Final answer:
The priority intervention for an anaphylactic reaction is administering epinephrine.
Step-by-step explanation:
The priority intervention when a person is experiencing an anaphylactic reaction is to administer epinephrine. Epinephrine is a medication that can quickly counteract the effects of an anaphylactic shock. It constricts blood vessels, increases blood pressure, relaxes bronchial smooth muscles, and reduces swelling in the airways. This helps to restore normal breathing and prevent further complications.