Can i take claritin (loratadine) and allegra on the same day?

Yes, but use caution: What are you taking them for is most important. Oral antihistamines can cause drowsiness although Allegra (fexofenadine) does not cross the blood brain barrier. The best treatment is to see an allergist for specific treatment. Also, choose whichever antihistamine works best and you can use this twice daily instead of one of each.