A monthly shot of the prescription drug naltrexone — plus counseling — could help reduce heavy drinking in people with alcoholism.

That's according to a new study in the April 6 issue of The Journal of the American Medical Association. The study was funded by Alkermes Inc., which makes naltrexone.

Naltrexone is already used to treat alcoholism. The monthly shot might be a more convenient approach than current daily oral doses, say the researchers, some of whom are Alkermes employees.

"Alcoholism is a serious disease that destroys lives. As we learn more about how the brain is affected by alcohol, we are discovering how best to provide treatment — like adding a safe medication to counseling. A long-acting injectable, which eliminates the burden of daily pill taking, will open new doors for our patients and give hope to them and their families," writes researcher Helen Pettinati, PhD, in a news release. Pettinati is a research professor in University of Pennsylvania's department of psychiatry and the director or the treatment research division in the Center for the Study of Addictions.

The news comes right before National Alcohol Screening Day. On April 7, more than 5,000 sites nationwide will offer free, anonymous screenings regarding alcohol use.

National Alcohol Screening Day is sponsored by several government agencies including the National Institute on Alcohol Abuse and Alcoholism, a branch of the National Institutes of Health.

Alcoholism: A Chronic Disease

Alcoholism is the fourth leading cause of disability worldwide. In the U.S., it may contribute to more than 100,000 preventable deaths annually and is present in 4 percent of the adult population, write the researchers, including James Garbutt, MD, of the University of North Carolina at Chapel Hill.

Alcoholism is increasingly viewed as a chronic disease that can be affected by genetics, social, and environmental factors, they note.

Treatment options include addiction counseling, behavioral approaches, self-help groups (such as Alcoholics Anonymous), and medications.

"As with other chronic diseases, long-term comprehensive management strategies are necessary to achieve and sustain the benefits of alcohol dependence treatment," researchers write.

New Use for Naltrexone

Naltrexone was approved by the FDA in 1994 for treating alcoholism. The drug had been shown to reduce drinking frequency and the likelihood that people would relapse back into heavy drinking, say the researchers.

But naltrexone hasn't gotten widespread clinical use. That may be partly due to variations in treatment response — which could be related to the drug's regimen, say Garbutt and colleagues.

Currently, patients take naltrexone orally every day. Sticking to a daily oral medication routine is a general problem in medicine (not just with alcoholism), write the researchers. They tried a different approach: long-acting monthly shots of naltrexone.

Testing the Shots

The six-month study included more than 600 adults with alcoholism at 24 hospitals, clinics, and Veterans' Administration health facilities across the country.

All had been diagnosed with alcohol dependence and had had at least two heavy drinking episodes per week in the last month. That's at least five drinks at a time for men and four or more for women.

Nearly 200 patients got a monthly injection of 380 milligrams of naltrexone. About 200 more got 190 milligrams of naltrexone in one monthly shot. The rest received a placebo shot. Everyone also took 12 counseling sessions for alcoholism.

Heavy Drinking Down, but Alcohol Not Eliminated

The biggest improvement was seen with the higher-dose shot. In that group, heavy drinking days decreased by 25 percent compared with the placebo group. Those taking the lower dose of naltrexone had 17 percent fewer heavy drinking days than the placebo group.

The results — which were based on patients' self-reports — were better for those who said they hadn't had a drink for a week before the study.

Neither dose of naltrexone significantly lowered the rate of "risky drinking" or any drinking, the study shows. For people facing alcoholism, risky drinking days are defined as more than two daily drinks for men or more than one for women.

Side Effects

At least 10 percent of those receiving naltrexone had side effects, researchers say. The most common side effects were nausea, headache, and fatigue.

About 14 percent of those taking the stronger shots quit the study because of side effects. So did 7 percent of each of the other two groups.

All in all, the treatment was well tolerated and could be beneficial, the researchers write.

Besides the Alkermes employees, several of the scientists have consulted for or received research support from the company, according to the journal.

By Miranda Hitti, reviewed by Brunilda Nazario, MD

SOURCES: Garbutt, J. The Journal of the American Medical Association, April 2, 2006; vol 293: pp 1617-1625. News release, JAMA/Archives. National Alcohol Screening Day, "Attend A Screening."