Antacids

What are antacids?

Antacids are a class (group) of drugs which help to neutralise the acid content of your stomach. Antacids include: aluminium hydroxide, magnesium carbonate, magnesium trisilicate, hydrotalcite, and come in various different brand names. They come as tablets and liquids.

Some antacids are combined with another drug called simeticone which helps to reduce flatulence (wind).

Another group of drugs called alginates may be found in some brands of antacid medication. Alginates are added to help protect the lining of the oesophagus (gullet) from stomach acid. Alginates include: sodium alginate and alginic acid and are present in antacid medications with various different brand names.

What conditions are antacids used to treat?

• To reduce the symptoms of acid reflux which may cause heartburn or oesophagitis (inflammation of the gullet). These conditions are sometimes called gastro-oesophageal reflux disease or GORD.
  
  
• To relieve some of the symptoms caused by ulcers in the stomach and duodenum (part of the gut).
  
  
• In other conditions where it is helpful to neutralise stomach acid. For example, for occasional bouts of dyspepsia (indigestion).

Before the discovery of other more modern drugs, antacids were commonly used for the above conditions. They were also used to help heal ulcers in the stomach and duodenum.

Modern drugs called proton pump inhibitors and H2 blockers are now more widely used for these conditions as they are much more effective than antacids. Unlike antacids, which simply neutralise the acid for a short period, these modern drugs work by reducing the amount of acid made by the stomach.

However, antacids still have a place. They are most commonly used to provide quick relief of symptoms caused by stomach acid. In particular, in people who get intermittent bouts of mild dyspepsia (indigestion) or heartburn.

How do antacids work?

Your stomach normally produces acid to help with the digestion of food and to kill bacteria. This acid is corrosive so your body produces a natural mucus barrier which protects the lining of the stomach from being eroded.

In some people this barrier may have broken down allowing the acid to damage the stomach, causing an ulcer. In others there may be a problem with the muscular band at the top of the stomach (the sphincter) that keeps the stomach tightly closed. This may allow the acid to escape and irritate the oesophagus (gullet). This is called ‘acid reflux’ which can cause heartburn and/or oesophagitis.

Antacids work by neutralising (counteracting) the acid in your stomach. They do this because the chemicals in antacids are bases (alkalis) which are the opposite of acids. A reaction between an acid and base is called neutralisation. This neutralisation makes the stomach contents less corrosive. This can help to relieve the pain associated with ulcers and the burning sensation in acid reflux.

When antacids work on stomach acid they can produce gas which may cause flatulence (wind). Simeticone helps to stop this ‘foaming’ effect and may sometimes be included within antacid medications.

Many of the common antacids also include alginates. Most alginates work by forming a gel which floats on top of the stomach contents. The gel acts as a protective barrier, preventing stomach acid from irritating the oesophagus.

Can I buy antacids or do I need a prescription?

You can buy most brands of antacids at pharmacies, or you may receive them on prescription.

How do I take antacids?

Antacids are often taken to relieve symptoms or when symptoms are expected. Your doctor or pharmacist will advise you of the dose needed and how often you should take it. Read the leaflet that comes with your particular brand for further information.

How quickly do antacids work?

Generally antacids provide quick relief for problems such as heartburn caused by reflux. However, the relief of symptoms may only be short-lived.

How long is treatment needed?

Your doctor may prescribe an antacid to have on 'standby' so that you only take it to relieve your symptoms when they occur, rather than every day. Read the leaflet that comes with your particular brand for further information.

Who can and cannot take antacids?

A full list of people who should not take antacids is included with the information leaflet that comes in the drug packet. If you are prescribed or buy an antacid, read this to be sure you are safe to take it.

What about side-effects?

Most people who take an antacid do not have any side effects. However, side effects occur in a small number of users. The most common side effects are diarrhoea, constipation and belching.

Magnesium-containing antacids tend to be laxative whereas aluminium-containing antacids tend to be constipating. Antacids containing both magnesium and aluminium may balance out these effects and so minimise any possible side effects of diarrhoea or constipation.

For a full list of all the side effects and possible interactions associated with your drug consult the leaflet that comes with your medication.

If you are taking antacids you should avoid taking them at the same time as you take other medication. This is because antacids can affect how well other medication is absorbed.

Other considerations

You should consult your doctor if your symptoms worsen, or if you experience any of the following problems which can indicate a serious gut disorder:

• Vomiting blood. This may be obviously fresh blood, but altered blood in vomit can look like ground coffee. Doctors call this 'coffee-ground vomit'.
• Blood in your stools (faeces). This may be obvious blood, or it may just make your stools black.
• Unintentional weight loss.
• Difficulty swallowing, including food getting stuck in the gullet.
• Persistent abdominal pain or persistent vomiting.