Prilosec (omeprazole) is a proton-pump inhibitor (PPI) that is used to help treat gastric ulcers, duodenal ulcers, gastroesophageal reflux disease GERD), and erosive esophagitis. Prilosec is also used to treat H. pylori (a common ulcer-causing bacteria). Prilosec was the first drug from this type of medication and is also over-the-counter by its generic name, omeprazole. It is approved for the treatment of frequent heartburn that occurs more than 2 times per week.
Proton pump inhibitors like Prilosec help to block gastric cells from producing acid in the stomach. It does so by blocking an enzyme that allows acid to be released from a proton pump in the gastric parietal cells. Prilosec prevents too much acid from being released that can cause harm to the tissue lining your esophagus, stomach, and intestines. Prilosec will generally start taking effect between 30 minutes and 3.5 hours.