are "metabolically neutral." Unlike beta-blockers or thiazides, they do not impair glucose tolerance and are, in fact, the preferred drugs for hypertensive patients with Diabetes Mellitus due to their nephroprotective effects [1]. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** ARBs (Losartan) are the preferred alternative for patients who develop a cough while on ACE inhibitors [1]. * **Teratogenicity:** Both ACEIs and ARBs are **strictly contraindicated in pregnancy** (Category X) as they cause fetal renal anomalies and oligohydramnios. * **Side Effects:** Both can cause hyperkalemia and angioedema (though angioedema is much rarer with ARBs) [1]. * **Losartan Unique Property:** It has a mild **uricosuric effect**, making it beneficial for hypertensive patients with gout.

Question 33: What is the drug of choice for hypertension in a patient with osteoporosis?

A. ACE inhibitors
B. Beta-blockers
C. Thiazide diuretics (Correct Answer)
D. Loop diuretics

Explanation: ### Explanation **Correct Option: C. Thiazide diuretics** **Mechanism and Rationale:** Thiazide diuretics (e.g., Hydrochlorothiazide, Chlorthalidone) are the drugs of choice for hypertensive patients with concomitant osteoporosis because of their unique effect on calcium handling in the kidney. [1] 1. **Calcium Retention:** Thiazides inhibit the $Na^+/Cl^-$ symporter in the distal convoluted tubule. This decreases intracellular sodium, which in turn stimulates the $Na^+/Ca^{2+}$ exchanger on the basolateral membrane, promoting the reabsorption of calcium from the tubular fluid back into the blood. [1] 2. **Bone Mineral Density:** By reducing urinary calcium excretion (hypocalciuria), Thiazides help maintain higher serum calcium levels and stimulate osteoblastic activity, thereby increasing bone mineral density and reducing the risk of hip and vertebral fractures. [1] **Why other options are incorrect:** * **A. ACE inhibitors:** While excellent for hypertension (especially in diabetics), they have a neutral effect on bone metabolism and do not provide the added benefit of calcium retention. * **B. Beta-blockers:** Although some studies suggest a minor protective effect on bone, they are not the primary choice for osteoporosis and are generally third-line agents for uncomplicated hypertension. * **D. Loop diuretics (e.g., Furosemide):** These are contraindicated in osteoporosis. They inhibit the $Na^+/K^+/2Cl^-$ co-transporter in the Thick Ascending Lamb, which abolishes the lumen-positive potential, leading to **increased calcium excretion** (hypercalciuria). [1] This can worsen bone loss. **NEET-PG High-Yield Pearls:** * **Thiazides:** Cause **Hyper**calcemia, **Hyper**uricemia, **Hyper**glycemia, and **Hyper**lipidemia (The "4 Hypers"). [1] * **Loop Diuretics:** Cause **Hypo**calcemia (Used acutely to treat hypercalcemia). [1] * **Clinical Tip:** In an elderly patient with both hypertension and kidney stones (calcium oxalate), Thiazides are also the drug of choice because they reduce the calcium concentration in urine. [1]

Question 34: Which of the following statements best describes long-acting nitrate preparations?

A. Tolerance often develops (Correct Answer)
B. Their effect can be blocked by high doses of beta-selective inhibitors
C. Transdermal patches are more likely to be associated with headaches than are sublingual nitrates
D. Oral preparations are more effective than sublingual ones

