Omeprazole is a proton pump inhibitor that is used to treat symptoms of gastroesophageal reflux disease and other conditions caused by excess stomach acid. Find patient medical information for Omeprazole (Prilosec, Prilosec OTC) on WebMD including its uses, side effects and safety, interactions, pictures, warnings, and user ratings NHS information about the medicine omeprazole, including what it's used for, who can take it, how to take it and side effects. Omeprazole is used for a variety of digestive issues, such as acid reflux. Several omeprazole side effects are possible, though dietary changes may help. Summary The NHS warns people not to take over-the-counter omeprazole for more than two weeks. Here’s why long-term use can be risky, which side effects to watch for, and when to see a GP. Omeprazole: learn about side effects, dosage, special precautions, and more on MedlinePlus Omeprazole is also used to treat dyspepsia, a condition that causes sour stomach, belching, heart burn, or indigestion. In addition, omeprazole is used to prevent upper gastrointestinal tract bleeding in seriously ill patients. Omeprazole is a proton pump inhibitor (PPI). It works by decreasing the amount of acid produced by the stomach. Omeprazole is a medication that reduces the amount of acid in your stomach. It treats heartburn, stomach ulcers and reflux disease. Omeprazole, sold under the brand names Prilosec and Losec among others, is a medication used in the treatment of gastroesophageal reflux disease (GERD), peptic ulcer disease, and Zollinger–Ellison syndrome. [1] Omeprazole can be helpful, especially if acid reflux, ulcers or other stomach issues are affecting your day-to-day life. But like any medication, it works best when you’re taking it for the right reason, at the right dose and for the right amount of time.