Short acting anti-histamine is:

Ans: B (Promethazine) Ref: Goodman & Gilman s The Pharmacological Basis of Therapeutics, 12th ed, 2011, Pg 921-922.Explanation:Hydroxyzine, is a long acting first generation antihistamine used in the treatment of skin allergies. It acts for a duration of 6-24 hrs.Cetirizine a second generation antihistamine acts for 12-24 hrs.Acrivastine belongs to second generation antihistamine and acts for a duration of 6-8 hrs.Promethazine, a first generation antihistamine acts for a duration of 4-6 hrs.Among the first generation antihistamines longer acting drugs include doxepin (6-24 hrs), chlorpheniramine (24 hrs) and meclizine (12-24 hrs ). Of the 2nd generation antihistamines longer acting drugs are cetirizine (12-24 hrs). levocetirizine (12-24 hrs), azelastine (12-24 hrs). loratadine (24 hrs). desloratadine (24 hrs). ebastine (24 hrs), mizolastine (24 hrs), and fexofenadine (12-24 hrs).