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Amphetamine

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Amphetamine (alpha-methyl-phenethylamine), also known as speed, is a synthetic stimulant used to suppress the appetite, control weight, and treat disorders including narcolepsy and Attention-deficit hyperactivity disorder. It is also used recreationally and for performance enhancement (these uses are illegal in most countries). 


Due to the widespread use of amphetamines as a treatment for ADD/ADHD in the USA, Canada, and other countries, they frequently find their way onto the street and are one of the most frequently-abused drugs in high schools and colleges. 





Contents





Toxicity

Patients with acute toxicity from amphetamines may have symptoms of psychosis, disorientation, temporary symptoms associated with schizophrenia, aggression, delusions, lock-jaw, diarrhea, palpitations, arrhythmia, syncope, hyperpyrexia, and hyperreflexia progressing to convulsions and coma. Patients with chronic use of amphetamines develop a rapid tolerance to the drug and may have to increase the dose to reach the desired effect and eventually develop addiction. Patients that develop addiction show symptoms of restlessness, anxiety, depression, insomnia, and suicidal behavior. A urine drug screen can be performed to determine the presence of amphetamines. Patients may need to be hospitalized. Supportive therapy is important. Cooling blankets may be used for hyperthermia. Sedation may be obtained with lorazepam or diazepam. Haloperidol may be given for agitation and delusions. Hypertension and arrhythmias should be treated.



Chemistry

Amphetamine was first synthesized in 1887 by the Romanian Chemist Lazar Edeleanu at the University of Berlin, who called it "phenylisopropylamine". 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-form rac-amphetamine sulfate (rac = levo- and dextro-form in equal amounts). In the United States, pharmaceutical products containing solely rac-amphetamine are no longer manufactured. Today, dextroamphetamine sulphate is the predominant form of the drug used; it consists entirely of the d-isomer. Attention disorders are often treated using Adderall or generic-equivalent formulations 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.



Pharmacology


Dextroamphetamine, the eutomer of amphetamine, exhibits its mode of central action via release and reuptake inhibition of the monoamine neurotransmitters norepinephrine (NE) and dopamine (DA), but not serotonin (5-HT). Its activity at the vesicular monoamine transporter VMAT2 is of crucial importance in the release process.



Application range


Amphetamine is a synthetic drug with strong stimulant effects. In the United States, it is most commonly used for treatment of attention-deficit disorders and narcolepsy, but is also approved as a weight-loss medication in certain cases of obesity. Within the armed forces only, it is also frequently prescribed as an anti-fatigue pill for pilots and other individuals in situations requiring vigilance and alertness. Amphetamine is also used illegally to take advantage of these effects. The wanted effects stem predominantly from d-amphetamine, l-amphetamine contributes to the unwanted peripheral side effects primarily nausea after the dose loses effects.



Medicinal use



Indicated for:


Recreational uses:


Other uses:


  • Used by the US military to combat fatigue and increase wakefulness

Contraindications:


  • CNS Stimulants
  • MAOI use

Side effects:

Cardiovascular:

Ear, nose, and throat:

Eye:

Gastrointestinal:

Musculoskeletal:

  • Muscle aches/cramps

Neurological:

Respiratory:


The experimental medical use of amphetamines began in the 1920s. It was introduced in most of the world in the form of the pharmaceutical Benzedrine in the late-1920s. The drug was used by the militaries of several nations, especially the air forces, to fight fatigue and increase alertness among servicemen. After decades of reports of abuse, the FDA banned Benzedrine inhalers, and limited amphetamines to prescription use in 1959, but illegal use became common. 


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, 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. 


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, for example, the United States.



Performance-enhancing use

Amphetamines are usually not used by athletes in sports involving extreme cardiovascular efforts, as methamphetamine and amphetamine put a great deal of additional stress on the heart.


The United States Air Force uses amphetamines (Dexedrine) as stimulants for pilots, calling them "go-pills." After a mission, the Air Force issues a "no-go pill" (Ambien or Temazepam) to help the pilot sleep.


Amphetamines have been popular among some truck drivers, construction workers, and factory workers whose jobs require long or irregular shift work or automatic, repetitive tasks. It is for this reason that they are sometimes labeled a "redneck drug." They are also used by white-collar workers trying to stay alert during long hours of multitasking, and by students hoping to improve their academic performance. There has also been at least one report of the coercive administration of amphetamines to cannery workers in Thailand, in order to enhance productivity (Seabrook, 1996).


The drug was also popular in the UK during the 1960s and 70s, playing a large part in Mod culture and later used by punks to continue dancing through the night.



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. 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. 



Physiological effects




Psychological effects




Addiction

Because of the widespread availability of prescription amphetamines today, mainly in the ADD/ADHD medicines Adderall and Dexedrine, there is an increased risk of abuse and addiction among persons of all ages. Tolerance is developed rapidly in amphetamine use, therefore increasing the amount of the drug that is needed to satisfy the addiction. 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.



Legal issues


Internationally, amphetamine is a Schedule II drug under the Convention on Psychotropic Substances.



Popular culture



Books



Related pages



See also



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References and Notes











 Phenethylamines [http://encycl.opentopia.com/ edit]






























































 Stimulants - [http://encycl.opentopia.com/ edit]



Caffeine | Nicotine | Modafinil | Adrafinil | Armodafinil


 














































 





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