Used primarily as a second-generation antihistamine, this compound was developed to treat allergic conditions such as hay fever, urticaria (hives), and other allergic skin reactions. It acts by blocking peripheral H1 receptors, which reduces the effects of histamine without crossing the blood-brain barrier significantly, thus minimizing sedation compared to first-generation antihistamines. Due to its effectiveness in relieving allergy symptoms with lower drowsiness, it was widely prescribed for seasonal allergies and chronic idiopathic urticaria. However, its use has been discontinued in many countries due to the risk of serious cardiac arrhythmias, particularly when taken with certain medications or in patients with liver impairment. It has since been replaced by safer metabolites such as fexofenadine.