Explanation: **Explanation:** **1. Why Option A is Correct:** Nitrate tolerance (tachyphylaxis) is a well-documented phenomenon where the clinical efficacy of the drug diminishes significantly with continuous exposure. The underlying mechanism involves the **depletion of free sulfhydryl (-SH) groups** (required to convert nitrates to Nitric Oxide) and increased production of free radicals (oxidative stress) that inhibit guanylyl cyclase. To prevent this, a **"nitrate-free interval"** of 8–12 hours (usually at night) is mandatory for long-acting preparations like isosorbide mononitrate or transdermal patches. **2. Why Other Options are Incorrect:** * **Option B:** Nitrates act directly on vascular smooth muscle to cause vasodilation. Their mechanism is independent of beta-receptors; therefore, beta-blockers do not inhibit their effect. In fact, they are often used together to prevent reflex tachycardia. * **Option C:** Sublingual nitrates cause a rapid, high-peak plasma concentration, which is **more** likely to cause immediate "nitrate headaches" compared to the slow, sustained release of transdermal patches. * **Option D:** Oral nitrates undergo extensive **first-pass metabolism** in the liver, making them significantly less potent and slower-acting than sublingual preparations, which bypass the liver and enter the systemic circulation directly. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice:** Sublingual Nitroglycerin (GTN) is the drug of choice for acute anginal attacks. * **Storage:** GTN is volatile and light-sensitive; it should be stored in dark glass bottles. * **Contraindication:** Never co-administer nitrates with **Sildenafil** (PDE-5 inhibitors) as it can lead to life-threatening hypotension. * **Side Effects:** Throbbing headache (most common), postural hypotension, and reflex tachycardia.

Question 35: Esmolol is a short-acting beta-blocker because:

A. It has more plasma protein binding.
B. Its plasma hydrolysis by esterases is rapid. (Correct Answer)
C. It has high lipid solubility.
D. It has high oral bioavailability.

Explanation: **Explanation:** **Why the correct answer is right:** Esmolol is a unique, ultra-short-acting cardioselective $\beta_1$ antagonist. Its rapid onset and extremely short duration of action (half-life of approximately **9 minutes**) are due to its chemical structure, which contains an **ester linkage**. This linkage is rapidly hydrolyzed by **red blood cell (RBC) esterases** (not plasma cholinesterase) into an inactive metabolite. Because these esterases are ubiquitous and highly efficient, the drug is cleared from the systemic circulation almost immediately once the infusion is stopped. **Analysis of incorrect options:** * **Option A:** High plasma protein binding generally prolongs a drug's half-life by protecting it from metabolism and excretion. Esmolol has moderate protein binding (~55%), which does not account for its short duration. * **Option C:** High lipid solubility (like Propranolol) allows drugs to cross the blood-brain barrier and undergo extensive hepatic metabolism, but it typically leads to a longer half-life and larger volume of distribution, not ultra-short action. * **Option D:** Esmolol has very low oral bioavailability and is administered exclusively via **intravenous infusion**. High oral bioavailability is irrelevant to its rapid clearance. **High-Yield Clinical Pearls for NEET-PG:** * **Indications:** Ideal for emergency situations requiring "minute-to-minute" control, such as **aortic dissection**, intraoperative hypertension, and supraventricular arrhythmias (AFib/Aflutter). * **Safety:** If side effects like bradycardia or hypotension occur, they resolve within 10–20 minutes of stopping the infusion. * **Metabolism:** It is metabolized by **RBC esterases**, making it safe to use in patients with liver or kidney dysfunction.

Question 36: What is the most effective drug for raising HDL levels?

A. Omega-3 fatty acids
B. Niacin (Correct Answer)
C. Fenofibrate
D. Rosuvastatin

Explanation: **Explanation:** **Niacin (Vitamin B3)** is the most potent agent currently available for increasing **HDL-C levels**, typically raising them by **20–35%** [2]. It achieves this by inhibiting the hepatic breakdown of Apolipoprotein A-I (the primary protein component of HDL) and reducing the clearance of HDL particles. Additionally, Niacin inhibits hormone-sensitive lipase in adipose tissue, reducing the delivery of free fatty acids to the liver, which subsequently lowers VLDL and LDL production. **Analysis of Incorrect Options:** * **Omega-3 fatty acids:** Primarily used to lower **Triglycerides (TGs)**. While they may slightly increase HDL, their effect is marginal compared to Niacin. * **Fenofibrate (Fibrates):** These are the first-line drugs for **Hypertriglyceridemia**. They increase HDL by 10–20% via PPAR-α activation, but their efficacy is generally lower than Niacin for this specific parameter [1]. * **Rosuvastatin (Statins):** These are the most effective drugs for lowering **LDL-C** (by inhibiting HMG-CoA reductase). While they provide a modest increase in HDL (5–10%), they are not the primary choice for isolated low HDL [4]. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effects of Niacin:** The most common side effect is **cutaneous flushing** (mediated by Prostaglandin D2/E2), which can be blunted by taking **Aspirin** 30 minutes prior. It can also cause **hyperuricemia** (precipitating gout) [3], **hyperglycemia** (caution in diabetics) [3], and hepatotoxicity. * **Drug of Choice (DOC):** While Niacin is best for raising HDL, **Statins** remain the first-line treatment for overall cardiovascular risk reduction. * **Fibrates** are the DOC for severe hypertriglyceridemia (TG >500 mg/dL) to prevent pancreatitis [1].

