The action of ephedrine, pseudoephedrine and epinephrine on the bronchioles.

Swanson showed that just 0.01 mg. of epinephrine was as vasconstrictive as 2 mg. of ephedrine and 4 mg. of pseudoephedrine. He also showed that all three of these drugs have bronchodilator properties, but epinephrine caused marked bronchodilation at only 0.2mg.

(Thanks to Juan Weiss for this reference and its interpretation.)