Methadone

Definition

Methadone is a powerful narcotic drug in the same class as heroin. This class is known as the opioids.

Purpose

Methadone, formerly known as dolophine, is a psycho-active drug, meaning that it affects the mind or behavior. It belongs to the class of opioids, drugs that share some of the analgesic properties, and mimic the action of some of the body's naturally occurring chemicals called peptides, such as endorphins and enkephalines.

Methadone is used to relieve chronic pain in cancer patients and as a maintenance drug to control withdrawal symptoms in people undergoing treatment for opiate addiction.

In opiate addiction treatment, methadone blocks the opioid receptors of the brain that bind opiates such as heroin. The blocking of these receptors leads to two major effects:

• because these chemical receptors remain blocked by methadone for up to 24 hours, even if a person addicted to heroin takes heroin after the administration of methadone, this person is not likely to feel the same effects of the heroin as he or she previously felt;
• because the action of methadone is associated with slower and less intense withdrawal symptoms than those of heroin, the patient can experience milder opiate effects while the addiction is being treated and avoid the unpleasant withdrawal symptoms associated with heroin.

Methadone has also been shown to reduce cravings for heroin while not altering a person's mood.

Precautions

Methadone magnifies the effects of alcohol and other central nervous system depressants, such as antihistamines, cold medicines, sedatives, tranquilizers, other prescription and over-the-counter (OTC) pain medications, barbiturates, seizure medications, muscle relaxants, and certain anesthetics including some dental anesthetics. Alcohol and other central nervous system depressants should not be taken or consumed while methadone is being taken.

Methadone is a powerful narcotic. It can cause some people to feel drowsy, dizzy, or light-headed. People taking methadone should not drive a car or operate machinery.

Intentional or accidental overdose of methadone can lead to unconsciousness, coma, or death. The signs of methadone overdose include confusion, difficulty speaking, seizures, severe nervousness or restlessness, severe dizziness, severe drowsiness, and/or slow or troubled breathing. These symptoms are increased by alcohol or other central nervous system (CNS) depressants. Anyone who feels that he or she, or someone else, may have overdosed on methadone, or a combination of methadone and other central nervous system depressants, should seek emergency medical attention for that person at once.

Description

A typical adult dosage for methadone is 5-20 mg as an oral solution, 2.5-10 mg as an oral tablet or injection, every four to eight hours as necessary for pain. When used for detoxification, methadone is initially given in a dose of 15-100 mg per day as an oral solution. This dose is then decreased until the patient no longer requires the medication. The injection form of methadone is only used for detoxification in patients who are unable to take the medication by mouth.

Preparation

No preparation is generally necessary prior to the intake of methadone as a pain reliever. In cases of maintenance treatments, it is important to be sure that the patient is not currently intoxicated by alcohol, heroin, other opioids, or taking other central nervous system depressants.

Aftercare

Patients receiving methadone should be monitored for adverse reactions to this drug, and/or possible accidental overdose.

Risks

Methadone can interfere with or exacerbate certain medical conditions. For these reasons, it is important that the prescribing physician be informed of any current case, or history of:

• alcohol abuse
• brain disease or head injury
• colitis
• drug dependency, particularly of narcotics
• emotional problems
• emphysema, asthma, or other chronic lung disease
• enlarged prostate
• gallstones or gallbladder disease
• heart disease
• kidney disease
• liver disease
• problems with urination
• seizures
• underactive thyroid

Side effects

The most common side effects of methadone include:

• constipation
• dizziness

• drowsiness
• itching
• nausea
• urine retention
• vomiting

Less common side effects of methadone include:

• abnormally fast or slow heartbeat
• blurred or double vision
• cold, clammy skin
• depression or other mood changes
• dry mouth
• fainting
• hallucinations
• hives
• loss of appetite
• nightmares or unusual dreams
• pinpoint pupils of the eyes
• redness or flushing of the face
• restlessness
• rigid muscles
• ringing or buzzing in the ears
• seizure
• severe drowsiness
• skin reaction at the site of injection
• stomach cramps or pain
• sweating
• trouble sleeping (insomnia)
• yellowing of the skin or whites of the eyes

Normal results

Normal results after the administration of methadone to treat chronic pain is the alleviation of that patient's pain, at least to the point where the pain is bearable.

Normal results of methadone treatment to control heroin addiction, is that the patient reduces heroin intake almost immediately upon starting methadone treatments, followed by complete abstinence, usually within two weeks after starting treatment.

KEY TERMS

Analgesic— Any agent that relieves pain.

Central nervous system (CNS) depressant— Any drug that tends to reduce the activity of the central nervous system. The major drug categories included in this classification are: alcohol, anesthetics, anti-anxiety medications, antihistamines, antipsychotics, hypnotics, narcotics, sedatives, and tranquilizers.

