PHILADELPHIA – When combined with counseling, a long-acting injectable treatment for alcoholism significantly reduces heavy drinking by men, a new study shows.
The once-a-month shot of naltrexone, which is now seeking U.S. Food and Drug Administration approval, is aimed at helping patients stick with medical treatment. A naltrexone pill was approved for alcoholism in 1994, but getting patients to comply with a daily regimen has proved difficult.
“This can almost guarantee compliance,” said Raye Z. Litten, associate director of treatment and recovery research at the National Institute on Alcohol Abuse and Alcoholism. “This could be a great help.”
The study, which appears in today’s Journal of the American Medical Association, also illustrates the intractable, complex nature of alcohol dependence. Of 624 participants at the University of Pennsylvania and 23 other centers, 40 percent dropped out, many of them toward the end of the six-month study. And, for unknown reasons, injectable naltrexone was no better than a placebo injection for women, who made up 32 percent of the patients.
Still, said Helen M. Pettinati, a psychologist who led the research at the University of Pennsylvania, “We consider this to be fairly impressive results. But it’s not the magic bullet. It’s not going to fix people’s lives. That’s why counseling is part of treatment.”
Over the past two decades, Penn researchers have pioneered and promoted the use of oral naltrexone for heroin addiction as well as alcoholism, but for various reasons – including patients’ poor compliance – most treatment programs do not use it.
In the United States, an estimated 18 million people are abusing or dependent on alcohol, and 2.3 million adults seek treatment each year.
The new study was funded by Alkermes, the Cambridge, Mass., developer of injectable naltrexone, brand name Vivitrex.
All patients in the study received twice-monthly counseling to assess their progress and advise them. They also received high-dose naltrexone, a medium dose or a placebo.
The study showed that both naltrexone doses helped men reduce heavy drinking, with the high dose being most effective. Heavy drinking was defined as at least five drinks a day for men, or at least four a day for women.
Men on the high dose reduced their heavy drinking from a median of 19 days when they started the study to 2 days a month, while placebo patients went from 19 days to 6 days.
While the women also reduced their heavy drinking, the drug did not appear to help. High-dose women went from a median of 21 days to about 5 days a month – the same as women taking placebo. Women taking the medium-dose went from 21 days to 4 days a month.
An analysis of factors such as side effect frequency – naltrexone initially can cause nausea – showed no difference between men and women, Pettinati said. Studies of oral naltrexone found it equally effective for women and men.
“When the study ended, women were just as eager to continue the medication as men,” he said. “So we really don’t know if this finding would go away” in a study with larger numbers of women.
Among all patients, complete abstinence from alcohol was achieved by only 14 patients on high dose naltrexone, 13 on the medium dose, and 11 on placebo. But addictions experts say this finding, which was not surprising, does not undermine the significance of reducing dangerous drinking. Indeed, an unusual aspect of the study was that it encouraged, but did not require, patients to abstain before beginning treatment. Campral, the only other alcoholism medication that targets brain chemistry, is approved for patients who have stopped drinking.