Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 991: Which of the following is a contraindication to the use of Beta Blockers:

A. Severe asthma with bronchospasm (Correct Answer)
B. Thyroid storm
C. Glaucoma
D. AV nodal reentrant tachycardia (AVNRT)

Explanation: ***Severe asthma with bronchospasm*** - Beta-blockers, especially **non-selective ones**, can block beta-2 receptors in the lungs, leading to **bronchoconstriction** and worsening asthma symptoms. - This can precipitate a severe **asthma attack** and respiratory distress, making it an **absolute contraindication**. - Even cardioselective beta-blockers should be avoided in severe asthma. *Thyroid storm* - Beta-blockers are often used in **thyroid storm** to manage hyperadrenergic symptoms like **tachycardia** and **tremors**. - Propranolol also has the added benefit of inhibiting peripheral conversion of T4 to T3. - They are not contraindicated but rather an important part of treatment. *Glaucoma* - Topical beta-blockers (e.g., timolol) are commonly used to treat **glaucoma** by **reducing aqueous humor production**, thereby lowering intraocular pressure. - Oral beta-blockers also have this effect and are not contraindicated in glaucoma. *AV nodal reentrant tachycardia (AVNRT)* - Beta-blockers are frequently used in the management of **AVNRT** by slowing AV nodal conduction. - They are effective in both acute termination and prophylaxis of AVNRT episodes. - **Note:** Beta-blockers ARE contraindicated in **atrial fibrillation with Wolff-Parkinson-White syndrome** (pre-excited AF), as blocking the AV node can preferentially conduct through the accessory pathway, potentially causing ventricular fibrillation.

Question 992: Drug of choice for Digoxin induced Ventricular Tachycardia:

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

Explanation: ***Lignocaine*** - **Lignocaine** (also known as lidocaine) is the drug of choice for digoxin-induced ventricular tachycardia due to its ability to suppress ventricular arrhythmias without further compromising cardiac contractility [1]. - It works by blocking **sodium channels** in the myocardium, reducing automaticity and stabilizing the cardiac membrane [1]. *Diltiazem* - **Diltiazem** is a calcium channel blocker primarily used for supraventricular tachycardias and angina [1]. - It is contraindicated in digoxin toxicity as it can worsen myocardial depression and AV nodal blockade [1]. *Propranolol* - **Propranolol** is a beta-blocker that can suppress some arrhythmias but is generally not the first-line treatment for digoxin-induced ventricular tachycardia [1]. - Beta-blockers can worsen **bradycardia** and **AV block** often seen in digoxin toxicity [1]. *Verapamil* - **Verapamil** is a calcium channel blocker similar to diltiazem and can exacerbate digoxin toxicity [1]. - It is known to increase serum **digoxin levels** and can worsen the underlying cardiotoxic effects.

Question 993: Which of the following causes vasodilation?

A. Thromboxane A2
B. Angiotensin II
C. Serotonin
D. Histamine (Correct Answer)

Explanation: ***Histamine*** - Histamine is a **potent vasodilator**, primarily through its effects on H1 receptors, leading to the relaxation of **vascular smooth muscle**. - This vasodilation contributes to the increased blood flow and **erythema** observed during inflammatory and allergic responses. - Acts via H1 receptors on endothelial cells to release **nitric oxide** and **prostacyclin**. *Thromboxane A2* - **Thromboxane A2** is a potent **vasoconstrictor** and platelet aggregator, playing a key role in hemostasis and thrombosis. - It is synthesized from **arachidonic acid** via COX-1 and is predominantly found in platelets. *Angiotensin II* - **Angiotensin II** is a powerful **vasoconstrictor** that increases blood pressure through direct arterial smooth muscle contraction. - Part of the **renin-angiotensin-aldosterone system (RAAS)**, it also promotes sodium retention and aldosterone release. - Targeted by ACE inhibitors and ARBs for hypertension management. *Serotonin* - Serotonin (5-hydroxytryptamine, 5-HT) has **complex effects on vascular tone**, causing both vasodilation and vasoconstriction depending on the receptor subtype and vascular bed. - In many contexts, particularly in damaged vessels, it acts as a **vasoconstrictor** and promotes platelet aggregation.

