Loratadine-d 4 -1 (Loratidine-d 4 -1) is deuterium labeled Loratadine. Loratadine (SCH-29851) is a selective inverse peripheral histamine H1-receptor agonist with an IC50 of >32 μM. Loratadine has anti- dengue-virus (DENV) activity. Loratadine can inhibit immunologic release of inflammatory mediators.