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Dexmethylphenidate




Dexmethylphenidate
Systematic (IUPAC) name
(R,R)-(+)-Methyl 2-phenyl-2-(2-piperidyl)acetate
Identifiers
CAS number 19262-68-1
ATC code N06BA04
PubChem 4158
DrugBank APRD00657
Chemical data
Formula C14H19NO2 
Mol. mass 233.31 g/mol
Pharmacokinetic data
Bioavailability 11 – 52%
Protein binding 30%
Metabolism Liver
Half life 2 – 4 hours
Excretion Urine
Therapeutic considerations
Pregnancy cat.

C

Legal status

Controlled (S8)(AU) Schedule III(CA) Class B(UK) Schedule II(US)

Routes Oral
Dexmethylphenidate (sold commercially by Novartis as Focalin, available generically as well) is a pharmaceutical drug used to treat Attention Deficit Hyperactivity Disorder. It is very similar to Ritalin, but it only contains the d-isomer of methylphenidate. It is a stimulant that affects the central nervous system. Dexmethylphenidate has approximately a 6-hour duration of effect (the XR version spans 12 hours covering a full day), and has been demonstrated to be more effective than methylphenidate at reducing the symptoms of childhood ADHD.[1]

Dexmethylphenidate has a similar side-effect profile to Methylphenidate[2] and can be administered without regard to food intake.[3] Recently, it has become available in extended-release form, and has been shown to be as effective as d, l-methylphenidate, with flexible dosing and good tolerability.[4][5]

Additional recommended knowledge

Contents

Mode of Action

Dexmethylphenidate likely functions in the same manner as methylphenidate (Ritalin): It is a relatively mild, relatively long-lasting stimulant. Ritalin, as usually synthesized, is a racemate (consisting of two molecules with identical chemical structures but different chirality). Dexmethylphenidate consists of a single isomer, with the other (levomethylphenidate) removed. Dexmethylphenidate appears to be primarily responsible for the therapeutic activity of methylphenidate, while levomethylphenidate may (as with other inactive isomers) interfere with metabolism or cause unwanted side effects. Because of this, an individual's therapeutic dose of dexmethylphenidate will generally be half their therapeutic dose of methylphenidate.

The CAS number of enantiomerically pure dextro-methylphenidate is 19262-68-1.

Because dexmethylphenidate is a stimulant, the same concerns that apply to methylphenidate and other stimulant drugs should be considered: Reports of sudden cardiac death in children caused Canada to stop marketing Adderall XR (another stimulant used to treat ADHD) for a period in 2005. Heart problems have been reported, predominantly in young people taking ADHD stimulants, though the FDA has not concluded that the category of stimulants increase risk of cardiac problems for a person without a heart condition. Suicidal thinking has been reported in young people who are taking antidepressants at the same time they are taking an ADHD stimulant.

Not enough comparative studies on all ADHD stimulants have been conducted to know the comparative effectiveness of different drugs, although initial evidence does point to the superiority of dexmethylphenidate to methylphenidate. Genetic differences affect responses to these drugs and results will be different based on individual symptoms of ADD and ADHD. [6]

Therapeutic Use

Dexmethylphenidate is used as a treatment for ADHD, ideally in conjunction with psychological, educational, behavioral, or other forms of treatment. It is proposed that it helps ameliorate the symptoms of ADHD by making it easier for the user to concentrate, avoid distraction, and control their behavior. Also, listening skills may improve, there is a possibility it will help stop fidgeting, and maybe help to organize tasks better. Because it is a stimulant, it may also help with narcolepsy, although it is not intended for ad lib use as a way of holding off sleep in people without a disorder.

An average daily dose is around 20mg. Typically an individual's active dose of dexmethylphenidate will be half their active dose of methylphenidate.

