To compare the efficacy and time course of single morning doses of Adderall®, extended-release, and immediate-release dextroamphetamine sulfate.

Thirty-five children with attention-deficit/hyperactivity disorder, combined type, were given Adderall, immediate-release dextroamphetamine, dextroamphetamine Spansules®, and placebo in a randomized, double-blind, crossover study. Behavior ratings, locomotor activity measurements, and academic measures were obtained over a period of 8 weeks.

All three drugs exhibited robust efficacy versus placebo on nearly all measures. The effects of dextroamphetamine Spansules were less robust in the morning, particularly compared with Adderall, but they lasted 3 to 6 hours longer, depending on the measure. Although parent behavior ratings and locomotor activity showed improvements up to 12 hours after single doses of all three drugs, the number of math problems attempted and completed correctly 4 hours after dosing were only robustly increased by Spansules.

Both immediate-release amphetamines demonstrated earlier onset of effects, but dextroamphetamine Spansules showed more sustained effects that were present on a wider range of measures.