Recent investigations into histamine pharmacology have shown the presence of two classes of histamine receptors analogous to the two types of receptors (a and β) for adrenergic stimulation.1 These studies have resulted in the current understanding that long-known histamine effects like bronchial constriction and capillary dilation are due to stimulation of H1 histamine receptors, these effects being blocked by the classical antihistaminic agents (H1 receptor antagonists). Other actions of histamine, such as its ability to promote acid production from the gastric parietal cell, are now known to be due to stimulation of a distinct histamine receptor, which is designated as an H2 receptor.
The recent research into histamine pharmacology has resulted in the development of a series of compounds that specifically block the H2 histamine receptor.1 In fact, at the annual meeting of the American Gastroenterological Association in the spring of 1974, great excitement was generated by
Castell DO. Sense With Cimetidine. JAMA. 1978;240(6):564. doi:10.1001/jama.1978.03290060066022