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] Prilosec is a proton pump inhibitor that decreases the amount of acid produced in the stomach. Prilosec is used to treat symptoms of gastroesophageal reflux disease (GERD) and other conditions caused by excess stomach acid. Omeprazole (Prilosec) is a proton pump inhibitor (PPI) that is used to reduce the amount of acid in your stomach and it can be bad for your kidneys. It can cause acute kidney injury and may also worsen the progression of chronic kidney disease (CKD). Prilosec (Omeprazole) may treat, side effects, dosage, drug interactions, warnings, patient labeling, reviews, and related medications including drug comparison and health resources. 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. Prilosec delayed-release oral suspension is a prescription medicine used to reduce the amount of acid in your stomach. Prilosec is a proton pump inhibitor. 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). GERD is a condition where the acid in the stomach washes back up into the esophagus.