Amphetamine

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Amphetamine or Amfetamine (Alpha-Methyl-PHenEThylAMINE), also known as, beta-phenyl-isopropylamine, and benzedrine, is a prescription stimulant commonly used to treat Attention-deficit hyperactivity disorder (ADHD) in adults and children. It is also used to treat symptoms of traumatic brain injury and the daytime drowsiness symptoms of narcolepsy and chronic fatigue syndrome. Initially it was more popularly used to diminish the appetite and to control weight. Brand names of the drugs that contain Amphetamine include Adderall, and Dexedrine. The drug is also used illegally as a recreational club drug and as a performance enhancer. The term "Amphetamine" may also refer to the class of compounds derived from Amphetamine, often referred to as the Substituted Amphetamines.

[edit] History

Amphetamine was first synthesized in 1887 by Lazar Edeleanu at the University of Berlin. He called the compound "phenylisopropylamine". It was one of a series of compounds related to the plant derivative Ephedrine, which had been purified two years previously by Nagayoshi Nagai. No pharmacological use was found for amphetamine until 1927, when pioneer psychopharmacologist Gordon Alles resynthesized it.^[1][2] Alles was part of a group of researchers looking for an ephedrine substitute. It was then introduced in most of the world in the form of the pharmaceutical Benzedrine. This drug was used by the militaries of several nations, especially the air forces, to fight fatigue and increase alertness among servicemen. After decades of reported abuse, the FDA banned Benzedrine inhalers, and limited amphetamines to prescription use in 1959, but illegal use became common.

The related compound methamphetamine was first synthesized from ephedrine in Japan in 1893 by chemist Nagayoshi Nagai. In 1919, crystallized methamphetamine was synthesized by Akira Ogata via reduction of ephedrine using red phosphorus and iodine. The German military was notorious for their use of methamphetamine in World War Two. The German pharmaceutical Pervitin is an oral pill of 3mg which was made available in 1938, but by mid-1941 it became a controlled substance, reportedly because of the amount of time needed for a soldier to rest and recover after use. Military doctors were then given guidelines on how they should issue it.^{[citation needed]}

In 1997^[3] and 1998,^[4] researchers at Texas A&M University reported finding amphetamine and methamphetamine in the foliage of two Acacia species native to Texas, A. berlandieri and A. rigidula. Previously, both of these compounds had been thought to be human inventions.^[5]

[edit] Chemistry

Amphetamine is a chiral compound. The racemic mixture can be divided into its optical antipodes: levo- and dextro-amphetamine. Amphetamine is the parent compound of its own structural class, comprising a broad range of psychoactive derivatives, e.g., MDMA (Ecstasy) and the N-methylated form, methamphetamine. Amphetamine is a homologue of phenethylamine.

Traditionally the medical drug came in the racemic salt d, l-amphetamine sulfate (racemic amphetamine contains levo- and dextro-form in equal amounts). Today, dextroamphetamine sulphate is the predominant form of the drug used;^{[citation needed]} it consists entirely of the d-isomer. Attention disorders are often treated using Adderall or a generic equivalent, a formulation of mixed amphetamine salts that contain both d/l-amphetamine and d-amphetamine in the sulfate and saccharate forms mixed to a final ratio of 3 parts d-amphetamine to 1 part l-amphetamine.

[edit] Pharmacology

Amphetamine, both as d-amphetamine (dextroamphetamine) and l-amphetamine (or a racemic mixture of the two isomers), is believed to exert its effects by binding to the monoamine transporters and increasing extracellular levels of the biogenic amines dopamine, norepinephrine (noradrenaline) and serotonin. It is hypothesized that d-amphetamine acts primarily on the dopaminergic systems, while l-amphetamine is comparatively norepinephrinergic. The primary reinforcing and behavioral-stimulant effects of amphetamine, however, are linked to enhanced dopaminergic activity, primarily in the mesolimbic DA system.