Question 994: Major mechanism of action of nitrates in acute attack of angina is:

A. Coronary vasodilation
B. Decreases in afterload
C. Decreases in heart rate
D. Decreases in preload (Correct Answer)

Explanation: ***Decreases in preload*** - Nitrates primarily cause systemic **venodilation**, leading to pooling of blood in the peripheral veins and reducing venous return to the heart. - This reduction in venous return directly decreases the **left ventricular end-diastolic volume** and pressure, thereby lowering myocardial oxygen demand. *Coronary vasodilation* - While nitrates can cause some **coronary vasodilation**, especially in epicardial arteries, this effect is less significant in relieving acute angina compared to their systemic venodilating effects, particularly in areas of fixed stenosis. - In atherosclerotic vessels, the ability to dilate is impaired, making the **reduction in demand** more critical than increased supply. *Decreases in afterload* - Nitrates can cause some **arterial vasodilation** leading to a modest decrease in afterload, but this is a secondary effect. - The primary and most profound action, especially at therapeutic doses for angina, is on the **venous system**. *Decreases in heart rate* - Nitrates generally do not directly decrease heart rate; in fact, a reflex **tachycardia** can sometimes occur due to the drop in blood pressure. - A decrease in heart rate would reduce myocardial oxygen demand, but this is not the **major mechanism of nitrates**.

Question 995: Which of the following is not used in heart failure?

A. Sacubitril
B. Metoprolol
C. Trimetazidine (Correct Answer)
D. Nesiritide

Explanation: ***Trimetazidine*** - While it has an anti-ischemic effect and can be used in **stable angina**, trimetazidine is *not* a primary or established drug for **heart failure** treatment. - Its mechanism involves metabolic modulation rather than direct hemodynamic or neurohormonal benefits critical for heart failure. *Sacubitril* - Sacubitril is a **neprilysin inhibitor**, often combined with valsartan (an ARB) as **sacubitril/valsartan**, and is a cornerstone in managing **heart failure with reduced ejection fraction (HFrEF)**. - It enhances beneficial natriuretic peptides, leading to vasodilation, natriuresis, and reduced cardiac remodeling. *Metoprolol* - **Beta-blockers** like metoprolol are essential in heart failure management, particularly in **HFrEF**, to reduce mortality and morbidity. - They work by blocking the effects of norepinephrine and epinephrine, thereby reducing heart rate, myocardial contractility, and preventing adverse cardiac remodeling. *Nesiritide* - Nesiritide is a **recombinant human B-type natriuretic peptide (BNP)** that is used intravenously in the acute setting for **decompensated heart failure**. - It promotes vasodilation, diuresis, and natriuresis, helping to reduce preload and afterload.

Question 996: Assertion: ACE inhibitors are contraindicated in bilateral renal artery stenosis. Reason: They cause acute kidney injury by reducing efferent arteriolar tone.

A. A true R false
B. Both A & R true, R explains A (Correct Answer)
C. Both A & R true, R doesn't explain A
D. A false R true

Explanation: ***Correct: Both A & R true, R explains A*** - **Assertion is TRUE**: ACE inhibitors are absolutely contraindicated in bilateral renal artery stenosis due to risk of acute kidney injury - **Reason is TRUE**: In bilateral renal artery stenosis, the kidneys depend on **angiotensin II** to maintain GFR by constricting the efferent arteriole - **R explains A**: ACE inhibitors block angiotensin II production → **efferent arteriolar dilation** → drastically reduced GFR → **acute kidney injury (AKI)** - This direct mechanistic link makes the reason a complete explanation of the assertion *Incorrect: A true R false* - While the assertion is true, the reason is also **true** (not false) - ACE inhibitors do reduce efferent arteriolar tone by blocking angiotensin II - This is the precise mechanism causing AKI in these patients *Incorrect: Both A & R true, R doesn't explain A* - Both statements are indeed true, but this option is incorrect because the reason **does explain** the assertion - The mechanism (reduced efferent arteriolar tone → decreased GFR) directly explains why ACE inhibitors are contraindicated - The causal relationship is clear and direct *Incorrect: A false R true* - The assertion is **true**, not false - ACE inhibitors are definitively contraindicated in bilateral renal artery stenosis - This is a well-established clinical contraindication to prevent renal failure

Question 997: A hypertensive diabetic patient with microalbuminuria should receive:

A. Losartan (Correct Answer)
B. Clonidine
C. Metoprolol
D. Amlodipine

Explanation: ***Losartan*** - **Losartan** is an **Angiotensin Receptor Blocker (ARB)**, which is a preferred treatment for hypertension in diabetic patients with microalbuminuria due to its **renoprotective effects**. - ARBs work by blocking the effects of **angiotensin II**, leading to **vasodilation** and a reduction in **glomerular hypertension**, thereby slowing the progression of diabetic nephropathy [2]. *Clonidine* - **Clonidine** is a centrally acting alpha-2 agonist, which can be used for hypertension but is not a first-line agent, especially in diabetic patients with microalbuminuria. - It is associated with side effects such as **sedation** and **rebound hypertension** if discontinued abruptly, and lacks the specific renoprotective benefits of ARBs. *Metoprolol* - **Metoprolol** is a **beta-blocker** that can be used for hypertension but is generally not the first choice for diabetic patients with microalbuminuria due to lack of specific renoprotective effects seen with ARBs [1]. - Beta-blockers can **mask symptoms of hypoglycemia** in diabetic patients and may also worsen **insulin resistance** in some individuals. *Amlodipine* - **Amlodipine** is a **calcium channel blocker** that is effective in lowering blood pressure but does not offer the same **renoprotective benefits** as ARBs in diabetic patients with microalbuminuria. - While safe for use in diabetics, it does not specifically address the underlying **glomerular hyperfiltration** associated with early diabetic kidney disease.

