Omeprazole

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. It is also used to prevent upper gastrointestinal bleeding in people who are at high risk. Omeprazole is a proton-pump inhibitor (PPI) and its effectiveness is similar to that of other PPIs. It can be taken by mouth or by injection into a vein. It is also available in the fixed-dose combination medication omeprazole/sodium bicarbonate as Zegerid and as Konvomep. Common side effects include nausea, vomiting, headaches, abdominal pain, and increased intestinal gas. Serious side effects may include Clostridioides difficile colitis, an increased risk of pneumonia, an increased risk of bone fractures, and the potential of masking stomach cancer. Whether it is safe for use in pregnancy is unclear. It works by blocking the release of stomach acid. Omeprazole was patented in 1978 and approved for medical use in 1988. It is on the World Health Organization's List of Essential Medicines. It is available as a generic medication. In 2023, it was the tenth most commonly prescribed medication in the United States, with more than 45 million prescriptions. It is also available without a prescription in the United States.