Cardiovascular Drugs Practice Questions

Q: Sodium nitroprusside's active metabolite acts by which mechanism?

Stimulating guanylyl cyclase. **Explanation:** **Sodium Nitroprusside (SNP)** is a potent, rapid-acting vasodilator used in hypertensive emergencies. Its mechanism of action involves the release of **Nitric Oxide (NO)**. 1. **Mechanism of the Correct Answer (B):** SNP is a prodrug that reacts with sulfhydryl groups on erythrocytes and albumin to release NO. This NO then diffuses into the vascular smooth muscle cells where it binds to and **stimulates soluble guanylyl cyclase**. This enzyme converts GTP to **cyclic GMP (cGMP)**. Increased levels of cGMP activate protein kinase G, leading to dephosphorylation of myosin light chains and sequestration of calcium, resulting in profound relaxation of both arterioles and venules (balanced vasodilator). 2. **Why Incorrect Options are Wrong:** * **Option A:** SNP does not inhibit phosphokinase; rather, it indirectly activates protein kinase G via cGMP. * **Options C & D:** Phospholipases (A and B) are involved in the metabolism of membrane phospholipids and the arachidonic acid cascade (prostaglandin synthesis). They are not the primary targets for the vasodilatory action of NO-donors. **High-Yield Clinical Pearls for NEET-PG:** * **Balanced Vasodilator:** Unlike Hydralazine (arteriolar) or Nitroglycerin (predominantly venous), SNP acts equally on **arteries and veins**, reducing both afterload and preload. * **Toxicity:** SNP contains five cyanide groups. Metabolism can lead to **Cyanide toxicity** (treated with Sodium Thiosulfate/Nitrites) and **Thiocyanate toxicity** (especially in renal failure). * **Light Sensitivity:** SNP is unstable in light; the infusion bottle must be covered with opaque foil. * **Drug of Choice:** Historically the gold standard for hypertensive emergencies, though now often replaced by Labetalol or Nicardipine due to toxicity concerns.

Q: If systemic vascular resistance is twice that of normal, which of the following treatments should be initiated?

Sodium nitroprusside. **Explanation:** The core concept in this question is the management of **increased Systemic Vascular Resistance (SVR)**, which clinically manifests as severe hypertension or hypertensive crisis. **1. Why Sodium Nitroprusside is Correct:** Sodium nitroprusside is a potent, direct-acting **mixed vasodilator** (acting on both arterioles and venules). It works by releasing Nitric Oxide (NO), which stimulates guanylyl cyclase to increase cGMP, leading to smooth muscle relaxation. By dilating the resistance vessels (arterioles), it rapidly decreases SVR and blood pressure, making it an ideal choice for hypertensive emergencies where SVR is pathologically high. **2. Why Other Options are Incorrect:** * **Adrenaline (Epinephrine):** At high doses, it stimulates $\alpha_1$ receptors, causing vasoconstriction and further **increasing SVR**. It would worsen the condition. * **Nor-adrenaline (Norepinephrine):** This is a potent $\alpha_1$ agonist. Its primary effect is intense vasoconstriction, which significantly **increases SVR**. It is used in shock, not for high SVR states. * **Isoprenaline:** This is a pure $\beta$-agonist ($\beta_1$ and $\beta_2$). While it can decrease SVR via $\beta_2$ vasodilation, its profound positive chronotropic and inotropic effects ($\beta_1$) make it unsuitable for treating hypertensive states; it is primarily used for bradyarrhythmias. **High-Yield NEET-PG Pearls:** * **Sodium Nitroprusside Toxicity:** Prolonged infusion can lead to **Cyanide and Thiocyanate toxicity**. The antidote is Sodium Thiosulfate or Hydroxocobalamin. * **Light Sensitivity:** Nitroprusside is photosensitive; the infusion bottle must be covered with opaque foil. * **Drug of Choice:** While Nitroprusside was historically the gold standard for hypertensive emergencies, **Labetalol** or **Nicardipine** are now often preferred due to better safety profiles.

Q: What is the antihypertensive of choice in a pregnant lady?

