Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 651: Mephenteramine can be used in hypovolemic shock, although intravenous fluid supplementation is primary treatment. It acts by:

A. Increasing cardiac output
B. Increasing systolic blood pressure
C. Increasing diastolic blood pressure
D. All of the above (Correct Answer)

Explanation: **Explanation:** Mephentermine is a **mixed-acting sympathomimetic** amine. It acts both directly by stimulating adrenergic receptors and indirectly by releasing endogenous norepinephrine from nerve endings. Its pharmacological profile makes it a potent cardiovascular stimulant. **Why "All of the above" is correct:** Mephentermine acts on both **$\alpha$ and $\beta$ receptors**, leading to a multi-faceted hemodynamic response: 1. **Increasing Cardiac Output (Option A):** Through its $\beta_1$-agonist action, it exerts positive inotropic (increased force) and chronotropic (increased rate) effects, thereby increasing the total cardiac output. 2. **Increasing Systolic Blood Pressure (Option B):** The increase in cardiac output directly elevates the systolic blood pressure (SBP). 3. **Increasing Diastolic Blood Pressure (Option C):** Through its $\alpha$-agonist action, it causes peripheral vasoconstriction, which increases systemic vascular resistance (SVR), leading to a rise in diastolic blood pressure (DBP). **Why individual options are insufficient:** While options A, B, and C are individually correct, they only describe a partial effect of the drug. Since Mephentermine simultaneously improves contractility and vascular tone, it raises all three parameters, making "All of the above" the most accurate clinical description of its action. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Use:** It is most commonly used to prevent or treat **hypotension following spinal anesthesia**. * **Hypovolemic Shock:** While it can support BP, it is **never** the first-line treatment; aggressive IV fluid resuscitation remains the priority. * **CNS Effect:** It has mild CNS stimulant properties (similar to amphetamines) but is much less potent. * **Metabolism:** It is not metabolized by MAO; hence, it has a longer duration of action compared to catecholamines.

Question 652: What is the most important adverse effect of sotalol?

A. Torsades de pointes (Correct Answer)
B. Heart block
C. Pulmonary fibrosis
D. Vomiting

Explanation: **Sotalol** is a unique antiarrhythmic agent that possesses both **Class II (Beta-blocking)** and **Class III (Potassium channel blocking)** properties [1]. **Why Torsades de Pointes (TdP) is the correct answer:** The most significant and life-threatening adverse effect of sotalol is related to its Class III action. By blocking the rapid delayed rectifier potassium current ($I_{Kr}$), sotalol prolongs the action potential duration and the **QT interval** on the ECG. Excessive prolongation of the QT interval can trigger a specific type of polymorphic ventricular tachycardia known as **Torsades de pointes** [3]. This risk is dose-dependent and is further increased in patients with renal impairment (as sotalol is renally excreted), hypokalemia [2], or bradycardia. **Analysis of Incorrect Options:** * **B. Heart block:** While sotalol’s beta-blocking (Class II) effect can cause bradycardia or AV block [1], it is generally less common and less life-threatening than the risk of TdP. * **C. Pulmonary fibrosis:** This is a classic side effect of **Amiodarone**, another Class III antiarrhythmic, but it is not associated with sotalol. * **D. Vomiting:** While gastrointestinal upset can occur with many drugs, it is a non-specific side effect and not the "most important" or characteristic risk of sotalol. **High-Yield NEET-PG Pearls:** * **Pure Class III vs. Mixed:** Unlike Amiodarone (which has Class I, II, III, and IV actions), Sotalol is primarily Class II and III [1]. * **Reverse Use-Dependence:** Sotalol exhibits "reverse use-dependence," meaning its QT-prolonging effect is **more pronounced at slower heart rates**, increasing the risk of TdP during bradycardia. * **Renal Dosing:** Always monitor creatinine clearance; sotalol is 100% renally excreted. * **Contraindication:** Avoid in patients with baseline QTc >450ms or significant asthma (due to non-selective beta-blockade).

Question 653: What is methyldopa useful in the treatment of?

