Nexium Mups 20mg contains esomeprazole as its main active ingredient, which acts as a proton pump inhibitor (PPI). It is prescribed for patients with gastroesophageal reflux disease (GERD) and peptic ulcers caused by NSAID use. Additionally, this medication helps prevent re-bleeding after endoscopic treatment for acute gastric ulcer bleeding and is used for gastric acid suppression when oral therapy is insufficient.