Which of the following regimens of medication for treating anaphylaxis is in the MOST appropriate order? Oxygen, diphenhydramine, methylprednisolone, epinephrine. Oxygen, epinephrine, methylprednisolone, diphenhydramine. Oxygen, epinephrine, diphenhydramine, methylprednisolone. Oxygen, methylprednisolone, diphenhydramine, epinephrine.