Endorphins— Any of several opiate peptides naturally produced in the brain that bind to certain neuron receptors and have the effect of relieving pain.

Enkephalines— Peptide produced by the body that have analgesic properties.

Morphine— Morphine is the naturally occurring opioid in the opium poppy, Papaver somniferum. It is a powerful narcotic analgesic, and its primary clinical use is in the management of moderately severe to severe pain. After heroin, morphine has the greatest potential for addiction of all narcotic analgesics.

Narcotic— Any drug that produces insensibility or stupor and/or generally causes effects similar to those caused by morphine.

Opiate— Any narcotic analgesic derived from a natural source, such as morphine from the opium poppy.

Opioid receptors— Receptors located in the brain and various organs that bind opiates or opioid substances.

Opioids— One of the major classes of semi or fully synthetic psycho-active drugs that includes methadone.

Psychoactive drugs— Any drug that affects the mind or behavior. There are five main classes of psychoactive drugs: opiates and opioids (e.g. heroin and methadone); stimulants (e.g. cocaine, nicotine), depressants (e.g. tranquilizers, antipsychotics, alcohol), hallucinogens (e.g. LSD), and marijuana and hashish.

Receptor— A molecular structure on the surface that selectively binds a specific substance resulting in a specific physiological effect.

Resources

PERIODICALS

Sadovsky, Richard. "Methadone Maintenance Therapy." American Family Physician July 15, 2000.

ORGANIZATIONS

National Alliance of Methadone Advocates (NAMA). 435 Second Avenue, New York, NY, 10010. (212) 595-6262. 〈http://www.methadone.org/〉.

National Clearinghouse for Alcohol and Drug Information. 11426-28 Rockville Pike, Suite 200, Rockville, MD 20852. (800) 729-6686. 〈http://www.health.org/〉.

Methadone

Definition

Methadone is classified as an opioid (an analgesic that is used for severe pain). In the United States, methadone is also known as dolophine, methenex and methadose.

Purpose

Methadone is used in the long-term maintenance treatment of narcotic addiction . Both heroin and methadone are opioids; as such, methadone and heroin bind to the same places in the brain . Methadone, however, is the opioid of choice for the treatment of narcotic addiction since it is longer lasting and patients don't experience the "high" associated with the drug of abuse. In opioid maintenance therapy, a person addicted to heroin receives methadone instead of heroin. Essentially, the person is switched from an opioid that gives a "high" to an opioid that does not. The dose of methadone may then be decreased over time so that the person can overcome his or her opioid addiction without experiencing withdrawal symptoms, or, after a person has received methadone for a period of time, he or she may choose to go through detoxification with clonidine . In the United States, methadone treatment is associated with a significant reduction in predatory crime, improvement in socially acceptable behavior, and psychological well-being.

Methadone may also be prescribed for pain relief, but in these cases, the physician must note this use on the prescription.

Description

Methadone has been used successfully to treat narcotic addiction for over twenty years in the United States. Methadone is the only FDA-approved agent in its class for the maintenance treatment of narcotic addiction.

Methadone for maintenance treatment is dispensed in methadone clinics. The program needs to be registered with the Drug Enforcement Agency. For admission to methadone treatment in clinical programs, federal standards mandate a minimum of one year of opiate addiction as well as current evidence of addiction. Pregnant, opiate-addicted females can be admitted with less than a one-year history and AIDS patients are routinely accepted. New patients must report daily, take medication under observation, and participate in recommended psychosocial treatments.

Some studies have shown that over 50% of patients in methadone clinics do not abuse drugs in the first month of treatment. After ten months, however, the success rate drops to approximately 20%. Moreover, major depression is a powerful predictor of relapse in methadone treatment. If the patient has dual addictions (alcoholism along with the heroin addiction, for example), management of the other addiction increases the success rate of the methadone therapy. Proper psychiatric and psychological treatment can considerably improve methadone treatment outcome.

In the cases of pregnant women who are addicted to heroin, detoxification (discontinuing the opioid altogether) is associated with a high rate of spontaneous abortions in the first trimester and premature delivery in the third trimester. Therefore, pregnant women can be in methadone maintenance programs if they are at risk of returning to drug dependence. These women should receive the lowest effective dose, receive appropriate prenatal care, and be warned about risks of returning to drug abuse, as well as the dangers associated with withdrawal effects of methadone. Methadone is associated with lower birth weights and smaller head circumference, but it has never been shown that this has any impact on the infants' further development.

Methadone is available in 5-, 10-, and 40-mg tablets and a solution.

Recommended dosage

The initial dose of methadone is 40 mg daily administered in single or divided doses. After achieving initial dosing of about 40 mg daily, the dose should be increased since there is evidence that the relapse rate is significantly lower in patients on 80-100 mg daily rather than 40-50 mg daily. The stabilization to maintenance dosing requires one to three months.

