I had been using Claritin Redi-tabs for over a decade. When I came down with bronchitis, my doctor prescribed Allegra D. At the time, it was by prescription only. I hated meds that made me drowsy and the doctor assured me it would not make me drowsy. All the other meds he prescribed for allergy in the past did not work. I've been prescribed nasal sprays which made my nose bleed (one of the side effects). This was the first time something actually worked. Now that Allegra is readily available OTC, I went out and bought it without the D. Although it does not provide 100% relief, the results are livable. I am not constantly blowing my nose or having sneezing fits. I suffer from allergy year round and I know it doesn't help that I have dogs and am allergic to their dander. So Allegra to the rescue! So far I have not had any side effects from taking Allegra--no headaches or nosebleeds that is common with the nasal sprays.