methadone(redirected from Metadol)
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methadone(mĕth`ədōn', –dŏn'), synthetic narcoticnarcotic,
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. similar in effect to morphinemorphine,
principal derivative of opium, which is the juice in the unripe seed pods of the opium poppy, Papaver somniferum. It was first isolated from opium in 1803 by the German pharmacist F. W. A. Sertürner, who named it after Morpheus, the god of dreams.
..... Click the link for more information. . Synthesized in Germany, it came into clinical use after World War II. It is sometimes used as an analgesic and to suppress the cough reflex.
In the brains of addicts, methadone prevents heroinheroin
, opiate drug synthesized from morphine (see narcotic). Originally produced in 1874, it was thought to be not only nonaddictive but useful as a cure for respiratory illness and morphine addiction, and capable of relieving morphine withdrawal symptoms.
..... Click the link for more information. or morphine from interacting with receptors for natural painkillers called endorphinsendorphins
, neurotransmitters found in the brain that have pain-relieving properties similar to morphine. There are three major types of endorphins: beta endorpins, found primarily in the pituitary gland; and enkephalins and dynorphin, both distributed throughout the nervous
..... Click the link for more information. , blocking the effects of the addictive drugs and reducing the physical cravings. In controlled doses it creates its own effects of mild euphoria and drowsiness, but lasts much longer (one to two days) and does not create the sometimes fatal respiratory depression that opiates do. Its continued use as a heroin substitute eventually restores sexual, immune, and adrenal function. When methadone is given to a heroin addict who is later withdrawn from methadone, the addict will undergo methadone withdrawal instead of the more severe heroin withdrawal.
In the 1960s the doctors Marie Nyswander and Vincent Dole promoted methadone as a therapeutic tool to rehabilitate narcotics addicts. The drug is now in use in maintenance programs in the United States, Thailand, Sweden, and Hong Kong. It is used to wean the addict from heroin and thus break out of the self-destructive lifestyle. In most maintenance programs methadone is dispensed in oral form under supervision; simultaneous drug counseling and medical care have been shown to make treatment more effective.
Supporters point out that methadone maintenance, being oral, breaks the dangerous ritual of intravenous injection, that it is legal and eliminates the addict's need to engage in crime to pay for drugs, and that it gives addicts a chance to reevaluate their lives. Critics counter that methadone patients are still addicts and that methadone therapy does not help addicts with their personality problems. In many cases multiple drug use and a strong psychological dependence undermine the gains made. Some addicts manage to resell the methadone they receive in order to buy heroin; this and other illegal diversion have resulted in methadone joining the group of addictive drugs sold on the street.
In the late 1990s methadone abuse began to become a more serious problem, and the number of methadone overdoses (an indicator of the prevalence of abuse) jumped dramatically. The increase in methadone abuse was apparently caused by heroin and oxycodone (OxyContin; a prescription painkiller) addicts using methadone when they could not get other drugs, as well as by an increase in the number of so-called recreational drug users who were abusing methadone. In 2003 the FDA approved the use of buprenorphine as a substitute for methadone in the treatment of narcotic addicts. Buprenorphine is a narcotic that typically prevents withdrawal symptons in dependent drug abusers at lower doses but can cause withdrawal symptoms at higher doses. Buprenorphine may be combined with naloxone, which prevents a euphoric high if the drug is crushed and injected instead of taken orally. Levomethadyl acetate (LAAM), a long-acting drug that is chemically similar to methadone, is also used in maintenance treatment.
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. .
See publications of the Drugs & Crime Data Center and Clearinghouse, the Bureau of Justice Statistics Clearinghouse, and the National Clearinghouse for Alcohol and Drug Information.