The active ingredient in Kirkland Signature Acid Controller Maximum Strength is Famotidine, 20 mg, an H2 Blocker. These tablets partially block production of acid in the stomach cells by inhibiting histamine, a substance that stimulates the secretion of stomach acid.1 Famotidine works to suppress the amount of stomach acid as well as the acid concentration.2 Over-the counter and prescription H2 blockers can prevent meal-induced heartburn as well as relieve the burning sensation associated with acid indigestion and sour stomach.
These acid reducers generally relieve symptoms for a longer period of time than antacids, but they take time to work initially.