Wikipedia
L-Norpseudoephedrine, or -norpseudoephedrine, also referable to as -threo-β-hydroxyamphetamine, is a psychostimulant drug of the amphetamine family. It is one of the four optical isomers of phenylpropanolamine, the other three being cathine -norpseudoephedrine), -norephedrine, and -norephedrine; as well as one of the two enantiomers of norpseudoephedrine (the other, of course, being cathine). Similarly to cathine, L-norpseudoephedrine acts as a releasing agent of norepinephrine ( EC = 30 nM) and to a lesser extent of dopamine (EC = 294 nM). Due to the 10-fold difference in its potency for inducing the release of the two neurotransmitters however, L-norpseudoephedrine could be called a modestly selective or preferential norepinephrine releasing agent, similarly to related compounds like ephedrine and pseudoephedrine.