FRIDAY, Feb. 27 (HealthDay News) -- A pill normally prescribed to help with infertility and menstrual disorders may also help treat alcoholism, a new study says.
When injected with cabergoline (Dostinex), rats addicted to alcohol decreased their drinking and addictive behavior while also being less prone to relapsing, a study by researchers at the University of California, San Francisco, found. The findings were published online in Biological Psychiatry.
Use of cabergoline also didn't seem to affect other behavior, such as the rats' intake of water or sugar.
"This is encouraging, because it demonstrates that cabergoline is specific for alcohol but does not affect general reward or pleasure. One of the problems with some existing drugs to treat alcoholism is a side effect that decreases pleasure, making compliance an obstacle to sobriety," associate professor of neurology Dorit Ron, a principal investigator at the university's Ernest Gallo Clinic and Research Center, said in a news release issued by the school.
The pill form of cabergoline has been approved by the U.S. Food and Drug Administration to counter conditions caused by the body producing too much of the hormone prolactin. The medication had been shown to increase the body's production of glial cell line-derived neurotrophic factor protein (GDNF), which the research team had previously found decreased the desire for alcohol in addicted rodents when injected straight into the region of the brain linked to drug-seeking behavior.
In the new experiment, rats were trained to press a lever to obtain alcohol. When given cabergoline injections, the rats were less likely to press the lever -- the higher the dose, the fewer presses of the lever, the researchers found. Also, the team reported that binge-drinking mice drank less alcohol after receiving cabergoline.
The drug also appeared effective at cutting the craving for alcohol and lowering the risk of relapse, a critical issue for recovering alcoholics.
The experiment was further strengthened when cabergoline was given to mice genetically modified to have only a single copy of the GDNF gene, which would mean less of the protein could be produced. The drug had no effect on the drinking habits of these altered mice, the researchers reported.
The study, while noting success with cabergoline in a pilot study on human cocaine addicts, also warned the drug had been linked to heart value issues when given in higher doses as a treatment for Parkinson's disease.
"However," Ron said, "we show that in mice and rats, a low dose of the drug is enough to reduce excessive alcohol consumption, alcohol seeking and relapse. The dose is similar to what is given to humans for the treatment of hyperprolactinemia."
Only three medications have FDA approval for treating alcohol dependence -- disulfiram (Antabuse), naltrexone (Depade, ReVia), and acamprosate (Campral).
The U.S. National Institutes of Health estimates that almost 18 million people in the United States -- approximately one in every 12 adults -- abuses alcohol or is alcohol-dependent.
The U.S. National Institute on Alcohol Abuse and Alcoholism has more about alcoholism.
SOURCE: University of California, San Francisco, news release, Feb. 23, 2009