Methyldopa. **Explanation:** **1. Why Methyldopa is the Correct Choice:** Methyldopa is a centrally acting alpha-2 adrenergic agonist. It has been the traditional **drug of choice** for chronic hypertension in pregnancy due to its long-standing safety profile and lack of teratogenicity. It does not affect fetal hemodynamics or uteroplacental blood flow. While **Labetalol** is increasingly used as a first-line agent in modern guidelines, Methyldopa remains the classic textbook answer for NEET-PG. **2. Why Other Options are Incorrect:** * **Furosemide (Option B):** Diuretics are generally avoided in pregnancy as they can decrease placental perfusion by reducing maternal plasma volume, potentially leading to fetal growth restriction. * **Nitroprusside (Option C):** It is contraindicated in pregnancy because its metabolism releases cyanide, which can lead to **fetal cyanide poisoning**. * **ACE Inhibitors (Option D):** These are strictly **contraindicated (Teratogenic)**. They cause "ACEI Fetopathy," characterized by fetal renal dysgenesis, oligohydramnios, skull hypoplasia, and pulmonary hypoplasia. **3. High-Yield Clinical Pearls for NEET-PG:** * **Safe Antihypertensives in Pregnancy (Mnemonic: "Better Mother Care During Hypertensive Pregnancy"):** **B**eta-blockers (Labetalol), **M**ethyldopa, **C**alcium Channel Blockers (Nifedipine), **D**ihydralazine. * **Drug of Choice for Preeclampsia/Eclampsia:** **Magnesium Sulfate (MgSO₄)** is used for seizure prophylaxis/treatment, while **Labetalol** or **Hydralazine** are used for acute blood pressure control. * **Contraindicated Drugs:** ACE inhibitors, ARBs, Direct Renin Inhibitors, Nitroprusside, and Statins.

Q: Which of the following drugs is used for termination as well as prophylaxis of paroxysmal supraventricular tachycardia?

Verapamil. **Explanation:** **Verapamil** (a non-dihydropyridine Calcium Channel Blocker) is the correct answer because it acts primarily on the **Sinoatrial (SA) and Atrioventricular (AV) nodes**. By blocking L-type calcium channels, it slows AV conduction and prolongs the functional refractory period. This makes it highly effective for both **terminating** an acute episode of Paroxysmal Supraventricular Tachycardia (PSVT) by breaking the re-entry circuit at the AV node, and for **prophylaxis** to prevent recurrence. **Analysis of Incorrect Options:** * **Digoxin (Option A):** While it increases vagal tone and slows AV conduction, its onset of action is too slow for the acute termination of PSVT. It is primarily used for rate control in atrial fibrillation. * **Propranolol (Option C):** As a Beta-blocker, it is effective for prophylaxis and can be used for termination, but Verapamil is traditionally considered more potent for the acute termination of narrow-complex SVT in hemodynamically stable patients. * **Quinidine (Option D):** This is a Class IA antiarrhythmic. It is rarely used for PSVT and can actually worsen tachycardia by its vagolytic effect, which paradoxically increases AV conduction. **High-Yield Clinical Pearls for NEET-PG:** * **Drug of Choice (DOC):** For the **acute termination** of PSVT, **Adenosine** is the first-line drug due to its rapid onset and short half-life. * **Verapamil** is the preferred alternative if Adenosine is contraindicated (e.g., in bronchial asthma) or ineffective. * **Contraindication:** Never use Verapamil in wide-complex tachycardias of unknown origin or in WPW syndrome with atrial fibrillation, as it may precipitate ventricular fibrillation. * **Verapamil + Digoxin:** Verapamil increases digoxin levels by displacing it from tissue binding sites and reducing renal clearance.

Q: Important adverse effect of nesiritide is

Hypotension. **Explanation:** **Nesiritide** is a recombinant form of human **B-type Natriuretic Peptide (BNP)**. It is primarily used in the management of acutely decompensated heart failure with dyspnea at rest. **1. Why Hypotension is the Correct Answer:** Nesiritide works by binding to particulate guanylyl cyclase receptors, leading to increased intracellular **cGMP**. This results in potent **vasodilation** of both arteries and veins (reducing both preload and afterload) and promotes natriuresis. Because of its potent vasodilatory properties, **dose-dependent hypotension** is its most common and significant adverse effect. It can sometimes be prolonged and require careful blood pressure monitoring during infusion. **2. Analysis of Incorrect Options:** * **A. Dysgeusia (Taste perversion):** This is a classic side effect associated with **Captopril** (an ACE inhibitor), often due to its sulfhydryl group. * **C. Cough:** This is a hallmark side effect of **ACE Inhibitors** (like Enalapril or Lisinopril) caused by the accumulation of bradykinin and substance P in the lungs. * **D. Angioedema:** This is a rare but life-threatening adverse effect primarily linked to **ACE Inhibitors** and, to a lesser extent, ARBs and Neprilysin inhibitors (Sacubitril). **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism:** Increases cGMP $\rightarrow$ Vasodilation + Natriuresis. * **Indication:** Acutely decompensated heart failure (ADHF). * **Key Side Effects:** Hypotension (most common) and potential renal impairment (azotemia). * **Half-life:** Short (approx. 18 minutes), administered via IV bolus followed by continuous infusion.

