Class I Antiarrhythmic Drugs

• Class I: Sodium Channel Blockers

• Sodium channel blocking antiarrhythmic drugs are classified as use-dependent in that they bind to open sodium channels.

  • Their effectiveness is therefore dependent upon the frequency of channel opening.

• There are three classes or types of sodium channel blocker

• • • Type Ia: prototype: quinidine gluconate . Oher Drugs: Procainamide , Disopyramide. Type Ia drugs slow the rate of AP rise and prolong ventricular effective refractory period.

    • Type Ib:often effective in treating ventricular arrhythmias. Example: lidocaine, Mexiletine,Tocainide, Phenytoin. Type Ib agents exhibit rapid association and dissociation from the channel.

    • Type Ic: Type Ic drugs slowly dissociate from resting sodium channels. Examples:Flecainide,Amiodarone,

Category: Pharmacology Notes