Try a different antihistimine. (with a different active ingredient) ie, lotradine is in several different allergy medications, and another drug with zyr... as part of its name is the basis for zyrtec, that particular med may not cut it for your daughter. I personally do well with lotradine (but NOT the walgreen brand as I am sadly finding out! I had the Costco's generic which does last a 24 hrs, but the Wal-itin HA, I am finding it only lasts maybe 16-20 hours before I'm in misery again. I plan to return it.) Anyway, lotradine doesnt help my husband much so he takes something else (not zyr.. not loratadine, but something else... I forgot...). I don't care for the one he takes as it makes me sleepy and dazed.
Just have to find which one works for her, by looking at the active ingredient and how it affects her. I'd stick with name brands for now until you know what is effective, then maybe switching to generic and seeing if they work the same or not. I liked one generic but NOT the other.
Also, allergy season is at a HIGH peak right now, I wonder if that "overwhelms" the medicine?
Just read some of the other answers. We moved here abt 5 yrs ago, and found a honey farm here in our town and bought a lot. My husband has honey just about everyday, and I do quite often. My son not as often (he is a BIG fan of the freezer strawberry jam I make.) It hasn't made a difference, that we can tell, with our allergies!
Sugar on the other hand... I have heard/read elsewhere that it does the opposite for your body what immunity boosters and such do - it can and does make you much more susceptible to getting sick (and yes, getting out of control too) Less sugar will NEVER hurt, ha.