Feb. 14, 2008 -- A drug known to inhibit the stress response in the brain may also be a potential weapon against alcohol addiction.
So suggests a small study on recovering alcoholics published Tuesday in the journal Science.
Researchers with the National Institutes of Health already knew that the drug in question neutralizes the action of a protein called NK1R (short for neurokinin-1 receptor), which is involved in the stress response in the brain. The first hint that the drug might be useful in cutting alcohol cravings surfaced when the investigators noticed that mice who didn't have NK1R seemed to have less desire to consume alcohol.
To test their suspicions, the scientists gave the NK1R-blocking drug to 25 recovering alcoholics, while giving 25 others an ineffective placebo treatment. They found that those who received the drug reported about 50 percent fewer alcohol cravings.
Lead study investigator Dr. Markus Heilig, clinical director of the NIH's National Institute on Alcohol Abuse and Alcoholism (NIAAA), says standard drug treatments to help curb drinking urges worked by reducing the pleasure that alcoholics get from drinking. This drug takes a different approach — reducing the anxiety that leads many alcoholics to reach for the bottle in the first place.
"It's a fairly new approach to treating alcoholism treatment," Heilig says. "We're really trying to open up a new category of treatments that would help most people."
Alcoholism experts not directly involved with the study say the finding offers tantalizing clues for new treatment — as well as hints to the connection between anxiety and drinking urges.
"This is a potentially important finding which indicates a novel mechanism for reducing craving in individuals who drink to reduce high anxiety," says Boris Tabakoff, professor and chairman of pharmacology at the University of Colorado at Denver.
But even if the findings eventually lead to an effective drug treatment option for alcoholism, some experts say, there is no therapy yet that provides a sure-fire, one-size-fits-all solution to alcohol cravings.
"It may be that this medication would help alcoholics who drink when stressed," says Dr. Charles O'Brien, vice chair of psychiatry and director of the Treatment Research Center for the University of Pennsylvania Health System. "It is wrong to think of all alcoholics as alike."
A New Hope for Alcoholics?
Current drug treatments for alcoholism include naltrexone and disulfiram. And it has been shown that these medications offer help for some alcoholics. But Tabakoff says more options are needed.
"The current treatments, although producing statistically significant benefit, are still of modest utility," Tabakoff says. "New approaches need to be introduced and tested. This represents one such novel treatment that seems to be particularly effective in reducing various measurements of craving."
The need for another option in drug-based alcoholism treatment is underscored by the fact that the drug treatments that currently exist are each most effective for the relatively small subset of alcoholics who seem to be genetically predisposed to get an extra addictive kick from alcohol.
"Generally, these sorts of new drugs may help 20 percent of alcoholics or addicts initially quit drug use, though I am not sure they would work that well on maintaining abstinence," says Steve Sussman, professor of preventive medicine and psychology at the University of Southern California.
"While this drug may be of assistance to the extreme users, I wonder about how well it would help the majority."
Further Study Needed
Despite the apparent success in the human part of the trial, more research will be needed before such a treatment can be considered reliable and safe. For example, the possible interaction effects of the drug with alcohol, just in case users fall off the wagon, must be determined.
And since the new study involved only patients who were under hospital care, it remains to be seen how effective the drug could be in a real-world setting, where temptations for alcoholics abound.
Heilig says additional, broader trials are currently in the works. But even at this early stage, alcoholism experts say it's possible that the most recent findings may be a sign that, at least for some alcoholics, more help could be on the way.
"The more types of treatment modalities available, the more people with addiction problems can be helped," Sussman says.
Tabakoff agrees. "All of medicine is moving more and more towards personalized treatments that target subgroups of patients, and I believe this report is one example of that trend," he says. "This may be an excellent option for a sub-group of alcoholics who also suffer symptoms of anxiety. Neither naltrexone nor disulfiram are focused on these subjects."