Amphetamine and other amphetamine type stimulants principally act to release dopamine into the synaptic cleft. Amphetamine has been shown to both diffuse through the intracellular membrane and travel via the DopAmine Transporter (DAT) to increase concentrations of amphetamine in the neuronal terminal. The increased amphetamine concentration releases endogenous stores of dopamine from Vesicular Monoamine Transporters (VMATs), thereby increasing intra-neuronal concentrations of transmitter. This increase in concentration effectively reverses transport of dopamine via the (DAT) into the synapse.^[6] In addition, amphetamine binds reversibly to the dopamine transporter (DAT) and blocks the transporter's ability to clear DA from the synaptic space. Amphetamine also acts in this way with norepinephrine (noradrenaline) and to a lesser extent serotonin.

Research published in the Journal of Pharmacology And Experimental Therapeutics (2007),^[7] indicates that amphetamine binds to a group of receptors called TrAce Amine Receptors (TAAR). TAAR are a newly discovered receptor system which seems to be affected by a range of amphetamine-like substances called trace amines.

[edit] Medicinal use

Along with methylphenidate (Ritalin, Concerta, etc.), amphetamine is one of the standard treatments for ADHD. Beneficial effects for ADHD can include improved impulse control, improved concentration, decreased sensory overstimulation, and decreased irritability. These effects can be dramatic, particularly in young children. The ADHD medication Adderall is composed of four different amphetamine salts, and Adderall XR is a timed release formulation of these same salt forms.

When used within the recommended doses, side-effects like loss of appetite tend to decrease over time. However, amphetamines last longer in the body than methylphenidate (Ritalin, Concerta, etc.), and tend to have stronger side-effects on appetite and sleep.^{[citation needed]}

Amphetamines are also a standard treatment for narcolepsy as well as other sleeping disorders. They are generally effective over long periods of time without producing addiction or physical dependence.

Amphetamines are sometimes used to augment anti-depressant therapy in treatment-resistant depression.

Medical use for weight loss is still approved in some countries, but is regarded as obsolete and dangerous in others.

[edit] Effects of use

Amphetamines release stores of norepinephrine and dopamine from nerve endings by converting the respective molecular transporters into open channels. Amphetamine also releases stores of serotonin from synaptic vesicles when taken in relatively high doses. This effect is more pronounced in methamphetamine use. Like methylphenidate (Ritalin), amphetamines also prevent the monoamine transporters for dopamine and norepinephrine from recycling them (called reuptake inhibition), which leads to increased amounts of dopamine and norepinephrine in synaptic clefts.

These combined effects rapidly increase the concentrations of the respective neurotransmitters in the synaptic cleft, which promotes nerve impulse transmission in neurons that have those receptors.

[edit] Physical effects

• Short-term physiological effects vary greatly, depending on dosage used and the method in which the drug is taken. At therapeutic levels these effects could include decreased appetite, increased stamina and physical energy, increased (in some cases decreased) sexual drive/response and in some cases bruxism (teeth grinding). When the drug is abused effects could include involuntary bodily movements, hyperhidrosis, hyperactivity, jitteriness, nausea, itchy, blotchy or greasy skin, tachycardia, irregular heart rate, hypertension, and headaches. Fatigue can often follow the dose's period of effectiveness. Overdose can be treated with chlorpromazine.^[8]

• Long-term abuse or overdose effects can include tremor, restlessness, changed sleep patterns, anxiety and increase in pre-existing anxiety, poor skin condition, hyperreflexia, tachypnea, gastrointestinal narrowing, and weakened immune system. Fatigue and depression can follow the excitement stage. Erectile dysfunction, heart problems, stroke, and liver, kidney and lung damage can result from prolonged abuse. When insufflated, amphetamine can lead to a deterioration of the lining of the nostrils.

[edit] Psychological effects

• Short-term psychological effects of the drug at therapeutic levels could include alertness, euphoria, increased concentration, rapid talking, increased confidence, and increased social responsiveness. Effects of the drug when abused could include, nystagmus (eye wiggles), hallucinations, and loss of REM sleep the night after use.

