Nexium 20mg tablets contain esomeprazole, a proton pump inhibitor medication used to treat acid reflux, heartburn, and other conditions related to excess stomach acid production. Each pack contains 14 tablets in a distinctive purple box manufactured by AstraZeneca. Nexium works by reducing acid production in the stomach. The active ingredient esomeprazole belongs to a group of medicines called proton pump inhibitors. This medication requires a prescription and should be taken as directed by your healthcare provider. The tablets should be swallowed whole with water and can be taken with or without food. Store at room temperature away from moisture and heat. Common uses include treatment of gastroesophageal reflux disease (GERD), peptic ulcers, and Zollinger-Ellison syndrome.