Lisdexamfetamine
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| Other names | (S)-2,6-diamino-N-[(S)-1-phenylpropan-2-yl]hexanamide |
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| Routes of administration | Oral |
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| Pharmacokinetic data | |
| Metabolism | Gastro-intestinal (initial); Hepatic (extensively CYP2D6) after conversion to d-amphetamine |
| Elimination half-life | < 1 hour (prodrug molecule) |
| Excretion | Renal: ~2% |
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| Chemical and physical data | |
| Formula | C15H25N3O |
| Molar mass | 263.378 g/mol g·mol−1 |
 | This article needs additional citations for verification. (September 2008) |
Lisdexamfetamine (L-lysine-D-amphetamine; sold as Vyvanse) is a psychoactive drug and stimulant prodrug of the phenethylamine and amphetamine chemical classes. Its molecular structure consists of dextroamphetamine coupled with the essential amino acid L-lysine. Lisdexamfetamine itself is inactive and acts as a prodrug to dextroamphetamine upon cleavage of the lysine portion of the molecule. It was developed for the intention of creating a longer-lasting and more difficult to abuse version of dextroamphetamine, as the requirement of conversion into dextroamphetamine in the gastrointestinal tract increases its duration and renders it ineffective upon any other ingestion routes than oral or intravenous.
Vyvanse was developed by New River Pharmaceuticals, who were bought by Shire Pharmaceuticals shortly before lisdexamfetamine began being marketed. Vyvanse is approved by the U.S. Food and Drug Administration (FDA) for the treatment of attention-deficit hyperactivity disorder in pediatric patients ages 6–12, also in adolescence and adults. Vyvanse pills are available in dosages of up to 70 mg for (12 Hours). Unlike Adderall, which contains roughly 75% dextroamphetamine and 25% levoamphetamine, lisdexamfetamine is a single-enantiomer amphetamine formula. This pure formulation may reduce side-effects, but certain individuals exhibit a better clinical response to the mixed isomer preparation, and so choose Adderall XR or equivalent generics.[2]
Dosage
A 25 mg Vyvanse capsule would be molecularly equivalent to a 10 mg Dexedrine Spansule (both the aforementioned pharmaceuticals are about 7.425 mg dextroamphetamine), although a 25 mg Vyvanse capsule is not commercially available (see dosage strengths below). However, this molecular equivalence ratio does not imply that these respective doses of Vyvanse and Dexedrine XR (Spansule) are bioequivalent--the two formulations have slightly different pharmacokinetic profiles. That is, while the area under the curve for the aforementioned pharmaceuticals is equivalent, the peak exposure (Cmax) to the active compound dextroamphetamine is about 50% higher for Vyvanse than for Dexedrine XR.[3]
On April 23, 2008, Vyvanse received FDA approval for the adult population [4]
On February 19, 2009, Health Canada approved 30 mg and 50 mg capsules of lisdexamfetamine for treatment of ADHD.[5] Vyvanse, however, is not yet available for sale in Canada as of March 2009.
Interactions
Acidic food and beverages reduce the effectiveness of amphetamines, while alkaline food and beverages increase the bio-availability of the drug. It is not known yet whether lisdexamfetamine, due to the fact that it is a amphetamine pro-drug, is subject to this interaction or other interactions that are relevant to standard amphetamines.
Abuse potential
In animal studies, lisdexamfetamine produced behavioral effects qualitatively similar to those of the CNS stimulant dextroamphetamine. In monkeys trained to self-administer cocaine, intravenous lisdexamfetamine maintained self-administration at a rate that was statistically less than that for cocaine, but greater than that of placebo.[citation needed]
Intravenous administration of 50 mg lisdexamfetamine to individuals with a history of drug abuse produced positive subjective responses on scales measuring "Drug Liking", "Euphoria", "Amphetamine Effects", and "Benzedrine Effects" that were greater than placebo but less than those produced by an equivalent dose (20 mg) of intravenous d-amphetamine.[citation needed]
Adverse effects
The chart below is for adults.
| Reaction | Occurrence with Lisdexamphetamine | Occurrence with Placebo |
|---|---|---|
| Dry Mouth | 26% | 3% |
| Decreased Appetite | 27% | 3% |
| Anorexia | 5% | 0% |
| Insomnia | 27% | 8% |
| Feeling Jittery | 4% | 0% |
| Anxiety | 6% | 0% |
The chart below is for children.
| Reaction | Occurrence with Lisdexamphetamine | Occurrence with Placebo |
|---|---|---|
| Dry Mouth | 5% | 0% |
| Decreased Appetite | 39% | 4% |
| Insomnia | 19% | 3% |
| Feeling Jittery | 4% | 0% |
| Irritability | 10% | 0% |
See also
References
- ^ "FDA-sourced list of all drugs with black box warnings (Use Download Full Results and View Query links.)". nctr-crs.fda.gov. FDA. Retrieved 22 Oct 2023.
- ^ "Vyvanse Vs. Adderall
- ^ FDA Approval of Vyvanse - Pharmacological Reviews
- ^ FDA Adult Approval of Vyvanse - FDA Label and Approval History
- ^ Health Canada Notice of Compliance - Vyvanse. February 19, 2009, retrieved on March 9, 2009.