Hello I Am Taking Cefnidir And Prednisone And Began To

Hello I am taking Cefnidir and prednisone and began to have a rash. I believe it is the Cefnidir since I have never taken it before. I have taken prednisone without any problems. I was to,d to stop taking the Cefnidir and take Benadryl. I am always skeptical about taking multiple drugs at once and have been unable to sleep taking Claritin so here is my question. Can I take Allegra and prednisone and still be able to sleep tonight and not have to worry about a drug interaction?