p-hydroxynorephedrine p-hydroxynorephedrine p-hydroxynorephedrine (phn), or 4-hydroxynorephedrine, is the para-hydroxy analog of norephedrine and an active sympathomimetic metabolite of amphetamine in humans. when it occurs as a metabolite of amphetamine, it is produced from both p-hydroxyamphetamine and norephedrine. p-hydroxynorephedrineclinical dataother names4-hydroxynorephedrinepara-hydroxynorephedrineidentifiers iupac name 4-(2-amino-1-hydroxypropyl)phenol cas number552-85-2 ypubchem cid11099chemspider10628 yuniio6914l7189chemical and physical dataformulac9h13no2molar mass167.208 g·mol−13d model (jsmol)interactive image smiles nc(c)c(o)c1ccc(o)cc1 inchi inchi=1s/c9h13no2/c1-6(10)9(12)7-2-4-8(11)5-3-7/h2-6,9,11-12h,10h2,1h3key:jaybqrkxefdrer-uhfffaoysa-n amphetamine metabolism metabolic pathways of amphetamine in humans 4-hydroxyphenylacetone phenylacetone benzoic acid hippuric acid amphetamine norephedrine 4-hydroxyamphetamine 4-hydroxynorephedrine para-hydroxylation para-hydroxylation para-hydroxylation cyp2d6 cyp2d6 unidentified beta-hydroxylation beta-hydroxylation dbh dbh oxidativedeamination fmo3 oxidation unidentified glycineconjugation xm-ligaseglyat in humans, para-hydroxynorephedrine is a metabolite of amphetamine. the aromatic ring hydroxylation of the substituted amphetamines in this image is mediated by cyp2d6 and dopamine β-hydroxylase. notes 4-hydroxyamphetamine has been shown to be metabolized into 4-hydroxynorephedrine by dopamine beta-hydroxylase (dbh) in vitro and it is presumed to be metabolized similarly in vivo. evidence from studies that measured the effect of serum dbh concentrations on 4-hydroxyamphetamine metabolism in humans suggests that a different enzyme may mediate the conversion of 4-hydroxyamphetamine to 4-hydroxynorephedrine; however, other evidence from animal studies suggests that this reaction is catalyzed by dbh in synaptic vesicles within noradrenergic neurons in the brain.