Cardiovascular Drugs Practice Questions

Q: Which of the following antiarrhythmic drugs is contraindicated in a patient with interstitial lung disease?

Amiodarone. ***Amiodarone*** - **Amiodarone** is contraindicated in patients with interstitial lung disease due to its well-known and potentially severe pulmonary toxicity, which can exacerbate or induce **pulmonary fibrosis**. - Its long half-life means that drug accumulation and persistent adverse effects, including **ILD exacerbation**, are significant concerns. *Sotalol* - **Sotalol** primarily carries risks of **prolonged QT interval** and **torsades de pointes** because it has both beta-blocking and Class III antiarrhythmic properties. - While it has cardiac and minor non-cardiac side effects, it is not specifically known to cause or worsen **interstitial lung disease**. *Lignocaine* - **Lignocaine** (lidocaine) is a Class Ib antiarrhythmic primarily used for **ventricular arrhythmias**, especially in acute settings. - Its adverse effects are mainly **neurological** (e.g., dizziness, seizures at high doses) and **cardiovascular** (e.g., hypotension, bradycardia), with no significant association with lung disease. *Quinidine* - **Quinidine** is a Class Ia antiarrhythmic that can cause a variety of side effects, including **gastrointestinal upset**, **cinchonism** (tinnitus, blurred vision), and **cardiac rhythm disturbances**. - While it can rarely cause a hypersensitivity pneumonitis, it is not a primary concern or contraindication in existing **interstitial lung disease** compared to amiodarone.

Q: In acute left ventricular failure with pulmonary edema, which drug can be administered for immediate management?

Morphine. ***Morphine*** - **Morphine** is a key drug in the **acute management of left ventricular failure with pulmonary edema** - It provides **anxiolysis**, reduces **sympathetic drive**, and decreases **preload** through venodilation - Reduces **oxygen demand** and **work of breathing** in acute decompensation - Standard dose: **2-5 mg IV**, can be repeated as needed - Caution needed for **respiratory depression** and **hypotension**, but benefits outweigh risks in severe pulmonary edema *Propranolol* - **Propranolol** is a **non-selective beta-blocker** that is **contraindicated in acute/decompensated heart failure** - Beta-blockers **reduce contractility** and can worsen acute cardiac output - While certain beta-blockers (carvedilol, metoprolol, bisoprolol) are used in **chronic stable heart failure**, propranolol is NOT a guideline-recommended agent for heart failure management - In acute settings, beta-blockers would precipitate or worsen decompensation *Amlodipine* - **Amlodipine** is a **dihydropyridine calcium channel blocker** used for hypertension and angina - **Not recommended in heart failure** as it can cause **negative inotropic effects** and peripheral edema - Does not provide mortality benefit and may worsen outcomes in LV dysfunction - Other vasodilators (nitrates, ACE inhibitors) are preferred *Epinephrine* - **Epinephrine** is a potent **catecholamine** with alpha and beta effects - Increases **heart rate**, **contractility**, and **systemic vascular resistance** - Would dramatically increase **myocardial oxygen demand** and **afterload** in LV failure - Reserved for **cardiac arrest** or **cardiogenic shock requiring inotropic support**, not routine LV failure management - Risk of **arrhythmias** and **ischemia**

Q: Clonidine is used as an antihypertensive agent, but if used as a fast intravenous injection, it can increase blood pressure due to:

