Proton Pump Inhibitors
The final common pathway in gastric acid secretion is the proton pump adenosine triphosphatase. Th e physiological essence of this enzyme is the exchange of hydrogen ions for potassium ions. Th us, hydrogen is secreted by the parietal cell into the gastric lumen in exchange for potassium. Proton pump inhibitors should be taken prior to meals, because these drugs are more potent when taken orally prior to meals. Th ey are also absorbed more effectively in the morning.

Mechanism of Action
Proton pump inhibitors or gastric pump inhibitors inhibit H+ and K+ ions, which generate gastric acids.

Indications
Proton pump inhibitors are widely used in the short-term therapy of duodenal and gastric ulcers. Proton pump inhibitor agents are also used in the treatment of gastroesophageal refl ux disease, gastric ulcer, and for long-term treatment of pathologic hypersecretory conditions such as Zollinger-Ellison syndrome.

• Omeprazole is used in the treatment of acid peptic disorders. It is approved for the short-term treatment of duodenal ulcers, severe gastroesophageal refl ux, and hypersecretory conditions. It is also eff ective in the prevention of NSAID ulcers and their complications. The antisecretory effect of omeprazole occurs within one hour, with maximum eff ect occurring within two hours. 
• Lansoprazole suppresses gastric acid formation in the stomach. Lansoprazole is indicated for the short-term treatment of acute duodenal ulcer, gastric ulcer, and erosive esophagitis. It is most effective given 30 to 60 minutes prior to a meal. Like other proton pump inhibitors, it is very effective in healing acid peptic disease.