In a randomized, double-blind, placebo-controlled study of 60 children aged 8-12 years with ADHD treated with two doses of methylphenidate (MPH), 0.25 and 0.5 mg/kg, and placebo, a linear improvement was obtained at both doses in alertness and focused and sustained attention. No significant improvement occurred for divided attention. Intensity-dimension functions are best influenced by higher doses, executive functions by moderate doses, and selective-dimension functions by variable doses. Responders defined by improved behavior did not differ from nonresponders. [1]

COMMENT. Multiple indices of efficacy should be monitored during treatment of ADHD, and the dosage of MPH selected according to the targeted area, inattention or hyperactivity-impulsivity. The clinical practice of determining response to stimulant therapy from parent or teacher rating may not be sufficient, and measures of several components of attention (sustained, focused, divided, stop-signal paradigm) should be considered when practical and available.

Antihistamine side-effects in children with allergic rhinitis. Antihistamines are frequently taken by children with ADHD and are sometimes considered to aggravate the symptoms. Cetrizine 10 mg, a second-generation antihistamine, increased P300 latency and had a sedative effect without a significant change in subjective somnolence, as measured by a visual analog scale [2]. Repeated dosing may be found to adversely affect attention, and antihistamines should be considered a potential risk factor for impaired learning.