• Long-term amphetamine abuse can induce psychological effects that include insomnia, mental states resembling schizophrenia, aggressiveness (not associated with schizophrenia), addiction or dependence with accompanying withdrawal symptoms, irritability, confusion, and panic. Chronic and/or extensively-continuous use can lead to amphetamine psychosis, which causes delusions and paranoia, but this is uncommon when taken as prescribed. The abuse of an amphetamine is highly addictive, and, with chronic abuse, tolerance develops very quickly. Withdrawal, although not physiologically threatening, is an unpleasant experience (including paranoia, depression, difficult breathing, dysphoria, gastric fluctuations and/or pain, and lethargia). This commonly leads chronic users to re-dose amphetamine frequently, explaining tolerance and increasing the possibility of addiction.

[edit] Addiction

Tolerance is developed rapidly in amphetamine abuse, therefore increasing the amount of the drug that is needed to satisfy the addiction.^[9] Many abusers will repeat the amphetamine cycle by taking more of the drug during the withdrawal. This leads to a very dangerous cycle and may involve the use of other drugs to get over the withdrawal process. Chronic abusers of amphetamines typically snort or resort to drug injection to experience the full effects of the drug in a faster and more intense way, with the added risks of infection, vein damage and higher risk of overdose. While continuous dosing with amphetamine causes tolerance, intermittent use can produce "reverse tolerance" or sensitization to some psychological effects.^{[10][11][12][13][14]} As a result, regular use commonly results in a quick decrease of unwanted side effects, but without an equivalent loss of its stimulant properties. Notably, the sensitization is induced more quickly, and persists far longer than withdrawal-related effects, suggesting a phenomenon more complex than a simple tolerance-induced withdrawal syndrome.

Because of the abuse of amphetamines in the U.S., most brands were discontinued by the 90's including the highly abused brand names such as Biphetamine (known as black beauties), and Preludin known on the street as Bams, which the coating was peeled and then injected. Only a few brands of amphetamines are still produced in the United States which are prescribed for narcolepsy, hyperactivity in children, or for extreme obesity.

[edit] Harm reduction approach to amphetamine use

Proponents of the harm reduction philosophy seek to minimize the harms that arise from the recreational use of amphetamines. Safer means of taking the drug—smoked, nasal, oral, and rectal—are encouraged due to the lower risk of overdose, infection, and contraction of bloodborne viruses associated with drug injection. Smoking drugs reveals their effects roughly as fast as injection, as blood directly picks up the drug at the lungs. Amphetamine, in contrast to methamphetamine, isn't smokable.

Where the strength of the drug is unknown, users are encouraged to try a small amount first to gauge the strength, to minimize the risks of overdose. For the same reason the use of two or more drugs at the one time is discouraged. Users are also discouraged from using amphetamines by themselves, as friends can assist in the event of an overdose or amphetamine psychosis.

Amphetamine users who choose to inject should always use new needles and syringes where possible, and not share these with other users. Governments that support a harm reduction approach often supply new needles and syringes on a confidential basis, as well as education on proper filtering prior to injection, safer injection techniques, and safe disposal of used injecting gear.

[edit] Legal issues

• In the United Kingdom, amphetamines were regarded as Class B drugs. The maximum penalty for unauthorised possession is five years in prison and an unlimited fine. The maximum penalty for illegal supply is fourteen years in prison and an unlimited fine. Methamphetamine has recently been reclassified to Class A, penalties for possession of which are more severe (7 years in prison and an unlimited fine).^[15]
• In the United States, amphetamine and methamphetamine are Schedule II drugs, classified as CNS (Central Nervous System) Stimulants.^[16] A Schedule II drug is classified as one that: has a high potential for abuse, has a currently-accepted medical use and is used under severe restrictions, and has a high possibility of severe psychological and physiological dependence.

Internationally, amphetamine is a Schedule II drug under the Convention on Psychotropic Substances.^[17]

[edit] Books

• Seabrook, Jeremy (1996). In the Cities of the South: scenes from a developing world. London; New York: Verso. ISBN 1-85984-986-5. 

[edit] Related pages

• Adderall
• Attention Deficit Hyperactivity Disorder
• Clandestine chemistry
• Ethylamphetamine
• Dextroamphetamine (Dexedrine)
• Methamphetamine (Desoxyn)
• Methylphenidate (Ritalin, Concerta)
• Phenethylamines
• Propylamphetamine
• Psychostimulants
• Eugeroic
  • Adrafinil
  • Modafinil

[edit] References and Notes