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H2-Receptor Antagonists is a class of drugs that are used for Gastritis, Heartburn, Gastroesophageal Reflux Disease also called (Gerd), stress ulcers, and dyspepsia.

This class of medications were the first type of medication for these medical conditions.

More recently another medication has been used called Protein Pump Inhibitor.

Method of Action

–  Blockage of parietal cells use or reaction to histamine
–  Parietal cells are located in the Stomach
–  This decreases the acid production

Types of H2-Receptor Antagonists:

1.)   Cimetidine  [Tagamet]

–  Uses: heartburn, peptic ulcers
–  Was the initial medication in this class

2.)   Ranitidine [Zantac]

–  Uses: heartburn, peptic ulcers, gastroesophageal reflux disease, hives

3.)  Famotidine [Pepcid]

–  Uses: heartburn, peptic ulcers, gastroesophageal reflux disease, hives
–  Appears to be more active then cimetidine
–  There is some difficulty with the availability of this drug

4.)  Nizatidine  [Tazac, Axid]

–  Uses: peptic ulcers, gastroesophageal reflux disease

Potential Adverse Effects:

–  Headache
–  Diarrhea
–  Rash
–  Fatigue
–  Others

History of this class of medications

Burimamide was first developed – but it was insufficiently potent for oral administration.

Metiamide was later developed and it was found to be mostly effective – but it had side effects of Nephrotoxicity and Agranulocytosis which did not allow for production.

Cimetidine was the first histamine H₂-receptor antagonist that was safe enough for use.

The later members of the class were developed after Cimetidine.

Ranitidine was developed in competition with Cimetidine – first introduced in 1981.

It became the world’s biggest-selling prescription in 1988.