How are pharmacokinetics of epinephrine?

Epinephrine has a rapid onset but a brief duration of action (due to rapid degradation). In emergency situations, epinephrine is given intravenously for the most rapid onset of action. It may also be given subcutaneously, by inhalation, or topically. Oral administration is ineffective, because epinephrine and the other catecholamines are inactivated by intestinal enzymes. Epinephrine, like the other catecholamines, is metabolized by two enzymatic pathways: MAO, and COMT Only metabolites are excreted in the urine.