Cardiovascular Drugs Practice Questions

Q: Renolazine is used in the management of which condition?

Angina. **Explanation:** **Ranolazine** is a novel anti-anginal drug used primarily in the management of **chronic stable angina**. **Why Angina is Correct:** The core mechanism of Ranolazine involves the **selective inhibition of the late inward sodium current ($I_{Na}$)** in myocardial cells. During ischemia, there is an excess influx of sodium through these channels, which leads to an overload of intracellular calcium (via the $Na^+/Ca^{2+}$ exchanger). High calcium levels cause wall stiffness and increased diastolic tension, further compromising coronary blood flow. By blocking the late $I_{Na}$, Ranolazine reduces calcium overload, improves myocardial relaxation (diastolic function), and enhances coronary perfusion without significantly affecting heart rate or blood pressure. **Why Other Options are Incorrect:** * **Hypertension:** Ranolazine has negligible effects on systemic blood pressure and is not indicated for hypertension. * **Tachycardia:** Unlike beta-blockers or calcium channel blockers, Ranolazine does not significantly reduce the heart rate. * **Arrhythmia:** While Ranolazine can cause a modest prolongation of the **QT interval** (by blocking $I_{Kr}$ channels), it is not used as a primary anti-arrhythmic agent. In fact, its effect on the QT interval requires cautious monitoring. **High-Yield Clinical Pearls for NEET-PG:** * **Metabolism:** It is metabolized by **CYP3A4**; therefore, it is contraindicated with potent inhibitors like ketoconazole or clarithromycin. * **Unique Feature:** It is a "p-FOX inhibitor" (partial fatty acid oxidation inhibitor), shifting myocardial metabolism from fatty acids to glucose, which requires less oxygen. * **Usage:** It is typically used as a **second-line** add-on therapy when symptoms are not controlled by first-line agents (Beta-blockers/CCBs). * **Side Effects:** Dizziness, headache, constipation, and QT prolongation.

Q: All of the following drugs cause arteriolar dilatation except?

Glyceryl trinitrate. The primary mechanism of action for vasodilators depends on whether they act on the arterial side, the venous side, or both. **Why Glyceryl Trinitrate (GTN) is the correct answer:** Glyceryl trinitrate (Nitroglycerin) is a **predominant venodilator** [1]. At therapeutic doses, it acts mainly on the capacitance vessels (veins), leading to peripheral pooling of blood, decreased venous return, and a reduction in **preload** [2]. While it can cause arteriolar dilatation at very high doses, its primary clinical effect and classification distinguish it from pure arteriolar dilators [2]. **Analysis of Incorrect Options:** * **Hydralazine:** A direct-acting **arteriolar dilator** [3]. It acts by increasing cGMP levels and interfering with calcium release from the sarcoplasmic reticulum in smooth muscle. It has minimal effect on veins [1], [3]. * **Diazoxide:** A potent **arteriolar dilator** that works by opening ATP-sensitive potassium channels ($K_{ATP}$), leading to hyperpolarization of smooth muscle cells [3]. It is used in hypertensive emergencies and insulinomas. * **Nifedipine:** A Calcium Channel Blocker (Dihydropyridine class) that specifically targets L-type calcium channels in the **arteriolar smooth muscle**, causing significant vasodilation and a reduction in afterload [3]. **NEET-PG High-Yield Pearls:** 1. **Pure Arteriolar Dilators:** Hydralazine, Minoxidil, Diazoxide, and Fenoldopam [3]. 2. **Mixed (Arterial + Venous) Dilators:** Sodium Nitroprusside (SNP), Alpha-blockers, and ACE inhibitors. 3. **Drug of Choice (DOC):** Hydralazine is the DOC for hypertension in pregnancy (though Labetalol is often preferred first-line now). 4. **Side Effect:** Pure arteriolar dilators often cause **reflex tachycardia** and fluid retention; therefore, they are frequently co-administered with Beta-blockers and diuretics [1], [3].

