How do antacids work?

Antacids work by neutralizing acid and coating the stomach. Antacids should be taken 1 hour after meals or when gastroesophageal reflux disease symptoms occur. Liquid antacids usually work faster than tablets or chewables. If symptoms occur soon after meals, they should be taken before the meal.

Antacids are useful because they relieve symptoms rapidly. But relief is only temporary. Over-the-counter antacids do not prevent symptoms from returning or rarely allow an injured esophagus to heal. If you need antacids for more than 2 weeks, talk with your health care provider to get a better diagnosis of your condition and appropriate investigation and treatment.

Most varieties of antacids you can buy without a prescription are combinations of aluminum hydroxide and magnesium hydroxide. Antacids containing these ingredients may produce unwanted diarrhea or constipation. Antacids containing calcium carbonate are the most potent in neutralizing stomach acid. Popular brands are Tums and Titralac.

When taking antacids, follow label instructions and do not take more than the recommended daily dose. Take antacids before or after meals and at bedtime—or when you have symptoms.

Always tell your health care provider about your antacid use.

What if lifestyle changes and antacids don't work?

If you still have symptoms after lifestyle modifications and antacids, your health care provider probably will prescribe a stronger drug. The usual choice is one of the histamine-2 (H2) blockers, or acid blockers.

What are acid blockers?

The name says it all. These drugs block the biochemical process that creates acid in the stomach. Less acid in the stomach means less acid available for back-up into the esophagus. Some examples are cimetidine (Tagamet), ranitidine (Zantac), and famotidine (Pepcid). Low doses of these drugs are available without a prescription. More potent doses require a prescription. These drugs relieve symptoms within 30 minutes and are taken twice a day. Pepcid Complete also has antacids in it.