Antacids are medicines that neutralize stomach acid. They are used for symptomatic treatment of heartburn, acid regurgitation, or stomach pain caused by acidity.
What is antacids?
Antacids are medicines that neutralize stomach acid. They are used for the symptomatic treatment of heartburn, acid regurgitation, or acid-related stomach pain. The group of antacids includes various drugs. In the past, sodium hydrogen carbonate was frequently used. In the 1970s, aluminum hydroxide gels or magnesium hydroxide gels were increasingly used. Similarly, calcium and magnesium carbona mixtures were first used as antacids. The active ingredient almasilate, which contains aluminum magnesium silicate hydrate, also gained acceptance. Today, aluminum hydroxide gels continue to be used. They are also referred to as algedrate. Algedrate can be combined with calcium carbonate or with magnesium hydroxide. In combination with the active ingredient simeticon, it is administered for larger gas accumulations in the stomach and intestinal tract. Other drugs belonging to the antacid group are carbaldrate, dexlansoprazole, magaldrate, oxetacaine, smectite or alginic acid. The acid-binding agents are administered when the stomach is acidic. They are intended to relieve acid-related complaints such as acid regurgitation or heartburn. The effect of antacids sets in after a short time. However, it lasts only a few hours.
Pharmacological effect
Gastric acid consists of hydrochloric acid in a strong dilution. Positively charged hydrogen ions are responsible for the low gastric pH. Acid-binding antacids, on the other hand, contain many negative ions. These bind to the positively charged protons and neutralize them. The alkaline reaction results in a balancing of the acids. One substance that can neutralize stomach acid is sodium hydrogen carbonate. Only non-toxic reaction products such as CO2 and water are formed. The agent is now considered obsolete, but is nevertheless contained in many products against acid-related stomach complaints or heartburn. Sodium hydrogen carbonate increases the pH value within the stomach very quickly to values above 7, resulting in the increased release of the hormone gastrin. Gastrin is produced in the gastrointestinal tract and stimulates the production of stomach acid. After ingestion of sodium hydrogen carbonate, the pH value therefore drops reactively. Sodium hydrogen carbonate is therefore not as effective as, for example, aluminum hydroxide gels. Aluminum-containing drugs such as algedrate bind gastric acid in the stomach and neutralize it. Inflammations in the gastrointestinal tract can thus heal better. Algedrate also strengthens the tissue and mucous membrane layers of the gastrointestinal tract by releasing aluminum ions. Inflammations and injuries can then not occur so easily. In addition, the drug ensures the connection of phosphates, so that they can be better excreted. As a result, the mucous membranes become less irritated. The antacid alginate is made from brown algae. The drug forms a physical barrier between the mucous membranes and stomach acid. Together with calcium carbonate or potassium hydrogen carbonate, alginic acid forms a foam that spreads over the stomach contents. This prevents reflux with heartburn.
Medical use and application
Antacids are used to bind acid in the gastrointestinal tract. They are intended to protect the stomach from acidosis and to relieve secondary symptoms of gastric acidosis. Typical sequelae include acid regurgitation and heartburn. Heartburn is the main symptom of reflux disease. In this disease, stomach contents or gastric acid flows upward from the stomach into the esophagus. Because the mucous membranes of the esophagus are much more sensitive than the mucous membranes of the stomach, there is an uncomfortable burning sensation behind the breastbone. The irritation can also cause laryngitis to develop with a chronic cough. Antacids can neutralize stomach acid and thus mitigate the effects. The drugs are administered orally. The dosage depends on the active ingredient. Preparations containing the drugs magaldrate and hydrotalcite have the highest acid binding capacity. The effect of the antacids sets in very quickly, but rarely lasts longer than two to three hours. Acid-binding agents should be taken two hours after a meal or immediately before bedtime. It should be noted that therapy with antacids is purely symptomatic.They do not treat the causes of increased acid production in the stomach. In the past, antacids were also administered for gastric ulcers. In the meantime, however, they are increasingly being replaced in treatment by proton pump inhibitors or H2 receptor antagonists. These do not neutralize stomach acid, but directly inhibit stomach acid production and therefore work more effectively and longer.
Risks and side effects
Sodium bicarbonate should no longer be used as an antacid. First, a reactive increase in acid production occurs rapidly after ingestion, and second, the drug is completely absorbed. Hypernatremia, metabolic alkalosis, or hypertension may develop when higher doses are taken or when taken over a long period of time. Antacids containing aluminum hydroxide may cause constipation. Magnesium hydroxide, on the other hand, stimulates intestinal activity and can thus have a laxative effect. However, most ready-to-use preparations contain both compounds, so that laxative and constipating effects balance each other out. Recent studies show that the aluminum salts from antacids with aluminum hydroxide are absorbed. Since it has not yet been fully clarified what effects the salts have in the human body, the daily intake should be limited. It should also be noted that antacids can reduce the absorption of other drugs. Therefore, the preparations should be taken with a time interval of several hours.