A. Pregnancy-induced hypertension (Correct Answer)
B. Parkinsonism
C. Hirsutism
D. Fever

Explanation: **Explanation:** **Methyldopa** is a centrally acting alpha-2 adrenergic agonist. It is considered a first-line antihypertensive agent for **Pregnancy-Induced Hypertension (PIH)** and chronic hypertension in pregnancy. **Why Option A is correct:** Methyldopa is a prodrug converted into $\alpha$-methylnorepinephrine, which stimulates central $\alpha_2$ receptors in the nucleus tractus solitarius. This decreases sympathetic outflow to the heart and blood vessels, leading to a reduction in peripheral vascular resistance. It is preferred in pregnancy because it has a long-standing safety record, is non-teratogenic, and does not compromise uteroplacental blood flow. **Why other options are incorrect:** * **B. Parkinsonism:** Methyldopa actually inhibits the enzyme DOPA decarboxylase, which can decrease dopamine levels in the brain. Consequently, it can worsen Parkinsonism or cause extrapyramidal side effects. * **C. Hirsutism:** Methyldopa has no anti-androgenic properties. Drugs used for hirsutism include Spironolactone or Finasteride. * **D. Fever:** Methyldopa is not an antipyretic. In fact, "Drug Fever" is a known side effect of methyldopa as part of a hypersensitivity reaction. **High-Yield Clinical Pearls for NEET-PG:** 1. **Coombs Test:** Long-term use of Methyldopa can cause a **Positive Direct Coombs Test** (in ~20% of patients), though hemolytic anemia is rare. 2. **Hepatotoxicity:** It can cause hepatitis and is contraindicated in active hepatic disease. 3. **Other Drugs for PIH:** Along with Methyldopa, **Labetalol** (often first choice now) and **Hydralazine** are commonly used. ACE inhibitors and ARBs are strictly contraindicated in pregnancy due to fetal renal dysgenesis.

Question 654: Latanoprost (a PGF2 alpha analog) is primarily used in the treatment of which condition?

A. Maintenance of the ductus arteriosus
B. Pulmonary hypertension
C. Gastric mucosal protection
D. Glaucoma (Correct Answer)

Explanation: **Explanation:** **Latanoprost** is a synthetic analog of **Prostaglandin F2-alpha (PGF2α)**. It is the first-line treatment for **Open-Angle Glaucoma** and ocular hypertension. **1. Why Option D is Correct:** Latanoprost acts as a selective agonist at FP receptors in the eye. Its primary mechanism of action is increasing the **uveoscleral outflow** of aqueous humor (rather than the traditional trabecular route). By enhancing drainage, it effectively lowers intraocular pressure (IOP). Its once-daily dosing and high efficacy make it a preferred agent over beta-blockers. **2. Why Other Options are Incorrect:** * **Option A:** Maintenance of ductus arteriosus is achieved using **Alprostadil (PGE1)**. Conversely, NSAIDs like Indomethacin are used to close a patent ductus arteriosus (PDA). * **Option B:** Pulmonary hypertension is treated with Prostacyclin (PGI2) analogs like **Epoprostenol, Treprostinil, or Iloprost**, which act as potent vasodilators. * **Option C:** Gastric mucosal protection is the role of **Misoprostol (PGE1 analog)**, which inhibits acid secretion and stimulates mucus/bicarbonate production. **3. High-Yield Clinical Pearls for NEET-PG:** * **Side Effects:** A unique and frequently tested side effect of Latanoprost is **increased brown pigmentation of the iris** and **hypertrichosis** (thickening and darkening of eyelashes). * **Other PGF2α analogs:** Travoprost and Bimatoprost (Bimatoprost is also used for eyelash hypotrichosis). * **Contraindication:** Caution should be exercised in patients with active intraocular inflammation (uveitis) or macular edema.

Question 655: Which of the following drugs does NOT cause pericarditis?

