Esomeprazole potassium salt is a proton pump inhibitor which reduces acid secretion through inhibition of the H+ / K+ ATPase in gastric parietal cells. IC50 value: Target: proton pump Esomeprazole potassium salt is a proton pump inhibitor and gastric antisecretory agent indicated for the short-term treatment of gastroesophageal reflux disease in patients with a history of erosive esophagitis.