Cardiovascular Drugs Practice Questions

Q: Niacin should be avoided in patients with which of the following conditions?

Peptic ulcer. **Explanation:** **Niacin (Nicotinic Acid)** is a lipid-lowering agent that inhibits the mobilization of free fatty acids from peripheral adipose tissue. While effective at increasing HDL levels, it has a distinct side-effect profile that dictates its contraindications. **Why Peptic Ulcer is the Correct Answer:** Niacin stimulates the release of **histamine**, which leads to an increase in gastric acid secretion via H2 receptors. This can exacerbate or reactivate a **peptic ulcer**. Therefore, active peptic ulcer disease is a relative contraindication for Niacin therapy. Additionally, Niacin is known to cause significant GI irritation and dyspepsia. **Analysis of Incorrect Options:** * **Hypertension:** Niacin actually causes peripheral vasodilation (mediated by Prostaglandin D2 and E2), which can lead to a slight *decrease* in blood pressure. It is not contraindicated in hypertensive patients. * **Alzheimer’s Disease & Parkinsonism:** Niacin has no known adverse interactions with the pathophysiology or treatment of these neurodegenerative conditions. In fact, some research suggests B-complex vitamins may have a supportive role in neurological health. **High-Yield Clinical Pearls for NEET-PG:** * **Cutaneous Flushing:** The most common side effect, mediated by **Prostaglandins**. It can be prevented by taking **Aspirin** 30 minutes before Niacin. * **Metabolic Effects:** Niacin causes **Hyperuricemia** (can precipitate Gout) and **Hyperglycemia** (should be used cautiously in Diabetics). * **Hepatotoxicity:** It is the most serious side effect, especially with sustained-release formulations. * **Acanthosis Nigricans:** A unique dermatological side effect associated with high-dose Niacin.

Q: A patient presents to the emergency department following a drug overdose, exhibiting severe tachycardia. The patient was previously on therapy for hypertension and angina. Which of the following medications can cause tachycardia?

Isosorbide dinitrate. The correct answer is **Isosorbide dinitrate (Option B)**. **Mechanism of Action:** Isosorbide dinitrate is a nitrate that acts as a potent vasodilator. It primarily causes venodilation (reducing preload) and, at higher doses, arterial dilation (reducing afterload) [1]. This sudden drop in systemic blood pressure triggers a **baroreceptor-mediated reflex increase in sympathetic outflow**, leading to **reflex tachycardia** [3]. This is a classic compensatory mechanism seen with rapidly acting vasodilators. **Analysis of Incorrect Options:** * **Guanethidine (A):** This is an adrenergic neuron blocker that inhibits the release of norepinephrine. It typically causes bradycardia and orthostatic hypotension, not tachycardia. * **Propranolol (C):** A non-selective beta-blocker ($ \beta_1$ and $\beta_2$). By blocking $\beta_1$ receptors in the heart, it decreases the heart rate (**bradycardia**) and myocardial contractility [4]. * **Verapamil (D):** A non-dihydropyridine calcium channel blocker (CCB) with significant negative chronotropic and inotropic effects. It acts directly on the SA and AV nodes to cause **bradycardia**; its interaction with beta-blockers can further worsen this effect [4]. **High-Yield NEET-PG Pearls:** * **Reflex Tachycardia:** Common with Nitrates, Hydralazine, and Dihydropyridine CCBs (e.g., Nifedipine) [1], [2]. * **Clinical Correlation:** To prevent reflex tachycardia and "steal phenomenon," nitrates are often co-administered with beta-blockers (like Propranolol) in angina patients. * **Contraindication:** Avoid using Nitrates in patients taking Sildenafil (PDE-5 inhibitors) due to the risk of life-threatening hypotension [1]. * **Drug of Choice:** For nitrate-induced tachycardia, the drug of choice is a beta-blocker.

Q: Which of the following conditions is a contraindication for the use of beta-blockers?

