Nexium works by reducing the amount of acid your stomach produces. It contains esomeprazole, a proton pump inhibitor, which works by reducing stomach acid secretion. It also prevents acid pumps in the parietal cells inside the stomach from secreting acid. This medicine is recommended for the following pain conditions: Treatment of esophagitis. Treatment of stomach and duodenal ulcers. Treatment of acid reflux. Treatment of H. pylori. How to use: One tablet once daily.