Heartburn: Antacids


What are antacids?

Antacids are the most commonly used product for treating heartburn discomfort. And because they start to work in seconds, they're also the fastest way to relieve your symptoms.

Available without a prescription, antacids are available in convenient chewable tablets or as a liquid. Most are relatively inexpensive, making antacids a popular product for fast relief.

How do Antacids work?

Antacids are the fastest acting heartburn relief available. That's because they start to weaken the acid in your stomach the second they reach it. The weaker the acid in your stomach, the less likely it is to give you heartburn.

Products that are not an antacid, like Zantac®, Pepcid®, Prilosec®, Prevacid®, Nexium®, Protonix®, Aciphex®, or Zegerid® take much longer to go to work. This is because they don't work on the acid that is in your stomach right now. They work by reducing the amount of acid your body produces.

The longer an antacid stays in the stomach, the longer it works. And having some food in yours stomach may actually prolong an antacids effect.

What's in an Antacid?

There are over 120 different antacid formulations in the United States alone. Most of them contain at least one of these key ingredients: Calcium Carbonate, Magnesium Hydroxide, Aluminum Hydroxide and/or Sodium Bicarbonate. And while all these ingredients work to neutralize your stomach's acid, it's important to know more about them so you can choose the one that's right for you.


Calcium Carbonate is a strong and fast-acting antacid. In fact, it has been used since the first century. And because it's so effective, products like TUMS® still use it today.

Antacids that contain calcium carbonate may work longer than those containing sodium bicarbonate or magnesium. They also provide calcium, which is lacking in most adult diets. The amount of calcium carbonate usually ranges between 500 and 1,000 milligrams per tablet. It's important to take this calcium carbonate as directed and not exceed the recommendation on the label.


Aluminum salts dissolve slowly in the stomach, gradually relieving your heartburn symptoms. But they may cause constipation. Magnesium salts on the other hand, act quickly to neutralize acid but are known to cause diarrhea.

You could say that two wrongs do make a right. Because the effects of aluminum and magnesium can balance each other out, using them together is often considered an effective treatment for digestive upset.

However, in recent years there have been questions about the long-term safety of taking aluminum. Because aluminum may deplete the body of phosphorus and calcium (increasing the risk of weak bones) some products are no longer using it.


Sodium bicarbonate is frequently found in products like Alka-Seltzer®, baking soda, or as store brand sodium bicarbonate. It can work quickly to relieve heartburn symptoms. But it's also quickly eliminated from your stomach so relief may not last long.

Because it reacts with stomach acid and can produce a significant amount of carbon dioxide gas, people often belch or get flatulence when using sodium bicarbonate.

Sodium bicarbonate has high sodium content and is not appropriate for people who are on salt restricted diets or have congestive heart failure, high blood pressure, or kidney problems. Because it provides such a significant amount of sodium, even people who are not sodium restricted should take this into consideration.

For pregnant women, antacids containing sodium bicarbonate are not considered to be safe for them to take.

Alginate Antacids

Alginate antacids (like Gaviscon®) don't work the way other antacids do. These antacids contain both calcium carbonate and alginic acid. The alginic acid helps form a barrier that floats on top of the acid in your stomach. This barrier helps prevent stomach acid from moving up into your esophagus.

The calcium carbonate works to neutralize the stomach acid that pushes through the barrier and into your esophagus. However the amount of calcium carbonate in these products is usually less than in other extra strength antacids.

Why should I talk to my Doctor or Pharmacist when taking an Antacid?

Though antacids are great at quickly relieving your heartburn symptoms, they usually don't treat underlying conditions that could be causing them. So if you suffer from heartburn for more than two weeks its important to talk to your doctor.

Like most medicine, antacids interact with other medications. When this happens, the effects of one or both drugs may change, or the risk of side effects may be greater. If you're on a prescription drug it's important to talk to your doctor or pharmacist before taking an antacid.

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