Q: Food reduces the oral bioavailability of the following angiotensin converting enzyme inhibitors EXCEPT?

Enalapril. **Explanation:** The oral bioavailability of most ACE inhibitors is affected by the presence of food in the gastrointestinal tract, which typically delays or reduces absorption. However, **Enalapril** is a notable exception. **1. Why Enalapril is Correct:** Enalapril is a prodrug that is converted into its active metabolite, enalaprilat, in the liver. Its gastrointestinal absorption is **not significantly affected by food**. This clinical advantage allows for flexible dosing (with or without meals), ensuring consistent therapeutic levels regardless of dietary timing. **2. Analysis of Incorrect Options:** * **Captopril:** This is the classic example of an ACE inhibitor whose bioavailability is significantly **reduced (by 30–40%)** when taken with food. It should ideally be taken one hour before meals. * **Ramipril:** Similar to many other ACE inhibitors, food can delay the rate of absorption of Ramipril, although the extent of reduction is less severe than Captopril. * **Fosinopril:** The absorption of Fosinopril is also slightly reduced or delayed by the presence of food. **3. High-Yield Clinical Pearls for NEET-PG:** * **Prodrug Status:** All ACE inhibitors are prodrugs **EXCEPT Captopril and Lisinopril**. * **Elimination:** All ACE inhibitors are primarily excreted renally **EXCEPT Fosinopril and Spirapril**, which have balanced hepatobiliary and renal excretion (making them safer in renal failure). * **Duration of Action:** Captopril has the shortest half-life and requires multiple daily dosing, whereas most others (like Enalapril and Ramipril) are suitable for once or twice-daily dosing. * **Key Side Effects:** Remember the mnemonic **CAPTOPRIL** (Cough, Angioedema, Proteinuria, Taste changes, Orthostatic hypotension, Pregnancy contraindication, Renal artery stenosis contraindication, Increased Potassium, Leukopenia).

Q: The dose of digoxin is NOT altered in which of the following conditions?

Hepatic disease. **Explanation:** The correct answer is **Hepatic disease** because of the pharmacokinetic profile of Digoxin. **1. Why Hepatic Disease is the correct answer:** Digoxin is a polar glycoside that is primarily excreted **unchanged by the kidneys** (approx. 60-80%) via glomerular filtration and tubular secretion (P-glycoprotein mediated) [2], [3]. It undergoes minimal hepatic metabolism [2]. Therefore, its clearance is not significantly affected by liver dysfunction, and dose adjustment is generally not required in patients with hepatic disease [1]. **2. Why the other options are incorrect:** * **Old Age:** Renal function naturally declines with age (reduced GFR). Additionally, elderly patients have lower skeletal muscle mass (the primary tissue reservoir for digoxin), leading to higher serum levels. Dose reduction is mandatory to avoid toxicity. * **Renal Disease:** Since the kidneys are the primary route of elimination, any degree of renal impairment increases the half-life of digoxin significantly (from 36 hours up to 5 days), necessitating strict dose reduction based on creatinine clearance [2], [3]. * **Hypercalcemia:** Digoxin works by inhibiting the Na+/K+ ATPase pump, which indirectly increases intracellular calcium. Hypercalcemia synergizes with digoxin, increasing the risk of cardiac arrhythmias. In this state, the heart is "sensitized" to digoxin, requiring a lower dose or cautious monitoring [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Digitoxin vs. Digoxin:** Unlike Digoxin, **Digitoxin** is primarily metabolized by the liver and is the drug of choice in patients with renal failure (though rarely used now) [2]. * **Electrolyte Triad:** Digoxin toxicity is precipitated by **Hypokalemia, Hypomagnesemia, and Hypercalcemia.** * **Monitoring:** The therapeutic range for digoxin is narrow (**0.5–2 ng/mL**) [2]. * **Antidote:** Digibind (Digoxin-specific Fab fragments) is used for life-threatening toxicity.

Q: Antihypertensives may act by blocking all of the following except?

