Nexium 20mg tablets contain esomeprazole, a proton pump inhibitor that reduces stomach acid production. Each pack contains 14 tablets in a distinctive purple box. This prescription medication is used to treat conditions like acid reflux, heartburn, and stomach ulcers. The active ingredient esomeprazole belongs to a group of medicines called proton pump inhibitors. These work by reducing the amount of acid that your stomach produces. The tablets should be swallowed whole with liquid, preferably taken in the morning. The usual recommended dose is one tablet per day or as prescribed by your healthcare provider. This medication requires a prescription and should be used under medical supervision. Store at room temperature away from moisture and heat.