What are the three classes of sodium channel blockers?

The three classes of sodium channel blockers are categorized as 1A, 1B, and 1C. This classification is based on how these drugs interact with sodium channels during different phases of the cardiac action potential and their effects on cardiac conduction.

Class 1A agents, such as quinidine and procainamide, moderate sodium channel blockade and have effects on both depolarization and repolarization. They prolong the action potential and can be used in treating various arrhythmias.

Class 1B agents, including lidocaine and mexiletine, have a weaker affinity for sodium channels and predominantly affect depolarized or ischemic tissue. They shorten the action potential duration and are particularly effective in ventricular arrhythmias.

Class 1C agents, such as flecainide and propafenone, exhibit stronger sodium channel blockade with little effect on action potential duration. They are effective for both atrial and ventricular arrhythmias.

The other classifications listed do not correspond with how sodium channel blockers are defined in clinical practice. The alphabets or Greek letters do not accurately reflect the pharmacological mechanisms of sodium channel blockers, and the terms related to Type I, Type II, and Type III often refer to different classes of antiarrh