Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 121: Which of the following drugs is commonly responsible for orthostatic hypotension?

A. Clonidine
B. Hydralazine
C. Captopril
D. Prazosin (Correct Answer)

Explanation: **Explanation:** **Prazosin** is the correct answer because it is a highly selective **alpha-1 ($\alpha_1$) adrenergic blocker**. Alpha-1 receptors are primarily located on vascular smooth muscle; blocking them leads to potent vasodilation of both arterioles and veins. When a patient stands up, the normal compensatory sympathetic reflex (vasoconstriction) is inhibited, leading to a sudden drop in blood pressure. This is famously known as the **"First-Dose Phenomenon,"** where severe orthostatic hypotension and syncope occur shortly after the initial dose. **Analysis of Incorrect Options:** * **Clonidine:** This is a central $\alpha_2$ agonist. While it reduces sympathetic outflow, it is more commonly associated with sedation and **rebound hypertension** upon abrupt withdrawal rather than significant orthostatic hypotension. * **Hydralazine:** A direct-acting arteriolar vasodilator. Because it does not affect the venous side (capacitance vessels) or the sympathetic reflex arc, it typically causes **reflex tachycardia** and fluid retention rather than postural hypotension. * **Captopril:** An ACE inhibitor. While it can cause a "first-dose effect" (especially in volume-depleted patients), it does not interfere with the sympathetic nervous system's baroreceptor reflex, making orthostatic hypotension less common than with alpha-blockers. **High-Yield Clinical Pearls for NEET-PG:** * **First-Dose Phenomenon:** To minimize this risk with Prazosin, advise patients to take the first dose at **bedtime** and start with a low dose. * **BPH:** Selective $\alpha_1$ blockers (like Tamsulosin) are preferred for Benign Prostatic Hyperplasia as they target $\alpha_{1A}$ receptors in the bladder neck with less effect on systemic blood pressure. * **Drug of Choice:** Prazosin is also used in the treatment of Raynaud’s phenomenon and scorpion sting (red scorpion) poisoning.

Question 122: Which antihypertensive drug is contraindicated in pregnancy?

A. Enalapril (Correct Answer)
B. Cardioselective beta blockers
C. Methyldopa
D. Hydralazine

Explanation: **Enalapril** is an ACE (Angiotensin-Converting Enzyme) inhibitor and is strictly **contraindicated** in pregnancy (FDA Category D) [1]. The underlying medical concept is its **teratogenic potential**, particularly during the second and third trimesters. ACE inhibitors interfere with the fetal renin-angiotensin system, which is crucial for fetal renal development [2]. This leads to **fetal renal dysgenesis**, oligohydramnios (due to decreased fetal urine output), pulmonary hypoplasia, intrauterine growth restriction (IUGR), and cranial ossification defects [1, 2]. **Analysis of Incorrect Options:** * **Methyldopa (Option C):** Historically the **drug of choice** for chronic hypertension in pregnancy. It is a centrally acting alpha-2 agonist with a long-standing safety profile. * **Hydralazine (Option D):** A direct vasodilator frequently used for the management of **acute hypertensive emergencies** in pregnancy (e.g., severe pre-eclampsia). * **Cardioselective Beta Blockers (Option B):** Drugs like **Labetalol** (a non-selective beta/alpha-1 blocker) are currently considered first-line agents. While some beta-blockers (like Atenolol) are avoided due to risks of placental insufficiency and fetal bradycardia, they are not 'contraindicated' in the absolute sense that ACE inhibitors are. **High-Yield Clinical Pearls for NEET-PG:** * **Safe drugs in pregnancy:** '**M**y **N**ew **L**ife **H**elps' (**M**ethyldopa, **N**ifedipine, **L**abetalol, **H**ydralazine). * **Labetalol** is now often preferred over Methyldopa due to fewer side effects. * **Contraindicated drugs:** ACE inhibitors, ARBs (e.g., Losartan), Direct Renin Inhibitors (Aliskiren), and Statins. * **Specific Teratogenicity:** ACE inhibitors cause 'ACEI Fetopathy,' characterized by renal failure and skull hypoplasia [1].