ATP dependent potassium channels. To understand this question, one must distinguish between **blocking** a channel/receptor and **activating** it to achieve a therapeutic effect. ### 1. Why Option B is Correct (The Concept) Antihypertensives do not work by *blocking* ATP-dependent potassium ($K_{ATP}$) channels; instead, they act as **Potassium Channel Openers** [2]. * **Mechanism:** Drugs like **Minoxidil, Diazoxide, and Nicorandil** open these channels, leading to an efflux of $K^+$ ions [2]. * **Result:** This causes membrane hyperpolarization, which prevents the opening of voltage-gated calcium channels, leading to smooth muscle relaxation and potent vasodilation. * **Note:** Blocking these channels (e.g., by Sulfonylureas) actually leads to depolarization and is used in treating Diabetes Mellitus, not hypertension. ### 2. Why Other Options are Incorrect * **Alpha adrenoceptors (A):** Drugs like **Prazosin and Phenoxybenzamine** block $\alpha_1$ receptors, preventing vasoconstriction and lowering peripheral resistance [1], [5]. * **Noradrenaline release (C):** Adrenergic neuron blockers like **Guanethidine and Reserpine** act by inhibiting the release or storage of noradrenaline, thereby reducing sympathetic tone [3]. * **Beta adrenoceptors (D):** Drugs like **Propranolol and Atenolol** block $\beta_1$ receptors in the heart (reducing cardiac output) and the kidney (reducing renin release) [1], [5]. ### 3. High-Yield Clinical Pearls for NEET-PG * **Minoxidil Side Effect:** Can cause **hypertrichosis** (excessive hair growth), hence its use in topical formulations for alopecia. * **Diazoxide Side Effect:** Can cause **hyperglycemia** because opening $K_{ATP}$ channels in pancreatic beta cells inhibits insulin release. * **Drug of Choice:** For hypertensive emergencies in pregnancy, **Labetalol** (alpha + beta blocker) is preferred; for aortic dissection, **Esmolol** is often used [4].

Question 1

A 54-year-old man with emphysema presents with a blood pressure of 157/101 mmHg. Despite treatment with angiotensin-converting enzyme inhibitors, diuretics, and calcium channel blockers, each agent had to be discontinued due to undesirable side effects. The physician then decides to prescribe a beta-antagonist. Which of the following would be most appropriate for this patient?

Accepted Answer

Metoprolol

Answer

Nadolol

Answer

Propranolol

Answer

Sotalol

Question 2

Sodium nitroprusside's active metabolite acts by which mechanism?

Accepted Answer

Stimulating guanylyl cyclase

Answer

Inhibiting phosphokinase

Answer

Activating phospholipase A

Answer

Activating phospholipase B

Question 3

If systemic vascular resistance is twice that of normal, which of the following treatments should be initiated?

Accepted Answer

Sodium nitroprusside

Answer

Adrenaline

Answer

Nor-adrenaline

Answer

Isoprenaline

Question 4

What is the antihypertensive of choice in a pregnant lady?

Accepted Answer

Methyldopa

Answer

Furosemide

Answer

Nitroprusside

Answer

ACE inhibitors

Question 5

Which of the following drugs is used for termination as well as prophylaxis of paroxysmal supraventricular tachycardia?

Accepted Answer

Verapamil

Answer

Digoxin

Answer

Propranolol

Answer

Quinidine

Question 6

Important adverse effect of nesiritide is

Accepted Answer

Hypotension

Answer

Dysgeusia

Answer

Cough

Answer

Angioedema

Question 7

Food reduces the oral bioavailability of the following angiotensin converting enzyme inhibitors EXCEPT?

Accepted Answer

Enalapril

Answer

Captopril

Answer

Ramipril

Answer

Fosinopril

Question 8

The dose of digoxin is NOT altered in which of the following conditions?

Accepted Answer

Hepatic disease

Answer

Old age

Answer

Renal disease

Answer

Hypercalcemia

Question 9

Antihypertensives may act by blocking all of the following except?

Accepted Answer

ATP dependent potassium channels

Answer

Alpha adrenoceptors

Answer

Noradrenaline release

Answer

Beta adrenoceptors

Question 10

Which of the following is NOT a true statement about clonidine?

Accepted Answer

Prazosin is used to antagonize its side effects.

Answer

It increases parasympathetic outflow.

Answer

It decreases sympathetic outflow by blocking central alpha receptors.

Answer

It is used in the management of hypertension.

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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