My Mother Was Admitted To Hospital With A Fib, Dr

My mother was admitted to hospital with A Fib, Dr started her on Dialtrim and Toprol. She has broke out in a severe rash from head to toe, nothing is helping rash and itching. Benadryl, steroids, Calamine Lotion. Dr told her It is very rare to get rash from Dialtrim. From my research this is a common side effect of Dialtrim, do you think stopping the Toprol or Dialtrim would be most effective with the rash and itch