Antiarrhythmics Flashcards
(48 cards)
Name the classes
Class 1 sodium channel blockers, class 2 beta-adrenoreceptor blockers, class 3 potassium channel blockers, class 4 calcium channel blockers
Class 1 acts on what phase of AP?
Phase 0
Subgroups of class 1 and their effects on AP?
1A prolong AP duration, 1B shorten AP duration, 1C no effect
Drugs in class 1A?
Procainamide, disopyramide, quinidine
MOA of class 1A drugs?
Use- and state-dependent block of Na current channels, some block potassium current channels, slowed conduction velocity and pacemaker activity, prolonged AP duration and refractory period
Treatment for class 1A overdose
Sodium Lactate
Class 1B drugs?
Mexiletine, Tocainide, Lidocaine
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1B is Best post MI
MOA of Class 1B?
Reduces AP duration, slows recovery of sodium channels from inactivation leading to prolonged ERP, selectively affects ischemic or depolarized Purkinje and ventricular tissue
SE of Tocainide
Agranulocytosis
Least cardiotoxic among antiarrhytmics
Lidocaine
Drugs that can cause agranulocytosis
CCCAPIT – clozapine, co-tri, colchicine, aminopyrine, phenylbutazone, PTU, indomethacin, Tocainide
DOC for ventricular arrhythmias post MI, digoxin-induced arrhythmia
lidocaine
Drugs in Class 1C
Propafenone, Encainide, Moricizine
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1C is Contraindicated post MI
Used in refractory arrhythmias
Class 1C
MOA of Class 1C
Selective use and state-dependent block of Na current, slowed conduction velocity and pacemaker activity
Used in WPW
Procainamide and amiodarone
MOA of Class 2
Primarily cardiac beta-adrenoceptor blockade and reduction in cAMP
Class 2 acts on what phase of AP?
Phase 4
Have class 2 and class 3 effects
Sotalol and amiodarone
Used in post MI prophylaxis against sudden death
Propranolol
Classification system
Singh-Vaughan Williams Classification
Beta blocker that lacks local anesthetic effect
Timolol
Class 3 acts on what phase of AP?
Phase 3
Which antiarrhythmics have the highest risk of causing torsades?
Class 3