Agonistic action on vascular Alpha 2 adrenergic receptors. ***Agonistic action on vascular Alpha 2 adrenergic receptors*** - When administered rapidly intravenously, clonidine initially acts as an agonist on **postsynaptic α2-adrenergic receptors** in the vascular smooth muscle. - This direct peripheral vasoconstrictive effect occurs before central effects dominate, leading to a transient increase in blood pressure. *Stimulation of the vasomotor center leading to increased sympathetic output* - Clonidine's primary antihypertensive effect is through **central α2-receptor agonism**, which *decreases* sympathetic outflow from the vasomotor center. - It would not stimulate the vasomotor center to *increase* sympathetic output, as this contradicts its fundamental mechanism of action. *Cardiac stimulation* - Clonidine is known for its **cardiac depressant effects** due to reduced sympathetic outflow, leading to decreased heart rate and contractility. - It does not directly stimulate the heart, and any initial blood pressure rise is due to vascular effects, not increased cardiac output. *Release of noradrenaline from adrenergic nerve endings* - Clonidine is an **α2-adrenergic agonist**, and activation of presynaptic α2-receptors typically *inhibits* the release of noradrenaline. - It does not cause a direct release of noradrenaline but rather modulates its release in the opposite direction.

Q: Statins act on:

HMG CoA reductase. ***HMG CoA reductase*** - **HMG-CoA reductase inhibitors** (statins) are the most effective and widely used class of hypolipidemic agents [1, 2, 3]. - This enzyme is the **rate-limiting step** in cholesterol biosynthesis in the liver [1, 2, 3]. *HMG CoA synthetase* - HMG-CoA synthetase is involved in the synthesis of **HMG-CoA** from acetyl-CoA and acetoacetyl-CoA. - This enzyme precedes the HMG-CoA reductase step and is **not the primary target** for cholesterol-lowering drugs. *Squalene epoxidase* - Squalene epoxidase is an enzyme involved in the later stages of the **cholesterol synthesis pathway**, specifically in converting squalene to squalene epoxide. - While inhibition of this enzyme would reduce cholesterol synthesis, it is **not the main target** of current widely used hypolipidemic agents. *HMG CoA hydratase* - HMG-CoA hydratase (also known as HMG-CoA lyase) is involved in the breakdown of HMG-CoA into **acetyl-CoA and acetoacetate** in ketogenesis. - It is **not directly involved** in the main pathway of cholesterol synthesis that is targeted by current hypolipidemic drugs.

Q: Dobutamine mainly acts on which receptor:

Beta 1. ***Beta 1*** - **Dobutamine** is a direct-acting **beta-1 adrenergic agonist**, which means it primarily stimulates beta-1 receptors. - Stimulation of **beta-1 receptors** in the heart leads to increased **cardiac contractility** (positive inotropy) and heart rate (positive chronotropy), making it useful in conditions like **heart failure**. *Beta 2* - **Beta-2 receptors** are primarily found in the lungs and **vascular smooth muscle**. - Stimulation of **beta-2 receptors** causes **bronchodilation** and **vasodilation**, effects that are not the primary therapeutic goal of dobutamine. *Alpha 1* - **Alpha-1 receptors** are mainly located in **vascular smooth muscle** and cause **vasoconstriction** when stimulated. - While dobutamine may have some weak effects on alpha-1 receptors at higher doses, its dominant action is on beta-1 receptors, and significant vasoconstriction is not its primary clinical effect. *Alpha 2* - **Alpha-2 receptors** are largely presynaptic and act to inhibit the release of **norepinephrine**. - **Dobutamine** has minimal to no significant activity at **alpha-2 receptors**.

Q: All of the following are centrally acting antihypertensive drugs except:

Trimethoprim. ***Trimethoprim*** - **Trimethoprim** is an **antibiotic** and is not used as an antihypertensive drug. - It works by inhibiting **dihydrofolate reductase**, an enzyme involved in bacterial folate synthesis. *Methyldopa* - **Methyldopa** is a **centrally acting alpha-2 adrenergic agonist** that reduces sympathetic outflow from the central nervous system. - It decreases peripheral vascular resistance and heart rate, leading to a reduction in blood pressure. *Clonidine* - **Clonidine** is a **centrally acting alpha-2 adrenergic agonist** that stimulates alpha-2 receptors in the brainstem. - This stimulation reduces sympathetic outflow, leading to vasodilation and decreased heart rate. *Guanabenz* - **Guanabenz** is also a **centrally acting alpha-2 adrenergic agonist**. - It acts similarly to clonidine by stimulating central alpha-2 receptors to decrease sympathetic tone and lower blood pressure.

