You can use regular Claritin or Zyrtec...but honestly, OTC meds almost never help w/ dog allergies. With bad allergies, you really need something like Atopica or Apoquel, or Temaril-P, or steroids.
I can email you a dosing sheet from my Vet Derm if needed.
Read this:
http://www.yorkietalk.com/forums/die...tart-here.html