Use Telfast 180mg for Relief of the Symptoms of Hayfever Allergies: Sneezing; Runny and Itchy Nose; Itchy and Watery Eyes; Itchy Throat. Relief of the Symptoms of Itchy Skin Rash / Hives (Urticaria): Itchy Skin Rash; Itch caused by Hives; Swelling related to Allergy; Swelling related to HivesTelfast contains an active ingredient called fexofenadine hydrochloride. It is one of a group of medicines called antihistamines. Antihistamines help reduce allergic symptoms by preventing the effects of a substance called histamine, which your body produces when exposed to certain substances. Telfast is a non-sedating antihistamine which means it has been shown to not cause drowsiness.