RESUMEN
BACKGROUND: Given the dosing limitations of methylphenidate short-acting preparations in treating ADHD, galenics with longer release of the substance were developed mainly to avoid drug intake during school hours. OBJECTIVES: This investigation was conducted to assess the efficacy and the duration of action of a new extended-release formulation of methylphenidate (Medikinet retard) as a once-daily treatment for children with attention-deficit hyperactivity disorder (ADHD). METHOD: This was a randomized, double-blind, crossover multicentre study with three treatment conditions: once-daily extended-release methylphenidate, twice-daily immediate-release methylphenidate and placebo given to 79 children (8-14 years old) with ADHD. Daily assessments in an analogue classroom setting included blind ratings of attention and deportment and a performance measure (math test) obtained 5 times over an 8-hour period. Secondary measures included an ADHD rating scale, based on DSMIV/ ICD-10 separately rated for the morning and the afternoon. RESULTS: Both active treatment conditions displayed significant time course effects and were superior to placebo in improving all efficacy measures. Once a day extended-release methylphenidate was not different from the same dose of twice daily immediate-release methylphenidate. CONCLUSIONS: These data provide support for the benefit of this novel, once-daily methylphenidate preparation in the treatment of ADHD. The longer duration of action of Medikinet Retard has the potential to simplify psychostimulant treatment, thus reducing dose diversion and eliminating the need for in-school administration.