Which statement best describes the role of epinephrine in anaphylaxis?

Which statement best describes the role of epinephrine in anaphylaxis?

• A. It neutralizes toxins
• B. It reverses bronchospasm and improves circulation by vasoconstriction
• C. It causes sedation
• D. It suppresses the immune response

Answer: (B)

In anaphylaxis, the main danger is both airway obstruction from bronchospasm and dangerous low blood pressure from widespread vasodilation and vascular leakage. Epinephrine addresses both problems: it stimulates beta-2 receptors in the airways to cause bronchodilation, helping to open the airways and ease breathing; and it stimulates alpha-1 receptors in blood vessels to cause vasoconstriction, which raises blood pressure and reduces edema and capillary leak. This combination rapidly reverses the two most life-threatening aspects of anaphylaxis and buys time for further treatment. Epinephrine also has other beneficial effects, like dampening further mediator release from mast cells, but its primary clinical actions in this context are reversing bronchospasm and improving circulation. The other statements don’t describe epinephrine’s actions in this scenario: it does not neutralize toxins, cause sedation, or suppress the immune response.

In anaphylaxis, the main danger is both airway obstruction from bronchospasm and dangerous low blood pressure from widespread vasodilation and vascular leakage. Epinephrine addresses both problems: it stimulates beta-2 receptors in the airways to cause bronchodilation, helping to open the airways and ease breathing; and it stimulates alpha-1 receptors in blood vessels to cause vasoconstriction, which raises blood pressure and reduces edema and capillary leak. This combination rapidly reverses the two most life-threatening aspects of anaphylaxis and buys time for further treatment. Epinephrine also has other beneficial effects, like dampening further mediator release from mast cells, but its primary clinical actions in this context are reversing bronchospasm and improving circulation. The other statements don’t describe epinephrine’s actions in this scenario: it does not neutralize toxins, cause sedation, or suppress the immune response.