A. Amiodarone and Bretylium (Correct Answer)
B. Hydralazine and Bretylium
C. Hydralazine and Amiodarone
D. Methysergide and Bretylium

Explanation: ### Explanation The correct answer is **Amiodarone and Bretylium**. **1. Why the correct answer is right:** Pericarditis is most commonly drug-induced via two mechanisms: **Drug-Induced Lupus Erythematosus (DILE)** or **Retroperitoneal/Mediastinal Fibrosis**. * **Amiodarone** is primarily associated with pulmonary fibrosis, thyroid dysfunction, and corneal deposits, but it does **not** cause pericarditis or DILE. * **Bretylium** is a Class III antiarrhythmic used in refractory ventricular fibrillation; it is not associated with pericardial inflammation or lupus-like syndromes. **2. Analysis of incorrect options:** * **Hydralazine:** This is a classic "high-yield" cause of **Drug-Induced Lupus Erythematosus (DILE)**. Patients present with fever, joint pain, and serositis (pleuritis or **pericarditis**). It is a common culprit in options B and C. * **Methysergide:** This drug (used for migraine prophylaxis) is notorious for causing **retroperitoneal, endocardial, and mediastinal fibrosis**, which can lead to constrictive pericarditis. This makes option D incorrect. * **Procainamide:** (Though not in the options, it is the most common cause of DILE) also causes pericarditis. **3. Clinical Pearls for NEET-PG:** * **DILE Mnemonics:** Remember **"SHIPP"** (Sulfonamides, Hydralazine, Isoniazid, Phenytoin, Procainamide) as drugs causing Lupus and subsequent pericarditis. * **Diagnostic Marker:** Anti-histone antibodies are positive in >95% of DILE cases, while Anti-dsDNA is usually negative. * **Amiodarone Side Effects:** Focus on the "Cs": **C**orneal deposits, **C**utaneous (Blue-man syndrome), **C**ardiac (Bradycardia), **C**hronic pulmonary fibrosis, and **C**irrhosis. Pericarditis is notably absent.

Question 656: Which one of the following drugs should be avoided in Wolff-Parkinson-White (WPW) Syndrome?

A. Digoxin (Correct Answer)
B. Adenosine
C. Procainamide
D. Amiodarone

Explanation: In **Wolff-Parkinson-White (WPW) Syndrome**, patients possess an accessory pathway (Bundle of Kent) that bypasses the AV node. The primary danger in WPW is the development of Atrial Fibrillation (AF), where rapid impulses can travel down the accessory pathway, leading to Ventricular Fibrillation and sudden cardiac death [1]. **Why Digoxin is Avoided (The Correct Answer):** Digoxin (along with Calcium Channel Blockers like Verapamil and Beta-blockers) primarily acts by slowing conduction through the **AV node** [2]. By blocking the physiological "gatekeeper," Digoxin paradoxically enhances conduction through the **accessory pathway**. This decreases the refractory period of the bypass tract, allowing more rapid impulses to reach the ventricles, potentially triggering fatal arrhythmias. **Analysis of Other Options:** * **Procainamide:** This is often the drug of choice for stable WPW with tachycardia. It works by increasing the refractory period of both the atrium and the **accessory pathway**, thereby slowing the rapid conduction. * **Amiodarone:** This is a Class III antiarrhythmic that increases the refractory period of all cardiac tissues, including the accessory pathway. It is generally considered safe in WPW. * **Adenosine:** While Adenosine blocks the AV node (similar to Digoxin), its ultra-short half-life makes it the drug of choice for terminating **Orthodromic** AVRT. However, it is avoided in WPW patients presenting with AF. In the context of this question, Digoxin is the classic "absolute" avoidance due to its prolonged effect. **High-Yield Clinical Pearls for NEET-PG:** * **The "ABCD" of drugs to avoid in WPW with AF:** **A**denosine (in AF), **B**eta-blockers, **C**alcium channel blockers (Verapamil/Diltiazem), and **D**igoxin. * **Treatment of Choice (Hemodynamically Unstable):** DC Cardioversion. * **Definitive Treatment:** Radiofrequency Catheter Ablation of the accessory pathway.

Question 657: Which one of the following drugs is most likely to block K+ channels in the heart responsible for the delayed rectifier current?

