Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 941: All of the following drugs can be administered in acute hypertension during labor, except?

A. IV Labetalol
B. IV Nitroprusside (Correct Answer)
C. IV Hydralazine
D. IV Esmolol

Explanation: **Explanation** The management of hypertensive emergencies in pregnancy (Preeclampsia/Eclampsia) requires drugs that are effective yet safe for the fetus. **Why IV Nitroprusside is the Correct Answer:** Sodium Nitroprusside is generally **contraindicated** in pregnancy, especially during labor, except as a last resort. Its metabolism involves the release of cyanide. In the fetus, the enzymes required to detoxify cyanide (rhodanase) are immature, leading to a high risk of **fetal cyanide poisoning** and potential fetal demise. Additionally, it can cause a sudden, drastic reduction in placental perfusion. **Analysis of Incorrect Options:** * **IV Labetalol:** This is a first-line agent for acute hypertension in pregnancy. As a combined alpha and beta-blocker, it effectively lowers blood pressure without causing significant reflex tachycardia or compromising uteroplacental blood flow. * **IV Hydralazine:** A traditional first-line vasodilator used in pregnancy. It acts directly on vascular smooth muscle. While it may cause reflex tachycardia, it has a long-standing safety profile for treating severe preeclampsia. * **IV Esmolol:** An ultra-short-acting beta-1 selective blocker. While not a first-line agent like Labetalol, it can be used in specific acute hypertensive scenarios (e.g., intubation during C-section) because its very short half-life allows for precise control. **NEET-PG High-Yield Pearls:** * **First-line drugs for Hypertensive Emergency in Pregnancy:** IV Labetalol, IV Hydralazine, and Oral Nifedipine. * **ACE Inhibitors/ARBs:** Strictly contraindicated (Teratogenic; cause fetal renal dysgenesis and oligohydramnios). * **Drug of choice for Eclampsia seizures:** Magnesium Sulfate ($MgSO_4$). * **Target BP in Pregnancy:** Aim to keep Systolic BP between 140–150 mmHg and Diastolic BP between 90–100 mmHg to prevent maternal cerebral hemorrhage while maintaining placental perfusion.

Question 942: Which of the following is a K+ channel opener?

A. Nifedipine
B. Minoxidil (Correct Answer)
C. Enalapril
D. Atenolol

Explanation: **Explanation:** **Mechanism of Action (The Correct Answer):** **Minoxidil** is a potent direct-acting vasodilator that acts as a **Potassium (K+) channel opener**. It works by opening ATP-sensitive K+ channels in the smooth muscle cells of peripheral arterioles. This leads to K+ efflux, causing membrane hyperpolarization, which prevents the opening of voltage-gated calcium channels. The resulting decrease in intracellular calcium leads to smooth muscle relaxation and profound vasodilation. **Analysis of Incorrect Options:** * **A. Nifedipine:** This is a **Dihydropyridine Calcium Channel Blocker (CCB)**. It lowers blood pressure by inhibiting L-type calcium channels in vascular smooth muscle, not by acting on K+ channels. * **C. Enalapril:** This is an **ACE Inhibitor**. It works by inhibiting the Angiotensin-Converting Enzyme, thereby reducing the production of Angiotensin II (a potent vasoconstrictor) and decreasing aldosterone levels. * **D. Atenolol:** This is a **Cardioselective $\beta_1$-blocker**. It reduces blood pressure primarily by decreasing cardiac output and inhibiting renin release from the juxtaglomerular apparatus. **High-Yield Clinical Pearls for NEET-PG:** * **Other K+ Channel Openers:** Nicorandil (used in angina), Diazoxide (used in insulinoma/hypertensive emergencies), and Pinacidil. * **Side Effects of Minoxidil:** It causes significant salt and water retention (often requiring diuretics) and reflex tachycardia (requiring $\beta$-blockers). * **Hypertrichosis:** A unique side effect of Minoxidil is excessive hair growth; hence, it is used topically for treating **Androgenetic Alopecia**. * **Diazoxide** is unique because it also inhibits insulin release, making it useful in treating hypoglycemia due to hyperinsulinism.

Question 943: What is true about Lovastatin?