Peripheral vascular disease. **Explanation:** **Why Peripheral Vascular Disease (PVD) is the Correct Answer:** Beta-blockers, particularly non-selective ones (like Propranolol), are contraindicated in PVD because they block **$\beta_2$ receptors** in the skeletal muscle vasculature. Normally, $\beta_2$ stimulation causes vasodilation. When these receptors are blocked, the **$\alpha_1$-mediated vasoconstrictor tone** remains unopposed. This leads to further narrowing of peripheral blood vessels, worsening symptoms like intermittent claudication, and potentially precipitating critical limb ischemia or Raynaud’s phenomenon. **Why the Other Options are Incorrect:** * **Angina:** Beta-blockers are a first-line treatment for stable angina. They reduce myocardial oxygen demand by decreasing heart rate and contractility. * **Hypertension:** They are standard antihypertensive agents, especially in patients with co-existing conditions like post-myocardial infarction or heart failure. * **Anxiety:** Beta-blockers (specifically Propranolol) are used to manage the peripheral autonomic symptoms of performance anxiety, such as palpitations and tremors. **NEET-PG High-Yield Clinical Pearls:** 1. **Cardioselectivity:** If a beta-blocker must be used in mild PVD, **$\beta_1$-selective blockers** (e.g., Atenolol, Metoprolol) or those with vasodilatory properties (e.g., **Nebivolol, Carvedilol**) are preferred as they have less effect on peripheral $\beta_2$ receptors. 2. **Absolute Contraindications:** Always remember the "ABCDE" of beta-blocker contraindications: **A**sthma/COPD, **B**lock (Heart block), **C**ardiogenic shock, **D**ecompensated heart failure, and **E**xtremity issues (Severe PVD/Raynaud's). 3. **Diabetes:** Beta-blockers can mask the warning signs of hypoglycemia (tachycardia) and should be used cautiously in diabetics.

Q: Which calcium channel blocker has predominant peripheral effects?

Amlodipine. **Explanation:** Calcium channel blockers (CCBs) are categorized into two main chemical classes based on their site of action and clinical effects: **Dihydropyridines (DHPs)** and **Non-dihydropyridines**. **Why Amlodipine is correct:** Amlodipine belongs to the **Dihydropyridine** class. These drugs have a high affinity for the L-type calcium channels located in the **vascular smooth muscle** rather than the myocardium. By blocking these channels, they cause potent peripheral vasodilation, making them highly effective for treating hypertension and chronic stable angina. Because they have minimal effect on the heart's conduction system at clinical doses, their effects are considered "predominantly peripheral." **Why the other options are incorrect:** * **Verapamil (Phenylalkylamine):** This is a non-dihydropyridine CCB with a high affinity for calcium channels in the **myocardium**. It has significant negative inotropic (contractility) and negative dromotropic (conduction) effects. It is primarily used for arrhythmias (PSVT) and has the least peripheral effect among CCBs. * **Diltiazem (Benzothiazepine):** This is also a non-dihydropyridine that occupies a middle ground. It acts on both the heart and the blood vessels, but its cardiac depressant effects are more clinically significant than its peripheral effects compared to DHPs. **High-Yield Clinical Pearls for NEET-PG:** * **Amlodipine Side Effect:** The most common side effect is **ankle edema** (due to preferential precapillary dilatation). * **Drug of Choice:** Verapamil is a drug of choice for prophylaxis of cluster headaches and rate control in atrial fibrillation. * **Nimodipine:** A DHP specifically used to prevent cerebral vasospasm following subarachnoid hemorrhage. * **Clevidipine:** An ultra-short-acting IV DHP used in hypertensive emergencies.

Q: A 50-year-old male presents with malignant hypertension. What is the drug of choice for its management?

