Why are adrenergic agonists such as epinephrine given parenterally or by inhalation instead of orally?

Question

Quizplus · Accepted Answer

Adrenergic agonists like epinephrine are metabolized by the enzyme catechol-O-methyltransferase (COMT) in the intestinal tract, which significantly reduces their effectiveness when taken orally. This is why they are administered parenterally or by inhalation to ensure they reach their target tissues before being metabolized.

Why Are Adrenergic Agonists Such as Epinephrine Given Parenterally or by Inhalation