H2 blockers, also called H2-receptor antagonists, are medicines that reduce the amount of acid the stomach produces by blocking one important producer of acid: histamine2.
Histamine2, a common chemical in the body, signals the stomach to make acid. H2 Blockers oppose histamine’s action and reduce the amount of acid the stomach produces. This type of medication is used to treat conditions in which the stomach produces too much acid, such as gastroesophageal reflux disease. They also have been prescribed for the treatment of peptic ulcer symptoms.
Drugs that work by this mechanism in the United States are Zantac (ranitidine), Pepcid (famotidine), Tagamet (cimetidine) and Axid (nizatidine).
Antihistamines are classified as H1 blockers and H2 blockers, depending on the type of receptors (on the surface of cells) that they act on. H1 receptors are associated with human tissue involving capillaries, and H2 receptors predominate in the lining of the stomach.
The H1 blockers are the meds generally used for allergic reactions.
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