Sodium nitroprusside. **Explanation:** **Sodium Nitroprusside** is the drug of choice for hypertensive emergencies (malignant hypertension) because of its rapid onset of action (seconds) and short duration of action (1–2 minutes). It is a potent balanced vasodilator that acts by releasing nitric oxide (NO), which stimulates guanylyl cyclase to increase cGMP, leading to the relaxation of both arteriolar and venous smooth muscles. This allows for precise, minute-to-minute titration of blood pressure in an ICU setting. **Why other options are incorrect:** * **Sublingual Nifedipine:** Previously used, it is now **contraindicated** in hypertensive emergencies. It causes an unpredictable, precipitous drop in blood pressure, which can trigger reflex tachycardia and sympathetic activation, potentially leading to myocardial infarction or stroke. * **Furosemide:** While it helps in cases of hypertension associated with fluid overload (e.g., acute heart failure), it is not the primary agent for lowering systemic vascular resistance in malignant hypertension. * **Enalapril:** As an ACE inhibitor, its onset is too slow for emergency management, and its effect can be unpredictable in patients who are volume-depleted or have high renin levels. **NEET-PG High-Yield Pearls:** * **Cyanide Toxicity:** Prolonged infusion of Nitroprusside can lead to cyanide accumulation. The antidote is **Sodium Thiosulfate** or **Hydroxocobalamin**. * **Light Sensitivity:** Nitroprusside solution is unstable in light; the IV bottle must be covered with opaque foil. * **Alternative:** **Labetalol** (alpha + beta blocker) is often preferred in clinical practice today, especially in aortic dissection and pregnancy-induced hypertension (Eclampsia). * **Fenoldopam:** A dopamine $D_1$ agonist used in hypertensive emergencies, particularly beneficial in patients with renal impairment.

Q: Which of the following prostaglandin analogues is used in transposition of great vessels to keep the ductus arteriosus patent?

Alprostadil (PGE1). **Explanation:** The correct answer is **Alprostadil (PGE1)**. **1. Why Alprostadil is correct:** In certain cyanotic congenital heart diseases, such as **Transposition of the Great Vessels (TGA)**, Tetralogy of Fallot, or Pulmonary Atresia, the infant’s survival depends on maintaining a connection between the systemic and pulmonary circulations. The **Ductus Arteriosus** normally closes shortly after birth due to a drop in prostaglandin levels. **Alprostadil**, a synthetic PGE1 analogue, is administered via continuous intravenous infusion to prevent this closure (maintain patency), allowing for adequate oxygenation of the blood until surgical intervention can be performed. **2. Why other options are incorrect:** * **Misoprostol (PGE1):** While also a PGE1 analogue, it is primarily used for **NSAID-induced peptic ulcers** and as an **abortifacient** (in combination with Mifepristone) or for postpartum hemorrhage. It is administered orally or vaginally, not IV for ductal patency. * **Bimatoprost (PGF2α):** This is a prostamide analogue used topically in the treatment of **glaucoma** (to increase uveoscleral outflow) and for eyelash hypotrichosis. * **Dinoprostone (PGE2):** This is primarily used in obstetrics for **cervical ripening** and induction of labor. **High-Yield Clinical Pearls for NEET-PG:** * **PDA Maintenance:** Alprostadil (PGE1) keeps the ductus **O**pen. * **PDA Closure:** NSAIDs like **Indomethacin** or **Ibuprofen** (non-selective COX inhibitors) are used to **C**lose a Patent Ductus Arteriosus by inhibiting prostaglandin synthesis. * **Side Effect:** A common side effect of Alprostadil infusion in neonates is **apnea**, necessitating close respiratory monitoring. * **Alprostadil** is also used in the treatment of erectile dysfunction (intracavernosal injection).

Q: Which of the following is NOT a contraindication for the use of digoxin?

