NCIt definition : A member of the class of histamine H2-receptor antagonists with antacid activity.
Ranitidine is a competitive and reversible inhibitor of the action of histamine, released
by enterochromaffin-like (ECL) cells, at the histamine H2-receptors on parietal cells
in the stomach, thereby inhibiting the normal and meal-stimulated secretion of stomach
acid. In addition, other substances that promote acid secretion have a reduced effect
on parietal cells when the H2 receptors are blocked.;