In managing acute anaphylactic reactions during dental procedures, the first-line treatment is epinephrine.

- Epinephrine acts rapidly to counteract the life-threatening symptoms of anaphylaxis by vasoconstriction, bronchodilation, and increasing cardiac output.
- It reverses airway obstruction, hypotension, and reduces edema, making it essential for immediate administration at the onset of anaphylaxis.

- While medications such as diphenhydramine, hydrocortisone, and albuterol can be helpful as adjunctive therapies, they do not address the primary pathophysiology of anaphylaxis as quickly or effectively as epinephrine.
- Diphenhydramine, an antihistamine, can alleviate hives and itching but has no role in managing airway compromise or shock.
- Hydrocortisone is useful for preventing biphasic or prolonged reactions but has a delayed onset of action.
- Albuterol can help treat bronchospasm but is secondary to the systemic effects needed in anaphylaxis.

Key Points:
- Epinephrine is the immediate and primary intervention in acute anaphylaxis.
- It acts by rapid vasoconstriction and bronchodilation.
- Adjunctive therapies such as antihistamines, corticosteroids, and bronchodilators are supportive but not first-line.
- Delay in epinephrine administration can result in progression to severe or fatal anaphylaxis.

Reference: Dental Management of the Medically Compromised Patient, 9th Edition, Chapter 12: Allergic and Anaphylactic Reactions, Page 345-350