TUESDAY, April 5, 2005 (HealthDay News) -- A monthly injection could help problem drinkers cut back or stop drinking alcohol altogether.
That's the conclusion of a study published in the April 6 issue of the Journal of the American Medical Association that found alcoholics given a monthly shot of naltrexone were able to reduce their heavy-drinking days from an average of 19 days per month to three days per month.
"Alcoholism is a very common problem, and medication is emerging as a new treatment," said study co-author Dr. James Garbutt, a professor of psychiatry at the University of North Carolina at Chapel Hill. "This long-acting shot was an effective way of providing medication."
Naltrexone is a type of medication known as an opioid antagonist. When someone takes the drug, it blocks the feel-good effects of alcohol, so users "feel less of a high, which may make it easier to move away from alcohol," Garbutt explained.
Up to 4 percent of American adults are dependent on alcohol, and alcohol dependence may contribute to as many as 100,000 preventable deaths annually, according to the study.
Current treatment options include counseling, behavior modification, self-help groups such as Alcoholics Anonymous and, sometimes, medications. Naltrexone was approved for use in the treatment of alcoholism in 1994, and is currently prescribed as a once-a-day oral medication.
The problem with the oral form is that it has to be taken daily, which means an alcoholic has to make the decision every day to not drink and to take the medication. Garbutt said this can be difficult because motivation levels vary on a daily basis. Additionally, if someone experiences side effects, such as nausea, while taking oral naltrexone, they may stop taking the drug.
That's why scientists developed a long-acting form of the drug, which is the formulation that Garbutt and his colleagues tested in this latest study.
The researchers recruited 624 people considered dependent on alcohol and randomly split them into three groups. The first group received monthly injections of 380 milligrams of naltrexone, the second received 190 milligrams of naltrexone, and the final group received placebo injections for up to six months.
The average age of the study participants was 45, and about two-thirds were male. To qualify for the study, each volunteer must have had at least two heavy drinking episodes per week during the previous month. A heavy drinking episode is four or more drinks for women, and five or more for men.
Those receiving 380 milligrams of naltrexone were 25 percent less likely to have a heavy drinking episode compared to those on placebo. Those on the smaller dose were 17 percent less likely to have a heavy drinking episode compared to those taking the placebo injection.
Men in the study, especially those on the higher dose of naltrexone, were much less likely to report a heavy drinking episode. People who hadn't had a drink in the week before the start of the study were also much less likely to have a heavy drinking event.
In general, Garbutt said the drug was well-tolerated. Fourteen percent of the high-dose naltrexone group dropped out due to side effects, such as nausea and headache, compared to 6.7 percent in both the low-dose naltrexone and placebo groups.
"This is an important study that shows this formulation of naltrexone was effective in treating alcoholism," Garbutt said.
"One of the major problems in treating alcoholism with pharmaceutical agents is the reluctance or inability of patients to take medication regularly," said Dr. Marc Galanter, director of the division of alcoholism and drug abuse in the department of psychiatry at New York University School of Medicine. "The use of injections could represent an important step forward in our attempts to address the problem of addiction with medical treatment in addition to psychotherapy and 12-step programs."
"This medication is not only useful in the treatment of alcoholism, but can be used to block the effects of opioid drugs, so it may be valuable in treating other addictions, such as heroin and narcotic analgesics such as oxycontin," he added.
More information
To learn more about alcoholism, visit the National Institute on Alcohol Abuse and Alcoholism.
