Antacids FAQ
Annette (Gbemudu) Ogbru, PharmD, MBA
Dr. Gbemudu received her B.S. in Biochemistry from Nova Southeastern University, her PharmD degree from University of Maryland, and MBA degree from University of Baltimore. She completed a one year post-doctoral fellowship with Rutgers University and Bristol Myers Squibb.
Jay W. Marks, MD
Jay W. Marks, MD, is a board-certified internist and gastroenterologist. He graduated from Yale University School of Medicine and trained in internal medicine and gastroenterology at UCLA/Cedars-Sinai Medical Center in Los Angeles.
- What are antacids, and how do they work?
- For what conditions are antacids used?
- Are there any differences among the different types of antacids?
- What are the warnings and precautions for antacids?
- What are the side effects of antacids?
- With which drugs do antacids interact?
- What antacids are available?
What are antacids, and how do they work?
Antacids are a class of drugs used to treat conditions caused by the acid that is produced by the stomach. The stomach naturally secretes an acid called hydrochloric acid that helps to break down proteins. This acid causes the contents of the stomach to be acidic in nature, with a pH level of 2 or 3. (pH levels are a measure of acidity in the stomach: the lower the number, the greater the acidity.) The stomach, duodenum, and esophagus are protected from acid by several protective mechanisms. When there is too much acid or protective mechanisms are inadequate, the lining of the stomach, duodenum or esophagus may become damaged by the acid, giving rise to various gastrointestinal symptoms such as abdominal pain, heartburn (due to gastroesophageal reflux disease or GERD), and other gastro-esophageal symptoms.
Antacids reduce acidity by neutralizing (counteracting) acid, reducing the acidity in the stomach, and reducing the amount of acid that is refluxed into the esophagus or emptied into the duodenum. Antacids also work by inhibiting the activity of pepsin, a digestive enzyme produced in the stomach that is active only in an acid environment and, like acid, is believed to be injurious to the lining of the stomach, duodenum, and esophagus.
It is important to note that when antacids are taken on an empty stomach they provide acid reduction for 20 to 40 minutes only because the antacid is rapidly emptied into the duodenum. When taken after a meal, (approximately 1 hour afterwards) antacids reduce acid for at least three hours since food from the meal slows emptying of the antacid from the stomach. It is important to discuss the use of antacids with a physician or pharmacist, especially if used in combination with other prescribed medications so as to avoid drug interactions.
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