Adderall
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Image:AdderallXR-15mg.png
Adderall XR 15 mg capsule
Adderall is a pharmaceutical psychostimulant comprised of mixed amphetamine salts. The drug is used primarily to treat attention-deficit hyperactivity disorder and narcolepsy. Adderall has also been used successfully to manage severe cases of treatment-resistant depression. It is a Schedule II controlled substance, meaning that it has been deemed to have a high potential for abuse and addiction, but has accepted medical uses.
HistoryBrand name Adderall was introduced in 1996 in the form of a multi-dose, instant-release tablet that came from the original formula used in the weight management drug Obetrol. It has since become available in a generic formulation of "mixed amphetamine salts". The active ingredients of Adderall include a combination of dextroamphetamine and racemic d/l-amphetamine salts. Shire Pharmaceuticals later introduced an extended-release preparation of these ingredients in a variety of dosages, under the brand name "Adderall XR" (extended release), on which Shire retains exclusive patent rights until 2009. ChemistrySpecifically, Adderall XR is composed of the following proportions of active ingredients[1]:
These four salts are metabolized at different rates and possess diverse half lives, therefore resulting in a less dramatic onset and termination of therapeutic action; as compared to single salt amphetamine preparations. The average elimination half-life in adults for dextroamphetamine and levoamphetamine is 10 hours and 13 hours respectively. Breakdown rates are affected by many factors including urinary and stomach pH, weight, gender, other medications being taken, and age. Urinary and stomach pH levels can have the strongest effect on (d,l)-amphetamine excretion and absorption. Co-administration of acidic substances (e.g. citric acid) causes an accelerated excretion of (d,l)-amphetamine while co-administration of alkaline agents (e.g. antacids) causes a marked increase in both retention and absorption of amphetamines potentially resulting in dangerously high serum amphetamine levels. Adderall's effects are similar to other CNS stimulants of the same class and preparation (see amphetamine for details). Dosing and administrationAdderall is marketed as either an immediate-release tablet, Adderall, or an extended-release capsule, Adderall XR ("eXtended Release"). Doses for the immediate-release tablet come in 5, 7.5, 10, 12.5, 15, 20, and 30 milligram strengths. Doses for the extended-release capsule come in 5, 10, 15, 20, 25, and 30 milligram strengths. Adderall XR utilizes the Microtrol extended-release delivery system, incorporating two types of beads. The first dissolves immediately, releasing half of the medication, while the second type dissolves much more slowly releasing the remaining medication four hours later. Maximum plasma concentration is achieved in seven hours, compared to regular Adderall, which reaches maximum plasma concentration within three hours. As a result of its high bioavailability, Adderall XR's effectiveness is not altered by food absorption in the gastrointestinal tract. However, mean plasma concentration is prolonged by 2.5 hours (using a standard high-fat meal as the control). Medications that alter urinary pH will cause variations in amount and method of excretion and usage should be monitored when taken concurrently with Adderall.[1] Manufacturer's claims of instant release have been disputed. A patent application for Adderall[2] was a pharmaceutical composition patent listing a rapid immediate release oral dosage form. No claim of increased or smooth drug delivery was made. A recent double-blind, placebo-controlled crossover study, conducted among children, indicated that patients behaved similarly to other immediate release amphetamines. The authors found that sustained-release dexamphetamine (the main isomeric-amphetamine component of Adderall) had a longer duration of action, though dextro-amphetamine was less effective in the first few hours.[3] Generic equivalents/alternativesThe closest generic equivilant to Adderall is dextroamphetamine sulfate also known as Dexadrine and available in a sustained release form called Dexadrine ER. It should be noted that Adderal uses "mixed amphetamine salts" and Dexadrine is a single salt therefore Dexedrine ER is not a strict generic equivalent for Adderall XR, though it may, in terms of physiological and psychological effects, be a de facto generic alternative. The savings between Adderall XR and generic Dexedrine ER are significant: 90 dextroamphetamine extended-release capsules cost $20 at a retail pharmacy in the United States, while the equivalent 90 Adderall XR® capsules cost $270. The difference is due to the fact that Adderal is still protected under patent in the United States. Until this patent expires, generic versions of Adderal will not become available. Vyvanse is a derivative of Dexedrine, yet it behaves differently in the body (see Dextroamphetamine at "Formulations"). The manufacturer has added extra ingredients (in the case of Adderall) or created a prodrug (a precursor) of dextroamphetamine (in the case of Vyvanse) in order to patent allegedly "improved" products that are similar to Dexedrine yet cannot be produced generically for the time being. Mechanism of actionAdderall’s inclusion of levoamphetamine provides the pharmaceutical with a quicker onset and longer clinical effect compared to pharmaceuticals exclusively formulated of dextroamphetamine.[4] Although it seems that where the human brain has a preference for dextroamphetamine over levoamphetamine, it has been reported that certain children have a better clinical response to levoamphetamine.[5] Double-blind, placebo-controlled studies of dextroamphetamine in prepubertal subjects have shown significant performance increases on cognitive tasks and decreased reaction time.[6] Side effectsIn children
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