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).
Tricyclic antidepressant
The TCAs were used in the past in the clinical treatment of ADHD, though they are not typically used anymore, having been replaced by more effective agents with fewer side effects such as atomoxetine (Strattera, Tomoxetin) and stimulants like methylphenidate (Ritalin, Focalin, Concerta), and amphetamine (Adderall, Attentin, Dexedrine, Vyvanse). ADHD is thought to be caused by an insufficiency of dopamine and norepinephrine activity in the prefrontal cortex of the brain. Most of the TCAs inhibit the reuptake of norepinephrine, though not dopamine, and as a result, they show some efficacy in remedying the disorder. Notably, the TCAs are more effective in treating the behavioral aspects of ADHD than the cognitive deficits, as they help limit hyperactivity and impulsivity, but have little to no benefits on attention.