Antacids are over-the-counter (OTC) medications that are used asadjunct therapy to treat peptic ulcers. They include:
· aluminum carbonate gel
· calcium carbonate
· magaldrate (aluminum-magnesium complex)
· magnesium hydroxide and aluminum hydroxide
Antacids work locally in the stomach by neutralizing gastric acid.They don’t need to be absorbed to treat peptic ulcers.
Antacids are distributed throughout the GI tract and are eliminat-ed primarily in stool.
The acid-neutralizing action of antacids reduces the total amount of acid in the GI tract, allowing peptic ulcers to heal.
Pepsin, one of the stomach secretions, acts more effectively when the stomach is highly acidic; therefore, as acidity drops, pepsin ac-tion is also reduced. Contrary to popular belief, antacids don’t work by coating peptic ulcers or the lining of the GI tract.
Antacids are primarily prescribed to relieve pain and are used ad-junctively in peptic ulcer disease.
Antacids also relieve symptoms of acid indigestion, heartburn, dyspepsia (burning or indigestion), or gastroesophageal reflux dis-ease (GERD), in which the contents of the stomach and duode-num flow back into the esophagus.
Antacids may be used to control hyperphosphatemia (elevated blood phosphate levels) in kidney failure. Because calcium binds with phosphate in the GI tract, calcium carbonate antacids pre-vent phosphate absorption.
All antacids can interfere with the absorption of oral drugs given at the same time. Absorption of digoxin, phenytoin, ketoconazole, iron salts, isoniazid, quinolones, and tetracyclines may be reduced if taken within 2 hours of antacids. (See Adverse reactions toantacids.)