Q: Effects of beta blockers on the heart are all of the following except:

Decreases duration of systole. ***Decreases duration of systole*** - Beta-blockers primarily prolong the **duration of systole** by extending the **ejection time** and slowing ventricular relaxation. - They also increase the **diastolic filling time** by reducing heart rate, impacting overall cardiac cycle duration. *Decrease in heart rate* - Beta-blockers block **beta-1 adrenergic receptors** in the heart, leading to a decrease in **sympathetic stimulation** and thus a reduced heart rate. - This effect is beneficial in conditions like **tachycardia** and **angina**, as it reduces myocardial oxygen demand. *May decrease cardiac output initially.* - By reducing heart rate and contractility, beta-blockers can initially decrease **cardiac output**, especially in patients with pre-existing **ventricular dysfunction**. - This effect is often transient, as chronic use can lead to beneficial remodeling and improved efficiency in some conditions. *May precipitate heart failure in acute settings.* - In patients with acutely decompensated heart failure or severe left ventricular dysfunction, beta-blockers can acutely worsen cardiac function due to their **negative inotropic effects**. - Therefore, beta-blockers are typically initiated cautiously at low doses in stable heart failure patients and are contraindicated in acute decompensation.

Q: Most common digoxin-induced arrhythmia is

Ventricular Premature Beats. ***Ventricular Premature Beats (VPBs)*** - **Most common** digoxin-induced arrhythmia overall, occurring in up to 50-90% of digoxin toxicity cases. - Digoxin increases intracellular calcium through Na+/K+-ATPase inhibition, leading to **increased automaticity** and **delayed afterdepolarizations** that trigger ventricular ectopy. - **Hypokalemia** (common with concurrent diuretic use) significantly increases the risk by enhancing digoxin binding to Na+/K+-ATPase and further elevating intracellular calcium. - VPBs can manifest in various patterns including isolated beats, couplets, or organized patterns like ventricular bigeminy. *Ventricular bigeminy* - While ventricular bigeminy (every other beat is a VPB) is highly **characteristic** and specific for digoxin toxicity, it is a specific *pattern* of VPBs rather than the most common arrhythmia overall. - Represents severe ventricular irritability and indicates significant digoxin effect, but occurs less frequently than isolated VPBs. - When present, it strongly suggests digoxin toxicity and warrants immediate attention. *Ventricular Fibrillation* - A rare but **life-threatening** complication of severe digoxin toxicity. - Usually preceded by other ventricular arrhythmias (VPBs, ventricular tachycardia) and represents advanced toxicity. - Not common enough to be considered the "most common" digoxin-induced arrhythmia. *Atrial Flutter* - Digoxin can cause various atrial arrhythmias, but atrial flutter is relatively uncommon. - The most characteristic **atrial** arrhythmia in digoxin toxicity is **paroxysmal atrial tachycardia (PAT) with AV block**, not atrial flutter. - Digoxin's primary atrial effect is to slow AV nodal conduction, which may actually help control atrial flutter rather than cause it.

Q: HMG-CoA reductase is inhibited by:

Lovastatin. ***Lovastatin*** - **Lovastatin** is part of the statin class of drugs, which are potent competitive inhibitors of **HMG-CoA reductase**. - By inhibiting this enzyme, statins reduce the synthesis of **mevalonate**, a precursor to **cholesterol**, thereby lowering LDL-cholesterol levels. *Gemfibrozil* - **Gemfibrozil** is a **fibrate**, a class of drugs that primarily act by activating **peroxisome proliferator-activated receptor alpha (PPAR-α)**. - Its main effect is to decrease **triglyceride** levels and increase **HDL cholesterol**, not directly inhibit HMG-CoA reductase. *Clofibrate* - **Clofibrate** is also a **fibrate** and operates similarly to gemfibrozil by activating **PPAR-α**. - It primarily reduces **triglycerides** and has a modest effect on increasing HDL, but does not inhibit HMG-CoA reductase. *Nicotinic acid* - **Nicotinic acid** (niacin or vitamin B3) reduces hepatic synthesis of **VLDL** and inhibits the release of **fatty acids** from adipose tissue. - This leads to a decrease in **LDL cholesterol** and triglycerides, and an increase in **HDL cholesterol**, but it does not directly inhibit HMG-CoA reductase.

