Antacid
An antacid (plural: antacids) is a medicine used to neutralise stomach acid. It is a weak base or the salt of a weak acid, so that its mechanism of action can be explained, among other things, by the buffering of gastric acid.
Indication for antacids is the symptomatic treatment of conditions where the stomach acid should be bound. These include heartburn, acid regurgitation and acid-related stomach pain. Mostly, however, antacids are used as over-the-counter self-medication against reflux esophagitis (inflammation of the esophagus).
The formerly often used sodium hydrogen carbonate - (sodium bicarbonate for short, obsolete trivial names double carbonic acid sodium bicarbonate or sodium bicarbonate, as colloquially food soda or food soda) - is obsolete as an antacid. It rapidly causes an increase in intragastric pH (above 7), resulting in increased gastrin release, which in turn leads to reactively increased secretion of gastric acid. Subjectively unpleasant is the rapid onset of CO2 development in the stomach. In addition, the sodium ions are completely absorbed, so that systemic undesirable effects can occur when large doses are taken or over a long period of time, such as hypernatremia, risk of metabolic alkalosis, edema formation, hypertension.
Therefore, in the 1970s, aluminium and magnesium hydroxide gels as well as mixtures of calcium and magnesium carbonate or aluminium-magnesium-silicate hydrate, which is contained in the active substance almasilate, gained acceptance. They are not only less absorbed and therefore only have an effect in the stomach, they are also characterized by a better tolerance. Moreover, aluminium-containing antacids like sucralfate stimulate the gastric mucus production as they increase the prostaglandin synthesis.
Caution should be exercised by patients with renal insufficiency, as chronic use of antacids can lead to accumulation of aluminum and magnesium hydroxide in the body. Furthermore, antacids impair iron absorption by increasing the pH of the gastric juice. Furthermore, aluminium has been suspected for some time to be responsible for damage to the nervous system and as a cause of Alzheimer's disease. (See Aluminium - Toxicity)
In recent years, antacids have become less important in the treatment of gastric ulcers. This is due to the breakthrough of so-called H2 antagonists and proton pump inhibitors, which directly inhibit gastric acid production and therefore act longer and more effectively.
Layered lattice antacids
Layered lattice antacids are active agents of the 2nd generation and differ substantially from conventional antacids. Two active ingredients, magaldrate (e.g. Riopan) and hydrotalcite (e.g. Talcid) are currently on the market.
Aluminium hydroxide can cause constipation, whereas magnesium hydroxide stimulates intestinal activity and has a laxative effect. Therefore, most of the ready-to-use preparations offered today are mixtures of both active ingredients. The combination of calcium and magnesium carbonate is also frequently used.
Recent findings since 2010
Scientific findings on the absorption of aluminium salts in the human organism have been re-evaluated and have led various national health authorities to limit the daily intake amounts. Intake routes are possible via food, medical devices and consumer products.
