omeprazole
Omeprazole (Prilosec) is a proton pump inhibitor that reduces the amount of acid the stomach makes. It treats frequent heartburn over the counter, and by prescription it is used for gastroesophageal reflux disease, acid-related ulcers, and conditions with excess stomach acid.
This page is based on FDA labeling and MedlinePlus information for omeprazole, cross-checked with the National Cancer Institute dictionary; the mechanism is explained in plain language, and analogies are used only where they stay accurate.
How it works
Explains what the medicine does in the body, not dosing, side effects, or safety.
An analogy
The stomach has millions of tiny acid pumps working around the clock, and heartburn happens when too much acid splashes upward. Omeprazole is a wrench thrown into the pumps: it locks onto each pump permanently, so acid output falls for as long as it takes the stomach to build new pumps.
In simple terms
Omeprazole belongs to the proton pump inhibitor class. After it is absorbed, it reaches the acid-producing parietal cells of the stomach and forms a stable bond with the hydrogen-potassium ATPase, the pump that pushes acid into the stomach. This blocks the final step of acid secretion, so less acid is made no matter what triggers it. With less acid, heartburn eases and irritated or ulcerated tissue in the esophagus and stomach can heal.
In depth
Omeprazole is a benzimidazole with selective and irreversible proton pump inhibition activity. It forms a stable disulfide bond with the sulfhydryl group of the hydrogen-potassium ATPase on the secretory surface of parietal cells, inhibiting the final transport of hydrogen ions into the gastric lumen and suppressing gastric acid secretion. The agent exhibits no anticholinergic activity and does not antagonize histamine H2 receptors, and because the inhibition is irreversible, acid secretion recovers only as new pump molecules are synthesised.
See it in motion
A schematic animation of the mechanism — simplified for clarity, not drawn to scale.
How omeprazole irreversibly locks the stomach's proton pump
- Omeprazole is a benzimidazole with selective and irreversible proton pump inhibition activity.
- It forms a stable disulfide bond with the sulfhydryl group of the hydrogen-potassium ATPase on the secretory surface of parietal cells, inhibiting the final transport of hydrogen ions into the gastric lumen and suppressing gastric acid secretion.
- The agent exhibits no anticholinergic activity and does not antagonize histamine H2 receptors, and because the inhibition is irreversible, acid secretion recovers only as new pump molecules are synthesised.
- With less acid, heartburn eases and irritated or ulcerated tissue in the esophagus and stomach can heal.
Target: Hydrogen-potassium ATPase (gastric proton pump)
The pump on the secretory surface of stomach parietal cells that moves acid into the stomach lumen, the final step of acid production; blocking it shuts down acid secretion regardless of the stimulus.
Approved uses
Approved uses differ by country and change over time. Always follow your local prescribing information.
Approved uses in United States
FDA- For the treatment of frequent heartburn (heartburn that occurs two or more days a week) in adults, as an over-the-counter product not intended for immediate relief
- For the treatment of symptoms of gastroesophageal reflux disease (GERD) in adults and children 1 year of age and older
- For the treatment of damage from GERD, and to allow the esophagus to heal and prevent further damage, in adults and children with GERD
- For the treatment of conditions in which the stomach produces too much acid, such as Zollinger-Ellison syndrome, in adults
- For the treatment of ulcers of the stomach or intestine, and with other medications to treat and prevent the return of ulcers caused by Helicobacter pylori, in adults
Official sources
The statements on this page trace back to these records.
- U.S. Food and Drug Administration: omeprazole drug facts
U.S. Food and Drug Administration
- MedlinePlus: omeprazole
MedlinePlus, U.S. National Library of Medicine
- National Cancer Institute: omeprazole
National Cancer Institute
This page explains how the medicine works — it isn’t the patient leaflet. For anything that applies to you, read the leaflet that came with your medicine or ask your pharmacist.
MedUnfold provides educational content and is not medical advice. Always follow your local prescribing information and healthcare professional.