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).
Metapramine
Metapramine has desipramine-like effects, acting as a norepinephrine reuptake inhibitor without affecting the reuptake of serotonin or dopamine. It has also been shown to act as a low-affinity NMDA receptor antagonist. Metapramine's direct effects on serotonin, histamine, and muscarinic acetylcholine receptors have not been assayed, but uniquely among most TCAs, it has anecdotally been reported to lack anticholinergic effects.