Since 1995, the drug naltrexone (Revia) has been available in the United States for the treatment of alcohol dependence. Previous studies have suggested that when combined with psychosocial counseling, naltrexone is effective at preventing relapse of heavy drinking, increasing sobriety, and reducing alcohol consumption. A recent study published in the New England Journal of Medicine (NEJM) calls naltrexone's effectiveness into question.

About the study

Researchers from the Department of Veterans Affairs conducted a study from April 1997 to October 2000, in which they studied the effectiveness of naltrexone in addition to counseling to treat alcohol dependence. Six hundred twenty-seven veterans (almost entirely men) with severe, chronic alcohol dependence were randomly assigned to one of three groups, each consisting of 209 participants. Participants and study interviewers did not know which patients received naltrexone and which received a placebo (an inactive pill). The groups were as follows:

  • Long-term naltrexone treatment – 12 months of naltrexone plus counseling
  • Short-term naltrexone treatment – 3 months of naltrexone plus counseling, then 9 months of a placebo pill plus counseling
  • Inactive placebo – 12 months of a placebo pill plus counseling

Counseling consisted of individual 12-step facilitation once per week for 16 weeks, once every two weeks from week 17 to 36, and once per month from week 37 to 56. In addition, all study participants were encouraged to attend Alcoholics Anonymous (AA) meetings.

On a monthly basis, participants reported the days on which they drank, how often they took their medications, and how often they attended counseling and AA meetings. To measure patient compliance in taking the medication, the pill bottles were equipped with caps that recorded each date and time the bottles were opened. In addition, blood levels of naltrexone were tested in some participants. Data from the caps and the blood tests indicated that 84% of patients were taking their medication.

Researchers looked at how many patients in each group relapsed in the first 13 weeks and the number of days from the start of the program to the date of relapse. Relapse was defined as the first day of heavy drinking (6 or more drinks for men and 4 or more drinks for women). They also looked at the percentage of drinking days during the entire 12-month study period and the number of drinks per drinking day.

The findings

In analyzing the data from the first 13 weeks, researchers found that the median number of days to relapse in the naltrexone group (short- and long-term combined) was 72.3 and the placebo group was 62.4. Although the naltrexone group lasted on average 10 days longer before relapsing, this difference was not statistically significant. When data from all 52 weeks were analyzed, there was no significant difference among the three study groups in terms of percentage of drinking days over the 12-month study period and number of drinks per drinking day. In other words, people who took a placebo pill and went to counseling fared as well as people who took naltrexone and went to counseling.

Does this mean that naltrexone is not effective as an adjunct to counseling in treating alcohol dependence? Unfortunately, it's not that simple. Other well-designed studies have indicated that naltrexone is effective, while only one other study suggested that naltrexone was not effective. This is simply one study suggesting that naltrexone does not provide any benefit over counseling alone.

There are limitations in the design of this study that may explain why the results differ from those noted in previous studies. The typical participant in this study had been drinking heavily for a longer period of time than participants in other studies. It is possible that naltrexone is more effective for people who have been dependent on alcohol for a shorter period of time.

The type and frequency of counseling also differed in this study from previous studies. The counseling offered in this study was 12-step facilitation, whereas previous studies employed coping-skills therapy or relapse prevention training. It may be that naltrexone works better in combination with these types of therapy. In addition, some previous studies included daily therapy rather than the weekly therapy in this study, which tapered off to biweekly and eventually monthly.

How does this affect you?

Is naltrexone a good treatment option for alcohol dependence? Although this recent study suggests that naltrexone plus counseling is no more effective than counseling alone, there are still reasons to consider taking naltrexone if you are being treated for alcohol dependence. First, other studies have suggested that naltrexone is effective. Second, more than 97% of the participants in this study were male and all were veterans who suffered from severe, chronic alcohol dependence. We don't know if the results of this study apply to women, non-veterans, or people with less severe, shorter-term alcohol dependence. It is also unclear whether naltrexone might be more effective in combination with other medications.

Unlike some other medical conditions, the treatment for chronic alcoholism is not clear-cut in every situation. An editorial by two independent reviewers accompanies this article in NEJM and sheds more light on the possible effectiveness of naltrexone. According to the authors of the editorial, "If additional studies find that naltrexone works, it will be important to identify which patients are likely to benefit and which are not. Until we have more information, we recommend that physicians continue to prescribe naltrexone for patients....who have been drinking heavily for 20 years or less and have stable social support and living situations."