FRIDAY, May 10 (HealthDay News) -- A vaccine that could help fight heroin addiction shows promise in early tests in rats, researchers report.
The vaccine targets heroin and its psychoactive breakdown products in the bloodstream, preventing them from reaching the brain, explained the scientists from The Scripps Research Institute in La Jolla, Calif.
"Heroin-addicted rats deprived of the drug will normally resume using it compulsively if they regain access, but our vaccine stops this from happening," George Koob, chair of the institute's addiction research group, said in a Scripps news release.
Initial tests of the vaccine, reported in 2011, showed that it could block some of the acute effects of heroin, such as reducing pain. The new study involved more rigorous tests of the vaccine.
"We gave the vaccine to rats that had already been exposed to heroin, a situation obviously relevant to a human clinical situation," study first author Joel Schlosburg, a postdoctoral research associate, said in the news release.
The vaccine did not block the effects of methadone, buprenorphine and other drugs that are commonly used to treat heroin addiction.
"It doesn't affect the opioid system per se, so in principle you could give this vaccine to heroin-dependent people and continue to treat them with standard therapies, too," Schlosburg said. "Opioid painkillers such as codeine or oxycodone also would continue to work."
The findings were published this week in the Proceedings of the National Academy of Sciences.
If the vaccine proves effective in human clinical trials, the researchers said, it could become a standard part of therapy for heroin addiction, which affects more than 10 million people worldwide. However, results obtained in animal experiments often aren't attainable in trials with humans.
The U.S. National Institute on Drug Abuse has more about heroin.