class 1a

Question 1

Quinidine

Answer 1

Action: Blocks fast activated Na+ channels/prolongs Repolarization time; weakly blocks K+ channels increasing AP duration; antimuscarinic activity (increases AV conduction ->tachy and arrhythmia)
Use: AFIB and A flutter; paroxysmal SVT, ventricular tachycardia (all forms of arrythmia)
Side effects: refractory heterogeneity leading to torsade de pointes which can lead to quinidine syncope (recurrent lightheadedness)
Contraindications:digitalis toxicity is a possibility due to its effect in increasing plasma digioxin levels

Question 2

procainamide

Answer 2

Action: Blocks fast activated Na+ channels/prolongs Repolarization time; weakly blocks K+ channels increasing AP duration; antimuscarinic activity (increases AV conduction ->tachy and arrhythmia)
Use: AFIB and A flutter; paroxysmal SVT, ventricular tachycardia good for sustained ventricular arrhythmias assoc. w/ acute MI
Side Effect: lupus-like condition; hyperkalemia

Question 3

disopyramide

Answer 3

Action: Blocks fast activated Na+ channels/prolongs Repolarization time; weakly blocks K+ channels increasing AP duration; antimuscarinic activity (increases AV conduction ->tachy and arrhythmia); (-) inotrope
Use: ventricular arrhythmias; PVST, AFIB and A flutter