Adrafinil (CRL-40028, Olmifon), prodrug of modafinil, is a mild central nervous system stimulant drug used to relieve excessive sleepiness and inattention, Adrafinil is believed to serve as an alpha-1 adrenoceptor agonist. IC50 value: Target: in vitro: in vivo: CRL 40028 antagonizes prazosin-induced hypothermia and hypomotility; prazosin antagonizes the anticonvulsant effect of CRL 40028 in the quaking mouse [1]. Adrafinil in rat serum was stable over three freeze-thaw cycles at ambient temperature for 6 h. The method had a lower limit of quantitation of 16.5 ng/ml, which offered high sensitivity for the determination of adrafinil in serum [2]. Aged beagle dogs were trained on either a size or intensity discrimination task 2 h following treatment with either 20 mg/kg of adrafinil or a placebo control. Treatment with adrafinil produced significant improvement in learning, as indicated by a decrease in both errors and trials to criterion. An effect of adrafinil on motivation may partially account for these findings; however, adrafinil did not significantly affect response latency. Adrafinil is believed to serve as an alpha-1 adrenoceptor agonist [3].