Cardiovascular Drugs — MCQs

Cardiovascular Drugs Indian Medical PG Practice Questions and MCQs

Question 591: What is the minimum recommended starting dosage of Candesartan?

A. 2 mg (Correct Answer)
B. 40 mg
C. 20 mg
D. 30 mg

Explanation: **Explanation:** **Candesartan cilexetil** is a potent, long-acting Angiotensin II Receptor Blocker (ARB) used primarily in the management of hypertension and heart failure. **Why 2 mg is the correct answer:** In clinical practice, the standard starting dose for hypertension in adults is typically 8 mg once daily. However, the **minimum recommended starting dose is 2 mg**. This low dose is specifically indicated for patients with **intravascular volume depletion** (e.g., those on high-dose diuretics) or patients with **hepatic impairment**, to avoid the risk of profound first-dose hypotension. For pediatric patients (ages 1 to <6 years), the starting dose is also calculated based on weight, often beginning at low increments. **Analysis of Incorrect Options:** * **B (40 mg):** This is incorrect as it exceeds the maximum recommended daily dose for hypertension, which is typically **32 mg**. * **C (20 mg) & D (30 mg):** These are not standard starting doses. While Candesartan is available in various strengths, the titration usually follows a doubling pattern (2mg → 4mg → 8mg → 16mg → 32mg). **High-Yield Clinical Pearls for NEET-PG:** * **Mechanism of Action:** Selective AT1 receptor antagonist; it does not inhibit ACE, thus it does not increase bradykinin levels (lower incidence of dry cough compared to ACE inhibitors). * **Prodrug Status:** Candesartan cilexetil is a **prodrug** that is completely converted to the active moiety, candesartan, during gastrointestinal absorption. * **Heart Failure (HFrEF):** The target dose in heart failure (based on the CHARM study) is **32 mg once daily**, starting from 4 mg. * **Contraindication:** Like all drugs acting on the RAAS, it is **absolutely contraindicated in pregnancy** due to teratogenicity (fetal renal toxicity).

Question 592: Which drugs are involved in the bradycardia algorithm?

A. Atropine, Dopamine, Epinephrine (Correct Answer)
B. Atropine, Norepinephrine, Dopamine
C. Atropine, Isoproterenol, Norepinephrine
D. Atropine, Dobutamine, Amiodarone

Explanation: ### Explanation The management of symptomatic bradycardia follows the **ACLS (Advanced Cardiovascular Life Support) Algorithm**. The primary goal is to increase the heart rate and improve cardiac output in patients with signs of poor perfusion (e.g., hypotension, altered mental status, or chest pain). **1. Why Option A is Correct:** * **Atropine:** The first-line drug. It is an anticholinergic that blocks the vagus nerve's inhibitory effect on the SA and AV nodes, thereby increasing the heart rate. (Dose: 1 mg IV every 3–5 mins; Max: 3 mg). * **Dopamine:** Used as a second-line infusion if Atropine is ineffective. At "cardiac doses" (5–10 mcg/kg/min), it acts on $\beta_1$ receptors to increase heart rate and contractility. * **Epinephrine:** Also a second-line infusion (2–10 mcg/min). It provides potent $\beta_1$ stimulation to increase chronotropy (rate) and inotropy (contractility). **2. Why Other Options are Incorrect:** * **Norepinephrine (Options B & C):** Primarily an $\alpha_1$ agonist used for septic shock. While it has some $\beta_1$ activity, it can cause **reflex bradycardia** due to intense vasoconstriction, making it unsuitable for the bradycardia algorithm. * **Isoproterenol (Option C):** Though a pure $\beta$ agonist, it is no longer a first-line ACLS recommendation due to the risk of arrhythmias and excessive myocardial oxygen demand. * **Dobutamine & Amiodarone (Option D):** Dobutamine is primarily for cardiogenic shock without severe hypotension. Amiodarone is an anti-arrhythmic used for **tachycardia** (VF/pVT), not bradycardia. **3. NEET-PG High-Yield Pearls:** * **Drug of Choice:** Atropine is the initial drug of choice for symptomatic bradycardia. * **Transcutaneous Pacing (TCP):** If drugs fail or the patient is unstable with high-degree blocks (Mobitz II or 3rd-degree), immediate TCP is indicated. * **Atropine Caution:** Use with caution in **Myocardial Ischemia** (may worsen ischemia by increasing O2 demand) and it is often ineffective in **Heart Transplant** patients (denervated heart) or **3rd-degree AV blocks** with wide QRS.

