Astemizole
Astemizole (marketed under the brand name Hismanal, developmental code R43512) was a second-generation antihistamine drug that has a long duration of action. Astemizole was discovered by Janssen Pharmaceutica in 1977. It has been withdrawn from the market in most countries because of rare but potentially fatal side effects (QTc interval prolongation and related arrhythmias due to hERG channel blockade).
Antihistamine
The first generation of antihistamine drugs became available in the 1930s. This marked the beginning of medical treatment of nasal allergies. Research into these drugs led to the discovery that they were H1 antagonists and also to the development of H2 antagonists, where H1 antihistamines affected the nose and the H2 antihistamines affected the stomach. This history has led to contemporary research into drugs which are H3 receptor antagonist and which affect the Histamine H4 receptor.