New Drug Fights Addiction

From the WebMD Archives

March 26, 2001 -- As the Oscar nominated movie Traffic demonstrates, the war on drugs is more like a losing battle. The fight against suppliers loses ground daily, and the demand continues to increase. Now it appears the good guys could have a new weapon, if only the problems associated with it can be ironed out.

A drug called gamma-vinyl GABA, known as GVG, could revolutionize drug treatment in the U.S., if approved by the FDA. It has been studied extensively in laboratory animals, and the next step would normally be very careful clinical trials in a limited number of human subjects. However, right now it's unclear whether those tests are ever going to happen.

"We believe we are going to make a difference," says the author of the most recent animal study, Madina Gerasimov, DDM. "We believe drug addiction is a disease, not a moral weakness, a disease that produces [structural] changes in the brain. We believe this medication can really help addicted people." Gerasimov is an assistant scientist at Brookhaven National Laboratory in Upton, N.Y.

Dopamine is a brain chemical associated with pleasure, and addictive drugs work by increasing dopamine levels in the brain. GVG appears to block increased dopamine levels, thus blocking the increased sensation of pleasure, thereby blocking the craving for the addictive drug.

In the most recent study of GVG, published in the March 7 issue of the European Journal of Pharmacology, researchers trained rats to associate cocaine with a certain environment (either black and white stripes or plain white walls.)

"On the day of the study, they weren't given any cocaine, but were put back in the same environment," Gerasimov tells WebMD. "They experienced increased dopamine levels, just because they'd been put in a space they associated with cocaine. However, in rats that were given GVG, this response was blocked. They did not experience increased dopamine levels."

GVG has been used in many countries to treat childhood epilepsy, but its antiaddictive effects were discovered only recently.

"We seem to have stumbled on a common pathway for all the drugs of abuse," says Jonathan Brodie, MD, PhD, a co-author of the study. He explains that the drug blocks the feeling of craving, the "high" associated with drugs, and the tendency for things associated with the drug to promote craving.

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"It's highly unlikely any pill is going to stop a behavior as complex as drug-taking all by itself," he says. "But this drug is a way to block the vicious cycle of craving and reward, long enough for other therapies to take effect. You wouldn't expect to keep people on GVG forever." Brodie is the Marvin Stern professor of psychiatry at New York University School of Medicine in New York City.

GVG has been tested extensively in rats and also in apes. "[The National Institute on Drug Abuse] promised us human clinical trials of GVG for addiction, although it hasn't been officially announced," Brodie tells WebMD.

That's not exactly the case, says Frank Vocci, PhD, who ought to know. "This drug has been under review by the FDA for over 10 years. There's a major problem because it produces visual field defects that may be irreversible." He's talking about a loss of peripheral vision, something most people don't even notice until it's discovered during an eye exam. Vocci is the director of the division of treatment, research, and development at the National Institute on Drug Abuse.

The NIDA did start to prepare clinical trails on GVG about two years ago, but ran into two issues, Vocci says. First, there may be problems obtaining a supply of the medication from the manufacturer; in addition, it's unclear whether the FDA will approve clinical trials. "We need to re-evaluate all possible information about visual field defects," Vocci says. "Right now, there is probably more unpublished information on this issue than published data."

When asked for an estimate on the likelihood of clinical trails, Vocci says, "I really don't know. It's a fair question, but I just don't have an answer for you. This is clearly a drug of great interest. If there were no concerns about side effects, we'd have started clinical trials two years ago."

Gerasimov and Brodie's study was funded by the U.S. Department of Energy Office of Biological and Environmental Research and the National Institutes of Mental Health.

Pagination