A drug may be classified by the chemical type of the active ingredient or by the way it is used to treat a particular condition. Each drug can be classified into one or more drug classes.
H2 antagonists competitively inhibits histamine at the H2 receptors and leads to a reduction in secretion of gastric acid.
Histamine stimulates the secretion of gastric acid by action on H2 receptors, which are found in the parietal cells of the gastric mucosa.
H2 antagonists are used to treat gastroesophageal reflux disease (GERD), gastrointestinal ulcers and other gastrointestinal hypersecretory conditions.