Q: A patient has been taking digoxin for several years and is about to receive atropine for some other indication. A common side effect of digoxin that can be blocked by atropine is:

Increased PR interval on the ECG. Explanation:The correct answer is C. Increased PR interval on the ECG.Mechanism of Action:Digoxin exerts its effects through two primary mechanisms: inhibition of the Na+/K+ ATPase pump (leading to positive inotropy) and parasympathomimetic (vagomimetic) action. By increasing vagal tone, digoxin slows conduction through the Atrioventricular (AV) node. On an ECG, AV nodal delay is represented by an increased PR interval [1]. Since atropine is a muscarinic antagonist (parasympatholytic), it blocks the vagal effects of digoxin on the AV node, thereby preventing or reversing the prolongation of the PR interval.Analysis of Incorrect Options: A. Decreased appetite: This is a common early sign of digoxin toxicity caused by direct stimulation of the Chemoreceptor Trigger Zone (CTZ). It is not mediated by the vagus nerve and thus cannot be blocked by atropine. B. Increased cardiac contractility: This is the therapeutic goal of digoxin, achieved by increasing intracellular calcium via Na+/K+ ATPase inhibition. This mechanical effect is independent of the autonomic nervous system and is not affected by atropine. D. Tachycardia: Digoxin typically causes bradycardia due to its vagomimetic effects. Tachycardia (specifically atrial tachycardia with AV block) is a sign of toxicity, but atropine would likely worsen a tachycardia rather than block it.High-Yield Clinical Pearls for NEET-PG: ECG Changes with Digoxin: Earliest change is a decreased QT interval [1]; most characteristic is the "reverse tick" or "sagging" ST-segment depression (Salvador Dali sign). Vagal Effect: Digoxin is used in Atrial Fibrillation primarily to control ventricular rate by increasing the refractory period of the AV node via the vagus nerve. Antidote: For life-threatening toxicity, the treatment of choice is Digoxin-specific antibody fragments (DigiFab). Atropine is specifically used to treat digoxin-induced symptomatic bradycardia or high-grade AV block.

Q: Which of the following drugs does not increase the QT interval?

Digitalis. **Explanation:** The correct answer is **Digitalis (Digoxin)**. **Why Digitalis is correct:** Digitalis acts by inhibiting the $Na^+/K^+$ ATPase pump, which leads to an increase in intracellular calcium. Electrophysiologically, Digitalis **shortens the action potential duration (APD)** and the **QT interval**. It is well-known for causing "ST-segment sagging" (reverse tick sign) and a shortened QT interval, which is a classic finding on an ECG of a patient on Digoxin. **Why the other options are incorrect:** * **Amiodarone (Class III Antiarrhythmic):** Its primary mechanism is blocking potassium channels, which prolongs Phase 3 of the action potential, thereby increasing the QT interval. * **Quinidine (Class IA Antiarrhythmic):** It blocks both sodium and potassium channels. By blocking potassium channels, it prolongs repolarization and increases the QT interval. It is a notorious cause of *Torsades de Pointes*. * **Amitriptyline (Tricyclic Antidepressant):** TCAs have "quinidine-like" effects on the heart. They block myocardial sodium and potassium channels, leading to QRS widening and QT interval prolongation, especially in overdose. **High-Yield Clinical Pearls for NEET-PG:** * **QT Prolonging Drugs (Mnemonic: ABCDE):** **A**ntiarrhythmics (Class IA, III), **B**iotics (Macrolides, Fluoroquinolones), **C**an't-be-depressed (TCAs, Antipsychotics), **D**efective electrolytes (Hypokalemia, Hypomagnesemia, Hypocalcemia), **E**metics (Ondansetron). * **Digitalis ECG Changes:** Shortened QT, ST-segment depression (scooped appearance), T-wave inversion, and PR interval prolongation. * **Torsades de Pointes:** A polymorphic ventricular tachycardia associated with a prolonged QT interval. Interestingly, while Amiodarone prolongs the QT, it has a lower risk of causing Torsades compared to other Class III drugs.

Q: A hypertensive patient is taking tablet atenolol 200 mg/day in divided doses. After anesthesia, their heart rate fell from 50 beats/min to 40 beats/min. What is the appropriate treatment to improve the heart rate?