Question 593: Which of the following agents is a Class C antiarrhythmic drug?

A. Quinine
B. Amiodarone (Correct Answer)
C. Propranolol
D. Lignocaine

Explanation: The classification of antiarrhythmic drugs follows the **Vaughan-Williams classification**, which categorizes agents based on their primary mechanism of action on the cardiac action potential. ### **Explanation of the Correct Answer** **Amiodarone** is the correct answer because it is the prototype **Class III** antiarrhythmic agent. These drugs primarily act by **blocking potassium (K+) channels**, which prolongs the duration of the action potential and the effective refractory period (ERP). While Amiodarone also possesses Class I, II, and IV properties, its dominant clinical effect is Class III. ### **Analysis of Incorrect Options** * **Quinine (Option A):** This is an antimalarial. Its isomer, **Quinidine**, is a **Class IA** antiarrhythmic. Class IA drugs block sodium channels and prolong the action potential. * **Propranolol (Option C):** This is a **Class II** antiarrhythmic. These are beta-blockers that decrease sympathetic activity, slowing the heart rate and AV conduction. * **Lignocaine (Option D):** This is a **Class IB** antiarrhythmic. It blocks sodium channels specifically in the inactivated state and is primarily used for ventricular arrhythmias, especially post-myocardial infarction. ### **High-Yield Clinical Pearls for NEET-PG** * **Amiodarone Side Effects:** Highly high-yield! Remember the "6 Ps": **P**ulmonary fibrosis, **P**hotodermatitis (Blue-grey skin), **P**eripheral neuropathy, **P**rolonged QT interval, **P**apillary (Corneal) microdeposits, and **P**roblems with Thyroid (Hypo/Hyperthyroidism due to high iodine content). * **Class IC Agents:** (e.g., Flecainide) are the most potent sodium channel blockers and are contraindicated post-MI. * **Drug of Choice:** Adenosine is the DOC for Paroxysmal Supraventricular Tachycardia (PSVT).

Question 594: Which of the following drugs can be used for both prophylaxis and treatment of angina?

A. Isosorbide mononitrate
B. Isosorbide dinitrate (Correct Answer)
C. Thyroxine
D. Sumatriptan

Explanation: **Explanation:** The correct answer is **Isosorbide dinitrate (ISDN)**. **1. Why Isosorbide dinitrate is correct:** Nitrates are the mainstay of angina management due to their ability to cause peripheral vasodilation (venodilation > arteriodilation), which reduces cardiac preload and myocardial oxygen demand. * **Treatment (Acute Attack):** When administered **sublingually**, ISDN has a rapid onset of action (2–5 minutes), making it effective for terminating an acute anginal episode. * **Prophylaxis (Chronic Management):** When administered **orally**, it has a longer duration of action (4–6 hours), making it suitable for preventing future attacks. **2. Analysis of Incorrect Options:** * **Isosorbide mononitrate (ISMN):** While it is an excellent drug for **prophylaxis** due to its high oral bioavailability and long half-life, it is not used for acute treatment because it is only available in oral formulations and lacks a rapid-onset sublingual form. * **Thyroxine:** This increases the metabolic rate and heart rate, which elevates myocardial oxygen demand. It can actually **precipitate or worsen** angina. * **Sumatriptan:** A 5-HT$_{1B/1D}$ agonist used for migraines, it can cause **coronary vasospasm** (Prinzmetal angina) and is strictly contraindicated in patients with ischemic heart disease. **3. NEET-PG High-Yield Pearls:** * **Nitrate Tolerance:** Continuous exposure leads to reduced efficacy (depletion of free sulfhydryl groups). To prevent this, a **"Nitrate-free interval"** of 8–12 hours (usually at night) is mandatory. * **Drug Interaction:** Nitrates are absolutely contraindicated with **Sildenafil** (PDE-5 inhibitors) as the combination can cause life-threatening hypotension. * **DOC for Acute Angina:** Sublingual Nitroglycerin (Glyceryl Trinitrate) remains the first choice for immediate relief.

