Methylphenidate or MPH, is an amphetamine-like prescription stimulant commonly
used to treat Attention Deficit Hyperactivity Disorder (ADHD) in children and
adults. It is also one of the primary drugs used to treat the daytime drowsiness
symptoms of narcolepsy. As of 2004 there are currently three non-generic drugs
that contain Methylphenidate: Ritalin, Concerta (a timed-release capsule), and
Focalyn (containing only dextro-methylphenidate, rather than the usual racemic
dextro- and laevo-methylphenidate mixture of other formulations).
History
Methylphenidate was patented in 1950 by the Ciba Pharmaceutical Company (later
Ciba-Geigy), 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 by a contract pharmaceutical
manufacturer 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.
[1] (http://www.bnl.gov/bnlweb/pubaf/pr/1998/bnlpr092998.html)
In the United States, methylphenidate is classified as a Schedule II narcotic,
the designation used for substances that have a recognized medical value but
which have a high potential for abuse. Some people abuse MPH by crushing the
tablets and snorting or smoking them, which produces a "high" similar to that of
cocaine or amphetamine and can lead to addiction. When taken orally in
prescribed doses, MPH is not addictive and does not produce a "high". Dependence
on the drug is present in a very small amount, and stops quickly. Whenever first
taking the drug or resuming if after going a month or more without it, it has a
more pronounced effect but after approximately the first week, the dependence
process ceases.
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 Focalyn, pure dextro-methylphenidate is
available for those who experience unwanted side effects from laevo-methylphenidate.
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
Treating children with stimulant medication, and methylphenidate in particular,
has become controversial as the number of children taking them has increased.
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.
However, the American Medical Association and the U.S. government have found
little evidence to support these contentions, and peer-reviewed studies have
produced conflicting and inconclusive results. Recent research [2] (http://www.nida.nih.gov/Infofax/ritalin.html)
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.
Researchers have found methylphenidate to be linked to a threefold increase in
chromosome abnormalities. These abnormalities can lead to an increase in the
chances of cancer and other adverse health effects1.
Although not common, Ritalin has been found by coroners to be the cause of a few
deaths among children. Retreived from
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