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amphetamine(ămfĕt`əmēn), any one of a group of drugs that are powerful central nervous system stimulantsstimulant,
any substance that causes an increase in activity in various parts of the nervous system or directly increases muscle activity. Cerebral, or psychic, stimulants act on the central nervous system and provide a temporary sense of alertness and well-being as well as
..... Click the link for more information. . Amphetamines have stimulating effects opposite to the effects of depressantsdepressant,
any one of various substances that diminish functional activity, usually by depressing the nervous system. Barbiturates, sedatives, alcohol, and meprobamate are all depressants. Depressants have various modes of action and effects.
..... Click the link for more information. such as alcohol, narcoticsnarcotic,
any of a number of substances that have a depressant effect on the nervous system. The chief narcotic drugs are opium, its constituents morphine and codeine, and the morphine derivative heroin.
See also drug addiction and drug abuse.
..... Click the link for more information. , and barbituratesbarbiturate
, any one of a group of drugs that act as depressants on the central nervous system. High doses depress both nerve and muscle activity and inhibit oxygen consumption in the tissues. In low doses barbiturates act as sedatives, i.e.
..... Click the link for more information. . They raise the blood pressure by causing the body to release epinephrineepinephrine
, hormone important to the body's metabolism, also known as adrenaline. Epinephrine, a catecholamine, together with norepinephrine, is secreted principally by the medulla of the adrenal gland.
..... Click the link for more information. , postpone the need for sleep, and can reverse, partially and temporarily, the effects of fatigue. Amphetamines enhance mental alertness and the ability to concentrate, and also cause wakefulness, euphoria, and talkativeness. Benzedrine is the trade name for the drug amphetamine; dextroamphetamine is marketed as Dexedrine. Methamphetamine, a potent stimulant marketed as Desoxyn, is the most rapidly acting amphetamine. They are available by prescription for limited uses; illegal sources include stolen or diverted supplies or clandestine laboratories.
Prescription amphetamines have been used for short periods of time in weight-control programs to suppress appetite and to treat narcolepsy. They were used as vasoconstrictors in inhalant therapy to shrink nasal mucous membranes in such conditions as nasal allergies and asthma; now such inhalants have been banned because of their toxicity. For unknown reasons, amphetamines have a paradoxically calming effect on some hyperactive children, but the use of these drugs to treat such children has been controversial.
Popularly known as bennies, crank, speed, pep pills, wakeups, or uppers, amphetamines are addictive and easily abused: users can become psychologically dependent on the drugs and, developing a tolerance for them, can require increasingly large doses (see drug addiction and drug abusedrug addiction and drug abuse,
chronic or habitual use of any chemical substance to alter states of body or mind for other than medically warranted purposes. Traditional definitions of addiction, with their criteria of physical dependence and withdrawal (and often an underlying
..... Click the link for more information. ). When the drugs wear off, a long period of sleep ensues, often followed by hunger and depression, which can lead to further use of amphetamines. Amphetamine addiction has been common among such diverse groups as truck drivers, students, and athletes, who have used the drugs for increased energy, alertness, or endurance. Methamphetamine, made from ephedrineephedrine
, drug derived from plants of the genus Ephedra (see Pinophyta), most commonly used to prevent mild or moderate attacks of bronchial asthma. Unlike epinephrine, to which it is chemically similar, ephedrine is slow to take effect and of mild potency and long
..... Click the link for more information. and other chemicals in clandestine laboratories in the the United States or Mexico, experienced a resurgence in use in the United States beginning the mid-1990s, and its abuse also has increased worldwide. Amphetamines are inhaled, taken orally, or injected; as with other injected drugs, needle sharing increases the risk of contracting the AIDSAIDS
or acquired immunodeficiency syndrome,
fatal disease caused by a rapidly mutating retrovirus that attacks the immune system and leaves the victim vulnerable to infections, malignancies, and neurological disorders. It was first recognized as a disease in 1981.
..... Click the link for more information. virus. One form of methamphetamine, "ice," is smoked. For law enforcement purposes in the United States, most amphetamines are grouped with such drugs as cocaine and morphine because of the similarity in their effects, medical usefulness, and high potential for abuse.
Amphetamines can produce severe systemic effects, including cardiac irregularities and gastric disturbances. Chronic use often results in insomnia, hyperactivity, irritability, and aggressive behavior. Addiction can result in psychosis or death from overexhaustion or cardiac arrest. Amphetamine-induced psychosis often mimics schizophrenia, with paranoia and hallucinations.