Cardiovascular Drugs Practice Questions

Q: In the treatment of shock, why is Dobutamine preferred over Dopamine?

All the above.. **Explanation:** Dobutamine is a synthetic sympathomimetic that primarily acts as a **$\beta_1$-selective agonist**, making it an ideal inotropic agent in cardiogenic shock. While both drugs increase cardiac output, Dobutamine offers several clinical advantages over Dopamine: 1. **Fewer Arrhythmias (Option A):** Dopamine triggers a significant release of endogenous norepinephrine and has a stronger effect on $\alpha$ and $\beta$ receptors at higher doses, leading to a higher incidence of tachyarrhythmias compared to Dobutamine. 2. **Renal Vasodilation (Option B):** While Dopamine at low doses ("renal dose") acts on $D_1$ receptors to cause vasodilation, this effect is often unpredictable in shock states and can lead to a "steal phenomenon." Dobutamine maintains systemic perfusion more steadily without the complex dose-dependent shifts (Dopaminergic $\rightarrow$ Beta $\rightarrow$ Alpha) seen with Dopamine. 3. **Coronary Vasoconstriction (Option C):** At the high doses often required in shock, Dopamine’s $\alpha_1$-agonist activity causes peripheral and coronary vasoconstriction, increasing afterload and myocardial oxygen demand. Dobutamine, through its mild $\beta_2$ activity, tends to decrease systemic vascular resistance (afterload), improving stroke volume without significant coronary constriction. **Clinical Pearls for NEET-PG:** * **Drug of Choice:** Dobutamine is the preferred inotrope for **Cardiogenic Shock** and is used in **Stress Echocardiography**. * **Dopamine Limitation:** It is no longer the first-line agent for shock due to the risk of arrhythmias and increased mortality in certain subsets of patients. * **Key Side Effect:** The most common side effect of Dobutamine is tachycardia. * **Vascular Effect:** Unlike Dopamine, Dobutamine is a **"Inodilator"** (Inotrope + Vasodilator).

Q: Which of the following drugs does not cause bradycardia?

Hydralazine. The correct answer is **Hydralazine** because it is a potent direct-acting arteriolar vasodilator [1, 2]. When systemic vascular resistance drops rapidly, the body compensates via the baroreceptor reflex. This triggers a significant increase in sympathetic outflow, leading to **reflex tachycardia**, not bradycardia [3]. In clinical practice, hydralazine is often co-administered with a beta-blocker to counteract this compensatory tachycardia [3]. **Analysis of Incorrect Options:** * **Propranolol:** A non-selective beta-blocker that decreases heart rate by blocking $\beta_1$ receptors in the SA node. It is a classic cause of bradycardia [4]. * **Clonidine:** An $\alpha_2$-adrenergic agonist that acts centrally to decrease sympathetic outflow and increase vagal tone, leading to a reduction in heart rate. * **Reserpine:** An alkaloid that depletes catecholamines (norepinephrine) from peripheral sympathetic nerve endings and the CNS. The loss of sympathetic stimulation to the heart results in bradycardia. **High-Yield Clinical Pearls for NEET-PG:** * **Vasodilator Paradox:** Direct vasodilators (Hydralazine, Minoxidil, Nifedipine) typically cause reflex tachycardia [3]. In contrast, centrally acting drugs (Clonidine, Methyldopa) and sympatholytics (Reserpine, Beta-blockers) cause bradycardia. * **Hydralazine Side Effects:** Apart from tachycardia, it is famously associated with **Drug-Induced Lupus Erythematosus (DILE)**, especially in "slow acetylators." * **Clinical Use:** Hydralazine is a preferred drug for managing hypertension in pregnancy (alongside Labetalol and Methyldopa).

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).

Question 1

Which of the following drugs causes an increase in the effective refractory period of the atrioventricular (AV) node?

Accepted Answer

amiodarone

Answer

bretylium

Answer

procainamide

Answer

quinidine

Question 2

In the treatment of shock, why is Dobutamine preferred over Dopamine?

Accepted Answer

All the above.

Answer

It causes fewer arrhythmias.

Answer

It causes less renal vasodilation.

Answer

It causes less coronary vasoconstriction.

Question 3

Which of the following drugs does not cause bradycardia?

Accepted Answer

Hydralazine

Answer

Propranolol

Answer

Clonidine

Answer

Reserpine

Question 4

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 5

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 6

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 7

What is the antihypertensive of choice in a pregnant lady?

Accepted Answer

Methyldopa

Answer

Furosemide

Answer

Nitroprusside

Answer

ACE inhibitors

Question 8

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 9

Important adverse effect of nesiritide is

Accepted Answer

Hypotension

Answer

Dysgeusia

Answer

Cough

Answer

Angioedema

Question 10

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

Accepted Answer

Enalapril

Answer

Captopril

Answer

Ramipril

Answer

Fosinopril

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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