PARIS – Long-term therapy with naltrexone can help keep alcohol-dependent patients on the wagon, Barbara J. Mason, Ph.D., said in a poster presentation at the 24th Congress of the Collegium Internationale Neuro-Psychopharmacologicum.
In a controlled study, “patients randomized to naltrexone had a significantly longer latency to their first heavy drinking episode, and longer latency to dropout due to treatment failure,” said Dr. Mason, director of the division of clinical pharmacology in the department of neuropharmacology at Scripps Research Institute in La Jolla, Calif.
“The results support using long-term treatment with naltrexone for alcohol-dependent patients who respond to [short-term] treatment with naltrexone,” she explained.
Although alcoholism is often a chronic, recurrent syndrome, most clinical studies of drug treatments for alcoholism have only assessed acute efficacy. This study focused on naltrexone's long-term efficacy for preventing alcohol abuse.
The investigators began by enrolling 159 people with alcohol dependence to an open-label phase in which they received 50 mg naltrexone daily plus a weekly session of cognitive-behavioral therapy.
After 12 weeks, there were 92 responders, defined as those who had two or fewer heavy drinking days during the final 6 weeks of the short-term phase or at least a 50% reduction in their alcohol use during the same period. These 92 patients were then entered into the randomized, long-term phase of the study.
In the second phase, 48 people were randomized to continued treatment with 50 mg naltrexone daily for an additional 40 weeks. The other 44 participants went into the control group and were treated with placebo. At baseline, all patients in the randomized phase were consuming an average of 8.5 drinks per day and had consumed alcohol on an average of 69 of the 90 days preceding the start of naltrexone treatment.
The average age of all patients in the randomized phase was 47 years. About 70% were men, and about 70% were white.
During the long-term treatment period, 75% of the patients who remained on naltrexone treatment refrained from a return to heavy drinking, compared with 60% of those in the control group, a statistically significant difference.
The average time that patients remained in the long-term treatment phase of the study without treatment failure was 32 weeks for those who continued naltrexone treatment and 22 weeks for those who came off naltrexone, which also was a statistically significant difference.
The study was funded by the National Institute on Alcohol Abuse and Alcoholism, not by DuPont Pharmaceuticals Co., which is the marketer of naltrexone (Revia).