IV atropine. ### Explanation **Correct Option: B. IV Atropine** The patient is experiencing symptomatic bradycardia (HR 40 bpm) likely due to the high dose of **Atenolol** (a cardioselective $\beta_1$ blocker) exacerbated by anesthesia. * **Mechanism:** Beta-blockers reduce heart rate by decreasing sympathetic drive to the SA node. In such cases, the primary treatment for hemodynamically significant bradycardia is **IV Atropine**. * Atropine is a muscarinic antagonist that blocks the parasympathetic (vagal) input to the heart. By inhibiting the "brake" (vagus nerve), it allows the heart rate to increase, effectively counteracting the beta-blocker-induced bradycardia. **Why Other Options are Incorrect:** * **A. IV Adrenaline:** While it increases heart rate, it is generally reserved for cardiac arrest or severe anaphylaxis. In a patient on beta-blockers, adrenaline can cause "unopposed alpha-stimulation," leading to severe hypertension and reflex bradycardia. * **C. IV Isoprenaline:** This is a non-selective beta-agonist. While it can increase heart rate, its effect is competitively inhibited by the high dose of Atenolol already present in the patient's system, making it less effective. * **D. Dobutamine:** This is primarily an inotrope used in cardiogenic shock. Like isoprenaline, its efficacy is reduced in the presence of beta-blockade. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC) for Beta-blocker Overdose:** If atropine fails, the specific antidote is **IV Glucagon**. Glucagon increases cAMP in the myocardium via independent receptors, bypassing the blocked beta-receptors. * **Atenolol Dosing:** The standard dose is 25–100 mg/day. 200 mg/day is a high dose, increasing the risk of profound bradycardia and loss of cardioselectivity. * **Vagal Tone:** Anesthesia often increases vagal tone; when combined with beta-blockers, it significantly predisposes patients to intraoperative bradyarrhythmias.

Q: All of the following are true about digoxin except:

It is 95% plasma protein bound. **Explanation:** The correct answer is **C** because Digoxin has **low plasma protein binding (approximately 20–25%)**. This is a high-yield pharmacokinetic fact; most of the drug is sequestered in skeletal muscle (its primary reservoir) rather than bound to albumin. **Analysis of Options:** * **Option A (True):** Digoxin exerts a **vagomimetic effect** on the SA and AV nodes. By increasing vagal tone, it slows the heart rate (negative chronotropy) and decreases conduction velocity through the AV node, making it useful in controlling ventricular rate in atrial fibrillation. * **Option B (True):** The primary mechanism of action is the inhibition of the **Na+/K+ ATPase pump** on the sarcolemma. This leads to an increase in intracellular Na+, which subsequently slows the Na+/Ca2+ exchanger, increasing intracellular Ca2+ levels and resulting in increased contractility (**positive inotropy**). * **Option D (True):** Digoxin is primarily eliminated **unchanged by the kidneys** via glomerular filtration. Its clearance is directly proportional to the Creatinine Clearance (CrCl), necessitating dose adjustments in renal failure. **High-Yield NEET-PG Pearls:** * **Volume of Distribution (Vd):** Digoxin has a very large Vd (~6–7 L/kg) because it binds extensively to skeletal muscle. * **Therapeutic Window:** It has a narrow therapeutic index (0.5–2.0 ng/mL). * **Toxicity:** Hypokalemia predisposes to digoxin toxicity because K+ and digoxin compete for the same binding site on the Na+/K+ ATPase pump. * **Antidote:** Digoxin-specific antibody fragments (**DigiFab**). * **ECG Changes:** Characterized by the "reverse tick" or "sagging" ST-segment depression (Salvador Dali mustache sign).

Q: Which antiarrhythmic drug is known to cause hypothyroidism?

