Methadone May Harm the Brain, Impair Attention

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Methadone can help heroin addicts kick their habit, but prolonged use of this form of treatment may also harm the brain. New findings from the Norwegian Institute of Public Health (NIPH) show that methadone affects brain function and impairs attention in experimental animals.

Methadone is a dangerous drug

Methadone is an opiate (narcotic) that is used to prevent withdrawal symptoms in individuals who are addicted to opiate drugs, such as heroin. Anyone who takes methadone to kick such a habit must enroll in a treatment program that is sponsored by the state and federal governments, and these programs must treat patients according to specific laws.

Even though methadone has been used to treat heroin addicts for nearly half a century, little is known about its possible side effects among people who use it for a prolonged time. In a new study, this information was sought using lab animals because of ethical and logistical reasons.

A research team headed by Jannike M. Andersen at the NIPH’s Division of Forensic Toxicology and Drug Abuse treated rats with methadone for three weeks. When the investigators evaluated the rats’ attention span, they found that methadone reduced attention, not only when the rats were on methadone, but also a day after treatment, when the drug had been excreted from the body.

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According to Andersen, “the fact that the attention is impaired even after the drug was no longer present in the body suggests that methadone causes changes in brain cells.” Although the scientists are unsure what those changes are or how long they last, the finding can be helpful in learning more about how methadone affects humans.

A possibility is that long-term methadone treatment could affect intellectual abilities in people, which then could have a negative impact on the outcome of treatment. Therefore, Andersen notes “we must now follow up the results from the animal studies to see if attention problems persist and to learn more about the biological mechanisms involved.”

Methadone is a dangerous drug. According to the National Center for Health Statistics, methadone overdoses increased 500 percent between 1999 and 2005: nearly 4,000 people had a methadone-related death in 2005, compared with less than 800 in 1999. Methadone also stays in the bloodstream for up to 59 hours (compared with 4-6 for heroin) and long after pain relief has worn off, which makes people more likely to overdose.

Another danger with methadone is that it can be lethal if taken with other drugs, including alcohol. If methadone is taken with other opiates, such as Vicodin, OxyContin, or morphine, the combination can slow down metabolism, cause a deep sleep, or even death.

The study’s authors point out that their results must be followed up to see if the attention impairment continues and to uncover the biological mechanisms involved. Only then will scientists be able to determine how their findings about methadone’s impact on the brain and attention can be translated to humans.

SOURCES:
Andersen JM et al. Pharmacology Biochemistry and Behavior 2011 online
Medline Plus/National Institutes of Health

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