Final answer:
Epinephrine is used in cardiac arrest to restart the heart and in anaphylactic shock to counteract the severe allergic reaction.
Step-by-step explanation:
In cardiac arrest, epinephrine is administered to help restart the heart and improve blood flow. Epinephrine raises blood pressure and increases the heart's contractions, which can be crucial in the event of cardiac arrest. In anaphylactic shock, epinephrine is used to counteract the severe allergic reaction. It constricts blood vessels to increase blood pressure, relaxes smooth muscles in the lungs to improve breathing, and helps to reduce swelling that may block the airways.