I have had very bad hayfever ever since I was little. I am also allergic to cats and dustmites. I was on Claritin....did not fully help........I was on Allegra and I still was miserable. My new allergist Dr. has me on Singulair AND Allegra-D 24 hour now. Along with Nasonex and Pataday whenever they are needed. So far, it is working GREAT!