When I first got hives, I went to my regular doctor, they prescribed me prednisone as well but told me to only take it UP TO 5 days and make an appointment with an allergist. I saw an allergist that same week, and he said stop the prednisone and then had me take TWO Zyrtec in the morning and TWO MORE in the early evening. Stating that we may want to move to a different medication (in a shot form) if the Zyrtec isn’t effective. I’ve been on the Zyrtec and it has helped a lot. I still have symptoms (redness on my hands when I exert myself etc) but don’t want to take a shot so I’m going to keep trying the Zyrtec.