• 107328  Infos

Methylphenidate



    Methylphenidate
    IUPAC name: methyl a-phenyl-2-piperidineacetate
    CAS number
    ATC code
    Chemical formula C14H19NO2
    Molecular weight 23331
    Bioavailability [1] 11 to 52% (Oral)
    Metabolism Liver
    Elimination half life 2 - 4 hours
    Excretion Urine
    Pregnancy category C
    Legal status Schedule II USA
    DeliveryRitalin: 5mg 10mg and 20mg tablets;
    Ritalin SR: 20mg tablets;
    Ritalin LA: 20mg 30mg and 40mg capsules;
    Methylin: 5mg 10mg and 20mg tablets;
    Methylin ER: 10mg and 20mg tablets;
    Metadate ER: 10mg and 20mg tablets;
    Metadate CD: 10mg 20mg and 30mg capsules;
    Concerta: 18mg 27mg 36mg 54mg and 72mg tablets;
    Rubifen: 5mg 10mg and 20mg tablets

    Indicated for:
  • attention disorder|ADD]
  • attention hyperactivity disorder|ADHD]
  • narcolepsy

  • Recreational uses:
  • Stimulant / "Speed" / "Uppers"

  • Other uses:
  • treatment-resistant depression
  • appetite suppressant
  • antidepressant augmentation

  • Contraindications:
  • Use of tricyclic antidepressants (eg desipramine) as MPH may dangerously increase their plasma concentrations leading to potential toxic reactions (mainly cardiovascular effects)
  • Use of MAO Inhibitors such as phenelzine (Nardil) or tranylcypromine (Parnate) and certain other drugs
  • MPH should not be given to patients who suffer from the following conditions: Severe Arrhythmia Hypertension or Liver damage
  • Drug-seeking behaviour
  • Pronounced agitation or nervousness
  • Side effects:Atypical sensations:
    • ?

    Cardiovascular:
    Ear nose and throat:
    • ?

    Endocrinal:
    • Appetite loss

    Eye:
    • Blurred vision
    • Pupil dilation (If snorted)

    Gastrointestinal:
    • Nausea/vomiting abdominal pain

    Hematological:
    • ?

    Musculoskeletal:
    • Muscle twitches

    Neurological:
    • Insomnia drowsiness dizziness headache

    Psychological:
    • Nervousness
    • Euphoria

    Respiratory:
    • Increased respiration rate

    Skin:
    • ?

    Urogenital and reproductive:
    • ?

    Miscellaneous:
    • ?

    Methylphenidate (MPH) is an amphetamine-like prescription stimulant commonly used to treat Attention Hyperactivity Disorder] (ADHD) in children and adults It is also one of the primary drugs used to treat symptoms of traumatic brain injury and the daytime drowsiness symptoms of narcolepsy and chronic fatigue syndrome Brand names of drugs that contain methylphenidate include Ritalin Concerta (a hi-tech timed-release capsule) Metadate Methylin Rubifen and Focalin (containing only dextro-methylphenidate rather than the usual racemic dextro- and laevo-methylphenidate mixture of other formulations)

    History

    Methylphenidate was patented in 1954 by the Ciba Pharmaceutical Company (a precursor to Novartis) and was initially prescribed as a treatment for depression chronic fatigue and narcolepsy among other ailments Beginning in the 1960s it was used to treat children with ADHD known at the time as hyperactivity or minimal brain dysfunction (MBD) Today methylphenidate is the medication most commonly prescribed to treat ADHD around the world According to most estimates more than 75 percent of methylphenidate prescriptions are written for children with boys being about four times as likely to take methylphenidate as girls Production and prescription of methylphenidate rose significantly in the 1990s especially in the United States as the ADHD diagnosis came to be better understood and more generally accepted within the medical and mental health communities
    Most brand-name Ritalin is produced in the United States although methylphenidate is also produced in Mexico and Argentina by respective contract pharmaceutical manufacturers and is marketed under the brand name "Ritalin" for Novartis In the United States various generic forms of methylphenidate are also produced by several pharmaceutical concerns (such as Methylin etc) and Ritalin is also sold in the United Kingdom Germany and other European countries (although in much lower volumes than the United States)

