Antacids are medications that soothe and neutralise stomach acids to provide relief from heartburn and indigestion. They may also be used to treat gastritis and stomach ulcers.

  1. Treats heartburn, gastritis, stomach ulcers and indigestion.
  2. Effective within a few hours of taking.
  3. Does not treat the underlying condition. 

If you are concerned about any symptoms you are experiencing relating to stomach acids, you can speak with one of our registered clinicians via our online video consultation service, from 9.30am-4.30pm, five days a week.  

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Product information

What are antacids?

Antacids neutralise the effects of stomach acids, and are available in a variety of forms. Some antacids contain alginate, which helps protect the gullet, and simethicone, which reduces flatulence. You should take antacids at a time that is most effective for treating symptoms, typically after a meal in the case of heartburn and indigestion. It should be noted that other treatments might be affected by use of antacids when taken within two to four hours of their dosage.

What is heartburn? 

Heartburn occurs when the acids of the stomach travel upwards towards the throat (acid reflux). Symptoms include a burning sensation in the chest and a metallic taste in the mouth. It may also result in bad breath, hoarseness, coughing, hiccups, bloating and nausea. These tend to occur when lying down or a short time after eating. The causes of heartburn vary, and it’s not always clear why, but certain foods and drinks, including coffee, spicy food, chocolate and fatty foods are likely triggers. Other possible causes include smoking, obesity, stress, anxiety, pregnancy and certain medications. Treatment for heartburn may include eating smaller meals, managing stress, losing weight, avoiding foods that trigger it and eating three to four hours before bed. Not wearing tight fitting clothing around the waist and quitting smoking may also help. In terms of specific medication however, antacids can be very effective.

What is indigestion?

Indigestion is very common, and almost everyone at some point in their lives experiences it. Symptoms include heartburn, bloating, nausea, bringing up small amounts of food without vomiting, belching and farting. If you experience a stomach ache or back pain it’s unlikely to be indigestion, and may be related to constipation. 

There are many ways to prevent indigestion from occurring if it is something you experience frequently. Lowering the amount of spicy or fatty foods, tea, coffee, alcohol or fizzy drinks you consume can be effective if these are triggers. Losing weight, quitting smoking and propping yourself up slightly in bed can also help. As with heartburn, antacids can be an effective treatment if changes to your lifestyle don’t ease your indigestion. 

What is gastritis?

Gastritis is a condition caused by inflammation of the stomach lining, which occurs when it becomes damaged. In the vast majority of cases, it has no serious long-term effects, but if left untreated it can persist for many years. 

There are two forms of gastritis: acute (where symptoms develop suddenly) and chronic (where symptoms are always present). Symptoms of gastritis include indigestion and heartburn, a gnawing pain in the stomach, nausea, vomiting and feeling unusually full after eating. In cases where the stomach lining has been worn away, which occurs if the condition has not been treated, pain, bleeding and stomach ulcers may be present. 

The most common cause of gastritis is a H pylori bacterial infection. Diagnosis for gastritis requires one or more tests to determine what is happening in the stomach. These tests may include an endoscopy, a breath test (to ascertain whether a bacterial infection is present), an X-ray or a stool test. 

Treatment for gastritis is essential and usually highly effective. Antacids can help relieve some of its symptoms, as can PPIs (proton pump inhibitors), but a course of antibiotics will also be required if the cause is a bacterial infection.

What are stomach ulcers?

Stomach ulcers are open sores that can develop in the lining of the stomach, or occasionally in the duodenum (the first part of the small intestine). They are sometimes referred to as peptic ulcers. Symptoms of a stomach ulcer are very similar to those described above for other conditions, with indigestion and heartburn common. Other symptoms are similar to gastritis, including a gnawing pain and nausea. Weight and appetite loss may also be present. 

The most common cause of stomach ulcers is a H pylori bacterial infection. Other triggers include NSAIDs (non-steroidal anti-inflammatory drugs) and lifestyle factors (such as stress and alcohol). Establishing whether a bacterial infection is present via a breath test is usually the first step a doctor will take. Stool samples and blood tests may also be required. 

In rarer cases, a gastroscopy may be advised, in which a thin tube with a camera is passed into the stomach. If an infection is present, a course of antibiotics will be prescribed, which should clear up the infection and its symptoms over a matter of a few days or weeks. 

If NSAIDs or other medications are the cause of your stomach ulcer, alternative treatments will likely be discussed, and antacids and proton pump inhibitors may be offered to help manage your symptoms.

You can consult one of our GMC-registered clinicians about stomach ulcers between 9.30am-4.30pm, Monday to Friday, using our online video consultation service. They may also be able to issue fit notes, and referrals to specialists for treatment, where appropriate.  

Page last reviewed:  18/06/2020
Side effects and warnings

Do antacids have side effects?

There are many forms of antacids available, and side effects may differ from product to product. There are few side effects for antacids, and not everyone will experience them, but it is important to know what they are before starting treatment. They include constipation and flatulence.

Taking antacids with other medications

Before undergoing treatment with antacids, if you have recently taken or are currently taking any of the following medications, you should inform your doctor: Digoxin, tetracycline or ciprofloxacin, bisphosphonates, water tablets, eltrombopag, fluoride, zinc or vitamin D, oral iron, levothyroxine, tablets or capsules with an enteric coating.

Because antacids may affect the way in which other medications work, you should make sure they are taken at least two hours before other treatments.

Are antacids suitable for everyone?

If any of the following apply to you, it’s essential that you do not use antacids, and you should speak to your doctor about alternative treatments: an allergy to any of the ingredients; kidney or liver problems (including kidney stones); high calcium levels in your blood or urine; a low phosphate diet. 

You should also inform your doctor if you have ever suffered from sarcoidosis or any condition that raises the level of calcium in your blood.

Antacids, pregnancy and breastfeeding

If you are pregnant, thinking of becoming pregnant or are breastfeeding, you should speak to your doctor before starting treatment.

Page last reviewed:  18/06/2020
Questions and Answers

What types of antacids are available? 

There are many forms of antacids available to buy in the UK. The most common types include magnesium carbonate, magnesium trisilicate, magnesium hydroxide, aluminium hydroxide, sodium carbonate and calcium carbonate. 

Is it safe to consume alcohol while using antacids?

While taking antacids and consuming alcohol presents no dangers, alcohol can worsen your existing symptoms. 

Do antacids affect your ability to drive?

There is no evidence to suggest that antacids have any effect on your ability to operate heavy machinery.

Are antacids available to buy over the counter?

Antacids can be bought from your local pharmacy and many shops without a prescription.

How can I buy antacids online?

Our GPhC-registered clinicians can discuss antacids with you via our online video consultation service. You can book an appointment with them between 9.30am and 4.30pm, five days a week.  

Page last reviewed:  18/06/2020

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