Esomeprazole is a Proton Pump Inhibitor (ppi) used to decrease the production of stomach acid and treat symptoms of acid reflux. In the united states, it is available by prescription or over-the-counter (otc) for short-term treatment of conditions such as Gastroesophageal reflux disease (gerd). Esomeprazole is a prodrug, meaning it is inactive until it is broken down in the body by the enzyme cyp2c19 into its active form, omeprazole. Esomeprazole is used to reduce stomach acid production and prevents the backflow of acid into the esophagus, helping to treat heartburn and other acid reflux symptoms. It is also used to prevent and treat stomach ulcers and can be used in combination with antibiotics to treat helicobacter pylori (h. Pylori) infections, a common cause of stomach ulcers. Esomeprazole is generally well-tolerated but may cause common side effects such as headache, nausea, and diarrhea. It is important to follow the instructions of your doctor or pharmacist when taking this medication.