Attention deficit hyperactivity disorder management
There are two major medications derived from methylphenidate's isomers: a racemic mixture of half d-threo-methylphenidate and half l-threo-methylphenidate called methylphenidate (Ritalin, Concerta), and an enantiopure formulation containing just d-threo-methylphenidate called dexmethylphenidate (Focalin).
Medifoxamine
Medifoxamine has been found to act preferentially as a relatively weak dopamine reuptake inhibitor, but also as an even weaker serotonin reuptake inhibitor (IC = 1,500 nM) and as a weak antagonist of the 5-HT and 5-HT receptors (IC = 950 and 980, respectively; notably greater affinity relative to amitriptyline and imipramine). It is known to produce two active metabolites during first-pass metabolism in the liver, CRE-10086 (N-methyl-2,2-diphenoxyethylamine) and CRE-10357 (N,N-dimethyl-2-hydroxyphenoxy-2-phenoxyethylamine). The IC values of CRE-10086 for serotonin transporter, 5-HT, and 5-HT binding are 450 nM, 330 nM, and 700 nM, respectively, while those of CRE-10357 are 660 nM, 1,600 nM, and 6,300  M. Medifoxamine and its metabolites lack affinity for other serotonin receptors including 5-HT, 5-HT, 5-HT, and 5-HT (>10,000 nM). As medifoxamine is metabolized extensively in the liver during first-pass metabolism, and as these metabolites have as much as 3-fold greater activity relative to medifoxamine, it is likely that they contribute significantly to the pharmacology of the parent drug.