Question 123: What is the agent of first choice in an acute attack of Prinzmetal's angina?

A. Diltiazem
B. Nitrates (Correct Answer)
C. Propranolol
D. Verapamil

Explanation: **Explanation:** **Prinzmetal’s Angina (Variant Angina)** is caused by a sudden, intense coronary artery vasospasm rather than fixed atherosclerotic obstruction. **1. Why Nitrates are the First Choice:** In an **acute attack**, the primary goal is immediate vasodilation to relieve the spasm. **Sublingual Nitroglycerin (Nitrates)** is the agent of choice because it acts as a potent smooth muscle relaxant [2]. Nitrates are converted into Nitric Oxide (NO), which increases cGMP levels, leading to rapid coronary vasodilation and immediate relief of the ischemic pain. **2. Analysis of Incorrect Options:** * **Diltiazem & Verapamil (Calcium Channel Blockers):** While CCBs are the **drugs of choice for long-term prophylaxis** (prevention) of Prinzmetal’s angina, they are not the first choice for an *acute* attack because their onset of action is slower compared to sublingual nitrates [1]. * **Propranolol (Beta-blockers):** These are **strictly contraindicated** in Prinzmetal’s angina. Blocking $\beta_2$ receptors (which cause vasodilation) leaves $\alpha_1$ receptors unopposed, leading to further vasoconstriction and worsening of the coronary spasm. **3. NEET-PG High-Yield Pearls:** * **Drug of choice for Acute Attack:** Sublingual Nitrates [2]. * **Drug of choice for Chronic Prophylaxis:** Calcium Channel Blockers (e.g., Nifedipine, Diltiazem, Verapamil) [1], [3]. * **Contraindicated Drug:** Non-selective Beta-blockers (Propranolol). * **ECG Finding:** Transient ST-segment **elevation** (unlike stable angina, which shows ST-depression). * **Trigger:** Often occurs at rest, typically in the early morning hours.

Question 124: Digitalis toxicity can cause which of the following?

A. Hyperkalemia
B. Nausea
C. Arrhythmias
D. All the above (Correct Answer)

Explanation: Digitalis (Digoxin) has a narrow therapeutic index, making toxicity a frequent and high-yield topic for NEET-PG. The correct answer is **All the above** because Digitalis toxicity manifests through both extracardiac and cardiac mechanisms. ### **Mechanism and Explanation:** 1. **Hyperkalemia (Option A):** Digoxin works by inhibiting the **Na⁺/K⁺-ATPase pump**. In toxicity, massive inhibition of this pump prevents potassium from entering the cells, leading to an extracellular rise in K⁺ levels. **Clinical Pearl:** In acute toxicity, the serum potassium level is a better predictor of prognosis than the digoxin level itself. 2. **Nausea (Option B):** Gastrointestinal symptoms are often the **earliest signs** of toxicity. Nausea, vomiting, and anorexia occur due to direct stimulation of the **Chemoreceptor Trigger Zone (CTZ)** in the area postrema of the medulla. 3. **Arrhythmias (Option C):** Digoxin increases vagal tone (slowing the AV node) and increases intracellular calcium (causing delayed after-depolarizations). This can lead to almost any arrhythmia. The most characteristic is **Atrial Tachycardia with AV block**, while the most common is **Ventricular Bigeminy**. ### **High-Yield Facts for NEET-PG:** * **Visual Disturbance:** Xanthopsia (yellow-green halos around lights) is a classic sign. * **Predisposing Factor:** While Digoxin *causes* hyperkalemia, **hypokalemia** *precipitates* Digoxin toxicity (as K⁺ and Digoxin compete for the same binding site on the Na⁺/K⁺-ATPase pump). * **Antidote:** Digoxin-specific antibody fragments (**DigiFab/Digibind**). * **ECG Changes:** "Reverse Tick" or "Sagging" ST-segment depression (Salvador Dali mustache sign) indicates digitalis effect, not necessarily toxicity.

