Antacid

Antacid tablets

An antacid is a substance which neutralizes stomach acidity, which in turn relieves heartburn, indigestion or stomach upset.

Medical uses

Wyeth amphojel tablets of aluminum hydroxide.

Antacids are available over the counter and are taken by mouth to quickly relieve occasional heartburn, the major symptom of gastroesophageal reflux disease and also indigestion. Treatment with antacids alone is symptomatic and only justified for minor symptoms.

Antacids are distinct from acid-reducing drugs like H₂-receptor antagonists or proton pump inhibitors and they do not kill the bacteria Helicobacter pylori, which causes most ulcers.

Side effects

Versions with magnesium may cause diarrhoea, and brands with calcium or aluminium may cause constipation and rarely, long-term use may cause kidney stones. Long term use of versions with aluminum may increase the risk for getting osteoporosis.

Mechanism of action

When excessive amounts of acids are produced in the stomach the natural mucous barrier that protects the lining of the stomach can damage the esophagus in people with acid reflux. Antacids contain alkaline ions that chemically neutralize stomach gastric acid, reducing damage and relieving pain.

Formulations

Antacids may be formulated with other active ingredients like simethicone to control gas or alginic acid to act as a physical barrier to acid.