Nexium 20mg is a prescription medication containing esomeprazole, a proton pump inhibitor used to treat acid reflux, heartburn, and other conditions caused by excess stomach acid. Each pack contains 14 tablets 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. The medication comes in a distinctive purple packaging with the AstraZeneca logo. The tablets should be taken as prescribed by your healthcare provider, typically once daily. This is a prescription-only medication that requires medical supervision for use.