Question 125: A 45-year-old patient has recently received a heart transplant. Patient education has included descriptions of the potential cardiovascular effects of pharmacologic agents. Which one of the following drugs is least likely to cause tachycardia?

A. Amphetamine (Correct Answer)
B. Dobutamine
C. Epinephrine
D. Isoproterenol

Explanation: **Explanation:**The core concept in this question is the physiological state of a **denervated heart** following a transplant. In a heart transplant recipient, the autonomic nerve supply (both sympathetic and parasympathetic) is severed. Consequently, the heart can only respond to drugs that act **directly** on cardiac receptors [1].**1. Why Amphetamine is the correct answer:**Amphetamine is an **indirect-acting sympathomimetic**. It works by displacing stored norepinephrine from the presynaptic nerve terminals. In a transplanted heart, these sympathetic nerve endings have degenerated (denervation). Therefore, there is no norepinephrine available for amphetamine to release, and it fails to produce its characteristic tachycardic effect [2].**2. Why the other options are incorrect:** * **Dobutamine, Epinephrine, and Isoproterenol** are all **direct-acting agonists**. They act directly on the $\beta_1$-adrenergic receptors located on the myocardium and the SA node. Since the receptors themselves remain functional after transplantation, these drugs will still cause tachycardia. In fact, due to "denervation supersensitivity," the heart may show an exaggerated response to direct-acting agents like Isoproterenol [1].**NEET-PG High-Yield Pearls:** * **Denervated Heart:** The resting heart rate is typically higher (90–100 bpm) because the inhibitory influence of the Vagus nerve is lost [1]. * **Atropine:** This drug will **not** work to treat bradycardia in a transplant patient because its mechanism (blocking vagal tone) requires intact innervation. * **Reflexes:** Baroreceptor reflex-mediated changes in heart rate (e.g., reflex tachycardia from Nitroglycerin) are absent in these patients. * **Direct vs. Indirect:** Always distinguish between these two for "denervation" questions.

Question 126: "Monday disease" is seen with which of the following?

A. Calcium channel blockers
B. Benzodiazepines
C. Isosorbide mononitrate (Correct Answer)
D. Chlorpromazine

Explanation: ### Explanation **Correct Answer: C. Isosorbide mononitrate** **Underlying Concept:** "Monday disease" (or Monday morning headache) is a classic phenomenon associated with industrial exposure to **organic nitrates** (like nitroglycerin or isosorbide mononitrate). * **Mechanism:** Nitrates cause potent vasodilation of meningeal vessels, leading to severe headaches. * **Tolerance:** Workers in explosives factories develop tolerance to these vasodilatory effects during the workweek. However, this tolerance is lost over the weekend (48 hours of no exposure). * **The "Monday" Effect:** When workers return to the factory on Monday, they are re-exposed to nitrate vapors, and because their tolerance has vanished, they experience intense headaches, tachycardia, and dizziness. **Why Incorrect Options are Wrong:** * **A. Calcium channel blockers:** While CCBs (like Nifedipine) can cause headaches due to vasodilation, they do not exhibit the specific "weekend loss of tolerance" pattern characteristic of Monday disease. * **B. Benzodiazepines:** These are sedative-hypnotics. Their withdrawal symptoms include anxiety, tremors, and seizures, but they are not associated with industrial "Monday" symptoms. * **D. Chlorpromazine:** This is a typical antipsychotic. Its primary side effects are extrapyramidal symptoms (EPS) and sedation, not nitrate-like vasodilatory headaches. **High-Yield Clinical Pearls for NEET-PG:** 1. **Nitrate Holiday:** To prevent therapeutic tolerance in patients, a "nitrate-free interval" of 8–12 hours (usually at night) is recommended daily. 2. **Steal Phenomenon:** Nitrates do *not* cause coronary steal (Dipyridamole does); instead, they redistribute blood to ischemic subendocardial areas. 3. **Contraindication:** Never co-administer nitrates with **Sildenafil** (PDE-5 inhibitors) as it can lead to life-threatening hypotension. 4. **Drug of Choice:** Sublingual Nitroglycerin remains the DOC for acute anginal attacks due to its rapid onset and avoidance of first-pass metabolism.

