Antiarrhythmics - Cardiovascular Poison

 ANTIARRHYTHMICS

Cardiac arrhythmias can be benign or malignant, and a wide array of drugs exist for their treatment or control.

Vaughan Williams’ classification of antiarrhy-thmicdrugs—

·      Class I: Sodium channel blockers

o     Moderate to marked sodium channel blockade —disop-yramide, procainamide, quinidine.

o     Mild to moderate sodium channel blockade—ligno-caine, phenytoin, mexiletine, tocainide.

o     Marked sodium channel blockade—encainide,flecainide, moricizine, propafenone.

·      Class II: Beta adrenergic blockers: atenolol, esmolol,metoprolol, propranolol, and timolol.

·      Class III: Potassium channel blockers: acecainide,amiodarone, bretylium, sotalol.

·      Class IV: Calcium channel blockers: diltiazem, nicardi-pine, nifedipine, verapamil.

·      Unclassified: adenosine.

Several of these drugs and their toxicities have been discussed elsewhere, and the toxicities of only those drugs which have not been adequately dealt with in other sections, will be discussed here.

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