There is a possibility of withdrawal symptoms if dexmethylphenidate use is discontinued suddenly. As with other stimulants, the withdrawal syndrome may include emotional or behavioral depression. Tapering off is recommended, under the supervision of a doctor. Addiction, which involves compulsive or harmful drug-seeking behavior, is rare but not impossible.[7]

Negative Effects

Focalin

Trouble sleeping, nausea, stomach pain, headache, nervousness, loss of appetite, or weight loss are are common side effects.

Rare but much more serious side effects: Uncontrolled muscle movements (e.g., stiffness, twitching, shaking), high fever, outbursts of words/sounds, swelling of the ankles/feet, blurred vision, mental/mood/behavior changes (e.g., agitation, aggression, mood swings, depression, hallucinations, abnormal thoughts/behavior), extreme tiredness, and severe sweating, easy bleeding/bruising, shortness of breath, fainting, chest/jaw/left arm pain, sudden vision changes, signs of infection (fever, persistent sore throat), fast/irregular/pounding heartbeat, weakness, seizures, confusion, slurred speech, and severe headaches.

Also, there is a potential for severe an allergic reaction, but it is extremely rare. Trouble breathing, itching, a rash, swelling, or severe dizziness are all signs/symptoms of this allergic reaction.

FocalinXR

FocalinXR has all the same negative effects that Focalin has; the XR also includes heartburn, dizziness, dry mouth as a more common negative effect. [8]

Usage

The Focalin XR capsules are sometimes prescribed over other extended release stimulants because the capsules can be opened and their contents mixed with applesauce or pudding to help children who cannot, or will not, swallow large capsules. This is possible due to the SODAS (Spheroidal Oral Drug Absorption System) delivery system, also used in Ritalin LA. Focalin XR come in five, ten, fifteen, and twenty milligram capsules. To determine appropriate dosage doctors first prescribe one to four 5mg capsules. An appropriate treatment plan is then based off of the patient's reaction to the initial dose. [9]

Misuse and Illegal Usage

Focalin XR is sometimes sold illegally on college campuses by other students for as little as $2 and as much as $7 per pill. Focalin increases concentration; it allows a student to study, without a break, for many hours. According to the University of Rochester, "between 4 and 25 percent of college students use or have used a prescription stimulant as a study aid". [10] .[11]

See also

References

  1. ^ Arnold, L.E., et al. (2004). "A double-blind, placebo-controlled withdrawal trial of dexmethylphenidate hydrochloride in children with attention deficit hyperactivity disorder". J Child Adolesc Psychopharmacol. 2004 Winter;14(4):542-54.
  2. ^ Keating, G.M. & Figgitt, D.P. (2002). "Dexmethylphenidate". Drugs. 2002;62(13):1899-904; discussion 1905-8.
  3. ^ Teo, S.K., et al. (2004). "A Single-Dose, Two-Way Crossover, Bioequivalence Study of Dexmethylphenidate HCl with and without Food in Healthy Subjects". J Clin Pharmacol. 2004 Feb;44(2):173-8.
  4. ^ McGough J.J., Pataki C.S., Suddath R. (2005). "Dexmethylphenidate extended-release capsules for attention deficit hyperactivity disorder". Expert Rev Neurother. 2005 Jul;5(4):437-41.
  5. ^ Silva, R., et al. (2004). "Open-Label Study of Dexmethylphenidate Hydrochloride in Children and Adolescents with Attention Deficit Hyperactivity Disorder". J Child Adolesc Psychopharmacol. 2004 Winter;14(4):555-63.
  6. ^ "Attention deficit disorder: Old questions, new answers".
  7. ^ "Oral Uses".
  8. ^ "Drug Treatments-Focalin".
  9. ^ "Focalin XR for ADHD".
  10. ^ "Prescription Stimulants"
  11. ^ "Other campuses: Some students use drugs to focus on studying"
 
This article is licensed under the GNU Free Documentation License. It uses material from the Wikipedia article "Dexmethylphenidate". A list of authors is available in Wikipedia.
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