The minimum effective dose is 60 mg daily taken at once or in divided doses. Patients on lower maintenance doses have recently been studied and have shown shorter treatment retention and have continued heroin use. If patients are stable on methadone for six months or longer, their methadone dose should not be increased by 33% or over, as this sudden increase in dose is associated with an increase in craving for the drugs that were previously abused. Some heroin patients need to be on doses up to 180 mg daily to provide adequate maintenance and to prevent relapse.

Precautions

Methadone should not be used in patients who have had hypersensitivity to methadone. Patients who experience an allergic reaction to other opioids, which may include a generalized rash or shortness of breath, such as morphine, hydromorphone, oxymorphone, or codeine may try methadone. They are less likely to develop the same reaction since methadone has a different chemical structure. Methadone should be administered carefully in patients with pre-existing respiratory problems, history of bowel obstruction, glaucoma, renal problems, and hyperthyroidism.

As stated, pregnant women can be in methadone maintenance programs if they are at risk of returning to drug dependence. Methadone is associated with smaller birth weights and smaller head circumference.

Side effects

Most adverse effects of methadone are mild and seen only in the beginning of therapy. Initially, patients may develop sedation and analgesia. It takes about four to six weeks for tolerance to these effects to develop. Tolerance to constipation and sweating may take longer to develop.

A few patients who are on larger doses of methadone may experience respiratory problems. These patients also may experience unwanted cardiac effects.

A small number of patients report a decrease in libido, impotence, and premature, delayed, or failed ejaculation. There are a few reports of occasional menstrual irregularities in female patients on methadone.

Interactions

Life-threatening interactions with other drugs have not been identified. One of the initial side effects of methadone could include dizziness and sedation, and these effects are worsened if the patient is also taking other narcotics, benzodiazepines, or is consuming alcohol.

Monoamine oxidase inhibitors (MAOIs), such as Parnate (tranylcypromine ) and Nardil (phenelzine ), should be avoided by people taking methadone. Medications such as naltrexone and naloxone should never be used concurrently with methadone. People must stop taking methadone for seven to 10 days before starting naltrexone or naloxone.

See also Alcohol and related disorders; Disease concept of chemical dependency; Opioids and related disorders

Resources

BOOKS

Albers, Lawrence J., M.D., Rhoda K. Hahn, M.D., and Christopher Reist, M.D. Handbook of Psychiatric Drugs. 2001–2002. Laguna Hills, CA: Current Clinical Strategies Publishing, 2001.

Kay, Jerald. Psychiatry: Behavioral Science and Clinical Essentials. Philadelphia: W. B. Saunders Company, 2000.

PERIODICALS

Curran, Valarie H. "Additional Methadone Increases Craving for Heroin: A Double-Blind, Placebo-Controlled Study of Chronic Opiate Users Receiving Methadone Substitution Treatment." Addiction 94 (1999):665-74.

Strain, Eric. "Moderate-vs High-Dose Methadone in the Treatment of Opioid Dependence." Journal of the American Medical Association 281 (1999):1000-5.

Ajna Hamidovic, Pharm.D.

methadone , synthetic narcotic similar in effect to morphine . 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 heroin or morphine from interacting with receptors for natural painkillers called endorphins , 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 abuse .

Bibliography: 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.

Methadone

Methadone is used as a substitute for heroin and morphine to treat opiate addiction. To understand what methadone does, it is first necessary to understand how opiates act on the body.

Heroin and morphine are opiates. They are both derived from opium, a product of the poppy plant. These drugs interact with the opiate receptors in the brain. The reaction of opiates in the brain causes sedation, analgesia (an inability to feel pain), and a euphoric (very happy), "high" sensation. It is because of these effects that opiates are considered addictive and are frequently abused.

Methadone is similar to morphine and opium in that it produces the same effects. The effects of methadone on the body last longer, however, than with opiates. It is the long-lasting effect of morphine that has made it a good treatment for opiate addiction.

In addition to having longer-lasting effects, methadone's withdrawal symptoms are much less severe than with opiates. Methadone also acts as a blocker in the brain so that addicts are less likely to go back to heroin because it will not give them the usual high.

Once a person is addicted to methadone, the standard treatment is to slowly wean them off the drug. This deliberate withdrawal is made easier because of methadone's less-severe withdrawal symptoms.

meth·a·done / ˈme[unvoicedth]əˌdōn/ • n. a synthetic analgesic drug that is similar to morphine in its effects but longer acting, used as a substitute drug in the treatment of morphine and heroin addiction.

methadone (meth-ă-dohn) n. a potent opioid (see opiate) administered by mouth or injection to relieve severe pain, as a linctus to suppress coughs, and to treat heroin (diamorphine) dependence. Trade names: Methadose, Physeptone, Synastone.

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