What is the best initial treatment for anaphylaxis?

The best initial treatment for anaphylaxis is administering epinephrine because it acts quickly to reverse the severe symptoms of anaphylaxis, which can include difficulty breathing, swelling, and low blood pressure. Epinephrine, a sympathomimetic agent, works by causing vasoconstriction, which helps to increase blood pressure, and bronchial dilation, which alleviates respiratory distress. The rapid onset of its action is crucial in this life-threatening situation, as it halts the progression of symptoms and stabilizes the patient.

Other treatments like antihistamines or corticosteroids may be necessary for ongoing management, but they do not provide the immediate relief that epinephrine does. Oxygen therapy can support respiratory function but does not address the underlying causes of anaphylaxis. Therefore, while these other options are important in the management of allergic reactions, they are secondary to the urgent need for epinephrine in anaphylaxis treatment.