Q: Cardiac hyperaemia/vasodilation is due to which mediator?

Adenosine. ***Adenosine*** - **Adenosine** is a potent endogenous vasodilator in the heart, released in response to increased myocardial oxygen demand or ischemia. - It acts on **A2A receptors** in vascular smooth muscle, leading to relaxation and increased coronary blood flow (hyperemia). *Acetylcholine* - **Acetylcholine** primarily causes vasodilation in skeletal muscle and some other vascular beds, mediated by nitric oxide release from endothelial cells. - In the heart, it mainly acts as a **negative chronotropic** and **dromotropic** agent, slowing heart rate and conduction, with variable direct effects on coronary vessels. *Adrenaline* - **Adrenaline** (epinephrine) typically causes vasoconstriction via **alpha-1 receptors** in many vascular beds, but can cause vasodilation via **beta-2 receptors** in some, such as skeletal muscle. - In the heart, its primary effect is positive chronotropy and inotropy, and it can cause **coronary vasoconstriction** or dilation depending on receptor distribution and dose. *Dopamine* - **Dopamine** has complex effects on the vasculature, depending on the dose and receptor subtypes activated. - At low doses, it can cause **renal and mesenteric vasodilation** via D1 receptors, but at higher doses, it can cause generalized vasoconstriction via alpha-adrenergic receptors.

Question 1

Which of the following antiarrhythmic drugs is contraindicated in a patient with interstitial lung disease?

Accepted Answer

Amiodarone

Answer

Lignocaine

Answer

Sotalol

Answer

Quinidine

Question 2

In acute left ventricular failure with pulmonary edema, which drug can be administered for immediate management?

Accepted Answer

Morphine

Answer

Amlodipine

Answer

Epinephrine

Answer

Propranolol

Question 3

Clonidine is used as an antihypertensive agent, but if used as a fast intravenous injection, it can increase blood pressure due to:

Accepted Answer

Agonistic action on vascular Alpha 2 adrenergic receptors

Answer

Cardiac stimulation

Answer

Stimulation of the vasomotor center leading to increased sympathetic output

Answer

Release of noradrenaline from adrenergic nerve endings

Question 4

Statins act on:

Accepted Answer

HMG CoA reductase

Answer

HMG CoA synthetase

Answer

HMG CoA hydratase

Answer

Squalene epoxidase

Question 5

Dobutamine mainly acts on which receptor:

Accepted Answer

Beta 1

Answer

Beta 2

Answer

Alpha 1

Answer

Alpha 2

Question 6

All of the following are centrally acting antihypertensive drugs except:

Accepted Answer

Trimethoprim

Answer

Methyldopa

Answer

Clonidine

Answer

Guanabenz

Question 7

Effects of beta blockers on the heart are all of the following except:

Accepted Answer

Decreases duration of systole

Answer

Decrease in heart rate

Answer

May decrease cardiac output initially.

Answer

May precipitate heart failure in acute settings.

Question 8

Most common digoxin-induced arrhythmia is

Accepted Answer

Ventricular Premature Beats

Answer

Ventricular bigeminy

Answer

Atrial Flutter

Answer

Ventricular Fibrillation

Question 9

HMG-CoA reductase is inhibited by:

Accepted Answer

Lovastatin

Answer

Gemfibrozil

Answer

Nicotinic acid

Answer

Clofibrate

Question 10

Cardiac hyperaemia/vasodilation is due to which mediator?

Accepted Answer

Adenosine

Answer

Acetylcholine

Answer

Adrenaline

Answer

Dopamine

Cardiovascular Drugs — MCQs

Cardiovascular Drugs — MCQs

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