Lisdexamfetamine
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Lisdexamfetamine
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| Systematic (IUPAC) name | |
| (S)-2,6-diamino-N-[(S)-1-phenylpropan-2-yl]hexanamide | |
| Identifiers | |
| CAS number | |
| ATC code | ? |
| PubChem | |
| Chemical data | |
| Formula | C15H25N3O |
| Mol. mass | 263.378 g/mol |
| Pharmacokinetic data | |
| Bioavailability | ? |
| Metabolism | Hepatic |
| Half life | < 1 hour (prodrug molecule) |
| Excretion | Renal: ~2% |
| Therapeutic considerations | |
| Pregnancy cat. |
C |
| Legal status | |
| Routes | Oral |
Lisdexamfetamine (L-lysine-d-amphetamine, Lisdexamphetamine) is a prodrug (brand name Vyvanse) consisting of the psychostimulant d-amphetamine coupled with the essential amino acid L-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. Essentially, this makes lisdexamfetamine an extended-release formulation of d-amphetamine; however, the release characteristics are integral to the molecule itself, rather than simply the pill construction.
Vyvanse is the dimesylate salt of lisdexamfetamine marketed by Shire Pharmaceuticals. Vyvanse is FDA approved for the treatment of attention-deficit hyperactivity disorder in pediatric patients ages 6–12, and in adults. Vyvanse pills are available in dosages of up to 70mg. 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 pharmaceutical market share. Shire will be applying for European approval for the treatment of adolescents and adult ADHD patients, and for adolescent FDA approval. Unlike Adderall, which contains roughly 75% d-amphetamine and 25% l-amphetamine, lisdexamfetamine is a single-enantiomer amphetamine formulation. Certain individuals exhibit a better clinical response to the mixed isomer preparation, thus they will likely continue to use Adderall XR or equivalent generics.
25 mg of Vyvanse capsule is molecularly equivalent to 10 mg Dexedrine Spansules (both the aforementioned pharmaceuticals are about 7.425 mg dextroamphetamine), although 20mg is the weakest dose of Vyvanse available. However, this molecular equivalence is not a bioequivalence ratio. While the AUC for the aforementioned pharmaceuticals is equivalent, the peak exposure of dextroamphetamine with Vyvanse is about 50% higher than that of dexedrine with 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]
On January 3rd, 2008, Shire Pharmaceuticals announced that the FDA approved three new dosage strengths of 20, 40, and 60 milligrams. These new dosages will supplement the 30, 50, and 70 milligram dosages that are already available.[3] On April 23rd, 2008, Vyvanse received FDA approval for the adult population.[4]
[edit] Notes and references
- ^ FDA Approval of Vyvanse - Pharmacological Reviews
- ^ VyvstdfullPILDXPI9 (Page 1)
- ^ Shire: FDA OKs new Vyvanse dosages - Boston.com
- ^ FDA Adult Approval of Vyvanse - FDA Label and Approval History
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