Can used Fexofenadine together with Benadryl?

Yes. You can take them at the same time. They are both antihistamines, but Allegra is a long-acting antihistamine and Benadryl is a short-acting antihistamine. Fexofenadine is Allegra. I have been given both at the same time to treat a severe sinus infection. You may get very drowsy or run down. But you will be ok. Because of this, it is recommended that Allegra be taken in the morning on a regular schedule and Benadryl be taken at night when needed to help with sleep issues due to Allergies.