all of the following drugs belongs to class 1 antiarrhythmic drugs except
Correct Answer: Propanolol
Description: Refer katzung 11e 235,237 rate-control agents. Class Known as Examples Mechanism Medical uses Ia Fast-channel blockers Quinidine Ajmaline Procainamide Disopyramide (Na+) channel block (intermediate association/dissociation) and K+ channel blocking effect; affects QRS complex class 1a prolong the action potential and has intermediate effect on the 0 phase of depolarization Ventricular arrhythmias Prevention of paroxysmal recurrent atrial fibrillation(triggered by vagal overactivity) Procainamide in Wolff-Parkinson-White syndrome Increases QT interval Ib Lidocaine Phenytoin Mexiletine Tocainide Na+ channel block (fast association/dissociation); can prolong QRS complex in overdose class 1b shoen the action potential of myocardial cell and has weak effect on intiation of phase 0 of depolarization Treatment and prevention during and immediately after myocardial infarction, though this practice is now discouraged given the increased risk of asystole Ventricular tachycardia Ic Encainide Flecainide Propafenone Moricizine Na+ channel block (slow association/dissociation) has no effect on action potential and has the strongest effect on initiation phase 0 the depolarization Prevents paroxysmal atrial fibrillation Treats recurrent tachyarrhythmiasof abnormal conduction system Contraindicated immediately after myocardial infarction II Beta-blockers Carvedilol Propranolol Esmolol Timolol Metoprolol Atenolol Bisoprolol Nebivolol Beta blockingPropranolol also shows some class I action Decrease myocardial infarctionmoality Prevent recurrence of tachyarrhythmias Propranolol has sodium channel-blocking effects III Amiodarone Sotalol Ibutilide Dofetilide Dronedarone E-4031 Vernakalant K+ channel blocker Sotalol is also a beta blockerAmiodarone has Class III mostly, but also I, II, & IV activity In Wolff-Parkinson-White syndrome (Sotalol:) ventricular tachycardias and atrial fibrillation (Ibutilide:) atrial flutter and atrial fibrillation (Amiodarone): prevention of paroxysmal atrial fibrillation, and haemodynamically stable ventricular tachycardia IV Calcium Channel Blockers Verapamil Diltiazem Ca2+ channel blocker Prevent recurrence of paroxysmal supraventricular tachycardia Reduce ventricular rate in patients with atrial fibrillation V Adenosine Digoxin Magnesium Sulfate Work by other or unknown mechanisms (direct nodal inhibition) Used in supraventricular arrhythmias, especially in hea failure with atrial fibrillation, contraindicated in ventricular arrhythmias. Or in the case of magnesium sulfate, used in torsades de pointes.
Category:
Pharmacology
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