How does claritin (loratadine) help my allergies?

Blocking histamine: Claritin (loratadine) is one of a group of drugs called antihistamines. These block the natural chemical histamine from binding to its receptors which then trigger your body into having an allergic reaction. So, basically, you have histamine in your system which increases when you are exposed to something you are allergic to. Claritin (loratadine) and others block that histamine from hurting you.

Reduce symptoms: Histamine produces the itching, eye and nasal swelling induced by allergic triggers. Claritin (loratadine, generic name) and other antihistamines block the action of histamine.