Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 1161: Which of the following is a selective beta-1 agonist?

A. Terbutaline
B. Albuterol
C. Dobutamine (Correct Answer)
D. Isoetharine

Explanation: ***Dobutamine*** - **Dobutamine** is a **selective beta-1 agonist** primarily used to increase **cardiac contractility** and output, making it valuable in cases of **heart failure** or **cardiogenic shock**. - Its selectivity for beta-1 receptors minimizes effects on **beta-2 receptors** in the lungs, reducing the risk of **bronchodilation** or **bronchospasm** compared to non-selective beta agonists. *Terbutaline* - **Terbutaline** is a **beta-2 selective agonist** primarily used as a **bronchodilator** in the treatment of **asthma** and **COPD**, and as a **tocolytic** to delay premature labor. - While it has some beta-1 activity at higher doses, its main therapeutic effect comes from **bronchodilation** via **beta-2 receptors**. *Albuterol* - **Albuterol** is a **short-acting beta-2 selective agonist (SABA)** used for the rapid relief of **bronchospasm** in conditions like **asthma**. - Its primary action is on **beta-2 receptors** in the airways, causing **bronchodilation**, and it has minimal activity on **beta-1 receptors** at therapeutic doses. *Isoetharine* - **Isoetharine** is a **beta-2 selective agonist** historically used as a **bronchodilator**, though it is less selective than newer agents like albuterol. - While predominantly acting on **beta-2 receptors**, it can have some **cardiac effects** (beta-1 stimulation) at higher doses, and has been largely replaced by more selective agents with better safety profiles.

Question 1162: All are fibric acid derivatives except which of the following?

A. Clofibrate
B. Gemfibrozil
C. Fenofibrate
D. Lovastatin (Correct Answer)

Explanation: ***Lovastatin***- **Lovastatin** is an example of a **statin drug**, which works by inhibiting **HMG-CoA reductase**, the rate-limiting enzyme in cholesterol synthesis, primarily lowering LDL cholesterol [1, 2].- Unlike fibric acid derivatives, statins do not primarily target **PPAR-alpha** receptors to reduce triglyceride levels.*Clofibrate*- **Clofibrate** is an older **fibric acid derivative** that primarily activates **PPAR-alpha** receptors, leading to decreased triglyceride production and increased lipoprotein lipase activity [1, 2].- It is one of the earliest drugs in this class, though now largely replaced by newer agents due to side effects.*Gemfibrozil*- **Gemfibrozil** is a commonly used **fibric acid derivative** that activates **PPAR-alpha**, resulting in a reduction of **triglycerides** and an increase in **HDL cholesterol** [1, 2].- It is effective in treating severe hypertriglyceridemia and mixed dyslipidemia.*Fenofibrate*- **Fenofibrate** is a **fibric acid derivative** that, like gemfibrozil, acts as a **PPAR-alpha agonist** to lower triglycerides and raise HDL cholesterol [1, 2].- It also has a beneficial effect on **uric acid levels** and can be used in patients with hyperuricemia.

Question 1163: Which of the following alpha-blocker drugs is used in the treatment of benign prostatic hyperplasia without producing significant hypotension?

A. Doxazosin
B. Phentolamine
C. Terazosin
D. Tamsulosin (Correct Answer)

Explanation: ***Tamsulosin*** - Tamsulosin is a **selective alpha-1a adrenergic receptor blocker**, which primarily targets receptors in the **prostate** and bladder neck. - Its selectivity minimizes effects on vascular alpha-1b receptors, thereby *reducing the incidence of orthostatic hypotension* compared to non-selective alpha-blockers. *Doxazosin* - Doxazosin is a **non-selective alpha-1 blocker** that affects both prostatic and vascular smooth muscle, making **hypotension a more common side effect**. - While effective for BPH, it is also used for hypertension, indicating its significant impact on **blood pressure**. *Phentolamine* - Phentolamine is a **non-selective alpha-adrenergic blocker** used in pheochromocytoma and hypertensive crises, but not typically for BPH. - It can cause **significant hypotension** due to its widespread alpha-receptor antagonism. *Terazosin* - Similar to doxazosin, terazosin is a **non-selective alpha-1 blocker** that causes peripheral vasodilation. - This property means it can lead to **symptomatic hypotension**, especially upon initiation of therapy.

