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Questions and Answers
What are the classes of antiarrhythmic medications?
What are the classes of antiarrhythmic medications?
What is the highest yield in antiarrhythmic pharmacology?
What is the highest yield in antiarrhythmic pharmacology?
How cardiac AP changes (Graph)
Class I antiarrhythmics are known as __________.
Class I antiarrhythmics are known as __________.
Na-Channel Blockers
Class IC antiarrhythmics are contraindicated post-myocardial infarction.
Class IC antiarrhythmics are contraindicated post-myocardial infarction.
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What is the effect of Class II agents on the phase 4 depolarization?
What is the effect of Class II agents on the phase 4 depolarization?
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Which Class I antiarrhythmic is known as the best post-MI?
Which Class I antiarrhythmic is known as the best post-MI?
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What do Class III antiarrhythmics primarily affect?
What do Class III antiarrhythmics primarily affect?
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Which of the following is a side effect of Class III antiarrhythmics?
Which of the following is a side effect of Class III antiarrhythmics?
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Name one class of antiarrhythmic that is a Ca-Channel Blocker.
Name one class of antiarrhythmic that is a Ca-Channel Blocker.
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Study Notes
Antiarrhythmics Overview
- Antiarrhythmics are classified into four primary classes based on their mechanisms of action.
- Class I: Sodium channel blockers
- Class II: Beta-blockers
- Class III: Potassium channel blockers
- Class IV: Calcium channel blockers
Class I - Sodium Channel Blockers
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1C: Contraindicated post-myocardial infarction (post-MI); causes the greatest decrease in Phase 0 depolarization slope.
- Drugs: Flecainide, Propafenone
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1A: Intermediate effect on Phase 0 slope; all agents have the potential to cause Torsades de Pointes (TdP) due to prolonged QT interval.
- Drugs: Quinidine (can cause cinchonism and drug-induced lupus erythematosus), Procainamide (risk of drug-induced SLE), Disopyramide.
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1B: Minimal effect on Phase 0 slope; most beneficial for post-MI situations.
- Drugs: Lidocaine, Mexiletine
Class II - Beta-Blockers
- Decrease depolarization slope in Phase 4, affecting SA and AV nodal activity.
- Commonly used beta-blockers include Propranolol, Metoprolol, Esmolol, and Atenolol.
- Adverse effects include exacerbation of COPD, impotence, hypoglycemic masking, and overdose management with glucagon.
Class III - Potassium Channel Blockers
- Increase repolarization during Phase 3, potentially causing TdP.
- Drugs include Amiodarone (associated with liver, lung, and thyroid issues), Ibutilide, Dofetilide, and Sotalol.
- Adverse effects can include TdP, liver function tests (LFTs), pulmonary function tests (PFTs), and thyroid function tests (TFTs).
Class IV - Calcium Channel Blockers
- Decrease the slope of phases 0, 3, and 4; increase repolarization during Phase 3; primarily affect AV nodal conduction.
- Common drugs are Verapamil and Diltiazem.
- Adverse effects include lower extremity edema and constipation.
Torsades de Pointes (TdP)
- Increase in QT interval can lead to TdP; associated conditions include:
- Class IA and IC agents (Na+ blockers)
- Class III agents (K+ blockers)
- Macrolide antibiotics (e.g., Azithromycin)
Graphical Representation of Cardiac Action Potential (AP)
- A Cardiac Action Potential graph is crucial for understanding how patients respond to different antiarrhythmic classes.
Key Drug Associations by Class
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Class I:
- 1C: Flecainide, Propafenone
- 1A: Quinidine, Procainamide, Disopyramide
- 1B: Lidocaine, Mexiletine
- Class II: Propranolol, Metoprolol, Esmolol, Atenolol
- Class III: Amiodarone, Ibutilide, Dofetilide, Sotalol
- Class IV: Verapamil, Diltiazem
Pharmacodynamics
- Each drug class alters specific phases of the cardiac action potential, affecting cardiac function and rhythm.
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Description
Explore key concepts related to antiarrhythmic drugs through these informative flashcards. Understand the different classes of antiarrhythmics, their mechanisms, and potential side effects. Perfect for pharmacology students looking to reinforce their knowledge.
