Common Remedies: Antacids

MOST families' medicine cupboards have some tablets, powder or liquid for the relief of indigestion. Symptoms such as a feeling of upper abdominal distension or discomfort, belching, a sick sensation or vomiting affect virtually everyone from time to time and are especially common in the middle-aged and elderly. These symptoms seem often to be due to acid formed in the stomach irritating it or surging up the gullet (oesophagus) towards the mouth and causing a burning sensation in the chest. Practical experience has shown that medicines that neutralise acid - antacids - bring swift relief to most people suffering from indigestion.

Any pharmacist will have on display scores of antacid tablets and mixtures, and at first sight the choice may be bewildering. In fact, almost all the well tried antacids are permutations of three metals: sodium, aluminium and magnesium - combined with four bases - hydroxides, trisilicates, carbonates and bicarbonates. Chalk and other calcium salts are rarely recommended nowadays; chalk neutralises acid but also stimulates its secretion. In the past, treatment of stomach ulcers with milk and calcium compounds has been shown, in rare instances, to lead to kidney failure - milk alkali syndrome.

Sodium bicarbonate (baking soda) acts quickly and is a popular treatment, partly because the chemical neutralisation of acid in the stomach releases quite large amounts of carbon dioxide gas, leading to dramatic, often noisy, belching. Some people find that the release of gas makes them feel better, mistakenly assuming that it had been lurking down there before the bicarbonate was taken. The drawback - apart from the gas - of bicarbonate of soda is that the amount of sodium it contains makes it unsuitable for repeated use, especially in the elderly, since excess sodium raises the blood pressure and strains the heart and kidneys.

Magnesium compounds also act quickly; their drawback is that they tend to cause diarrhoea. By contrast, aluminium compounds act more slowly and tend to cause constipation, which may be really troublesome. Physicians used to take pride in devising a personal mixture for each patient, balancing the proportions of magnesium and aluminium to keep the bowels in optimum working order. Mixtures of antacids do taste chalky, and pharmaceutical manufacturers have done their best to improve their palatability by adding peppermint and other flavourings. Tablets and mixtures intended for the relief of reflux of acid oesophagitis often contain alginic acid, said to help the mixture stick on to the lining of the oesophagus, and dimethicone, an anti-foaming agent said to reduce flatulence.

Self treatment with antacids makes sense for short-lived indigestion, but if symptoms persist a more precise diagnosis is needed. Cancer of the stomach is less common than it used to be, but it can be cured only if recognised very early. In the past 20 years drugs which block the formation of stomach acid and which encourage the healing of stomach ulcers have improved enormously - operations for stomach ulcers have become almost obsolete. Indigestion remedies based on antacids are good for simple indigestion, but for more serious stomach disorders they are yesterday's choice.