Question 37: What is the best antihypertensive drug used in pulmonary hypertension?

A. Digoxin
B. Furosemide
C. Amlodipine
D. Bosentan (Correct Answer)

Explanation: **Explanation:** **Bosentan** is the correct answer because it is a competitive **dual endothelin receptor antagonist (ERA)**, blocking both $ET_A$ and $ET_B$ receptors. Endothelin-1 is a potent endogenous vasoconstrictor that is significantly elevated in patients with Pulmonary Arterial Hypertension (PAH). By blocking these receptors, Bosentan promotes vasodilation and inhibits the proliferation of vascular smooth muscle cells, thereby reducing pulmonary vascular resistance. **Analysis of Incorrect Options:** * **Digoxin (A):** A cardiac glycoside used primarily in heart failure and atrial fibrillation. While it may be used in PAH to manage right-sided heart failure or arrhythmias, it does not treat the underlying pulmonary hypertension. * **Furosemide (B):** A loop diuretic used to manage fluid overload and peripheral edema in right heart failure. It provides symptomatic relief but is not a definitive antihypertensive for the pulmonary vasculature. * **Amlodipine (C):** A Calcium Channel Blocker (CCB). While CCBs are used in PAH, they are only effective in a small subset of patients (approx. 10%) who show a positive response during **Vasoreactivity Testing**. Bosentan is more broadly indicated for PAH (WHO Group 1). **High-Yield Clinical Pearls for NEET-PG:** * **Adverse Effect:** Bosentan is notorious for causing **hepatotoxicity** (elevated LFTs); regular monitoring of liver enzymes is mandatory. * **Teratogenicity:** It is highly teratogenic (Category X) and requires a negative pregnancy test before initiation. * **Other PAH Drugs:** Sildenafil (PDE-5 inhibitor), Epoprostenol (Prostacyclin analogue), and Riociguat (Guanylate cyclase stimulator). * **Macitentan:** A newer ERA with better tissue penetration and less hepatotoxicity than Bosentan.

Question 38: Which of the following is NOT a potassium channel opener?

A. Pinacidil
B. Diazoxide
C. Nicorandil
D. Amiodarone (Correct Answer)

Explanation: **Explanation:** The correct answer is **Amiodarone** because it is a **Class III antiarrhythmic agent** that primarily acts as a **potassium channel blocker**, not an opener. By blocking outward $K^+$ channels, it prolongs the action potential duration and the effective refractory period, which is the hallmark of its antiarrhythmic effect. **Why the other options are Potassium Channel Openers:** Potassium channel openers work by activating ATP-sensitive $K^+$ channels ($K_{ATP}$), leading to $K^+$ efflux, membrane hyperpolarization, and subsequent closure of voltage-gated calcium channels. This results in smooth muscle relaxation. * **Pinacidil:** A potent vasodilator used historically for hypertension; it acts directly on vascular smooth muscle. * **Diazoxide:** Used intravenously for hypertensive emergencies and orally to treat hyperinsulinemic hypoglycemia (as it inhibits insulin release by opening $K_{ATP}$ channels in pancreatic beta cells). * **Nicorandil:** A unique "dual-action" drug used in angina. It acts as both a $K_{ATP}$ channel opener and a nitrate-like nitric oxide donor, providing both arterial and venous dilation. **High-Yield Clinical Pearls for NEET-PG:** * **Minoxidil** is another important $K_{ATP}$ opener used for refractory hypertension and androgenic alopecia (side effect: hypertrichosis). * **Amiodarone** is "broad-spectrum"; while classified as Class III, it also exhibits Class I, II, and IV activities. * **Side Effects of Amiodarone:** Pulmonary fibrosis, thyroid dysfunction (due to high iodine content), corneal microdeposits, and blue-gray skin discoloration.