Hyperkalemia. **Explanation:** Digoxin is a cardiac glycoside that inhibits the Na+/K+-ATPase pump. Understanding its contraindications is crucial for NEET-PG, as it has a narrow therapeutic index. **Why Hyperkalemia is the Correct Answer:** Hyperkalemia is **not** a contraindication; in fact, **Hypokalemia** is the major contraindication. Potassium and digoxin compete for the same binding site on the Na+/K+-ATPase pump. When potassium levels are low (hypokalemia), more digoxin binds to the pump, leading to digoxin toxicity. Conversely, hyperkalemia antagonizes the actions of digoxin. Notably, digoxin is used with caution in renal failure (where hyperkalemia occurs), but the electrolyte state itself does not prohibit its use. **Analysis of Incorrect Options:** * **Acute Rheumatic Carditis:** Digoxin is contraindicated here because the inflamed myocardium is highly sensitive to digitalis, significantly increasing the risk of drug-induced arrhythmias. * **Thyrotoxicosis:** In hyperthyroid states, there is a high-output state and increased sympathetic activity. Digoxin is relatively ineffective and can predispose the patient to arrhythmias due to the hypermetabolic state of the heart. * **WPW Syndrome:** Digoxin is strictly contraindicated. It shortens the refractory period of the accessory pathway (Bundle of Kent) while slowing AV node conduction. This can lead to a rapid ventricular rate and potentially fatal ventricular fibrillation. **High-Yield Clinical Pearls:** * **Antidote:** Digibind (Digoxin-specific antibody fragments). * **ECG Changes:** Characterized by the "Reverse Tick" sign or "Sagging" ST-segment depression. * **Toxicity Marker:** The most common arrhythmia in toxicity is **PVCs** (Premature Ventricular Contractions); the most characteristic is **PAT with block** (Paroxysmal Atrial Tachycardia with AV block). * **Electrolyte Triad:** Toxicity is precipitated by **Hypokalemia, Hypomagnesemia, and Hypercalcemia.**

Question 1

Niacin should be avoided in patients with which of the following conditions?

Accepted Answer

Peptic ulcer

Answer

Hypertension

Answer

Alzheimer's disease

Answer

Parkinsonism

Question 2

Which of the following enzymes metabolizes nitrates to produce nitric oxide (NO)?

Accepted Answer

Aldehyde dehydrogenase

Answer

Alcohol dehydrogenase

Answer

Nitrate reductase

Answer

Phosphodiesterase-5

Question 3

A patient presents to the emergency department following a drug overdose, exhibiting severe tachycardia. The patient was previously on therapy for hypertension and angina. Which of the following medications can cause tachycardia?

Accepted Answer

Isosorbide dinitrate

Answer

Guanethidine

Answer

Propranolol

Answer

Verapamil

Question 4

Which of the following conditions is a contraindication for the use of beta-blockers?

Accepted Answer

Peripheral vascular disease

Answer

Angina

Answer

Hypertension

Answer

Anxiety

Question 5

Which calcium channel blocker has predominant peripheral effects?

Accepted Answer

Amlodipine

Answer

Verapamil

Answer

Diltiazem

Answer

None of these

Question 6

Tadalafil acts on Phosphodiesterase 5 and causes accumulation of?

Accepted Answer

cGMP

Answer

cAMP

Answer

PAF

Answer

IL 10

Question 7

A 50-year-old male presents with malignant hypertension. What is the drug of choice for its management?

Accepted Answer

Sodium nitroprusside

Answer

Sublingual nifedipine

Answer

Furosemide

Answer

Enalapril

Question 8

Which of the following prostaglandin analogues is used in transposition of great vessels to keep the ductus arteriosus patent?

Accepted Answer

Alprostadil (PGE1)

Answer

Misoprostol (PGE1)

Answer

Bimatoprost (PGF2)

Answer

Dinoprostone (PGE2)

Question 9

Which of the following is NOT a side-effect of captopril?

Accepted Answer

Hemolytic anemia

Answer

Cough

Answer

Hyperkalemia

Answer

Renal dysfunction

Question 10

Which of the following is NOT a contraindication for the use of digoxin?

Accepted Answer

Hyperkalemia

Answer

Acute rheumatic carditis

Answer

Thyrotoxicosis

Answer

WPW syndrome

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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