Question 998: A 35-year-old with migraines needs prophylaxis. Which is suitable?

A. Acetaminophen
B. Sumatriptan
C. Verapamil (Correct Answer)
D. Tramadol

Explanation: ***Verapamil*** - **Verapamil**, a calcium channel blocker, is often used off-label for **migraine prophylaxis**, particularly in cases where other first-line agents are contraindicated or ineffective. - While not a first-line treatment, it can reduce the frequency and severity of migraine attacks by modulating **vasoconstriction** and **vasodilation**. *Acetaminophen* - **Acetaminophen** is an analgesic used for **acute pain relief**, but it does not have properties that prevent migraine attacks from occurring. - It is unsuitable for long-term **prophylactic management** of migraines. *Sumatriptan* - **Sumatriptan** is a **triptan** medication used for **acute migraine treatment**, meaning it is taken to stop a migraine attack once it has started. - It is not indicated for **migraine prophylaxis** and should not be used regularly to prevent migraines. *Tramadol* - **Tramadol** is an **opioid analgesic** used for moderate to severe pain, and it carries risks of dependence and side effects. - It is not recommended for **migraine prophylaxis** due to its addictive potential and lack of evidence for preventing migraine attacks.

Question 999: What is the primary mechanism by which digoxin improves symptoms in heart failure?

A. Inhibits Na+/K+ ATPase (Correct Answer)
B. Increases intracellular calcium levels
C. Increases heart rate
D. Decreases heart rate

Explanation: Inhibits Na+/K+ ATPase - Digoxin's primary mechanism involves inhibiting the Na+/K+ ATPase pump in cardiac myocytes [1]. - This inhibition leads to an increase in intracellular sodium, which in turn reduces the efficiency of the Na+/Ca2+ exchanger, ultimately increasing intracellular calcium [1]. Increases intracellular calcium levels - While digoxin does increase intracellular calcium, this is a downstream effect of its initial action on the Na+/K+ ATPase pump, not its primary mechanism of action [2]. - The elevated calcium then leads to increased contractility of the cardiac muscle [2]. Increases heart rate - Digoxin actually tends to decrease heart rate by increasing vagal tone, which is beneficial in heart failure, especially in patients with atrial fibrillation [1], [3]. - An increased heart rate would worsen cardiac output in a failing heart. Decreases heart rate - While digoxin does decrease heart rate, this is an indirect effect through vagal stimulation, and not its primary cellular mechanism of action for improving contractility in heart failure [3]. - The direct and primary mechanism is the inhibition of the Na+/K+ ATPase [1].

Question 1000: A 60-year-old patient with atrial fibrillation is prescribed digoxin. Which of the following is the MOST common EARLY side effect of digoxin?

A. Nausea and vomiting (Correct Answer)
B. Hypertension
C. Visual disturbances
D. Hyperkalemia

Explanation: ***Nausea and vomiting*** - **Gastrointestinal symptoms** such as nausea, vomiting, and anorexia are the **most common early signs** of **digoxin toxicity** due to its effect on the **chemoreceptor trigger zone**. - These symptoms can occur even at therapeutic levels, especially in susceptible individuals or with slight increases in concentration. - GI symptoms typically appear **before** other manifestations of toxicity, making them important early warning signs. *Hypertension* - Digoxin primarily affects **cardiac contractility** and **heart rate**, and it is not typically associated with causing **hypertension**. - In fact, digoxin can somewhat lower blood pressure due to its effects on **cardiac output** and **vasodilation** in some circumstances, though this is not its primary mechanism or side effect. *Visual disturbances* - **Visual disturbances**, including blurred vision, halos around lights, and changes in color perception (e.g., **yellow-green halos**), are a classic and **common symptom of digoxin toxicity**. - However, these typically appear **later** than gastrointestinal symptoms and often occur after or concurrently with GI manifestations. - While significant indicators of toxicity, they are not usually the **earliest** warning sign. *Hyperkalemia* - Digoxin inhibits the **Na+/K+-ATPase pump**, which can lead to **intracellular sodium accumulation** and **extracellular potassium accumulation**. However, **hyperkalemia** is primarily seen in cases of **acute, severe digoxin toxicity** or in patients with **renal impairment**. - More commonly, **hypokalemia** can actually potentiate digoxin's effects and increase the risk of toxicity, rather than digoxin directly causing hyperkalemia at therapeutic or mildly toxic levels.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

Practice Questions

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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