Prilosec is the brand name for omeprazole and anti acid drug that is used to decrease the amount of acid in the stomach. This drug can also be used to treat any burning or irritation in the esophagus. Prilosec is also used to cure gastric ulcers and duodenal ulcers especially when combined with antibiotics. Prilosec works by blocking an enzyme that stimulates the gastric juice stimulation in the stomach. By doing so, this drug lowers the amount of acid that is being produced in the stomach. Prilosec can be got over the counter but you should produce a prescription when buying the drug.