Prilosec OTC Oral belongs to the class of Proton Pump Inhibitors (PPIs). This over-the-counter medicine is used for the treatment of gastrointestinal disorders. Prilosec OTC Oral is prescribed for the treatment of Gastroesophageal Reflux Dissease (GERD), esophagitis, H.Pylori ulcer, duodenal ulcer, gastric ulcer, dyspepsia, belching, indigestion, GIT bleeding and Zollinger-Ellison Syndrome. The side effects of Prilosec OTC Oral include - Headache - Cough - Abdominal pain - Rash - Nausea - Vomiting - Acid reflux - Flatulence - Infection of upper respiratory tract - Loss of appetite - Taste changes - Unusual dreams Prilosec Oral OTC interacts with the following drugs. - Erlotinib - Nelfinavir - Rilpirvirine