Methylphenidate
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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).
| Missing image Ritalin-SR-20mg-thumb.jpg Ritalin 20mg Sustained Release tablets. | |
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| IUPAC name: | |
| CAS number 113-45-1 | ATC code ? |
| Chemical formula | C14H19NO2 |
| Molecular weight | 369.42 |
| Bioavailability [1] (http://www.mentalhealth.com/drug/p30-r03.html) | 11 to 52% (Oral) |
| Metabolism | Liver |
| Elimination half life | 2 - 4 hours |
| Excretion | Urine |
| Pregnancy category | C |
| Legal status | Schedule II USA |
| Delivery |
Ritalin: 5mg, 10mg, and 20mg tablets; |
| Indicated for: Recreational uses: Other uses:
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Contraindications:
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| Side effects:
Severe: Atypical sensations:
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Urogenital and reproductive:
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| Contents |
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. [2] (http://www.bnl.gov/bnlweb/pubaf/pr/1998/bnlpr092998.html)
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] (http://www.incb.org/pdf/e/list/green.pdf). Some people abuse MPH by crushing the tablets and snorting 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 it after going a month or more without it, it has a more pronounced effect but after approximately the first week, the dependence process ceases.
Methylphenidate is also used by some university students who do not suffer from ADHD as a stimulant to assist with coursework and examinations. [4] (http://pittsburghlive.com/x/tribune-review/trib/regional/s_265518.html) [5] (http://pages.sssnet.com/ohiobar/education-ritalinabuse-kw.html) 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.
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 [6] (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.
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 theoretically.
Although not common, Ritalin has been found by coroners to be the cause of a few deaths among children.[7] (http://ritalindeath.com/crusade.htm)
Reference
- Note 1: News article (http://www.newswise.com/articles/view/510069/)
See also
External links
- Erowid Methylphenidate Vault (http://www.erowid.org/pharms/methylphenidate/methylphenidate.shtml)
- Rhodium.ws Chemistry Section, Includes syntheses for Ritalin (http://www.rhodium.ws/chemistry/index.html)
- Information from the U.S. Surgeon General on ADHD and MPH (http://www.surgeongeneral.gov/Library/MentalHealth/chapter3/sec4.html)
- U.S. Drug Enforcement Administration statement on MPH abuse (http://edworkforce.house.gov/hearings/106th/ecyf/ritalin51600/woodworth.htm)
- Dep't of Energy 1998 Sep 29 press release on Ritalin (http://www.bnl.gov/bnlweb/pubaf/pr/1998/bnlpr092998.html)
- CBS: Kiddie Cocaine (http://www.cbsnews.com/stories/2002/01/31/health/main327150.shtml)
- Ritalindeath.com (http://ritalindeath.com/)
- Students without ADHD are using Ritalin to help them study (http://www.nsba.org/site/doc_sbn.asp?TRACKID=&VID=58&CID=1063&DID=11584)
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