Final answer:
Epinephrine is used to treat anaphylaxis by countering the drop in blood pressure and relaxing bronchial smooth muscles.
Step-by-step explanation:
Epinephrine is used to treat anaphylaxis, a severe allergic reaction, by countering the drop in blood pressure and relaxing bronchial smooth muscles. It is commonly administered through auto-injectors like EpiPens®. Epinephrine constricts blood vessels to increase blood pressure, relaxes smooth muscles in the lungs to improve breathing, and reduces swelling that may block the airways.