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Antacids

Key points about antacids

Antacids are a group of medicines that are used to lower acid levels in the stomach.
Antacids are available as chewable tablets or liquid. Liquids are more effective than tablets.
Find out how to take them and possible side effects.

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Antacids are a group of medicines used to relieve symptoms of reflux disease (GORD), heartburn (dyspepsia) and peptic ulcer. Antacids work by neutralising (lowering) the acid in your stomach that is used to help digestion. This can reduce the symptoms of heartburn and relieve pain. Antacids work quickly but the effect doesn’t last for very long. They won't treat the underlying conditions or prevent the discomfort from happening again.

Antacids are usually only used for short term relief and aren't recommended to be used long-term. There are more effective medicines appropriate for long term use such as proton pump inhibitors and famotidine. If you find that you need to take antacids regularly, every day for more than 1 or 2 weeks, talk to your healthcare professional.

Antacids are available as chewable tablets or liquid. Liquids are more effective than tablets. They are sold as many brand names, but they have similar ingredients, including:

aluminium hydroxide
calcium carbonate
magnesium carbonate, hydroxide and trisilicate.

Examples of antacids available in Aotearoa New Zealand are Mylanta®, Alu-tab® and Quick-Eze®.

Some antacids contain alginates to prevent acid flowing into your oesophagus (the tube between your mouth and your stomach). They coat the surface of your oesophagus with a protective barrier against stomach acid, or form a gel on the stomach’s surface which helps stop acid going into your oesophagus.

Examples are Acidex® and Gaviscon®. For babies with reflux, read more about Gaviscon Infant.

Taking antacids may not be suitable if you have any of the following problems

Bringing up (vomiting) blood. This may be fresh blood that is bright red but it can also look like ground coffee (called coffee-ground vomit).
Blood in your poo (stools or faeces). This may look like blood, or it may just make your poo look black.
Weight loss without any reason or cause you can think of.
Difficulty swallowing, including food getting stuck in your throat (oesophagus).
Ongoing tummy pain or vomiting (being sick).

If you have any of the symptoms listed above you should contact your doctor urgently.

Dose: The dose of antacids will be different for different people and depends on your symptoms and location of your discomfort. Follow the dose instructions on the label or check with your healthcare provider.
Antacids come as chewable tablets or liquid.
- Chewable tablets: chew the tablets well, don't swallow them whole.
- Liquid: shake the bottle well so that the medicine is evenly mixed before you measure out a dose.
Acidex® and Gaviscon® tablets and liquids: These medicines sit on top of your stomach contents to form a protective layer so don’t lie down immediately after taking a dose. If you need to take a dose at bedtime, take it at least half an hour before getting into bed.
Timing: It's best to take antacids soon after eating because this is when you're most likely to get indigestion or heartburn.
Use only when needed: Antacids are best taken when symptoms occur or are expected, usually after meals and just before going to bed (about 4 times a day).

While most people can safely use antacids now and again, and they can be bought from supermarkets or over-the-counter from your pharmacy, they aren't suitable for everyone.

High blood pressure, heart failure, kidney disease or problems with your liver

Some antacids aren't suitable if you have an illness where you need to control how much salt (sodium) is in your diet, such as high blood pressure, heart failure, kidney disease or problems with your liver.

This is because antacids have high levels of sodium, which could make you unwell. If any of these apply to you, it’s important that you tell your healthcare provider before taking antacids.

Pregnant

If you're pregnant, check with your healthcare provider to find out whether antacids are safe for you to take. It’s best to use the least amount of antacid to manage your symptoms, for the shortest possible time.

Here are some things to know when you're taking antacids. Other things may be important as well, so ask your healthcare provider what you should know about.

Other medicines: Antacids can interfere with the absorption of other medicines (eg, iron) so you shouldn't take these together. Generally, don't take other medicines within 2 to 4 hours of taking antacids.
Alcohol: Avoid or limit alcohol as this can irritate your stomach and make your symptoms worse.
Don't use antacids all the time: Antacids are okay for occasional use but aren't usually prescribed regularly or long-term. If you find that you need to take antacids regularly, every day for more than 1 or 2 weeks, talk to your healthcare provider.

Like all medicines, antacids can cause side effects, although most people who occasionally take antacids don’t have any. Side effects can vary depending on the specific ingredients in the antacid. Long term use or overuse can lead to serious side effects.

Side effects	What should I do?
Diarrhoea (runny poo)	This can happen with antacids that contain magnesium. Tell your doctor if this bothers you.
Constipation (hard poo)	This can happen with antacids that contain aluminium. Tell your doctor if this bothers you.
Bloating, gas or flatulence (wind) Stomach cramps Feeling sick (nausea)	Tell your doctor if these bother you.

There are lifestyle changes you can make to help prevent symptoms of reflux disease(external link) (GORD), heartburn(external link) (dyspepsia) and peptic ulcer(external link) from occurring.

These include:

avoiding overeating or eating large meals
avoiding foods that trigger your symptoms
quitting smoking
reducing alcohol and caffeine intake (tea and coffee)
avoiding or reducing the use of non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen and diclofenac.

Indigestion
Heartburn (Mate taratarawai)
Gastric reflux support
Reflux in babies

The following links have more information on antacids. Be aware that websites from other countries may have information that differs from New Zealand recommendations.

Antacids(external link) Patient Info, UK