Question 1164: Which of the following drugs is primarily indicated for improving symptoms in congestive heart failure?

A. Beta blockers
B. Diuretics (Correct Answer)
C. ACE inhibitor
D. Aldosterone antagonist

Explanation: ***Diuretics*** - **Diuretics** are the PRIMARY agents for **symptom relief** in congestive heart failure. - They directly target fluid overload, providing immediate relief of symptoms like **dyspnea** and **edema**. - According to ACC/AHA guidelines, diuretics are recommended for **all CHF patients with fluid retention** for symptom management. - While they improve quality of life significantly, their main role is **symptom control** rather than mortality reduction. *ACE inhibitor* - **ACE inhibitors** are foundational in heart failure treatment, primarily improving **mortality** and preventing **cardiac remodeling**. - They reduce preload and afterload by inhibiting the **renin-angiotensin-aldosterone system**. - While they do improve symptoms secondarily through hemodynamic effects, their **primary indication** is mortality benefit and disease modification, not direct symptomatic relief. *Beta blockers* - While essential for **reducing mortality** and improving left ventricular function in heart failure, beta-blockers' primary aim is not direct symptomatic relief. - They can initially worsen symptoms in some patients due to a **negative inotropic effect**, although this usually improves over time. - Their main benefit is long-term mortality reduction and prevention of disease progression. *Aldosterone antagonist* - **Aldosterone antagonists** (e.g., spironolactone, eplerenone) are added to therapy to reduce **mortality** and hospitalizations in patients with reduced ejection fraction. - While they can help with fluid balance, their primary benefit is blocking the harmful effects of **aldosterone** on the heart and kidneys, not direct symptom improvement.

Question 1165: Which alpha-1 blocker is known for having minimal effects on blood pressure?

A. Tamsulosin (Correct Answer)
B. Prazosin
C. Doxazosin
D. Terazosin

Explanation: ***Correct: Tamsulosin*** - **Tamsulosin** is a **selective alpha-1A blocker**, primarily targeting alpha-1A receptors in the prostate and bladder neck. - Due to its **uroselective** nature, it causes less systemic vasodilation and thus has **minimal effects on blood pressure** compared to non-selective alpha-1 blockers. - This selectivity makes it the preferred agent for **benign prostatic hyperplasia (BPH)** in patients where blood pressure stability is important. *Incorrect: Prazosin* - **Prazosin** is a **non-selective alpha-1 blocker** that acts on both alpha-1A and alpha-1B receptors in the vasculature. - It commonly causes **postural hypotension** and is often used as an antihypertensive agent, indicating significant blood pressure effects. - Requires dose titration to minimize first-dose hypotension. *Incorrect: Doxazosin* - **Doxazosin** is also a **non-selective alpha-1 blocker** that affects vascular smooth muscle. - It is used for both **benign prostatic hyperplasia (BPH)** and **hypertension**, demonstrating its notable blood pressure-lowering effects. - Longer half-life allows once-daily dosing but maintains significant cardiovascular effects. *Incorrect: Terazosin* - **Terazosin** is another **non-selective alpha-1 blocker** with significant effects on vascular smooth muscle. - Similar to prazosin and doxazosin, it can cause **orthostatic hypotension** and a more pronounced reduction in blood pressure. - Also used for dual indication of BPH and hypertension.

Question 1166: Which of the following is the MOST effective agent for prophylaxis of high-altitude pulmonary edema?