A. Inhibits HMG CoA synthetase
B. Inhibits HMG CoA reductase (Correct Answer)
C. Myositis may result from its prolonged use
D. Decreases synthesis of cholesterol and causes lenticular opacity

Explanation: ### Explanation **Correct Option: B. Inhibits HMG CoA reductase** **Mechanism of Action:** Lovastatin belongs to the 'Statin' class of drugs. It acts as a competitive inhibitor of **HMG-CoA reductase**, the rate-limiting enzyme in the mevalonate pathway of cholesterol synthesis [1], [2]. By inhibiting this enzyme, statins decrease intracellular cholesterol levels, leading to an up-regulation of LDL receptors on hepatocytes, which subsequently increases the clearance of LDL-cholesterol from the plasma [3]. **Analysis of Incorrect Options:** * **Option A:** Statins inhibit HMG-CoA **reductase**, not HMG-CoA synthetase [2]. The synthetase enzyme is involved in an earlier step of the pathway and is not the target for these drugs. * **Option C:** While myopathy and rhabdomyolysis are known side effects, they are typically **acute or subacute** idiosyncratic reactions rather than a guaranteed result of "prolonged use." Most patients tolerate long-term therapy without developing myositis. * **Option D:** While statins decrease cholesterol synthesis, **lenticular opacity (cataracts)** is not a proven clinical side effect in humans. Although early animal studies suggested a link, large-scale human clinical trials have failed to show a significant association between statin use and cataract formation. **NEET-PG High-Yield Pearls:** * **Pleiotropic Effects:** Statins provide cardiovascular benefits beyond lipid-lowering, including plaque stabilization, anti-inflammatory effects, and improved endothelial function [3], [4]. * **Timing:** Lovastatin is a prodrug and should be taken with the **evening meal** to maximize absorption and coincide with peak cholesterol synthesis (which occurs at night) [1], [4]. * **Drug Interactions:** Risk of myopathy increases when statins are co-administered with **fibrates (especially Gemfibrozil)** or CYP3A4 inhibitors (e.g., Erythromycin, Ketoconazole). * **Contraindication:** Statins are strictly **contraindicated in pregnancy** (Teratogenic) [4].

Question 944: What are the most potent drugs for reducing plasma cholesterol levels?

A. Plant sterols
B. Fibrates
C. Anion exchange resins
D. Statins (Correct Answer)

Explanation: **Statins (HMG-CoA Reductase Inhibitors)** are the most potent drugs for lowering LDL-cholesterol [2]. They work by competitively inhibiting the rate-limiting enzyme in cholesterol synthesis, HMG-CoA reductase [1, 2]. This reduction in intracellular cholesterol triggers a compensatory **upregulation of LDL receptors** on hepatocytes, leading to increased clearance of LDL from the plasma. Statins can reduce LDL levels by 20% to over 60%, depending on the dose and potency (e.g., Atorvastatin, Rosuvastatin) [2]. **Why other options are incorrect:** * **Plant sterols:** These compete with cholesterol for micellar solubilization in the intestine. While they reduce absorption, their efficacy is modest (approx. 10% reduction) compared to statins. * **Fibrates (e.g., Fenofibrate):** These are agonists of **PPAR-α**. Their primary role is reducing **triglycerides** and increasing HDL; they have a variable and much weaker effect on LDL-C. * **Anion exchange resins (e.g., Cholestyramine):** These sequester bile acids in the gut. While effective, they are less potent than statins and often cause GI side effects, limiting their clinical utility as first-line monotherapy. **High-Yield NEET-PG Pearls:** * **Pleiotropic effects:** Statins provide cardiovascular benefits beyond lipid lowering, such as plaque stabilization and anti-inflammatory effects [2]. * **Side effects:** Monitor for **myopathy/rhabdomyolysis** (increased risk when combined with fibrates) and hepatotoxicity [2]. * **Timing:** Most statins are given at bedtime because hepatic cholesterol synthesis peaks at night (except Atorvastatin and Rosuvastatin, which have long half-lives). * **Newer agents:** PCSK9 inhibitors (e.g., Evolocumab) are now considered more potent than statins but were not listed in the options.

Question 945: Which of the following drugs is commonly associated with causing a cough?

A. Lisinopril (Correct Answer)
B. Propranolol
C. Verapamil
D. Sodium nitroprusside

Explanation: **Explanation:** **Lisinopril** is an **ACE (Angiotensin-Converting Enzyme) inhibitor**. The dry, hacking cough associated with this class of drugs occurs in approximately 5–20% of patients. * **Mechanism:** ACE is identical to Kininase II, the enzyme responsible for the degradation of **bradykinin** and **Substance P**. When ACE is inhibited, these inflammatory autacoids accumulate in the upper respiratory tract and lungs. Bradykinin sensitizes sensory nerve endings, leading to the characteristic dry cough. **Analysis of Incorrect Options:** * **B. Propranolol:** A non-selective beta-blocker. While it can cause **bronchospasm** (especially in asthmatics) by blocking $\beta_2$ receptors, it does not typically cause a dry cough. * **C. Verapamil:** A non-dihydropyridine Calcium Channel Blocker (CCB). Its most characteristic side effect is **constipation** and peripheral edema, not cough. * **D. Sodium nitroprusside:** A potent vasodilator used in hypertensive emergencies. Its major toxicity is related to **cyanide and thiocyanate accumulation**, leading to metabolic acidosis and psychosis. **NEET-PG High-Yield Pearls:** 1. **Management:** If a patient develops an ACEI-induced cough, the drug should be discontinued and switched to an **ARB (Angiotensin Receptor Blocker)** like Losartan, as ARBs do not affect bradykinin levels. 2. **Gender Predilection:** The cough is more common in **females** and patients of Chinese descent. 3. **Other ACEI Side Effects:** Remember the mnemonic **CAPTOPRIL** (Cough, Angioedema, Proteinuria/Potassium excess, Taste changes, Orthostatic hypotension, Pregnancy contraindication, Renal artery stenosis contraindication, Increased renin, Leukopenia).

