Pharmacology Drug Safety Quiz

References

• Karch, A. M. (2020): Focus on nursing pharmacology, 8th Edition, Lippincott Williams & Wilkins, ISBN: 978-1-9751-0096-4, Chapter 44: 2294-2352

Drugs Acting on Cardiovascular System

• Antiarrhythmic Agents

The Conducting System of the Heart

• SA node
• AV node
• Bundle of His
• Right bundle branch
• Left bundle branch
• Purkinje fibers

Five Phases of the Action Potential of the Cardiac Muscle Cell

• Phase 0: Occurs when the cell reaches a point of stimulation
• Phase 1: Short period during which sodium ion concentration equalizes inside and outside of the cell
• Phase 2: (Plateau Stage): Occurs as the cell membrane becomes less permeable to sodium, calcium slowly enters the cell and potassium begins to leave the cell
• Phase 3: Repolarization
• Phase 4: The cell comes to rest; the sodium-potassium pump returns the membrane to its resting membrane potential.

Causes of Cardiac Arrhythmias

• Electrolyte disturbances that alter the action potential
• Structural damage
• Pathway changes
• Acidosis of waste products
• Drugs that alter action potential or cardiac conduction

Types of Cardiac Arrhythmias

• Tachycardia (faster heart rate)
• Bradycardia (slower heart rate)
• Premature atrial contractions (PACS)
• Premature ventricular contractions (PVCs)
• Atrial flutter
• Atrial fibrillation or (ventricular fibrillation)
• Heart Blocks
• Bundle branch blocks

Classifications of Antiarrhythmics

• Class I: Block sodium channels in the cell membrane during an action potential
• Class II: Block beta-receptors, causing a depression of phase 4 of the action potential
• Class III: Block potassium channels, prolonging phase 3 of the action potential
• Class IV: Block calcium channels in the cell membrane

Use of Antiarrhythmic Across the Lifespan

• Children: Minimized use, careful monitoring for adverse effects, and calculated dosing based on weight and age.
• Adults: Monitor total drug regimen, frequent monitoring, and medical follow-up.
• Older adults: Start with lower doses, monitor closely, and adjust based on response.

Prototype Class I Antiarrhythmic - Lidocaine

• Indications: Management of acute ventricular arrhythmias, typically during cardiac surgery or acute myocardial infarction (MI)
• Route: IV administration
• Actions: Decreases depolarization, resulting in fewer impulses. Increases ventricular fibrillation threshold
• Adverse effects: Dizziness, light-headedness, fatigue, arrhythmias, cardiac arrest, and nausea
• Usual indications: Treatment of life-threatening ventricular arrhythmias, also used during acute myocardial infarction (MI) and cardiac surgery.

Class II Antiarrhythmic - Propranolol

• Indications: Treats cardiac arrhythmias (particularly supraventricular tachycardias)
• Route: Oral or IV
• Actions: Blocks beta-receptors, decreasing heart rate, and cardiac excitability
• Adverse effects: Bradycardia, heart failure, cardiac arrhythmias, heart blocks, cerebrovascular accident
• T1/2: 3 to 6 hours

Class III Antiarrhythmic- Amiodarone

• Indications: Life-threatening ventricular arrhythmias
• Route: Oral or IV
• Actions: Primarily prolongs action potential
• Adverse effects: Malaise, fatigue, dizziness, heart failure, cardiac arrhythmias, cardiac arrest

Class IV Antiarrhythmic - Diltiazem

• Indications: Paroxysmal supraventricular tachycardia (SVT) in Adults
• Route: Oral or IV
• Actions: Blocks movement of calcium ions, slows automaticity and conduction through AV node
• Adverse effects: Dizziness, light-headedness, headache, asthenia, peripheral edema, bradycardia

Other Drugs Used to Treat Arrhythmias

• Adenosine (Adenocard): Used to convert supraventricular tachycardia to sinus rhythm
• Digoxin: Slows calcium from leaving cell, prolonging action potential
• Dronedarone (Multaq): Reduces risk of hospitalization in patients with persistent atrial fibrillation (AF).

Nursing Considerations for Antiarrhythmic Therapy

• Assess patient history and physical exam (allergies, kidney/liver function, hypotension, shock, electrolyte imbalances.)
• Pregnancy and lactation status
• Baseline ECG, and appropriate lab values

Coronary Artery Disease (CAD)

• Definition: narrowing of the heart arteries.
• Symptoms: Stable angina, unstable angina, myocardial infarction.

Types of Angina

• Stable Angina: Partial blockage with typical chest pain relieved with rest or medication
• Unstable Angina: Increasing chest pain not relieved by rest or medication.
• Prinzmetal’s Angina: Related to coronary spasm

Actions of Antianginal Drugs

• Improved blood delivery to heart muscle
• Increased oxygen delivery
• Decreasing the heart's workload
• Decreasing oxygen demand

Factors Affecting Myocardial Oxygen Demand

• Myocardial oxygen consumption, heart rate,
• Blood volume (preload), blood pressure (afterload)
• Left ventricular muscle size, muscle contractility

Use of Antianginal Agents across the Lifespan

• Consideration of age-related physiological changes to adjust drug dosages.
• Monitoring patients for adverse reactions

Question 1

• Swallowing the sublingual tablet is incorrect. The tablet needs to be placed under the tongue.

Question 4

• Bronchospasm is a known side effect of the class II antiarrhythmics

Question 3

• Increasing absorption is the primary reason why nitroglycerin is given sublingually; it's intended to avoid first-pass metabolism by the liver.

Question 2

• Pounding headaches can result from vasodilation of cerebral vessels caused by nitrates' effects

Test your knowledge on the side effects and safety considerations of a specific drug. This quiz covers important information regarding patient demographics, potential toxicity symptoms, and immediate effects after administration. Perfect for those studying pharmacology or healthcare.