A. ACE inhibitor
B. Acetazolamide (Correct Answer)
C. Nifedipine
D. Digoxin

Explanation: ***Acetazolamide*** - **Acetazolamide** is a **carbonic anhydrase inhibitor** and the **first-line prophylactic agent** for high-altitude pulmonary edema (HAPE). - It works by inducing **metabolic acidosis**, which stimulates **ventilation** and improves **oxygenation**, facilitating acclimatization to high altitude. - It reduces the incidence of **acute mountain sickness (AMS)** and has proven efficacy in **HAPE prevention** by improving arterial oxygenation and reducing pulmonary artery pressure. - Recommended dosing: **125-250 mg twice daily**, starting 1-2 days before ascent. *Nifedipine* - **Nifedipine** is a calcium channel blocker that causes pulmonary vasodilation and reduces pulmonary arterial pressure. - While effective for HAPE prevention, it is typically reserved as a **second-line agent** or for individuals with a **history of recurrent HAPE**. - It is more commonly used for **treatment** of established HAPE rather than primary prophylaxis. *ACE inhibitor* - **ACE inhibitors** primarily affect the systemic renin-angiotensin-aldosterone system and are used for **hypertension** and **heart failure**. - They do not have a direct role in reducing **pulmonary artery pressure** or preventing HAPE. - Not recommended for altitude illness prophylaxis. *Digoxin* - **Digoxin** is a cardiac glycoside used for **heart failure** and **atrial fibrillation** to increase cardiac contractility and control heart rate. - It has no role in preventing or treating **HAPE** as it does not reduce pulmonary vascular resistance or facilitate acclimatization. - Not used for altitude-related conditions.

Question 1167: What is the drug of choice in paroxysmal supraventricular tachycardia?

A. Amiodarone
B. Quinidine
C. Adenosine (Correct Answer)
D. Lidocaine

Explanation: ***Adenosine*** - **Adenosine** is the drug of choice for acute termination of most paroxysmal supraventricular tachycardias (PSVT) due to its rapid onset and short duration of action [1]. - It works by transiently blocking the **atrioventricular (AV) node**, interrupting the re-entrant circuit common in PSVT [1]. *Amiodarone* - **Amiodarone** is a potent antiarrhythmic primarily used for both supraventricular and ventricular arrhythmias, but it is not the first-line agent for acute PSVT due to a slower onset of action and more significant side effects. - It is typically reserved for **refractory arrhythmias** or for maintaining sinus rhythm in patients with recurrent atrial fibrillation or flutter. *Lidocaine* - **Lidocaine** is primarily used for **ventricular arrhythmias**, particularly in the setting of acute myocardial infarction. - It has little to no efficacy in treating **supraventricular tachycardias** because its main action is on ventricular sodium channels. *Quinidine* - **Quinidine** is a Class IA antiarrhythmic drug used for various supraventricular and ventricular arrhythmias, but it is not the first-line treatment for acute PSVT. - Its use has declined due to a high incidence of side effects like **QT prolongation**, torsades de pointes, and gastrointestinal upset.

Question 1168: Which anti-hypertensive drug is known to cause a positive Coombs' test, indicating potential autoimmune hemolytic anemia?

A. Methyldopa (Correct Answer)
B. Clonidine
C. Hydralazine
D. Sodium nitroprusside

Explanation: ***Methyldopa*** - **Methyldopa** is a well-known antihypertensive drug that can induce a **positive Coombs' test** in a significant number of patients, indicating the presence of antibodies on red blood cells. - While many patients with a positive Coombs' test remain asymptomatic, a small percentage can develop **autoimmune hemolytic anemia**. *Clonidine* - **Clonidine** is an alpha-2 adrenergic agonist used to treat hypertension but is not typically associated with inducing a **positive Coombs' test** or hemolytic anemia. - Its primary side effects relate to its central nervous system action, such as **sedation** and **dry mouth**. *Hydralazine* - **Hydralazine** is a direct vasodilator that can cause a **drug-induced lupus-like syndrome**, but it is generally not associated with a **positive Coombs' test** or hemolytic anemia. - The lupus-like syndrome presents with symptoms like arthralgia, myalgia, and fever. *Sodium nitroprusside* - **Sodium nitroprusside** is a potent vasodilator used in hypertensive emergencies, working by releasing nitric oxide. - It is not associated with a **positive Coombs' test** or drug-induced hemolytic anemia; its primary toxicity concern is **cyanide poisoning** with prolonged or high-dose use.