    Effects

    Methylphenidate is a central nervous system (CNS) stimulant It has a "calming" effect on many children who have ADHD reducing impulsive behavior and the tendency to "act out" and helps them concentrate on schoolwork and other tasks Adults who have ADHD often find that MPH increases their ability to focus on tasks and organize their lives
    The means by which methylphenidate helps people with ADHD are not well understood Some researchers have theorized that ADHD is caused by a dopamine imbalance in the brains of those affected MPH is a dopamine reuptake inhibitor which means that it increases the level of the dopamine neurotransmitter in the brain by partially blocking the transporters that remove it from the synapses [2]
    In the United States methylphenidate is classified as a Schedule II controlled substance the designation used for substances that have a recognized medical value but which have a high potential for abuse Internationally methylphenidate is a Schedule II drug under the Convention on Psychotropic Substances[3] Some people abuse MPH by crushing the tablets and snorting them the "high" resulting from the higher equivalent dose being absorbed rapidly into the bloodstream The effect of Ritalin is similar to that of cocaine or amphetamine and such abuse can lead to addiction When taken orally in prescribed doses MPH is less addictive and may not produce a "high" After taking the drug or resuming it after going a month or more without it, the effects of dependence will tend to level off after a week and again after a month
    Methylphenidate is also used by some university students as a stimulant to assist with coursework and examinations [4] [5] It is also done recreationally in combination with alcohol to counter the downing effects of excessive drinking allowing the user to stay fairly awake and social while being heavily intoxicated late into the night Users often prefer to crush and snort the pills nasally for a more intense rush rather than swallowing them

    Formulations

    Most products containing methylphenidate contain a racemic mixture of dextro-methylphenidate and laevo-methylphenidate although it is only dextro-methylphenidate which is considered to provide the pharmacologically useful effects of mental focus However with the introduction of Focalin pure dextro-methylphenidate is available - described as a fast-acting form of the drug it is absorbed more quickly by the body with a shorter time to peak concentration (and excretion) than with the heterogeneous compound
    The pharmacological profiles and relative usefulness of dextro- and laevo-methylphenidate is analogous to what is found in amphetamine where dextro-amphetamine is considered to have a more beneficial effect than laevo-amphetamine

    Criticism

    Overprescription

    Treating children with stimulant medication and methylphenidate in particular has become controversial as the number of children taking them has increased dramatically over the years Critics contend that MPH is extensively overprescribed in the United States especially among children; that the drug is used primarily to control or sedate "problem" schoolchildren so that they will not disrupt class; that it transforms healthy children into "zombies" stifling their creativity and intellectual energy; and that it can lead children into dangerous drug addictions later in life State laws have been passed to prevent school districts from requiring students to undergo any kind of treatment for ADHD as a pre-requisite for attending school And in the cases of abused and neglected children who regularly 'act out' within a classroom situation false diagnoses and subsequent medication can mask the real problems and thus prevent Child Protective Services from getting involved in what could be a serious child abuse or child neglect situation
    However criticism that methylphenidate is overprescribed may be unfounded; the incidence of ADHD is believed to be between three and five percent of the population while the number of children in America taking Ritalin is estimated at one to two percent [6] In a sense the drug could be both overprescribed and underprescribed; that is, some children taking MPH may not benefit from it, while an even greater number of children would benefit from MPH but are not taking it

    Addiction

    Recent research [7] suggests that ADHD boys who are treated with stimulants like MPH are actually less likely to abuse drugs including alcohol later in life Also the only time when the usage of the drug is known to induce zombie-like effects (known to parents and those familiar with the drug as "zombie syndrome" or "zombification") is in an overdose situation When prescribed in the correct amount MPH only creates a zombie-like effect in the first 2-4 days of use when beginning the drug or resuming it after going without it for a month and even that effect is significantly less than the effect produced in overdoses

    Long-term effects

    As long-term use of methylphenidate was relatively uncommon before the 1990s the long-term neurological effects are not well researched As documented for amphetamines the potential of methylphenidate use over many years causing permanent neurological damage to dopaminergic systems exists at least in theory For example Adriani et al (2005) [8] found plastic changes in reward related behavior in rats after they were in a drug-free state

    Effects on stature

    Some research has also looked into the role of methylphenidate in affectingstature with some studies finding slight decreases in height acceleration [9]Other studies indicate height may normalize by adolesence [10][11]

    Risk of death

    Although not common Ritalin has been found by coroners to be the cause of a few deaths among children[12]

    Potential Carcinogen

    In February 2005 researches from The University of Texas MD Anderson Cancer Center announced that a small scale study of 12 children indicated that methylphenidate may be carcinogenic In the study 12 children were given standard therapeutic doses of methylphenidate At the conclusion of the 3 month study all 12 children displayed significant treatment induced chromosomal aberrations The researches indicated that while their study was too small to derive meaningful conclusions they indicated more studies should be done as the link between chromosomal aberrations and cancer is well documented

    Reference


    See also

    • Amphetamine
    • Methamphetamine
    • Phenethylamines
    • Benzedrine
    • Psychoactive drug

    External links