Drug similar to naltrexone shows promise in early research

It is much too early to tell whether a compound closely related to the drug naltrexone could end up helping to prevent alcohol dependence among young drinkers. But a newly published study involving research on mice offers some encouraging signs about the drug, which acts on the brain's immune system.

Jonathan Jacobsen, a PhD student at the University of Adelaide's Discipline of Pharmacology in Australia, tells Addiction Professional that the drug, referred to as (+)-naltrexone, “is made up of the same molecules as naltrexone but they are arranged slightly differently.”

Focusing on the toll-like receptor 4, an immune receptor in the brain, the research team administered (+)-naltrexone to mice and found a significant reduction in drinking behavior, especially at times when alcohol-related reward was at its peak. This finding has researchers speculating that this drug ultimately could assist young people who have engaged in risky drinking behavior, possibly warding off the onset of more serious problems later in life.

The study was published in the journal Brain, Behavior and Immunity.

This research opens up new avenues in its examination of the immune system. Unlike naltrexone, which targets brain cells more generally, (+)-naltrexone appears to target only the toll-like receptor 4 immune receptor.

“Alcohol is the world's most commonly consumed drug, and there is a greater need than ever to understand the biological mechanisms that drive our need to drink alcohol,” Jacobsen said in an article from The Lead news service in South Australia.

(+)-naltrexone, created in the early 2000s and originally tested as a pain treatment, has now been used to stop stimulant and opioid reward in mice in laboratory research, Jacobsen says. He emphasizes that a great deal more research must take place before the drug's potential in humans becomes clear.

“The translational potential of this drug is currently uncertain and will require a lot more research before it is ready for the clinic,” Jacobsen says in his comments to Addiction Professional. “The next step is to determine how, when and if the immune system is also active in humans following alcohol use and to determine whether it influences drinking behavior.”