Dexmethylphenidate is the dextrorotary form of methylphenidate. It is a norepinephrine-dopamine reuptake inhibitor (NDRI) and thus a psychostimulant. It is used for treatment of Attention Deficit Hyperactivity Disorder (ADHD).
The lower limit of quantification of the analytical method for d-threo-methylphenidate was 0.15, 0.15, and 0.05 ng/mL for the 54, 36 and 18 mg doses, respectively.
The upper limit of quantification of the analytical method for d-threo-methylphenidate was 30, 30, and 10 ng/mL for the 54, 36, and 18 mg doses, respectively.
Ritalin LA® and Focalin XR® (both Novartis Pharmaceutical Corporation, East Hanover, New Jersey, USA) use Spheroidal Oral Drug Absorption System (SODAS®) technology to provide 50% of the MPH dose immediately and 50% as extended release [6,7].
Focalin XR® contains only the d-MPH isomer and can, therefore, achieve similar efficacy at a lower total daily dose than the racemic MPH formulations .
Guanfacine, Dexmethylphenidate (d-MPH), and l-methylphenidate (l-MPH) levels were measured in plasma produced from blood samples collected predose and at 0.5, 1.0, 1.5, 2.0, 3.0, 4.0, 6.0, 8.0, 12, 24, 30, 48, and 72 h postdose.
Also, recent comparisons of Medikinet-R vs Concerta  and between extended-release Dexmethylphenidate vs extended-release mixed Amphetamine salts , as well as a meta-analysis of MPH vs Atomoxetine  came to similar/non-inferior efficacy, and acceptability when similar doses were given.
Using Dexmethylphenidate does allow for a lower dose to be used and increases the duration of action by 1–2 hours.
The efficacy data in adults with ADHD treated with Dexmethylphenidate is confined to one double-blinded, fixed-dose, placebo-controlled, 5 week trial20 and a 6-month, open label extension phase.
Adler et al21 demonstrated dose-related increases in weight loss with Dexmethylphenidate.
Dexmethylphenidate (Focalin®) is a more potent d-threo enantiomer of racemic methylphenidate approved for ADHD treatment with a high affinity for Dopamine transporter (DAT) and requires only half the total dose of immediate acting MPH preparations.