Scarce data are available on methylphenidate (MPH) plasma concentrations reached after doses higher than 180 mg. The inter-and intraindividual variability in the exposure of MPH and ritalinic acid (RA) enantiomers was examined in 28 patients with ADHD and Substance Use Disorders, with MPH daily doses between 30 to 600 mg (median 160 mg). MPH and RA plasma concentrations were analysed with an enantioselective LC-MS/MS method. d-MPH plasma concentration/dose varied 25-fold between subjects but was…