A. Amiodarone (Correct Answer)
B. Encainide
C. Lidocaine
D. Phenytoin

Explanation: **Explanation:** The question tests the classification of antiarrhythmic drugs based on the **Vaughan-Williams classification**. **Why Amiodarone is Correct:** Amiodarone is a **Class III antiarrhythmic agent**. The primary mechanism of Class III drugs is the blockade of **potassium (K+) channels**, specifically the **delayed rectifier current ($I_{Kr}$)** [2]. By blocking these channels during Phase 3 of the cardiac action potential, Amiodarone prolongs the action potential duration (APD) and the effective refractory period (ERP) [2]. While Amiodarone has Class I, II, and IV activities, its K+ channel-blocking effect is its defining Class III characteristic. **Why the Other Options are Incorrect:** * **Encainide (Option B):** This is a **Class IC** agent. Its primary action is the potent blockade of fast sodium (Na+) channels (Phase 0), significantly slowing conduction velocity with minimal effect on the action potential duration [1]. * **Lidocaine (Option C):** This is a **Class IB** agent. It blocks Na+ channels in the inactivated state and actually tends to *shorten* the action potential duration, rather than blocking K+ channels. * **Phenytoin (Option D):** Also classified as a **Class IB** antiarrhythmic, it is primarily used for digitalis-induced arrhythmias. Like lidocaine, it blocks Na+ channels and does not target the delayed rectifier K+ current. **High-Yield NEET-PG Pearls:** * **Amiodarone Side Effects:** Pulmonary fibrosis, hypothyroidism/hyperthyroidism (due to high iodine content), corneal microdeposits, and "blue-gray" skin discoloration. * **ECG Changes:** Class III agents typically cause **QT interval prolongation**, which carries a risk of *Torsades de Pointes* [2] (though this risk is lower with Amiodarone compared to Sotalol). * **Pure Class III:** While Amiodarone is mixed, **Dofetilide and Ibutilide** are considered "pure" K+ channel blockers.

Question 658: A male patient presents with headache, profuse sweating, and palpitations with a blood pressure of 180/120 mm Hg. What is the drug of choice?

A. Nifedipine
B. Labetalol (Correct Answer)
C. Prazosin
D. Phenoxybenzamine

Explanation: ### Explanation **Correct Answer: B. Labetalol** **Clinical Reasoning:** The patient presents with the classic triad of **headache, sweating, and palpitations** alongside severe hypertension (180/120 mm Hg). This presentation is highly suggestive of a **Pheochromocytoma** or a **Hypertensive Emergency**. In states of catecholamine excess (like pheochromocytoma or clonidine withdrawal), there is massive stimulation of both alpha ($\alpha$) and beta ($\beta$) receptors. **Labetalol** is the drug of choice here because it is a **combined $\alpha$ and $\beta$ blocker** (ratio of 1:7 for IV administration). It simultaneously lowers peripheral resistance (via $\alpha_1$ blockade) and prevents reflex tachycardia (via $\beta$ blockade), providing rapid and balanced blood pressure control. **Analysis of Incorrect Options:** * **A. Nifedipine:** While a Calcium Channel Blocker, it can cause significant reflex tachycardia, which may worsen palpitations and cardiac workload in a catecholamine-excess state. * **C. Prazosin:** This is a selective $\alpha_1$ blocker. While it lowers BP, it does not address the $\beta$-mediated tachycardia and is generally used for chronic management, not acute hypertensive crises. * **D. Phenoxybenzamine:** This is an irreversible, non-selective $\alpha$ blocker. It is the **drug of choice for preoperative management** of pheochromocytoma to expand vascular volume, but it is not used for the acute management of a hypertensive crisis due to its slow onset and risk of profound orthostatic hypotension. **High-Yield Clinical Pearls for NEET-PG:** * **Gold Standard Rule:** Never give a pure $\beta$-blocker (e.g., Propranolol) alone in pheochromocytoma. Blocking $\beta_2$ (vasodilation) while $\alpha$ receptors are stimulated leads to **"unopposed alpha stimulation,"** causing a paradoxical, life-threatening rise in BP. * **Labetalol in Pregnancy:** It is also a first-line agent for Hypertensive Emergencies in pregnancy (Preeclampsia/Eclampsia). * **Phentolamine:** If the question specifically mentions a "hypertensive crisis due to pheochromocytoma" or "cheese reaction," Phentolamine (non-selective $\alpha$ blocker) is also a classic correct answer.

Question 659: What is the drug of choice for torsades de pointes?