Question 595: Which of the following is a bile acid sequestrant?

A. Atorvastatin
B. Resin (Correct Answer)
C. Fibrates
D. Niacin

Explanation: **Explanation:** **Bile Acid Sequestrants (Resins)** are a class of lipid-lowering agents that include **Cholestyramine, Colestipol, and Colesevelam** [1, 2]. These are large, positively charged polymers that bind to negatively charged bile acids in the intestinal lumen [1]. By preventing the enterohepatic circulation of bile acids, they force the liver to convert more cholesterol into new bile acids [1]. This leads to an upregulation of LDL receptors on hepatocytes, resulting in decreased serum LDL levels [1]. **Analysis of Options:** * **Option B (Resin):** Correct. As described above, resins are the primary bile acid sequestrants [1, 2]. * **Option A (Atorvastatin):** Incorrect. This belongs to the **HMG-CoA Reductase Inhibitors** class, which inhibits the rate-limiting step of cholesterol synthesis [2]. * **Option C (Fibrates):** Incorrect. Drugs like Fenofibrate and Gemfibrozil are **PPAR-alpha agonists** that primarily lower triglycerides by increasing the activity of lipoprotein lipase [2]. * **Option D (Niacin):** Incorrect. Also known as Vitamin B3, it inhibits lipolysis in adipose tissue and reduces hepatic VLDL synthesis [2]. **High-Yield Clinical Pearls for NEET-PG:** * **Side Effects:** Resins often cause GI distress (bloating, constipation) and can cause **hypertriglyceridemia** (they are contraindicated if baseline triglycerides are >300 mg/dL) [2]. * **Drug Interactions:** They interfere with the absorption of fat-soluble vitamins (A, D, E, K) and acidic drugs like Warfarin, Digoxin, and Thiazides [1]. * **Safe Population:** Colesevelam is often considered the drug of choice for treating hypercholesterolemia during **pregnancy**.

Question 596: Which of the following statements regarding verapamil is incorrect?

A. It does not produce reflex tachycardia.
B. It is less potent as a coronary vasodilator.
C. It is contraindicated in patients with supraventricular tachycardia. (Correct Answer)
D. It can cause constipation.

Explanation: ### Explanation **Verapamil** is a non-dihydropyridine Calcium Channel Blocker (CCB) with a predominant effect on the myocardium rather than peripheral vasculature. **Why Option C is the Correct (Incorrect Statement):** Verapamil is actually a **drug of choice** for the acute termination of Paroxysmal Supraventricular Tachycardia (PSVT). It acts by blocking L-type calcium channels in the AV node, thereby increasing the refractory period and slowing conduction. It is **not** contraindicated in SVT; rather, it is used to control the ventricular rate in atrial flutter and fibrillation. **Analysis of Other Options:** * **Option A (Correct statement):** Unlike dihydropyridines (e.g., Nifedipine), Verapamil causes significant negative inotropic and chronotropic effects. This direct cardiac suppression offsets any potential baroreceptor reflex, thus it **does not produce reflex tachycardia**. * **Option B (Correct statement):** While Verapamil does dilate coronary arteries, it is **less potent** as a vasodilator compared to dihydropyridines (like Amlodipine or Nifedipine), which have a much higher affinity for vascular smooth muscle. * **Option D (Correct statement):** **Constipation** is the most common side effect of Verapamil (occurring in up to 25% of patients) due to the blockade of calcium channels in the gastrointestinal smooth muscle, leading to decreased motility. **High-Yield Clinical Pearls for NEET-PG:** * **Contraindications:** Verapamil is strictly contraindicated in **Sick Sinus Syndrome, 2nd or 3rd-degree AV block, and Heart Failure** (due to negative inotropy). * **Drug Interaction:** Avoid combining Verapamil with **Beta-blockers**, as this can lead to additive bradycardia or complete heart block. * **Wolff-Parkinson-White (WPW) Syndrome:** Verapamil is contraindicated in WPW with atrial fibrillation as it may enhance conduction through the accessory pathway, leading to ventricular fibrillation.

