Levocetirizine
"I live in Central Texas where we have allergens year round. I have suffered from allergies all my life and eventually everything just stopped working, and nasal sprays made things worse. Xyzal has been amazing for me- I take it at night and have zero side effects (that I'm aware of!) 

It is TOTALLY worth trying if Claritin and Zyrtec don't work for you anymore."