Lansoprazole is an anti-secretion that works to suppress gastric acid secretion by inhibiting the activity of the H/K ATPase (proton pump) enzyme on the glandular surface of parietal gastric cells at pH <4. Lansoprazole which binds to proton (H) rapidly will be converted to sulfonamide, an active proton pump inhibitor. Oral use of Lansoprazole inhibits secretion of basal gastric acid and penta-gastric stimulation.