Question 597: What is the mechanism of action of Sodium nitroprusside?

A. Increased cAMP
B. Stimulation of guanylate cyclase (Correct Answer)
C. Calcium channel blockers
D. Potassium channel blocker

Explanation: **Mechanism of Action: Sodium Nitroprusside (SNP)** Sodium nitroprusside is a potent, rapid-acting parenteral vasodilator used in hypertensive emergencies [1][2]. Its primary mechanism involves the release of **Nitric Oxide (NO)**. 1. **Why Option B is Correct:** SNP is a prodrug that reacts with sulfhydryl groups on erythrocytes and tissue proteins to release inorganic iodine and NO [4]. NO activates the enzyme **soluble guanylate cyclase**, which increases the conversion of GTP to **cyclic GMP (cGMP)** [3][4]. Elevated cGMP levels lead to dephosphorylation of myosin light chains, resulting in profound relaxation of both **arterioles and venules** (balanced vasodilator) [1][3]. 2. **Why Other Options are Incorrect:** * **Option A (Increased cAMP):** This is the mechanism for drugs like Milrinone (PDE-3 inhibitor) or Beta-2 agonists, not SNP. * **Option C (CCBs):** Drugs like Nifedipine or Amlodipine work by blocking L-type calcium channels to prevent contraction; SNP works via the NO-cGMP pathway. * **Option D (Potassium channel openers):** Drugs like Minoxidil, Diazoxide, and Hydralazine act by opening K+ channels, leading to hyperpolarization [1]. **High-Yield NEET-PG Pearls:** * **Balanced Vasodilator:** Unlike Hydralazine (arteriolar only), SNP reduces both **Preload** and **Afterload** [1]. * **Toxicity:** Metabolism of SNP releases **Cyanide** and **Thiocyanate**. * *Cyanide toxicity treatment:* Sodium thiosulfate, Sodium nitrite, or Hydroxocobalamin. * **Light Sensitivity:** SNP is unstable in light; the infusion bottle must be covered with opaque foil. * **Drug of Choice:** Historically used for hypertensive emergencies and aortic dissection (along with beta-blockers) [2].

Question 598: All of the following are true about HMG CoA reductase inhibitors except:

A. CNS accumulation of simvastatin and lovastatin is high, and less for pravastatin and fluvastatin.
B. Simvastatin is rapidly and pravastatin is least metabolized.
C. Bioavailability is minimally modified when pravastatin is taken with food.
D. Fibrinogen levels are increased by pravastatin. (Correct Answer)

Explanation: **Explanation:** Statins (HMG-CoA reductase inhibitors) are the cornerstone of dyslipidemia management. This question tests the specific pharmacokinetic and pleiotropic differences between various statins. **Why Option D is the correct answer (False statement):** Statins are known for their **pleiotropic effects**, which extend beyond cholesterol lowering. These include anti-inflammatory actions, plaque stabilization, and improvement in endothelial function. Crucially, statins like pravastatin and atorvastatin **decrease** or have a neutral effect on fibrinogen levels, thereby reducing blood viscosity and thrombotic risk. They do not increase fibrinogen. **Analysis of Incorrect Options (True statements):** * **Option A:** Statins are classified by solubility. **Lovastatin and Simvastatin** are lipophilic, allowing them to cross the blood-brain barrier more easily (higher CNS accumulation). **Pravastatin and Fluvastatin** are hydrophilic and have minimal CNS penetration. * **Option B:** Most statins undergo extensive hepatic metabolism. Simvastatin is a prodrug with rapid first-pass metabolism via CYP3A4. **Pravastatin** is unique as it is not metabolized by the Cytochrome P450 system (it is metabolized in the cytosol), making it the statin with the least metabolic transformation and fewer drug-drug interactions. * **Option C:** Food significantly decreases the absorption of most statins (like lovastatin and atorvastatin). However, the bioavailability of **Pravastatin** is minimally affected by food intake. **NEET-PG High-Yield Pearls:** * **Prodrug Statins:** Lovastatin and Simvastatin. * **Longest Acting Statin:** Rosuvastatin (followed by Atorvastatin). * **Statin of choice in Renal Failure:** Atorvastatin (primarily excreted via bile). * **Best time to dose:** Short-acting statins (Simvastatin, Lovastatin) should be taken at **night** because cholesterol synthesis peaks between midnight and 2:00 AM. * **Major Side Effects:** Myopathy (monitored by CPK levels) and Hepatotoxicity (monitored by ALT/AST). Risk of myopathy increases when combined with **Fibrates** (especially Gemfibrozil).

