Dextroamphetamine is the active metabolite of the prodrug lisdexamfetamine (L-lysine-dextroamphetamine), available by the brand name Vyvanse (Elvanse in the European market) (lisdexamfetamine dimesylate). Dextroamphetamine is liberated from lisdexamfetamine enzymatically following contact with red blood cells. The conversion is rate-limited by the enzyme, which prevents high blood concentrations of dextroamphetamine and reduces lisdexamfetamine's drug liking and abuse potential at clinical doses. Vyvanse is marketed as once-a-day dosing as it provides a slow release of dextroamphetamine into the body. Vyvanse is available as capsules, and chewable tablets, and in seven strengths; 10 mg, 20 mg, 30 mg, 40 mg, 50 mg, 60 mg, and 70 mg. The conversion rate between lisdexamfetamine dimesylate (Vyvanse) to dextroamphetamine base is 29.5%.