January 1, 1999

A study in the December 2 issue of the journal Synapse shows that a European drug for epilepsy blocks the reinforcing effects of nicotine in rodents and primates. A related study published this summer found that the drug, vinyl-GABA (GVG), exerted similar blocking of cocaine's reinforcing effects. (GABA stands for gamma-aminobutyric acid.)

The study by Stephen Dewey, Ph.D., of the U.S. Department of Energy's Brook-haven National Laboratory in Upton, N.Y.; Charles Ashby of St. John's University; Jonathan Brodie, M.D., Ph.D., of New York University; and colleagues found that the GVG dose needed to block nicotine's effects was about one-tenth of that needed to block cocaine's effects.

"We've shown in animals that the proper dose of GVG can stop nicotine's effects entirely," said lead author Dewey in a statement issued by BNL. Given that GVG has proven effective in blocking the reinforcing properties of both cocaine and nicotine, said coauthor Brodie, the research offers hope that it may prove useful as a treatment for a variety of addictions.

"Since the same brain chemistry changes may be common to all these addictions, it follows that a single well-aimed strategy combined with a person's desire to quit could assist in defeating them all."

Dewey and Brodie are nearing completion of research into GVG's efficacy in blocking craving for alcohol, heroin, morphine, and amphetamines.

The study "confirms the importance of the brain's GABA system as an important target for potential anti-addiction medications," said Alan Leshner, Ph.D., director of the National Institute on Drug Abuse, in a statement. The research also suggests that there are "common brain mechanisms underlying addiction to all drugs and gives hope that we can develop a single medicine to use in treating addiction, whatever the primary addictive drug," he added.

Although GVG is not approved in the United States, it has been used safely in Europe for epilepsy treatment for more than a decade. Human clinical trials on GVG's anticraving effects are being planned in Europe, Canada, and the U.S.

GVG blocks nicotine's capacity to boost brain dopamine levels. Dopamine is believed to play a significant role in drug reinforcement, although recent research has shown that a variety of other neurotransmitters also modulate drug reinforcement. GVG increases the brain's release of GABA, which, in turn, decreases dopamine production.