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] Nonprescription (over-the-counter) omeprazole is used to treat frequent heartburn (heartburn that occurs at least 2 or more days a week) in adults. Omeprazole is in a class of medications called proton-pump inhibitors. It works by decreasing the amount of acid made in the stomach. Omeprazole, approved by the FDA, is available as a prescription and over-the-counter (OTC) drug used as a treatment for frequent heartburn. Learn about side effects, drug interactions, dosages, warnings, and more. Omeprazole is used to treat excess stomach acid in conditions such as stomach ulcers, heartburn or gastroesophageal reflux disease (GERD), active duodenal ulcer, Zollinger-Ellison syndrome and erosive esophagitis. Omeprazole delayed-release capsules, USP, in combination with clarithromycin and amoxicillin, are indicated for treatment of patients with H. pylori infection and duodenal ulcer disease (active or up to 1-year history) to eradicate H. pylori in adults. Dual Therapy Omeprazole delayed-release capsules in combination with clarithromycin are indicated for treatment of patients with H. pylori infection and duodenal ulcer disease to eradicate H. pylori in adults. What is this medication? OMEPRAZOLE (oh ME pray zol) is used to treat heartburn, stomach ulcers, reflux disease, or other conditions that cause too much stomach acid. It works by reducing the amount of acid in the stomach. It belongs to a group of medications called PPIs. Overview: Omeprazole is used for heartburn, acid reflux, and other conditions where you have too much acid in your stomach. It works by reducing how much acid your stomach makes and usually takes. Omeprazole is used to treat certain conditions where there is too much acid in the stomach. It is used to treat gastric and duodenal ulcers, erosive esophagitis, and gastroesophageal reflux disease (GERD). Learn about the side effects of omeprazole, from common to rare, for consumers and healthcare professionals.