A. Terfenadine
B. Quinidine
C. Isoprenaline
D. Magnesium sulphate (Correct Answer)

Explanation: **Explanation:** **Torsades de Pointes (TdP)** is a specific form of polymorphic ventricular tachycardia characterized by a "twisting of points" around the isoelectric line, typically occurring in the setting of a prolonged QT interval. **Why Magnesium Sulphate (MgSO₄) is the Correct Answer:** Magnesium sulphate is the **drug of choice** for both the treatment and prevention of recurrences of TdP, regardless of the patient's baseline magnesium levels. It works by blocking **L-type calcium channels**, which suppresses the early after-depolarizations (EADs) that trigger the arrhythmia. It also stabilizes the cardiac membrane without significantly shortening the QT interval itself. **Analysis of Incorrect Options:** * **A. Terfenadine:** This is a non-sedating antihistamine that was withdrawn from the market because it actually **causes** TdP by blocking hERG potassium channels (leading to QT prolongation), especially when taken with CYP3A4 inhibitors. * **B. Quinidine:** A Class IA antiarrhythmic known for causing "Quinidine Syncope." It blocks potassium channels, prolongs the QT interval, and is a notorious **precipitant** of TdP. * **C. Isoprenaline:** While it can be used to increase heart rate (overdrive pacing) to shorten the QT interval in bradycardia-dependent TdP, it is a second-line agent and not the initial drug of choice. **NEET-PG High-Yield Pearls:** * **Dose:** 2 grams IV bolus over 1–2 minutes. * **Congenital Long QT Syndromes:** For Jervell and Lange-Nielsen or Romano-Ward syndromes, **Beta-blockers** (like Propranolol) are the mainstay of chronic management, but MgSO₄ remains the acute treatment for TdP episodes. * **Avoid:** Class IA (Quinidine, Procainamide) and Class III (Sotalol, Amiodarone) antiarrhythmics, as they worsen QT prolongation.

Question 660: Propranolol is contraindicated in a patient of angina pectoris who is already receiving which of the following medications?

A. Nifedipine
B. Aspirin
C. Verapamil (Correct Answer)
D. Isosorbide mononitrate

Explanation: ### Explanation The correct answer is **Verapamil**. **Why Verapamil is the Correct Answer:** The combination of **Propranolol** (a non-selective beta-blocker) and **Verapamil** (a non-dihydropyridine calcium channel blocker) is contraindicated due to their synergistic depressant effects on the heart. Both drugs: 1. **Decrease Heart Rate (Negative Chronotropy):** Both suppress the SA node. 2. **Decrease AV Conduction (Negative Dromotropy):** Both prolong the refractory period of the AV node. 3. **Decrease Contractility (Negative Inotropy):** Both reduce myocardial force. Co-administration carries a high risk of severe **bradycardia, AV block, and even cardiac arrest or heart failure.** **Why Other Options are Incorrect:** * **A. Nifedipine:** This is a dihydropyridine (DHP) CCB. Unlike Verapamil, DHPs primarily cause vasodilation and may trigger reflex tachycardia. Beta-blockers are actually **combined** with DHPs to counteract this reflex tachycardia and provide a synergistic anti-anginal effect. * **B. Aspirin:** This is an antiplatelet agent used routinely in angina for secondary prevention of MI. There is no contraindication for its use with Propranolol. * **D. Isosorbide mononitrate:** Nitrates cause peripheral vasodilation and reflex tachycardia. Combining them with Propranolol is a standard therapeutic strategy to balance heart rate and reduce myocardial oxygen demand. **NEET-PG High-Yield Pearls:** * **The "Safe" Combination:** Beta-blocker + Dihydropyridine (e.g., Amlodipine/Nifedipine). * **The "Dangerous" Combination:** Beta-blocker + Non-Dihydropyridine (Verapamil > Diltiazem). * **Propranolol Specifics:** It can also cause **bronchospasm** (contraindicated in Asthma/COPD) and mask **hypoglycemic symptoms** in diabetics (except sweating). * **Variant Angina (Prinzmetal):** Propranolol is contraindicated here as it may cause unopposed alpha-mediated coronary vasospasm.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

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

Practice Questions

Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

Practice Questions

Cardiovascular Effects of Non-Cardiovascular Drugs

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