allergic rhinitis
"Two of us have used Zyrtec for many years because it is stronger than the other so-called non-drowsy antihistamines such as Allegra and Claritin.  

We need relief mostly for sinus itching, throbbing, pressure, and discomfort; also useful for itchy allergic skin.

This medicine will usually cause pronounced drowsiness for the first 3 days, so the best way to get used to it is: take 1/2 a pill daily for 3 days, then the whole pill daily.  Also, it may increase urination.  But as I say, it is very effective."