Stimulant: Wikis

  
  
  

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Ritalin Slow-Release (SR) 20 mg tablets.

Stimulants (also sometimes called psychostimulants[1]) are psychoactive drugs which induce temporary improvements in either mental or physical function or both. Examples of these kinds of effects may include enhanced alertness, wakefulness, and locomotion, among others. Due to their effects typically having an "up" quality to them, stimulants are also occasionally referred to as "uppers". Depressants or "downers", which decrease mental and/or physical function, are in stark contrast to stimulants and are considered to be their functional opposites. Stimulants are widely used throughout the world as prescription medicines and as illicit substances of recreational use or abuse.

Contents

Effects

Stimulants produce a wide variety of different kinds of effects by enhancing the activity of the central and peripheral nervous systems. Common effects, which vary depending on the substance in question, may include enhanced alertness, awareness, wakefulness, endurance, productivity, and motivation, increased arousal, locomotion, heart rate, and blood pressure, and the perception of a diminished requirement for food and sleep. Many stimulants are also capable of improving mood and relieving anxiety, and some can even induce feelings of euphoria. It should be noted, however, that many of these drugs are also capable of causing anxiety, even the ones that may paradoxically reduce it to a degree at the same time. Stimulants exert their effects through a number of different pharmacological mechanisms, the most prominent of which include facilitation of norepinephrine (noradrenaline) and/or dopamine activity (e.g., via monoamine transporter inhibition or reversal[2]), adenosine receptor antagonism, and nicotinic acetylcholine receptor agonism.

Indications

Stimulants are used both individually and clinically for therapeutic purposes in the treatment of a number of indications, including the following:

  • To counteract lethargy and fatigue throughout the day while at work or while doing other activities.
  • To reduce sleepiness and to keep the person awake when necessary, as well as to treat narcolepsy.
  • To decrease appetite and promote weight loss, as well as to treat obesity.
  • To improve concentration and focus while at work or school, especially for those with attentional disorders such as ADHD.
  • Occasionally, they are also used to treat clinical depression.

Types

Caffeine

Roasted coffee beans, the world's primary source of caffeine.

Caffeine is a compound that is found naturally in coffee, tea, and to a lesser degree, in cocoa or chocolate. It is included in many soft drinks, particularly energy drinks. Caffeine is the world's most widely used psychoactive drug and by far the most common stimulant. The vast majority (over 80%) of people in the United States consume caffeine on a daily basis. Few jurisdictions restrict its sale and use. Caffeine is also included in some medications, usually for the purpose of enhancing the effect of the primary ingredient, or reducing one of its side effects (especially drowsiness). Pure caffeine tablets are also widely available.

Nicotine

Nicotine is the active chemical constituent in tobacco, of which is available in many forms, including cigarettes, cigars, and chewing tobacco, among others. Nicotine is used widely throughout the world for its stimulating effects.

Amphetamines

A chart comparing the chemical structures of different amphetamine derivatives

Amphetamines are a group of phenylethylamine stimulants such as amphetamine and methamphetamine. Like NDRIs, amphetamine increases the levels of norepinephrine and dopamine in the brain via reuptake inhibition; however, the more important mechanism by which amphetamines cause stimulation is through the direct release of these catecholamines from storage vesicles in cells. Amphetamines are known to cause elevated mood and euphoria as well as rebound depression and anxiety.[3]

Amphetamines are sometimes prescribed therapeutically by physicians and their availability makes them prime candidates for misuse [http://www.drugabuse.gov/Testimony/7-26-Deficit Hyperactivity Disorder (ADD and ADHD). Dextrorotary methamphetamine is occasionally used in the treatment of AD(H)D that does not respond sufficiently to traditional amphetamines. On occasion, major depression is treated with amphetamines as well. Amphetamines can be used as an add-on to antidepressant therapy as well, with some success in certain populations.[citation needed]

MDMA ("Ecstasy")

Manufactured illicit tablets containing MDMA.

Methylenedioxymethamphetamine (MDMA), known by its common street name "Ecstasy", is an illicit substance that typically comes in either tablet, capsule, or powder/crystal form. MDMA is said to be a cross between an amphetamine stimulant and a psychedelic hallucinogen. Notably, MDMA is also unique and very popular for its entactogenic properties. The stimulant effects of MDMA include hypertension, anorexia, insomnia (or enhanced wakefulness), improved energy, increased arousal (users are occasionally said to get an uncontrollable urge to dance), and increased perspiration, among others.