Question 127: Bosentan is a/an:

A. Serotonin uptake inhibitor
B. Endothelin receptor antagonist (Correct Answer)
C. Leukotriene modifier
D. Phosphodiesterase inhibitor

Explanation: **Bosentan** is a non-selective, competitive **Endothelin receptor antagonist (ERA)**. It blocks both **ET-A** [2] and **ET-B** receptors, which are normally activated by Endothelin-1 (a potent endogenous vasoconstrictor) [3]. By blocking these receptors, Bosentan reduces pulmonary vascular resistance, making it a first-line oral treatment for **Pulmonary Arterial Hypertension (PAH)** (WHO Group 1) [3]. **Analysis of Options:** * **Option A (Serotonin uptake inhibitor):** These are antidepressants (e.g., SSRIs like Fluoxetine). While serotonin pathways are involved in pulmonary remodeling, Bosentan does not act on these transporters. * **Option C (Leukotriene modifier):** These include drugs like Montelukast (receptor antagonist) or Zileuton (synthesis inhibitor) used primarily in bronchial asthma, not PAH. * **Option D (Phosphodiesterase inhibitor):** While PDE-5 inhibitors (e.g., Sildenafil, Tadalafil) are used to treat PAH, they work by increasing cGMP levels, whereas Bosentan targets the endothelin pathway. **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Dual ET-A and ET-B blockade. * **Adverse Effects:** The most significant side effect is **Hepatotoxicity** (elevation of serum transaminases); therefore, monthly Liver Function Tests (LFTs) are mandatory [1]. * **Teratogenicity:** It is highly teratogenic (Category X) and contraindicated in pregnancy. * **Other ERAs:** **Ambrisentan** (Selective ET-A blocker; less hepatotoxic) [1] and **Macitentan** (Tissue-selective dual antagonist).

Question 128: Nitroglycerine exerts beneficial effects in variant angina primarily by:

A. Coronary vasodilation (Correct Answer)
B. Decreased ventricular contractility
C. Reduction of cardiac preload
D. Reduction of cardiac afterload

Explanation: **Explanation:** The primary pathology in **Variant (Prinzmetal) Angina** is a sudden, intense spasm of the coronary arteries rather than fixed atherosclerotic obstruction. This leads to transmural ischemia and ST-segment elevation. **1. Why Option A is Correct:** Nitroglycerine (NTG) acts as a prodrug that releases **Nitric Oxide (NO)**, stimulating guanylyl cyclase and increasing cGMP levels. This leads to dephosphorylation of myosin light chains and relaxation of smooth muscle. In variant angina, the therapeutic goal is to reverse the acute vasospasm. NTG directly causes **coronary vasodilation**, increasing oxygen supply to the myocardium and effectively terminating the spasm. **2. Why Other Options are Incorrect:** * **Option B:** Nitrates do not have a direct negative inotropic effect; they do not decrease ventricular contractility. * **Options C & D:** While reduction of preload (venodilation) and afterload (arteriolar dilation) are the primary mechanisms by which nitrates benefit **Stable Angina** (by reducing myocardial oxygen demand), they are secondary effects in variant angina. In the specific context of a coronary spasm, restoring blood flow via direct vasodilation is the definitive beneficial action. **High-Yield NEET-PG Pearls:** * **Drug of Choice:** For acute attacks of variant angina, **Sublingual Nitroglycerine** is used. For long-term prophylaxis, **Calcium Channel Blockers (CCBs)** are the drugs of choice. * **Contraindication:** **Non-selective Beta-blockers** (e.g., Propranolol) are contraindicated in variant angina as they can worsen spasms due to unopposed alpha-adrenergic activity. * **Monday Disease:** Refers to nitrate tolerance and withdrawal symptoms (tachycardia, dizziness) seen in industrial workers exposed to nitrates.

