Some active ingredients found in different antacid tablets are aluminum hydroxide, magnesium hydroxide and calcium carbonate. Although these antacids are effective, the strongest active ingredient used in an antacid is calcium carbonate, states the International Foundation for Functional Gastrointestinal Disorders (IFFGD).
Calcium carbonate can be an effective acid neutralizer, but it also has associated risks, such as elevating calcium blood levels and the formation of kidney stones. A brand name antacid with this active ingredient is Tums.
Aluminum hydroxide and magnesium hydroxide are other active ingredients commonly found in these medications used for heartburn or an upset stomach. Antacids containing these ingredients, but there also can be risk factors connected with their use, such as taking large doses of aluminum hydroxide can decrease the levels of phosphate in the body, leading to different bone issues, notes IFFGD. In the case of magnesium hydroxide, there also are some contraindications, including patients with renal failure should not use this type of antacid.
These active ingredients are effective at neutralizing gastric acid because they are weak bases, states Louisiana Tech University.