Abstract

Oral antihistamines are used to relieve symptoms in allergic rhinitis, conjunctivitis, urticaria and eczema. Traditional H₁ receptor antagonists have sedative, and in some cases anticholinergic, side effects. A significant advance has been the development of more specific H₁ antagonists in which these other properties are greatly reduced. Terfenadine and astemizole were the first;¹ acrivastine (Semprex - Wellcome), cetirizine (Zirtek - A&H) and loratadine (Clarityn - Schering Plough) are three newer ones. Are they better than terfenadine and astemizole?