Question 39: Timolol is contraindicated in which of the following conditions?

A. Hypertension
B. Glaucoma
C. COPD (Correct Answer)
D. Aphakia

Explanation: **Explanation:** **Timolol** is a potent, **non-selective beta-adrenergic antagonist** (blocks both $\beta_1$ and $\beta_2$ receptors). **1. Why COPD is the Correct Answer:** The contraindication in **COPD** (and Bronchial Asthma) stems from the blockade of **$\beta_2$ receptors** located in the bronchial smooth muscles. Under normal physiological conditions, these receptors mediate bronchodilation. Blocking them leads to **bronchoconstriction**, which can precipitate a life-threatening bronchospasm in patients with reactive airway diseases. Even when administered topically as eye drops, systemic absorption through the nasolacrimal duct can occur, leading to systemic side effects. **2. Analysis of Incorrect Options:** * **A. Hypertension:** Timolol is actually used to treat hypertension (though less commonly now than newer agents) as it reduces cardiac output and renin release. * **B. Glaucoma:** This is the primary clinical indication for Timolol. It reduces aqueous humor production by the ciliary body, making it a first-line treatment for Open-Angle Glaucoma. * **C. Aphakia:** This refers to the absence of a lens. While epinephrine is contraindicated in aphakia (due to the risk of cystoid macular edema), Timolol is safe and commonly used to manage post-operative intraocular pressure. **Clinical Pearls for NEET-PG:** * **Betaxolol** is a $\beta_1$ selective (cardioselective) blocker and is the preferred beta-blocker for glaucoma patients who also have co-existing respiratory issues, as it has a lower risk of causing bronchospasm. * **Other Contraindications for Timolol:** Bradycardia, second or third-degree AV block, and overt heart failure (due to negative inotropic and chronotropic effects). * **Tip:** To minimize systemic absorption of Timolol eye drops, patients are advised to perform **nasolacrimal occlusion** (pressing the inner corner of the eye) for 1-2 minutes after instillation.

Question 40: What ECG changes occur after administration of Digoxin?

A. ST elevation
B. PR prolongation
C. QT prolongation
D. ST depression (Correct Answer)

Explanation: **Explanation:** Digoxin, a cardiac glycoside, exerts its effects by inhibiting the **Na+/K+-ATPase pump**. This leads to characteristic electrophysiological changes on an ECG, often referred to as the "Digoxin effect." **Why ST depression is correct:** Digoxin causes a characteristic **down-sloping ST-segment depression**, often described as a **"reverse tick"** or **"Salvador Dali mustache"** appearance. This occurs due to the shortening of the ventricular action potential duration and altered repolarization. It is a sign of therapeutic drug presence and does not necessarily indicate toxicity. **Analysis of Incorrect Options:** * **A. ST elevation:** This is typically seen in myocardial infarction or pericarditis. Digoxin causes depression, not elevation. * **B. PR prolongation:** While Digoxin *does* cause PR interval prolongation (due to increased vagal tone slowing AV node conduction), it is not the classic morphological change described in this context. However, in many exams, if both are present, ST depression is the most "pathognomonic" visual hallmark. * **C. QT prolongation:** Digoxin actually **shortens the QT interval** (due to decreased action potential duration). QT prolongation is associated with drugs like Class IA and III antiarrhythmics. **High-Yield Clinical Pearls for NEET-PG:** * **Most common ECG change:** Shortened QT interval. * **Most characteristic ECG change:** "Reverse Tick" ST depression. * **Earliest sign of toxicity:** Sinus bradycardia or PR prolongation. * **Most common arrhythmia in toxicity:** Ventricular Bigeminy. * **Most specific arrhythmia for toxicity:** Atrial Tachycardia with AV block. * **Electrolyte interaction:** Hypokalemia, hypomagnesemia, and hypercalcemia predispose a patient to Digoxin toxicity.

Practice by Chapter

Antihypertensive Agents

Practice Questions

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

Practice Questions

Thrombolytic Agents

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Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

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Cardiovascular Effects of Non-Cardiovascular Drugs

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