As of 2015, the active ingredients in Gaviscon regular and extra-strength liquids are aluminum hydroxide and magnesium carbonate, according to Drugs.com. Inactive ingredients in the over-the-counter drug include benzyl alcohol, edetate disodium, saccharin sodium, sodium alginate and sorbitol solution. Available as a liquid and a tablet, Gaviscon relieves acid indigestion, heartburn, and sour and upset stomach, according to GlaxoSmithKline. Consumers should take the drug immediately upon experiencing symptoms, and then drink half of a glass of water.
Aluminum hydroxide is a mineral-based antacid, and doctors prescribe it for patients with particular kidney conditions, to reduce the level of phosphate in their systems, according to Everyday Health. Patients should not take aluminum hydroxide for more than 14 days without consulting their doctors. Serious side effects include painful urination; black, bloody or tar-like stools; severe constipation or stomach pain; and extreme drowsiness. If patients experience any such symptoms or an allergic reaction, including breathing difficulties, hives or facial swelling, they should seek medical attention immediately.
Doctors prescribe magnesium carbonate, a mineral supplement, when treating patients with low levels of magnesium in their blood, according to WebMD. Magnesium plays a significant role in keeping the heart, nerves, bones and cells functioning properly. When taking magnesium carbonate, common side effects include diarrhea, constipation and upset stomach. Serious side effects are rare, but include allergic reactions.