Question 946: A patient on antihypertensive medication develops a dry cough. Which of the following drugs might be responsible for this condition?

A. Diuretics
B. ACE inhibitors (Correct Answer)
C. Calcium channel blockers
D. Beta blockers

Explanation: **Explanation:** **Correct Option: B. ACE inhibitors** ACE inhibitors (e.g., Enalapril, Lisinopril) are the most common cause of drug-induced dry cough, occurring in 5–20% of patients. The underlying mechanism involves the inhibition of **Angiotensin-Converting Enzyme (ACE)**, which is also responsible for the degradation of **Bradykinin** and **Substance P**. When ACE is inhibited, these inflammatory peptides accumulate in the upper respiratory tract and lungs, sensitizing sensory nerve endings and triggering a persistent, non-productive cough. **Incorrect Options:** * **A. Diuretics:** Common side effects include electrolyte imbalances (hypokalemia) and hyperuricemia, but they do not affect the kinin system or cause a cough. * **C. Calcium Channel Blockers (CCBs):** These typically cause peripheral edema (Amlodipine), headache, or constipation (Verapamil), but not respiratory symptoms. * **D. Beta-blockers:** While non-selective beta-blockers (e.g., Propranolol) can cause **bronchospasm** or wheezing in asthmatics due to $\beta_2$ blockade, they do not cause a dry cough in the general hypertensive population. **High-Yield Clinical Pearls for NEET-PG:** * **Management:** If a patient develops an ACEI-induced cough, the drug should be stopped. The cough usually resolves within 1–4 weeks. * **Alternative:** **Angiotensin Receptor Blockers (ARBs)** like Losartan are the preferred alternative because they do not affect ACE or bradykinin levels. * **Other Side Effects of ACEIs:** Remember the mnemonic **CAPTOPRIL**: **C**ough, **A**ngioedema, **P**roteinuria, **T**aste changes, **O**rthostatic hypotension, **P**regnancy contraindication (Teratogenic), **R**enal artery stenosis contraindication, **I**ncreased potassium (Hyperkalemia), **L**eukopenia.

Question 947: A patient with hypertension, tachycardia and early renal involvement is prescribed an ARB (telmisartan). What is the most likely mechanism by which the drug helps improve heart rate and blood pressure?

A. By decreasing cardiac output directly
B. By decreasing peripheral vascular resistance (Correct Answer)
C. By directly blocking beta-1 receptors
D. By increasing sodium excretion via loop diuretics

Explanation: ***By decreasing peripheral vascular resistance*** - ARBs (Angiotensin Receptor Blockers) like **telmisartan** selectively block AT1 receptors, preventing angiotensin II from binding - This blockade leads to **vasodilation** (reduced vasoconstriction) → decreased peripheral vascular resistance (afterload reduction) - Lower afterload reduces **blood pressure** and decreases cardiac workload, which secondarily **improves heart rate** - ARBs also provide **renoprotection** by reducing intraglomerular pressure, making them ideal for hypertension with early renal involvement *By decreasing cardiac output directly* - ARBs do not have direct negative inotropic effects on the heart - Any reduction in cardiac output is secondary to decreased afterload, not a primary mechanism *By directly blocking beta-1 receptors* - This describes the mechanism of **beta-blockers** (e.g., metoprolol, atenolol), not ARBs - Beta-blockers directly reduce heart rate and contractility; ARBs work via peripheral vasodilation *By increasing sodium excretion via loop diuretics* - This describes the mechanism of **loop diuretics** (e.g., furosemide), not ARBs - While ARBs may have mild diuretic effects, their primary mechanism is reducing peripheral vascular resistance through AT1 receptor blockade

Question 948: A patient with a history of hypertension is given the drug 'X'. Identify 'X'?

