antacid

An antacid is a substance that neutralizes stomach acid (gastric hydrochloric acid) to relieve symptoms of indigestion, heartburn, and sour stomach. Antacids are typically available over the counter and are used for short-term relief of mild to moderate symptoms. They do not heal the underlying causes of acid-related disorders but may provide rapid symptomatic relief.

Most antacids contain basic minerals such as aluminum hydroxide, magnesium hydroxide, calcium carbonate, or sodium bicarbonate. Combinations of minerals are common to balance effects on bowel movements, since aluminum and calcium can cause constipation while magnesium tends to cause diarrhea. Some products also include alginates to form a protective barrier and simethicone to reduce gas. The onset of relief is usually within minutes, but the duration is limited, often one to three hours.

Candidates for use include individuals with intermittent heartburn or indigestion. They should be used as directed and not as a substitute for medical evaluation in persistent, severe, or recurrent symptoms. Caution is advised in kidney disease, where excess aluminum or magnesium can accumulate, and in people who require a low-sodium diet, as some formulations contain substantial sodium. High calcium-containing preparations may contribute to hypercalcemia or kidney stone formation with prolonged use.

Antacids can interfere with the absorption of other medicines by changing gastric pH; dosing should be spaced apart from other drugs when possible. They should not be used to treat chest pain that could signify a heart attack, and persistent symptoms warrant medical attention. In some cases, longer-term acid suppression with H2 blockers or proton pump inhibitors may be more appropriate.