The common way to treat mild allergies is giving antihistaminergic drugs and/or steroids (such as fluticasone).

I understand that adrenaline can also be used, and is used, mostly for severe, emergency allergies, via Epinephrine (adrenaline) autoinjector also known as EpiPen.

From Wikipedia (Epinephrine (medication)):

It is given intravenously, by injection into a muscle, by inhalation, or by injection just under the skin.[5]

Why is adrenaline typically not prescribed as pills (tablets/capsules)?


1 Answer 1


From Furukawa, C. T., & Lodewick, M. J. (2007). β-adrenergic agonists. In Allergic Diseases (pp. 335-342). Humana Press.:

Epinephrine has both α- and β-adrenergic actions, which make it the drug of choice for the treatment of anaphylaxis. It is effective as an injection, but not orally, because epinephrine and other catecholamines are rapidly inactivated by the action of catechol O-methyltransferase (COMT), an enzyme present in the gastrointestinal wall

So, it's not effective to give orally because it breaks down in the GI tract and isn't effectively absorbed. I'd also add that it's not really an anti-allergy medicine but rather for specifically treating anaphylaxis, and it also is not great for anything besides emergencies because it has a lot of (especially cardiovascular) side effects and has a short half-life.

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