A. Aliskiren (Correct Answer)
B. Losartan
C. Spironolactone
D. Captopril

Explanation: ***Aliskiren*** - Aliskiren is a **direct renin inhibitor**. The diagram shows that drug 'X' directly inhibits the release or action of **renin** from the kidneys. - By inhibiting renin, it blocks the first and rate-limiting step of the **Renin-Angiotensin-Aldosterone System (RAAS)**, preventing the conversion of **angiotensinogen** to **angiotensin I**. *Captopril* - Captopril is an **Angiotensin-Converting Enzyme (ACE) inhibitor**. It acts later in the pathway to block the conversion of **angiotensin I** to **angiotensin II**. - This mechanism is different from drug 'X', which acts on **renin** at the beginning of the cascade. *Spironolactone* - Spironolactone is an **aldosterone antagonist** and a potassium-sparing diuretic. It acts at the end of the RAAS pathway. - It works by blocking **aldosterone receptors** in the distal tubules of the kidney, preventing sodium and water reabsorption, which is downstream from the action of renin. *Losartan* - Losartan is an **Angiotensin II Receptor Blocker (ARB)**. It prevents **angiotensin II** from binding to its receptors on blood vessels and the adrenal glands. - This action occurs much later in the pathway compared to the direct inhibition of **renin** shown by drug 'X'.

Question 949: Which of these drugs stimulates PPAR-alpha (Peroxisome proliferator-activated receptor alpha)?

A. Ezetimibe
B. Colestipol
C. Simvastatin
D. Gemfibrozil (Correct Answer)

Explanation: ***Gemfibrozil***- It belongs to the **fibrate class** of lipid-lowering drugs, and its primary mechanism is activating the **Peroxisome Proliferator-Activated Receptor alpha (PPAR-alpha)**.- PPAR-alpha activation leads to increased synthesis of **lipoprotein lipase (LPL)**, enhancing the catabolism of **VLDL** and chylomicrons, which effectively lowers **triglyceride** levels.*Ezetimibe*- This drug selectively inhibits the absorption of dietary and biliary cholesterol by blocking the **NPC1L1 (Niemann-Pick C1-Like 1)** transporter protein located on the brush border of the small intestine enterocytes.- It does not interact with PPAR-alpha but is typically used to reduce **LDL cholesterol**, often in combination with statins.*Colestipol*- It is a **bile acid sequestrant** (resin) that binds negatively charged bile acids in the intestinal lumen, forming a non-absorbable complex that is excreted in stool.- The loss of bile acids forces the liver to increase the synthesis of new bile acids from cholesterol, thereby upregulating hepatic **LDL receptors** and reducing plasma LDL levels.*Simvastatin*- This drug is an HMG-CoA reductase inhibitor (**statin**), which is the rate-limiting enzyme in hepatic cholesterol synthesis.- By reducing intracellular cholesterol synthesis, it causes upregulation of surface **LDL receptors** on hepatocytes, increasing LDL clearance from the blood.

Question 950: A patient with atrial fibrillation is started on a medication that prolongs the QT interval by blocking potassium channels. Which of the following is the most likely adverse effect of this antiarrhythmic drug?

A. Hypotension
B. Bradycardia
C. Atrial flutter
D. Torsades de pointes (Correct Answer)

Explanation: ***Torsades de pointes*** - Prolongation of the **QT interval**, often secondary to **potassium channel blockade** (Class III antiarrhythmics), is the major risk factor for developing **Torsades de pointes (TdP)**, a polymorphic ventricular tachycardia. - TdP is related to early afterdepolarizations (EADs) that occur during the prolonged repolarization phase (QT prolongation) of the ventricular action potential. *Bradycardia* - While some antiarrhythmics like beta-blockers (Class II) or calcium channel blockers (Class IV) can cause bradycardia, direct potassium channel blockers (Class III) primarily impact repolarization, not heart rate initiation or conduction velocity. - Bradycardia is more commonly associated with drugs that decrease automaticity (e.g., **Amiodarone** has mixed effects, but its beta-blocking action can cause bradycardia). *Hypotension* - Hypotension can be a side effect of rapidly infused antiarrhythmics or those with significant peripheral vasodilatory effects (e.g., **Amiodarone** or Class I agents), but it is not the classic, unique cardiotoxic adverse effect linked specifically to QT prolongation. - This adverse effect is related to systemic pharmacodynamics rather than the electrophysiological mechanism of potassium channel blockade. *Atrial flutter* - Atrial flutter is a regular, rapid atrial rhythm (often 250-350 bpm) that can occur as a primary disease or sometimes transition from atrial fibrillation, but it is typically not a direct, life-threatening adverse effect cause by potassium channel blocking that prolongs QT interval. - Antiarrhythmic therapy (especially Class I and III agents) can rarely turn pre-existing **atrial fibrillation** into slower, organized **atrial flutter** with 1:1 conduction, which is dangerous, but TdP remains the principal concern for QT-prolonging drugs.

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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