What are antacids? Definition and How They Work
Antacids are a common class of drugs that are sold over the counter for the relief of heartburn, GERD, and indigestion.
Antacids work by neutralising stomach acid (more specifically, by neutralising the hydrochloric acid found in gastric juice). They also stop an enzyme called pepsin, which is normally involved in stomach acid production but can damage the oesophagus when refluxed.
Different antacids have different active ingredients, each with slightly varying abilities to neutralise stomach acid. Speak to your doctor or pharmacist to find the best antacid for you.
Overall, antacids contain salts derived from the following ingredients:
- Magnesium
- Aluminium
- Calcium
- Sodium
- Bismuth
Most antacids are formed by combining two salts, like magnesium and aluminium.
What Are the Most Common Antacids?
Common types of antacids include:
- Calcium carbonate. When calcium carbonate reacts with stomach acid, the resulting chemical reaction neutralises the stomach acid, raising the stomach’s pH levels.
- Sodium bicarbonate, which is an antacid. Sodium bicarbonate, also known as baking powder or bicarbonate soda for heartburn, is often combined with citric acid. This combination raises the stomach’s pH.
- Magnesium salts (or magnesium hydroxide) and aluminium salts (aluminium hydroxide) both react with stomach acid, decreasing the concentration of hydrogen ions in the stomach and therefore raising its pH.
Symptoms Relieved by Antacids
Antacids can help relieve the following:
- Heartburn — an uncomfortable or painful burning sensation in the chest, behind the breastbone, that is sometimes felt up and down the throat.
- Acid reflux, which occurs when food contents and stomach acid travel back up, irritating the food pipe (oesophagus), causing heartburn and other symptoms.
- Symptoms of gastro-oesophageal reflux disease (GERD) — a chronic condition where acid reflux and heartburn occur often.
- Inflammation of the oesophagus, which happens as a result of GERD.
- Indigestion (also called upset stomach or sour stomach), which can cause heartburn and other symptoms, like fullness, belching, bloating, nausea, and pain in the upper abdomen.
Antacids relieve these symptoms by:
- Neutralising excess stomach acid
- Stabilising the pH of the stomach (also called buffering)
By limiting bile acids and pepsin, a digestive enzyme that helps break down protein, antacids can help allow the stomach lining to heal.
Some antacids also contain ingredients that may help reduce additional symptoms, such as:
- Simeticone, which helps reduce flatulence
- An alginate, which helps keep stomach acid and food contents down by creating a ‘raft-like’ protective layer on top of your stomach contents.
Proper Usage: How and When to Take Antacids
Some antacids need to be taken a few times a day, others only once, depending on the type of antacid and the dose of the active ingredient.
Antacids can come in powder and liquid form, as well as tablet form, which may be more convenient. Effects may last for several hours after you take them.
It’s a good idea to take antacids with meals or soon after eating, as that’s when you’re most likely to have symptoms. The effects of antacids may also last longer if you take them with food.
For instructions on how to take antacids correctly, always read the product’s leaflet.
Warnings and Precautions
Antacids can interact with other medications, so it’s best to discuss with a healthcare professional before taking them.
Some antacids (like sodium bicarbonate) may not be suitable if you have a condition that requires you to limit your salt intake. You should also consult a doctor or a pharmacist before taking antacids if:
- You’re pregnant or breastfeeding
- Are on a low-sodium diet
- Have heart failure or high blood pressure
- Have a kidney or liver condition
Antacids are generally well tolerated, but you shouldn’t take them continuously or for longer than is recommended in the leaflet or by your healthcare professional. Antacids are only intended for short-term use. Speak to your doctor if you find yourself needing them all the time.
Potential Side Effects of Antacids
Antacids are generally well tolerated. However, sometimes they may cause some problems, especially if you take them for too long or more than the recommended dose.
Different antacids may cause different side effects:
- Sodium bicarbonate and calcium carbonate may cause nausea, headache, and weakness because they can reduce the acid levels in the blood too much, making it alkaline.
- Aluminium hydroxide may cause weakness, nausea, loss of appetite, or constipation (because it may reduce calcium and phosphate in the body).
- Magnesium hydroxide may cause diarrhoea because magnesium is a laxative.
Speak to a healthcare professional if you experience side effects or are worried about the risks of antacids, as you may need to change to another medication.
Conclusion
Antacids are generally well tolerated and an effective way to manage heartburn and other indigestion symptoms. Antacids can offer relief for acid reflux, but they are only meant to be used in the short term — speak to a doctor or pharmacist if your symptoms persist.
To find out more about ways to manage your digestive health and discover some antacid foods that may help your heartburn, read our article, Heartburn remedies that you could consider.
This article is for general information only and not intended as a substitute for medical advice. All information presented on these web pages is not meant to diagnose or prescribe. In all health-related matters, always consult your healthcare professional.
Always read the product label. Use only as directed. Incorrect use could be harmful. If symptoms persist consult your healthcare professional.
