Q. A 5-year-old male presents to the emergency department with an allergic reaction. The patient's mother reports that her son consumed a peanut butter sandwich for lunch and within minutes, started to develop symptoms of an allergic reaction including itching, hives, and wheezing. She states her son was previously healthy and has no history of similar episodes. His immunizations are up to date, and he takes no medications. On initial physical examination, significant bilateral periorbital edema is noted (see image). The patient’s blood pressure is 95/60 mm Hg, heart rate 90/min, respiratory rate 30/min, and oxygen saturation is 95 percent on room air. He is alert and oriented, and appears anxious. The patient has a persistent cough, which his mother notes is a new symptom. He is stridorous with audible inspiratory and expiratory wheezing. You immediately place him on supplemental oxygen. The patient's oxygen saturation levels begin to improve with supplemental oxygen therapy. While you are discussing treatment options with his parents, you are called back into the patient’s room. His blood pressure is now 80/50 mm Hg and his wheezing has stopped. What is the next best therapeutic step in managing this patient?