Question 599: Tolazoline is used as:

A. A thrombin inhibitor in peripheral angiography
B. A vasodilator in treating coronary artery stenosis during angioplasty procedures (Correct Answer)
C. A vasoconstrictor in the treatment of varices
D. An antispasmodic during biliary spasm

Explanation: **Explanation:** **Tolazoline** is a non-selective **alpha-adrenergic antagonist** (blocking both $\alpha_1$ and $\alpha_2$ receptors) with direct histamine-like vasodilator effects. 1. **Why Option B is Correct:** Tolazoline acts as a potent peripheral vasodilator. In the context of interventional cardiology, it is used during coronary angioplasty to reverse or prevent **coronary artery vasospasm**. By blocking alpha-receptors on vascular smooth muscle, it induces relaxation, improves blood flow, and helps manage "no-reflow" phenomena or catheter-induced spasms. 2. **Why Other Options are Incorrect:** * **Option A:** Tolazoline has no anticoagulant or antiplatelet properties; it does not inhibit thrombin (drugs like Heparin or Bivalirudin are used for this). * **Option C:** Tolazoline causes vasodilation, not vasoconstriction. Vasoconstrictors like Terlipressin or Octreotide are used for varices. * **Option D:** While it has some histamine-like effects, it is not a standard antispasmodic for biliary colic; anticholinergics or nitrates are preferred for smooth muscle relaxation in the biliary tract. **High-Yield Clinical Pearls for NEET-PG:** * **Primary Use:** Historically used for **Persistent Pulmonary Hypertension of the Newborn (PPHN)**, though largely replaced by inhaled Nitric Oxide. * **Mechanism:** Competitive $\alpha$-blocker with direct vasodilatory action. * **Side Effects:** Can cause GI stimulation (diarrhea, exacerbation of peptic ulcers) due to its histamine-like (H1 and H2) agonistic activity. * **Related Drug:** **Phentolamine** is another non-selective $\alpha$-blocker used in the diagnosis/management of Pheochromocytoma.

Question 600: All of the following statements about nesiritide are true EXCEPT:

A. It is a BNP analogue
B. It can be used in decompensated CHF
C. It can be administered orally (Correct Answer)
D. It causes loss of Na+ in the urine

Explanation: Nesiritide is a recombinant form of human B-type Natriuretic Peptide (BNP) [1]. The correct answer is Option C because Nesiritide, being a polypeptide, is degraded by gastrointestinal enzymes if taken orally. Therefore, it must be administered via intravenous (IV) infusion. Analysis of Options: * Option A (True): It is a synthetic analogue of endogenous BNP, produced using recombinant DNA technology [1], [3]. * Option B (True): It is specifically indicated for the management of acutely decompensated congestive heart failure (CHF) in patients who have dyspnea at rest or with minimal exertion [1]. It helps by reducing pulmonary capillary wedge pressure (PCWP). * Option D (True): As a natriuretic peptide, it stimulates guanylyl cyclase, increasing cGMP [2]. This leads to potent vasodilation and natriuresis (excretion of sodium in the urine), which helps reduce fluid overload. Clinical Pearls for NEET-PG: 1. Mechanism of Action: Increases cGMP in vascular smooth muscle and kidney cells, leading to balanced vasodilation (venous and arterial) and diuresis [1], [2]. 2. Hemodynamic Effects: It reduces both Preload (venous dilation) and Afterload (arterial dilation) without increasing heart rate (unlike dobutamine). 3. Side Effects: The most common dose-limiting side effect is hypotension. There have also been concerns regarding its impact on renal function (potential increase in serum creatinine). 4. Half-life: It has a short half-life of approximately 18 minutes.

Practice by Chapter

Antihypertensive Agents

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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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