16.01.3 Histamine H2 Receptor Antagonist

Histamine H­2 receptor antagonists have previously been discussed (Chapter 10).  An example of an H2-receptor antagonist is ranitidine.  Ranitidine is a relatively safe drug and is available over-the-counter in low doses.  As histamine acting at the H2-receptor is only one of the stimulants of acid secretion, H2-receptor antagonists are only effective against this component.  There are other stimulants of gastric secretion e.g. gastrin and acetylcholine, and H2-receptor antagonists do not inhibit this secretion whereas proton pump inhibitors do.  Thus, proton pump inhibitors are often preferred to H2-receptor antagonists in peptic acidity conditions.  H2-receptor antagonists can be used for dyspepsia, heartburn, and GERD.