What Are Antacids? Uses, Warnings, Side Effects, and More

Antacids are over-the-counter drugs that help relieve symptoms of pain and discomfort caused by conditions such as heartburn, indigestion, and acid reflux, according to the Cleveland Clinic.

Antacids work quickly to neutralize the acid in your stomach. They can also inhibit the activity of pepsin, an enzyme that creates acid that breaks down food for digestion. Reducing the acid in your stomach relieves symptoms of pain and discomfort.

While antacids will relieve symptoms for a few hours, they don’t treat the underlying medical conditions that cause these symptoms.

The U.S. Food and Drug Administration has approved antacids for treating mild cases of heartburn and indigestion. This means heartburn or indigestion that happens every once in a while, per the Cleveland Clinic.

Antacids contain combinations of various compounds with salts of calcium, magnesium, and aluminum as active ingredients, according to the National Library of Medicine.

Antacids tend to come in two forms: liquids or pills. Liquid antacids coat, soothe, and relieve, and they work a bit faster than pills to relieve symptoms of heartburn and indigestion. Baking soda (sodium bicarbonate) is also an antacid.

Examples of antacids you’ll find at your local supermarket or pharmacy include:

Tums (calcium carbonate)
Mylanta (aluminum hydroxide, magnesium hydroxide, simethicone)
Rolaids (calcium carbonate and magnesium hydroxide)

Antacids should be taken about one hour after eating or when you have heartburn, according to MedlinePlus. If you’re taking them at night, taking them with food is not recommended.

You shouldn’t take antacids if you are allergic or hypersensitive to any ingredients in a specific brand or formulation, per the National Library of Medicine.

Ask your doctor before taking antacids if you:

Have kidney, liver, or heart disease
Are on a low-sodium diet
Have edema (swelling)
Are pregnant or plan to become pregnant
Are taking other medications
Are under 12 years old
Have heart failure
Have high blood pressure
Are already taking calcium

Taking antacids on a frequent basis is not recommended. Talk to your doctor if you feel you need to use antacids on most days, advises MedlinePlus.

According to the Cleveland Clinic, side effects of antacids may include:

Gas (flatulence)
Constipation (especially when the brand contains calcium or aluminum)
Diarrhea (especially when the antacid contains magnesium)
Nausea and vomiting
Stomach cramps or pain in the abdomen

Serious side effects could include:

Acid rebound (when antacids cause your body to make more acid, which can make your symptoms worse)
Neurotoxicity (when antacids affect the nervous system)
Iron deficiency
Rarely, weakened bones over the course of years (especially if you take large amounts of antacids that contain aluminum)
Hypercalcemia (too much calcium in your blood)

In rare cases, antacid brands with calcium may cause kidney stones, notes MedlinePlus.

Antacids can interact with how other medicines are absorbed into your body. To prevent interactions, you should take other medications one hour before, or at least four hours after, taking an antacid, per the Cleveland Clinic.

Antacids can mix badly with a wide variety of medications used for serious health issues, including seizures, heart rhythm issues, Parkinson’s disease, antibiotics, and psychiatric conditions, so ask your doctor before combining antacids with any other drugs.

Additional reporting by Jennifer D'Angelo Friedman.

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