ANSWER:

PPI stands for proton-pump inhibitor.  The proton-pump is the enzymatic system in the gastric
parietal cell which secretes hydrochloric acid.  This is the final step in the production of stomach
acid, therefore treatment with a PPI will prevent acid production regardless of the cause.  In
contrast, H2 blockers such as ranitidine, inhibit the histamine receptor of the parietal cell.

There are three PPI's available in Canada: omeprazole, pantoprazole and lansoprazole.  Only
pantoprazole is available in an injectable form.

PPI's are preferred over H2 blockers for the treatment of esophagitis, gastric ulcers, in
combination with antibiotics for the treatment of H. pylori, and possibly in the treatment of upper
GI bleeding.  H2 blockers are as effective as PPI's for the treatment of gastric reflux disease,
duodenal ulcers, and the prophylaxis of stress induced ulcers.

Lynne Kelly, B.Sc.Pharm.
June 30, 2000