Histamine and the classic antihistamines

The first steps leading to the recognition of histamine's biological activity were taken in 1907. The existence of histamine in the body was finally recognized by 1910, and many researchers were keen to establish its physiological role, especially with regard to clinical shock and hypersensitivity reactions. The Pasteur Institute succeeded in finding a drug that would act as a biochemical tool to block the actions of histamine in the body and thereby reveal more about its physiological role, but none of its compounds was potent or safe enough to use in humans. Developments over the following years were made in producing compounds safe enough for clinical application in the treatment of allergies, and variations in these early antihistamines led to other uses. The first of the ethanolamine-based antihistamines marketed in the 1940s were used as antiallergy drugs, motion sickness remedies and antiemetics. The problem of drowsiness induced by antihistamines was overcome by the 1980s with drugs such as terfenadine and acrivastine.