Chapter 14: Antiarrhythmic Drugs Flashcards
Class 1 Antiarrhythmics aka Group 1 (\_\_\_\_\_) MOA: \_\_\_\_\_ Prototypes and mnemonic: \_\_\_\_\_
Class 1 Antiarrhythmics
Group 1 - Na channel blockers
MOA: slow the upstroke of sodium-dependent action potentials and usually prolong QRS duration
Group 1A (prototype procainamide)
- Prolong the AP
- “Double Quarter Pounder”
- Disopyramide, Quinidine, Procainamide
Group 1B drugs (prototype lidocaine)
- Shorten the AP in some cardiac tissues, especially Purkinje fibers.
- “with Lettuce, Mayo, Tomato”
- Lidocaine, Mexeletine, Tocainide
Group 1C drugs (prototype flecainide)
- Have no effect on AP duration.
- “More Fries Please”
- Moricizine, Flecainide, Profepanone
Class 2 Antiarrhythmics aka Group 2 (\_\_\_\_\_) MOA: \_\_\_\_\_ Prototypes and mnemonic: \_\_\_\_\_
Class 2 Antiarrhythmics
aka Group 2 (Beta blockers)
MOA:
- Primarily cardiac β-adrenoceptor blockade and reduction in cAMP, which results in a modest reduction of both sodium and calcium currents and the suppression of abnormal pacemakers
- PR interval is usually prolonged
Prototype:
- Propranolol
- Esmolol
Mnemonic:
-LOL (Propranolol, Atenolol, Metoprolol)
Class 3 Antiarrhythmics aka Group 3 (\_\_\_\_\_) MOA: \_\_\_\_\_ Prototypes and mnemonic: \_\_\_\_\_
Class 3 Antiarrhythmics
aka Group 3 (Potassium Ik channel blockers)
MOA:
- Antiarrhythmic action through K-channel block
- Markedly prolongs AP duration as well as blocking other channels and β receptors
- AP prolongation is caused by blockade of the IK potassium channels, chiefly IKr, that are responsible for the repolarization of the AP
Prototypes:
- Dofetilide
- Ibutilide
Mnemonic:
- This is “SAD”
- Sotalol, Amiodarone, Dofetilide
Class 4 Antiarrhythmics aka Group 4 (\_\_\_\_\_) MOA: \_\_\_\_\_ Prototypes and mnemonic: \_\_\_\_\_
Class 4 Antiarrhythmics
aka Group 4 (Calcium L-Type channel blockers)
MOA:
- Effective in arrhythmias that must traverse calcium-dependent cardiac tissue such as the AV node
- These agents cause a state- and use-dependent selective depression of calcium current
- AV conduction velocity is decreased, and effective refractory period and PR interval are increased by these drugs
Prototype:
- Verapamil
Mnemonic:
- I and V in Class IV
Antiarrhythmic group acting on Phase 0 (zero) of the cardiac action potential
Class 1
Antiarrhythmic Group 1 subtype that prolong the AP duration
Group 1A
Antiarrhythmic Group 1 subtype that shorten the AP duration
Best post MI
Group 1B
Antiarrhythmic Group 1 subtype that have no effect on the AP duration
Contraindicated for post-MI arrhythmias
Group 1C
Class 1A antiarrhythmic used for atrial and ventricular arrhythmias, especially after MI
Crosses the breastmilk and may cause lupus-like syndrome
Procainamide
Class 1A antiarrhythmic used for atrial and ventricular arrhythmias
May cause antimuscarinic effects, heartfailure; crosses the breastmilk
Disopyramide
Class 1A antiarrhythmic used for atrial and ventricular arrhythmias, and malaria
May cause cinchonism (headache, vertigo, tinnitus), cardiac depression, GI upset, and ITP
Quinidine
Treatment of Class 1A antiarrhythmic drug overdose
- Sodium lactate (for drug-induced arrhythmias)
2. Pressor sympathomimetics (to reverse drug-induced hypotention) if indicated
Class 1B antiarrhythmic used as drug of choice for ventricular arrhythmias post-MI, and digoxin-induced arrhythmias.
This is the least cardiotoxic among conventional antiarrhythmics
Lidocaine
Class 1C antiarrhythmic used for refractory arrhythmia
Flecainide
Class 1 antiarrhythmic for Wolff-Parkinson-White Syndrome (WPW)
- Procainamide
2. Amiodarone
Antiarrhythmic group acting on Phase 4 of the cardiac action potential
Class 2
