This page is read only. You can view the source, but not change it. Ask your administrator if you think this is wrong. ===== Classification of Antiarrhythmic Drugs ===== |**Class** |**Drugs** |**Action** | |**I****a** |Quinidine, Procainamide, Disopyramide |Block fast sodium current. These also block repolarising potassium currents and hence lengthen action potential duration | |**Ib** |[[:wikitox:lignocaine|Lignocaine]], Mexiletine, [[:wikitox:2.1.11.2.1_phenytoin|Phenytoin]] |Block fast sodium current. This slows rate of depolarisation and reduces conduction velocity. These shorten action potential duration | |**Ic** |[[:wikitox:flecainide|Flecainide]], Encainide |Block fast sodium current with slow offset kinetics. Cause marked depression of depolarisation with little change in action potential duration. | |**II** |[[:beta_blocker_toxicity|Beta-Blocker]]s |Block effects of catecholamines | |**III** |[[:wikitox:3.4.3.4.3_amiodarone|Amiodarone]], Sotalol |Lengthen action potential duration by blocking potassium currents | |**IV** |[[:wikitox:2.1.6.1.1_calcium_channel_blockers|Calcium channel blockers]] |Block inward calcium current particularly notable in AV node | CKG Edit