Cocaine

Cocaine is made from the leaves of the coca shrub, which grows in the mountain regions of South American countries such as Bolivia, Colombia, and Peru. In Europe, North America, and in some part of Asia, the most common form of cocaine is a white crystalline powder. Cocaine is a stimulant but is not normally prescribed therapeutically for its stimulant properties, although it sees clinical use as a local anesthetic, particularly in ophthalmology. Most cocaine use is recreational and its abuse potential is high, and so its sale and possession are strictly controlled in most jurisdictions. Other tropane derivative drugs related to cocaine are also known such as troparil and lometopane but have not been widely sold or used recreationally.[4]

NRIs & NDRIs

These drugs inhibit the reuptake of norepinephrine and/or dopamine, resulting in increased extracellular levels and therefore enhanced neurotransmission, ultimately producing a stimulant effect. Many of these compounds are used as ADHD medications and antidepressants. The two most well known NDRIs are methylphenidate (Ritalin, Concerta) and bupropion (Wellbutrin, Zyban), and the two most well known NRIs are atomoxetine (Strattera) and reboxetine (Edronax). Many of these drugs have a considerably lower abuse potential in comparison to other stimulants like the amphetamines and cocaine.

Modafinil

Modafinil (Provigil/Alertec/Modavigil) is an analeptic drug approved by the (FDA) for the treatment of narcolepsy, shift work sleep disorder, and excessive daytime sleepiness associated with obstructive sleep apnea. Modafinil, like other stimulants, increases the release of monoamines but also elevates hypothalamic histamine levels, leading some researchers to consider Modafinil a "wakefulness promoting agent" rather than a classic amphetamine-like stimulant . Modafinil has been shown to be effective in the treatment of Attention-Deficit Hyperactivity Disorder (ADHD), depression, cocaine addiction, Parkinson's Disease, schizophrenia, shift workers' sleep disorder and disease-related fatigue.

Ampakines

Recently, there have been improvements in the area of stimulant pharmacology, producing a class of chemicals known as ampakines, or eugeroics, (good arousal). These stimulants tend to increase alertness without the peripheral (body) effects or addiction/tolerance/abuse potential of the traditional stimulants. They have minimal effect on sleep structure, and do not cause rebound hypersomnolence or "come down" effects. Ampakines such as ampalex and CX717 have been developed but are still in clinical trials and have not yet been sold commercially. Another compound with similar effects to these drugs is carphedon, which is sold as a general stimulant in Russia under the brand name Phenotropil.

Yohimbine

Yohimbine is a psychoactive drug of the tryptamine chemical class with stimulant and aphrodisiac effects.

Abuse

Abuse of central nervous system stimulants is common. Addiction to CNS stimulants can quickly lead to medical, psychiatric and psychosocial deterioration. Drug tolerance, dependence, sensitisation as well as a withdrawal syndrome can occur.[5]

Testing

The presence of stimulants in the body may be tested by a variety of procedures. Serum and urine are the common sources of testing material although saliva is sometimes used. Commonly used tests include chromatography, immunologic assay and mass spectrometry.[6]

See also

External links

References

  1. ^ "Dorlands Medical Dictionary:psychostimulant". http://www.mercksource.com/pp/us/cns/cns_hl_dorlands_split.jsp?pg=/ppdocs/us/common/dorlands/dorland/seven/000088218.htm. 
  2. ^ Riddle EL, Fleckenstein AE, Hanson GR (2005). "Role of monoamine transporters in mediating psychostimulant effects". The AAPS journal 7 (4): E847–51. doi:10.1208/aapsj070481. PMID 16594636. 
  3. ^ P Knapp. Amphetamine and addiction. Journal of Nervous and Mental Disorders. 115:406-409, 1952
  4. ^ AJ Giannini, WC Price. Contemporary drugs of abise. American Family Physician.33:207-213,1986
  5. ^ Dackis CA, Gold MS (1990). "Addictiveness of central stimulants". Adv Alcohol Subst Abuse 9 (1-2): 9–26. PMID 1974121. 
  6. ^ AJ Giannini. Drug Abuse. Los Angeles, Health Information Press,1999, pp.203-208.

Simple English

Stimulants are drugs that can increase alertness and awareness, usually for a short time only. Most stimulants have more side-effects than other drugs. Some are classified as illegal drugs, most can cause addiction. For this reason, most legal stimulants are only available on prescription. Stimnulants act on the nerves:

Most stimulants fall into one of the following groups:

Some of the substances mentioned above can be used to treat certain diseases. Some are mostly used as illegal drugs.









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