H2RAs decrease gastric acid secretion by reversibly binding to histamine H2 receptors located on gastric parietal cells, thereby inhibiting the binding and action of the endogenous ligand histamine. H2 blockers thus function as competitive antagonists.

How do histamine H2 receptor antagonists work?

The H2 receptor blockers act by binding to histamine type 2 receptors on the basolateral (antiluminal) surface of gastric parietal cells, interfering with pathways of gastric acid production and secretion.

How do histamine H2 blockers help heal gastric ulcers?

How It Works. H2 blockers reduce the production of stomach acid, which may reduce irritation to the stomach lining and help an ulcer heal.