Question 129: Nimodipine is indicated for which of the following conditions?

A. Extradural hemorrhage
B. Subdural hemorrhage
C. Intracerebral hemorrhage
D. Subarachnoid hemorrhage (Correct Answer)

Explanation: **Explanation:** **Correct Answer: D. Subarachnoid hemorrhage** **Mechanism and Rationale:** Nimodipine is a second-generation **Dihydropyridine (DHP) Calcium Channel Blocker**. Unlike other DHPs, Nimodipine is highly **lipophilic**, allowing it to readily cross the blood-brain barrier. Its primary clinical utility lies in its ability to prevent and treat **delayed cerebral ischemia (DCI)** caused by **vasospasm** following an aneurysmal Subarachnoid Hemorrhage (SAH). By blocking L-type calcium channels in cerebral smooth muscle, it induces vasodilation and provides neuroprotection, significantly improving neurological outcomes. **Why other options are incorrect:** * **A & B (Extradural and Subdural Hemorrhage):** These are typically traumatic bleeds (arterial and venous respectively) where the primary pathology is mass effect and increased intracranial pressure. Vasospasm is not a characteristic secondary complication in these conditions; therefore, Nimodipine has no therapeutic role. * **C (Intracerebral Hemorrhage):** While vasospasm can occur, it is not the defining clinical challenge as it is in SAH. Management focuses on blood pressure control and surgical evacuation if necessary, rather than calcium channel blockade. **High-Yield Clinical Pearls for NEET-PG:** * **Route of Administration:** Usually given **orally** (60mg every 4 hours for 21 days). *Warning:* IV administration must be done with extreme caution to avoid severe hypotension. * **Specific Indication:** It is the **only** calcium channel blocker FDA-approved specifically for SAH to reduce the incidence of ischemic deficits. * **Drug Class:** Remember the "Dipines" (Amlodipine, Nifedipine, Nimodipine). Nimodipine = **"Brain-specific"** DHP. * **Side Effects:** Hypotension and flushing are the most common adverse effects due to peripheral vasodilation.

Question 130: Which of the following is NOT a calcium channel blocker used in the management of hypertension?

A. Amlodipine
B. Clevidipine
C. Captopril (Correct Answer)
D. Nifedipine

Explanation: **Explanation:** The correct answer is **Captopril** because it belongs to the class of **ACE (Angiotensin-Converting Enzyme) Inhibitors**, not Calcium Channel Blockers (CCBs). It works by inhibiting the conversion of Angiotensin I to Angiotensin II, a potent vasoconstrictor, and by preventing the breakdown of bradykinin. **Analysis of Options:** * **Amlodipine:** A long-acting **Dihydropyridine (DHP) CCB**. It is one of the most commonly used first-line agents for hypertension due to its once-daily dosing and minimal myocardial depression. * **Clevidipine:** A third-generation **DHP-CCB** characterized by its ultra-short duration of action (half-life ~2 minutes). It is administered intravenously for the management of **hypertensive emergencies**. * **Nifedipine:** A prototype **DHP-CCB**. While the short-acting oral form is avoided due to reflex tachycardia, the extended-release formulations are standard treatments for hypertension and chronic stable angina. **High-Yield NEET-PG Pearls:** 1. **Classification of CCBs:** * **Dihydropyridines (Suffix "-dipine"):** Act primarily on vascular smooth muscle (L-type channels) causing vasodilation (e.g., Amlodipine, Nifedipine). * **Non-Dihydropyridines:** Act on the heart; include **Verapamil** (Phenylalkylamine) and **Diltiazem** (Benzothiazepine). 2. **Side Effects:** A common side effect of DHP-CCBs like Amlodipine is **ankle edema** (due to precapillary vasodilation). 3. **Clevidipine Fact:** It is formulated in a **lipid emulsion**; therefore, it is contraindicated in patients with soy or egg allergies. 4. **Drug of Choice:** CCBs are preferred first-line agents for hypertension in elderly patients and those of African descent.

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

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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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