Pfizer’s anti-smoking drug Chantix may also be effective in curbing alcohol dependence, according to a new animal study conducted by researchers at the University of California, San Francisco.
The study, led by Selena Bartlett, director of the preclinical development group at the UCSF-affiliated Gallo Clinic and Research Center, involved studies with rats who had access to unlimited amounts of alcohol. Under these conditions, they steadily increased their alcohol intake over several months but the first day they received just one dose of Chantix (varenicline), marketed in the UK as Champix, they cut their drinking in half.
Furthermore, the rats received varenicline every other day for a week, and during this period maintained their lower drinking level when the drug was discontinued, they returned to their previous level but no higher. In addition, the drug did not kill appetite, unlike naltrexone, currently the most effective treatment to curb alcohol dependence. The findings have been published online by the Proceedings of the National Academy of Sciences journal.
“The biggest thrill is that this drug, which has already proved safe for people trying to stop smoking, is now a potential drug to fight alcohol dependence,” Dr Bartlett says. “Alcoholism takes a tremendous toll, and so few drugs are available to counter it.” She added that 85% of alcoholics smoke, so if clinical trials confirm varenicline is effective against alcoholism, physicians can prescribe the drug to treat both conditions. Her team, in collaboration with Markus Heilig at the National Institute on Alcohol Abuse and Alcoholism, is now planning clinical trials of Chantix’ effectiveness against alcohol craving and dependence.
Varenicline probably reduces both drinking and smoking because nicotine and alcohol trigger the same “reward circuitry” in the brain, Dr Bartlett noted. Consumption of either substance activates receptors on neurons within this circuitry, deep in the brain in an area known as the ventral tegmental area and this action is thought to release the “feel good” neurotransmitter dopamine into another part of the circuitry, the nucleus accumbens.
The receptor involved is called the neuronal nicotinic acetylcholine receptor. Nicotine binds directly to it, while alcohol induces the release of another neurotransmitter, acetylcholine, which then activates the receptor. Either way, dopamine is released, the UCSF researchers said, noting that Chantix also binds to the receptor, and so prevents its activation by nicotine, and maybe alcohol.
Since its safety has already been established, varenicline can be put to clinical use much more quickly if it is found effective in people, Dr Bartlett argues: “Treatments for alcoholism today are like those for schizophrenia in the ‘60s. People don’t talk about it. There are very few treatments, and most drug companies are not interested in it.”
She concluded that “it’s a disease. If you’ve inherited a gene variant, or if some other cause leads you to alcohol dependence, it should be treated – like any disease.