Lisdexamfetamine (L-lysine-d-amphetamine) is a prodrug of the psychostimulantd-amphetamine coupled with the essential amino acidL-lysine. Lisdexamfetamine was developed so that the psychostimulant is released and activated more slowly as the prodrug molecule is hydrolyzed—consequently cleaving off the amino acid—during the first pass through the intestines and/or the liver.
Vyvanse is the dimesylate salt of lisdexamfetamine marketed by Shire Pharmaceuticals. Vyvanse is FDA approved—in strengths up to 70 mg—for the treatment of attention-deficit hyperactivity disorder in pediatric patients ages 6–12. Not only does Shire aspire to have Vyvanse replace Adderall XR as their flagship ADHD product, they also have their marketing target set at 50% of the ADHD pharmaceuticalmarket share. Shire will be applying for FDA—as well as European—approval for the treatment of adolescents and adult patients with ADHD. Shire has stated prospects of applying Vyvanse for FDA approval for the treatment of depression.
A 25 mg strength Vyvanse capsule is molecularly equivalent to 10 mg Dexedrine Spansules (both the aforementioned pharmaceuticals are about 7.425 mg dextroamphetamine). However, this molecular equivalence is not a bioequivalence ratio; as it turns out, the AUC for the aforementioned pharmaceuticals is equivalent, however, the peak exposure of dextroamphetamine in Vyvanse is about 50% higher than Dexedrine Spansules.[1]
In human oral abuse-liability studies, 150 mg Vyvanse produced a "likeability"—euphoric effect—that was determined to be indistinguishable from 200 mg of the Schedule IV drug diethylpropion hydrochloride or 40 mg of dextroamphetamine.[2]
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