Lisdexamfetamine: Wikis

  

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Lisdexamfetamine
Systematic (IUPAC) name
N-[(1S)-1-methyl-2-phenylethyl]-L-lysinamide
Identifiers
CAS number 608137-32-2
ATC code none
PubChem 11597697
ChemSpider 9772457
Chemical data
Formula C15H25N3O 
Mol. mass 263.378 g/mol
Synonyms (S)-2,6-diamino-N-[(S)-1-phenylpropan-2-yl]hexanamide
Pharmacokinetic data
Metabolism Gastro-intestinal (initial); Hepatic (extensively CYP2D6) after conversion to d-amphetamine
Half life < 1 hour (prodrug molecule)
Excretion Renal: ~2%
Therapeutic considerations
Pregnancy cat. C
Legal status Schedule II (US)
Routes Oral
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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 the oral route.[citation needed] Intravenously administered lisdexamfetamine produced effects similar to placebo and therefore is completely ineffective.[1]

As opposed to Adderall, which contains roughly 75% dextroamphetamine and 25% levoamphetamine, lisdexamfetamine is a single-enantiomer (dextro) 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]

Contents

Dosage

70mg Vyvanse capsules

Lisdexamfetamine is available under the brand-name Vyvanse. Vyvanse comes in several different dosages (see table below), all of these Vyvanse dosages available come in the form of 30 capsules each of which containing the labeled dose to be taken once daily.[3]

Vyvanse dosage strengths available[3]
Strength Appearance Imprint (unique label)
20 milligrams Capsule with ivory colored body and cap NRP104 20 mg
30 milligrams Capsule with white colored body and orange colored cap NRP104 30 mg
40 milligrams Capsule with white colored body and cyan colored cap NRP104 40 mg
50 milligrams Capsule with white colored body and blue colored cap NRP104 50 mg
60 milligrams Capsule with aqua blue colored body and cap NRP104 60 mg
70 milligrams Capsule with blue colored body and orange colored cap NRP104 70 mg

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 base), although a 25 mg Vyvanse capsule is not commercially available.[citation needed]

However, the molecular equivalence ratio does not mean that the respective doses of Vyvanse and Dexedrine XR (Spansule) are bioequivalent because the two formulations have slightly different pharmacokinetic profiles. For example, 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.[4]

History

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. Vyvanse pills are available in dosages of up to 70 mg (for 12 Hours).[citation needed]

On April 23, 2008, Vyvanse received FDA approval for the adult population [5]

On February 19, 2009, Health Canada approved 30 mg and 50 mg capsules of lisdexamfetamine for treatment of ADHD.[6]

Interactions

Amphetamine drugs (in this section lisdexamfetamine will be referred to as amphetamine or an amphetamine) possess a variety of possible drug-drug interactions and reactions.

Decreased blood levels of amphetamine

Urinary acidifying agents

These agents increase the concentration of the ionized amphetamine molecular species resulting in an increase of urinary excretion of amphetamine.[3]

Methenamine therapy

The acidifying agents used in methenamine therapy increases the urinary excretion of amphetamine.[3]

Increased blood levels of amphetamine

Urinary alkalizing agents

These agents increase the concentration of the non-ionized amphetamine molecular species resulting in an overall decrease in the urinary excretion of amphetamine.[3]

MAO inhibitors

MAOI drugs, generally used medically as antidepressant drugs, inhibit (slow) the metabolism of amphetamines. The inhibition leads to potentiation of amphetamine's effects, resulting in the increased release of norepinephrine and other monoamines from the adrenergic nerve endings. This release of monoamines can result in a hypertensive crisis which can cause toxic neurological reactions and hyperpyrexia (unusually high increase in body temperature).[3]

Decreased effects of amphetamine

Chlorpromazine and haloperidol

Both chlorpromazine and haloperidol produce dopamine receptor antagonism, resulting in the inhibition of amphetamine's central nervous system stimulation. Either drug could be useful in treating amphetamine poisoning[3], and may also be useful for toxicity caused by other phenethylamines such as MDMA, 4-Fluoromethamphetamine, phentermine, etc.[citation needed]

Lithium carbonate

Lithium carbonate may inhibit the anorectic and stimulant effects of amphetamine.[3]

Increased effects of amphetamine

Propoxyphene overdosage

If an overdosage of propoxyphene occurs, the central stimulant effects of amphetamine are increased and lethal convulsions may occur.[3]

Decreased effects of other drugs

Adrenergic blockers

The effects of adrenergic blockers are inhibited by amphetamine drugs.[3]

Antihistamines

Amphetamines may reduce the level of sedation caused by antihistamines.[3]

Antihypertensives

It is possible for amphetamines to inhibit the blood pressure lowering effects of antihypertensive drugs.[3]

Veratrum alkaloids

Amphetamines may counteract the hypotensive effects of the veratrum alkaloids.[3]

Increased effects of other drugs

Tricyclic antidepressants

Amphetamines may enhance the activity of tricyclic antidepressants, with some tricyclic drugs there may be a significant and sustained increase in the concentration of amphetamine in the brain along with increased cardiovascular activity and effects.[3]

Meperidine

Amphetamine causes an increase of the degree of analgesia produced by meperidine.[3]

Phenobarbital

Amphetamines may slow the intestinal absorption of phenobarbital and may also produce an enhanced and synergistic anticonvulsant action.[3]

Phenytoin

Amphetamines may slow the intestinal absorption of phenytoin and may also produce an enhanced and synergistic anticonvulsant action.[3]

Medical testing interactions

Amphetamines may create a significant rise in plasma levels of corticosteroids, with the greatest elevation occurring in the evening. Amphetamine may interfere with urinary steroid testing.[3]

Misuse potential

Lisdexamfetamine has a lower potential for drug misuse than dextroamphetamine and other amphetamines[citation needed] because it must be administered orally because lisdexamfetamine itself is an inactive pro-drug[citation needed].

Lisdexamfetamine has potential for causing severe addiction, especially if used for long periods of time. Misuse of lisdexamfetamine may cause serious and potentially fatal cardiovascular abnormalities or even sudden death.[7]

Adverse effects

The side effects of lisdexamfetamine are similar to other amphetamine preparations.[3][8] Many individuals taking lisdexamfetamine will experience side effects, but for the majority the severity of the side effects is not severe. Lisdexamfetamine, like other amphetamines, can cause severe and possibly life-threatening side effects and even sudden death in sensitive individuals.[3][7]

In a clinical study for Vyvanse, 10% of patients taking lisdexamfetamine withdrew from the study due to adverse reactions compared to 1% taking placebo.[3]

Common effects

Common side effects (side effects that have average rates of presentation; usually presenting in >5% of patients) of lisdexamfetamine use include:[3][7]

Severe effects

Very infrequent but possibly severe side effects requiring immediate medical attention may be caused by lisdexamfetamine, these serious reactions include:[3][7]

See also

References








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