Amiodarone. **Explanation:** **Amiodarone** is the correct answer because it is a Class III antiarrhythmic drug with a unique chemical structure containing approximately **37% iodine by weight**. Each 200 mg tablet provides about 75 mg of iodine, which is significantly higher than the daily requirement. The high iodine content can lead to thyroid dysfunction via two mechanisms: 1. **Hypothyroidism:** Occurs due to the **Wolff-Chaikoff effect**, where an iodine overload inhibits the synthesis of thyroid hormones. This is more common in iodine-sufficient areas. 2. **Hyperthyroidism:** Occurs via the **Jod-Basedow phenomenon** (excess iodine acting as a substrate for hormone synthesis) or through destructive thyroiditis. **Analysis of Incorrect Options:** * **B. Amrinone:** A phosphodiesterase-3 (PDE3) inhibitor used in heart failure. Its primary side effect is **thrombocytopenia**, not thyroid dysfunction. * **C. Digoxin:** A cardiac glycoside used for rate control in atrial fibrillation. Common toxicities include gastrointestinal upset, visual disturbances (xanthopsia), and various arrhythmias. * **D. Procainamide:** A Class IA antiarrhythmic. Its most characteristic high-yield side effect is **Drug-Induced Lupus Erythematosus (DILE)**, especially in slow acetylators. **High-Yield Clinical Pearls for NEET-PG:** * **Amiodarone Side Effects:** Remember the mnemonic **"6 P's"**: **P**ulmonary fibrosis (most serious), **P**hotosensitivity, **P**igmentation (Blue-gray skin), **P**eripheral neuropathy, **P**rolonged QT interval, and **P**arent (Thyroid) dysfunction. * **Monitoring:** Baseline and periodic Thyroid Function Tests (TFTs) and Liver Function Tests (LFTs) are mandatory for patients on long-term Amiodarone. * **Half-life:** Amiodarone has an exceptionally long half-life (approx. 3–8 weeks) due to its high lipid solubility.

Question 1

Renolazine is used in the management of which condition?

Accepted Answer

Angina

Answer

Hypertension

Answer

Tachycardia

Answer

Arrhythmia

Question 2

The antianginal effect of beta-blockers may be attributed to which one of the following?

Accepted Answer

Increase in diastolic perfusion time

Answer

Increased heart rate

Answer

Decreased end-diastolic ventricular volume

Answer

Increase in ejection time

Question 3

All of the following drugs cause arteriolar dilatation except?

Accepted Answer

Glyceryl trinitrate

Answer

Hydralazine

Answer

Diazoxide

Answer

Nifedipine

Question 4

A patient has been taking digoxin for several years and is about to receive atropine for some other indication. A common side effect of digoxin that can be blocked by atropine is:

Accepted Answer

Increased PR interval on the ECG

Answer

Decreased appetite

Answer

Increased cardiac contractility

Answer

Tachycardia

Question 5

Which of the following drugs does not increase the QT interval?

Accepted Answer

Digitalis

Answer

Amiodarone

Answer

Quinidine

Answer

Amitriptyline

Question 6

A hypertensive patient is taking tablet atenolol 200 mg/day in divided doses. After anesthesia, their heart rate fell from 50 beats/min to 40 beats/min. What is the appropriate treatment to improve the heart rate?

Accepted Answer

IV atropine

Answer

IV adrenaline

Answer

IV isoprenaline

Answer

Dobutamine infusion intravenously

Question 7

Lignocaine is used in which of the following conditions?

Accepted Answer

Ventricular tachycardia

Answer

Atrial fibrillation

Answer

Atrial flutter

Answer

PSVT

Question 8

All of the following are true about digoxin except:

Accepted Answer

It is 95% plasma protein bound

Answer

Causes bradycardia due to increased vagal tone

Answer

Acts by inhibiting Na+K+ ATPase in myocardial fibres

Answer

Primarily excreted unchanged by glomerular filtration

Question 9

Which antiarrhythmic drug is known to cause hypothyroidism?

Accepted Answer

Amiodarone

Answer

Amrinone

Answer

Digoxin

Answer

Procainamide

Question 10

A 45-year-old female patient with essential hypertension was started on ramipril, furosemide, and aspirin. Two weeks later, she presented with well-controlled blood pressure but developed a persistent dry cough. Which alteration should be made to manage her cough without affecting her controlled blood pressure?

Accepted Answer

Replace ramipril with other angiotensin receptor blockers like valsartan.

Answer

Replace aspirin with clopidogrel.

Answer

Replace all drugs with beta blockers.

Answer

Replace furosemide with other diuretics.

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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