Final answer:
The immediate intervention for a patient experiencing an anaphylactic reaction is to administer epinephrine.
Step-by-step explanation:
The immediate intervention for a patient experiencing an anaphylactic reaction is to administer epinephrine. Anaphylaxis is a severe allergic reaction that can be life-threatening, characterized by a drop in blood pressure, changes in heart rate, shortness of breath, and swelling of the tongue and throat. Epinephrine injection helps counteract these effects by constricting blood vessels, relaxing smooth muscles in the lungs, modulating heart rate, and reducing swelling. It is important for individuals with known severe allergies to carry an epinephrine auto-injector for self-administration in case of exposure to an allergen.