Lisdexamfetamine

lisdexamfetamine (also known as lisdextroamphetamine, l-lysine-dextroamphetamine, or lisdexamfetamine dimesylate when under the brand names elvanse and vyvanse) is a prescription stimulant substance of the amphetamine class. lisdextroamphetamine is a prodrug for d-amphetamine (dexamphetamine, or dextroamphetamine) which is a strong central nervous system (cns) stimulant.

lisdexamfetamine is approved for the treatment of attention deficit hyperactivity disorder (adhd) and moderate to severe binge-eating disorder. this means that outside of the oral route, its effects are independent of route of administration. other routes of administration like insufflation, smoking or injection do not provide faster absorption or onset.

subjective effects are essentially identical to that of dextroamphetamine except with a slower onset and a longer duration. these include stimulation, focus enhancement, motivation enhancement, and euphoria. as with amphetamine, it is sometimes sold and used illicitly as a study drug as well as a recreational substance.

despite the marketed anti-abuse design, many users report that lisdexamfetamine is capable of producing dependence and addiction like other euphoric stimulants, particularly when it is taken above the recommended dosage. for this reason, it is highly advised to use harm reduction practices if using this substance.

history and culture

chemistry

lisdexamphetamine consists of the dextro-rotary stereoisomer of amphetamine bonded to the essential amino acid l-lysine. amphetamine is comprised of a phenethylamine core featuring a phenyl ring bound to an amino (nh₂) group through an ethyl chain with an additional methyl substitution at r_α. it can be referred to as a methyl homologue of phenethylamine as it has the same general formula, differing only in the addition of one methyl group.

pharmacology

lisdexamfetamine was developed with the goal of providing a long duration of effect that remains consistent throughout the day as well as reduced potential for abuse. the attachment of the amino acid lysine slows down the relative amount of dextroamphetamine that is released into the bloodstream. because no free dextroamphetamine is present in lisdexamfetamine capsules, dextroamphetamine does not become available through mechanical manipulation, such as crushing or simple extraction. there is, therefore, no way to speed up absorption via alternate routes of administration, such as via insufflation, vaporization, or injection, making the drug theoretically less abusable.

pharmacokinetics

as a prodrug, lisdexamfetamine is inactive in the form administered. once ingested, it is enzymatically cleaved into two parts: l-lysine, a naturally occurring essential amino acid, and d-amphetamine, a central nervous system stimulant. thus lisdexamfetamine functions as an extended release version of dexamphetamine. because d-amphetamine needs to be liberated from lysine via contact with red blood cells, effects are independent of route of administration. conversion of lisdexamfetamine into active d-amphetamine is enzymatically rate-limited, slowing down the time to achieve peak concentrations and decreasing its magnitude and dampening consequent striatal dopamine release, which is thought to be responsible for its euphoric and compulsive redosing effects.

pharmacodymanics

amphetamine is a full agonist of the trace amine-associated receptor 1 (taar1), which is a key regulator of common and trace brain monoamines such as dopamine, serotonin and noradrenaline. the agonism of this set of receptors results in the release of increased concentrations of dopamine, serotonin and noradrenaline in the synaptic cleft. this leads to cognitive and physical stimulation within the user.

d-amphetamine’s affinity for the taar1 receptor is twice that of l-amphetamine. as a result, d-amphetamine produces three to four times as much central nervous system (cns) stimulation as l-amphetamine. l-amphetamine, on the other hand, has stronger cardiovascular and peripheral effects.

conversion rate

29.7% of the weight of lisdexamfetamine dimesylate (the usual prescribed form) is dexamphetamine: 30 mg lisdexamfetamine dimesylate is equivalent to 8.9 mg of dexamfetamine,

the subjective experience will differ due to the slower, more steady release of active substance in the prodrug. an equivalent dose of dexamphetamine will have a higher peak plasma concentration and shorter duration.