Two new studies have suggested that the controversial anti-smoking drug varenicline (Chantix) may also help people fight cocaine and alcohol addictions.
The first study, published this month in the journal Alcohol and Drug Dependence, was a nine-week clinical trial that included 37 people with cocaine addiction. Researchers at the University of Pennsylvania found that participants who took varenicline were half as likely to use cocaine — as measured by urine tests three times a week — as those given placebo.
Additionally the participants drank less alcohol while on varenicline. Further, in an experiment in which participants were given a choice between cocaine and money in varying sums, people taking varenicline valued cocaine less than those on placebo, suggesting that the quit-smoking drug made cocaine less rewarding.
The second study will soon be published in the Alcoholism: Clinical and Experimental Research. It involved 15 moderate to heavy social drinkers. While taking varenicline, they, too, found their drug of choice to be less enjoyable and more unpleasant. This comports with anecdotal reports of smokers who have told researchers that they found alcohol less desirable and therefore drank less while using varenicline to quit smoking.
“There are only currently three medications approved by the FDA for the treatment of alcohol-use disorders,” says Sherry McKee, an associate professor in the department of psychiatry at Yale University in New Haven, Conn. She says that although those treatments work for some people, “Not all drinkers respond to those treatments, so we need to identify novel targets.” McKee is studying Chantix for alcohol addiction. She was not involved in the current research.
The reason the drug may do that, Childs says, is that alcohol and nicotine may both exert their influence through the same receptor on brain cells. Chantix blocks that receptor, which appears to blunt some of the physical effects of alcohol. As expected, as people in the study drank, their performance declined on the eye tracking tests. But after taking Chantix, people in the study were able to perform some of the tasks just as well as they could before they’d started drinking, suggesting that Chantix was blocking some of the alcohol’s influence.
Neither study was funded by the pharmaceutical industry nor the authors report conflicts of interest.
Varenicline is unique among anti-addiction medications in the way it affects the brain. Like nicotine, varenicline activates a specific receptor for a neurotransmitter called acetylcholine, but it does so less intensely than the active ingredient of cigarettes does. The net effect is that the drug seems to help by both cutting cravings and making the formerly desired drug less pleasant — without making non-drug pleasures less intense. Alcohol works on the same chemical receptors in the brain as nicotine, and it may enhance the pleasurable effects of smoking.
“A single medication that could decrease the use of both substances would be ideal,” said Hugh Myrick, associate professor of psychiatry at the Medical University of South Carolina and co-author of the drinking study, said in a statement, noting that many people are addicted to both alcohol and cocaine.
But varenicline is not without a downside. It carries a black box warning from the FDA because of serious psychiatric side effects, including suicidal thoughts and behavior. One study found that people taking varenicline to quit smoking were eight times more likely to engage in suicidal or self-injuring behavior than those using nicotine-replacement treatments like the patch. Other research has linked varenicline to an increased risk of heart problems in people with pre-existing cardiovascular disease, although the risk-benefit calculation here is complicated by the fact that smoking carries far greater risk to the heart and blood vessels than varenicline.