Long-term methadone treatment can affect nerve cells in brain

August 15, 2012

Long-term methadone treatment can cause changes in the brain, according to recent studies from the Norwegian Institute of Public Health. The results show that treatment may affect the nerve cells in the brain. The studies follow on from previous studies where methadone was seen to affect cognitive functioning, such as learning and memory.

Since it is difficult to perform controlled studies of patients and unethical to attempt in healthy volunteers, rats were used in the studies. Previous research has shown that methadone can affect cognitive functioning in both humans and experimental animals.

Sharp decrease in key signaling molecule

Rats were given a daily dose of methadone for three weeks. Once treatment was completed, which are central for learning and memory were removed and examined for possible neurobiological changes or damage.

In one study, on the day after the last exposure to methadone, there was a significant reduction (around 70 per cent) in the level of a signal molecule which is important in learning and memory, in both the hippocampus and in the frontal area of the brain. This reduction supports findings from a previous study (Andersen et al., 2011) where impaired attention in rats was found at the same time. At this time, methadone is no longer present in the brain. This indicates that methadone can lead to that affect after the drug has left the body, which may be cause for concern.

No effect on cell generation

The second study, a joint project with Southwestern University in Texas, investigated whether methadone affects the formation of nerve cells in the hippocampus. Previous research has shown that new nerve cells are generated in the in both adult humans and rats, and that this formation is probably important for . Furthermore, it has been shown that other such as morphine and heroin can inhibit this formation. It was therefore reasonable to assume that methadone, which is also an opiate, would have the same effect.

However, the researchers did not find any change in the generation of new nerve cells after long-term methadone treatment. If the same is true in humans, this is probably more positive for methadone patients than continuing with heroin. However, the researchers do not know what effect methadone has on nerve cells that have previously been exposed to heroin.

Large gaps in knowledge

Since the mid-1960s, methadone has been used to treat heroin addiction. This is considered to be a successful treatment but, despite extensive and prolonged use, little is known about possible side effects. There are large knowledge gaps in this field.

Our studies show that prolonged methadone treatment can affect the , and thus behaviour, but the results are not always as expected. Many more pre-clinical and clinical studies are needed to understand methadone's effect on the brain, how this can result in altered cognitive function, and, if so, how long these changes last. Knowledge of this is important - both for the individual methadone patient and the outcome of treatment.

Explore further: Methadone linked to 30 percent of painkiller overdoses

More information: Andersen JM, Klykken C, Mørland J. (2012) Long-term methadone treatment reduces phosphorylation of CaMKII in rat brain. J Pharm Pharmacol. 64(6):843-7.

Related Stories

Methadone linked to 30 percent of painkiller overdoses

July 4, 2012
The prescription drug methadone is linked to over 30 percent of painkiller overdose deaths, according to a report released by the Centers for Disease Control (CDC) and Prevention Tuesday.

Heroin addicts have higher pain sensitivity, even during treatment

April 25, 2012
(HealthDay) -- Heroin addicts often have an increased sensitivity to pain, and this sensitivity does not subside over the course of treatment with methadone or other opioids, new research finds.

Medically prescribed heroin more effective, less costly than current methadone treatment

March 12, 2012
Medically prescribed heroin is more cost-effective than methadone for treating long-term street heroin users, according to a new study by researchers at Providence Health Care and the University of British Columbia.

Recommended for you

Cancer drugs' high prices not justified by cost of development, study contends

September 12, 2017
(HealthDay)— Excusing the sky-high price tags of many new cancer treatments, pharmaceutical companies often blame high research and development (R&D) costs.

Non-psychotropic cannabinoids show promise for pain relief

September 4, 2017
Some cancers love bone. They thrive in its nutrient-rich environment while gnawing away at the very substrate that sustains them, all the while releasing inflammatory substances that cause pain—pain so severe that opioids ...

Fentanyl drives rise in opioid-linked deaths in U.S.

August 31, 2017
(HealthDay)—Fentanyl, a synthetic narcotic, is a key player in America's continuing epidemic of opioid-related overdose deaths, two new studies report.

Eating triggers endorphin release in the brain

August 28, 2017
Finnish researchers have revealed how eating stimulates brain's endogenous opioid system to signal pleasure and satiety.

Cholesterol-lowering drugs may fight infectious disease

August 21, 2017
That statin you've been taking to lower your risk of heart attack or stroke may one day pull double duty, providing protection against a whole host of infectious diseases, including typhoid fever, chlamydia, and malaria.

Data revealed under FOI shows benefits of multiple sclerosis drug currently blocked by regulators

August 17, 2017
A drug that is blocked by the EU regulatory system has now been found to improve the quality of life of people with multiple sclerosis (MS), according to a study by Queen Mary University of London (QMUL).

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.