Antacids

Antacids, drugs used for the treatment of dyspepsia or indigestion, also an effective treatment for the pain from peptic and duodenal ulcers.

Antacids are bases which act by raising the pH of the stomach, that is, by making it more alkaline (a pH below 7 indicates acid, a pH above 7 indicates alkaline). The stomach pH is normally between 1 and 2, but this is sometimes raised by food as far as 5. Antacids normally raise the pH to around 3 or 4, but different antacids vary in their efficacy. The reduction in the acidity of the gastric contents by antacids has an effect on the enzyme pepsin, reducing its activity. Antacids may also increase stomach/oesophageal sphincter pressure and adsorb bile acids. Smoking, stress, irregular meals, and alcohol can aggravate this condition in some people. See also Acids and Bases.

Antacids contain aluminium salts (for example, aluminium hydroxide), magnesium salts (for example, magnesium trisilicate or magnesium hydroxide), or sodium salts (for example, sodium bicarbonate). They may be taken in either liquid or tablet form, the liquid form taking effect slightly more quickly. The widely used antacid cimetidine (which goes by various brand names in different countries) acts on the acid-producing cells lining the stomach to reduce acid release. Other effective therapies for the symptoms of hyperacid production include hydrogen receptor blockers or antibiotics to eradicate the microbe Helicobacter pylori, which can cause peptic ulcerations.

There are some side effects with antacids. Magnesium salts may cause diarrhoea, and aluminium salts constipation. These problems may be overcome by choosing an antacid appropriate for the patient, and by using a mixture of different antacids. Patients who suffer from hypertension or cardiac failure should not take an antacid with a high sodium content. Elderly patients may also suffer from kidney problems and feelings of confusion when taking some antacids.

Antacids may partially mask the symptoms of underlying disease, such as stomach cancer. For this reason, patients over 45 years developing indigestion for the first time or those experiencing persistent or recurring symptoms should seek advice from a doctor.