Examples of ion channel blockers include:

a. Tetrodotoxin

b. Amiloride

c. Xylocaine

Channel blockade is an important mechanism of action for toxins and some therapeutic agents. The deadly toxin of the puffer fish, tetrodotoxin, acts by blocking the Na+ channels that are responsible for the conduction of nerve impulse. The diuretic, amiloride, acts by blocking the Na+ channels that inhabit the apical membrane of the epithelial cells of the distal nephron. Local anesthetics such xylocaine also act by blocking ion channels.