To the Editor Ching et al1 are commended for their careful and insightful study of stimulant dosing and titration and analysis of current practice. The commonly accepted notions of an evidence basis for describing maximal doses of stimulants are refuted.
The articles reviewed in their meta-analysis show that more than half were studies of either the osmotic-release oral system (OROS) (4 of 14 randomized clinical trials, Table 1; 18 of 38 cohort studies, Table 2; 42% overall) or transdermal delivery systems (1 of 14 randomized clinical trials and 4 of 38 cohort trials; 10% overall). These 2 products are notable for delivering less than their stated content of methylphenidate (80%-90% for Concerta-branded OROS2 and <50% for Daytrana-branded transdermal methylphenidate3). Such a broad range of bioavailability among products limits the relevance of determining appropriate dosing from the labeling.