Questions and Answers
Antiarrhythmic drugs directly or indirectly alter membrane ion ____.
conductance
Antiarrhythmic drugs also alter _____ characteristics of cardiac APs.
physical
Classified using the _____ ____ Classification structure.
Vaughn Williams
Class Ia-Ic are all ____ channel blockers. What distinguishes them?
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What distinguishes Class Ia, Ib, and Ic drugs?
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Class II are _____.
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Class III are _____.
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Class IV are _____.
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What phase do Class I drugs work?
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What phase do Class IV drugs work?
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What phase do Class III drugs work?
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What phase do Class II drugs work?
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What is the mnemonic for the Classes?
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What drugs are Class 1A AADs?
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What mnemonic is used for Class 1A AADs?
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What drugs are Class 1B AADs?
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What mnemonic is used for Class 1B AADs?
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What drugs are Class 1C AADs?
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What mnemonic is used for Class 1C AADs?
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What drugs are Class III AADs?
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What mnemonic is used for Class III AADs?
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The Vaughn-Williams Classification limitations include: it is _____; does not include all agents, agents may have properties of more than ____ class, and it does not incorporate: ____ of arrhythmia termination/prevention, clinical ____, or _____ _____.
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Antiarrhythmic drugs are used to alter conduction _____, alter excitability of cardiac cells by changing the duration of the ____ _____ _____ (ERP), and ____ abnormal automaticity.
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Antiarrhythmic drugs alter excitability of cardiac cells by changing the duration of the _____ _____ _____ (ERP).
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Antiarrhythmic drugs are used to suppress _____ automaticity.
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Study Notes
Antiarrhythmic Drug Classification
- Antiarrhythmic drugs modify membrane ion conductance (sodium, potassium, calcium) and physical characteristics of cardiac action potentials (APs).
- The Vaughn Williams Classification categorizes antiarrhythmic drugs.
Classifications of Antiarrhythmic Drugs
- Class Ia, Ib, and Ic act as sodium channel blockers with distinct characteristics:
- Class Ia: intermediate block duration
- Class Ib: fast block duration
- Class Ic: slow block duration
Specific Class Functions
- Class II consists of beta-blockers.
- Class III includes potassium channel blockers.
- Class IV consists of calcium channel blockers.
Drug Phase Interactions
- Class I drugs inhibit phase 0 of the cardiac action potential.
- Class IV drugs affect phase 2.
- Class III drugs interact during phase 3.
- Class II drugs act at phase 4.
Mnemonic for Drug Classes
- A helpful mnemonic is "Some Block Potassium Channels," aiding in memorization of the drug classes.
Class 1A Antiarrhythmic Drugs
- Includes Disopyramide (PO), Quinidine (PO, IV), Procainamide (IV).
- Remembered by the mnemonic: "Double Quarter Pounder."
Class 1B Antiarrhythmic Drugs
- Comprises Lidocaine (IV) and Mexiletine (PO).
- Mnemonic: "Lettuce Mayo."
Class 1C Antiarrhythmic Drugs
- Contains Flecainide (PO) and Propafenone (PO).
- Mnemonic: "Fries Please."
Class III Antiarrhythmic Drugs
- Includes Amiodarone (PO, IV), Dofetilide (PO), Dronedarone (PO), Ibutilide (IV), and Sotalol (PO, IV).
- Mnemonic: "A Dirty Dog is Scary."
Limitations of the Vaughn-Williams Classification
- The classification is incomplete and does not encompass all antiarrhythmic agents.
- Some drugs may exhibit properties of multiple classes.
- The classification does not reflect mechanisms for arrhythmia termination, clinical indications, or side effects.
General Functions of Antiarrhythmic Drugs
- Used to change conduction velocity in cardiac tissues.
- Alter excitability by modifying the effective refractory period (ERP).
- Suppress abnormal automaticity in cardiac cells.
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Description
Test your knowledge on antiarrhythmic drugs and their classifications through this flashcard quiz. Explore the Vaughn Williams classification and the distinguishing features of Class Ia-Ic sodium channel blockers. Perfect for pharmacy students or anyone interested in cardiovascular pharmacology!