Question 1169: Which beta-blocker is known to cause decreased libido and impotence?

A. Atenolol (Correct Answer)
B. Propranolol
C. Metoprolol
D. Carvedilol

Explanation: ***Atenolol*** - **All beta-blockers can cause sexual dysfunction** including decreased libido and impotence, primarily through **peripheral mechanisms** (reduced cardiac output, decreased peripheral blood flow) and effects on the autonomic nervous system. - **Atenolol** is a **hydrophilic (water-soluble)** beta-1 selective blocker with **poor CNS penetration**, so its effects on sexual function are mainly through peripheral mechanisms rather than central effects. - While sexual dysfunction is a recognized class effect of beta-blockers (occurring in 10-15% of patients), there is **no strong evidence that Atenolol causes this side effect significantly more than other beta-blockers**. - The question may be testing awareness that sexual dysfunction is a known side effect of beta-blocker therapy in general. *Propranolol* - **Propranolol** is a **lipophilic (fat-soluble)** non-selective beta-blocker that **readily crosses the blood-brain barrier**. - Due to its CNS penetration, it can cause sexual dysfunction through both **central and peripheral mechanisms**. - Sexual dysfunction with Propranolol is well-documented and occurs at similar rates to other beta-blockers. *Metoprolol* - **Metoprolol** is a **moderately lipophilic** beta-1 selective blocker with moderate CNS penetration. - Sexual dysfunction is a recognized side effect, occurring at rates similar to other beta-blockers in the class. - Effects are dose-dependent and may vary between immediate and extended-release formulations. *Carvedilol* - **Carvedilol** is a non-selective beta-blocker with additional **alpha-1 blocking activity** that causes vasodilation. - Sexual dysfunction can occur, though the alpha-1 blockade may theoretically provide some peripheral vascular benefit. - Like all beta-blockers, it carries the class warning for sexual dysfunction.

Question 1170: Which of the following medications is primarily used to decrease preload?

A. Hydralazine
B. Nifedipine
C. Nitroglycerine (Correct Answer)
D. Losartan

Explanation: ***Nitroglycerine*** - **Nitroglycerine** primarily causes **venodilation**, leading to pooling of blood in the peripheral veins and a reduction in venous return to the heart. - This decrease in venous return directly lowers the **preload** on the heart, reducing ventricular end-diastolic volume and pressure. *Hydralazine* - **Hydralazine** is an **arteriolar vasodilator** that primarily acts to decrease **afterload** by relaxing arterial smooth muscle. - While it can indirectly affect cardiac output, its main effect is not on preload. *Nifedipine* - **Nifedipine** is a **calcium channel blocker** that mainly causes **arterial vasodilation**, leading to a reduction in systemic vascular resistance and **afterload**. - It has minimal direct effects on venodilation or preload. *Losartan* - **Losartan** is an **angiotensin receptor blocker (ARB)** that primarily acts by blocking the effects of angiotensin II. - This leads to **vasodilation** (both arterial and venous, though more arterial) and a decrease in blood pressure, impacting both preload and afterload but not primarily focused on preload reduction like nitroglycerine.

Practice by Chapter

Antihypertensive Agents

Practice Questions

Drugs for Heart Failure

Practice Questions

Antiarrhythmic Drugs

Practice Questions

Antianginal Agents

Practice Questions

Lipid-Lowering Drugs

Practice Questions

Anticoagulants and Antiplatelet Drugs

Practice Questions

Thrombolytic Agents

Practice Questions

Drugs Used in Pulmonary Hypertension

Practice Questions

Drugs Used in Shock

Practice Questions

Cardiovascular Effects of Non-Cardiovascular Drugs

Practice Questions

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