Drug Advances Help Fight Alcoholism
Studies support use of naltrexone and acamprosate
WEDNESDAY, July 14, 2004 (HealthDayNews) -- Millions of Americans with a history of alcohol abuse know how hard it can be to stay off the bottle, but two medical advances may soon provide them with just a little more help.
One drug, naltrexone, works to dull alcohol cravings and has been available in capsule form in the United States for years. However, a new once-a-month injection of the drug might soon help alcoholics get their daily dose of naltrexone without having to pop a pill each day.
"People came in saying that they really wanted to try this because they had a hard time remembering to take the drug on their own," said lead researcher Dr. Henry Kranzler a psychiatry professor at the University of Connecticut School of Medicine.
A second study investigated the action of acamprosate, a drug approved for use in Europe but still awaiting approval from the U.S. Food and Drug Administration. That research was led by Elizabeth Houtsmuller, a professor of behavioral biology at Johns Hopkins University School of Medicine.
Both studies appear in the July issue of Alcoholism: Clinical and Experimental Research.
Groups such as Alcoholics Anonymous (AA) and the support of family and friends are critical to helping recovering alcoholics stay sober for good.
However, pharmaceutical agents have also been developed to help fight the addiction. In the United States, two drugs, naltrexone (brand name ReVia) and disulfiram (Antabuse), are used by many alcoholics. Naltrexone was actually first developed to fight heroin addiction, but researchers discovered it curbed alcohol cravings by blocking opiate receptors in the brain.
Patient compliance is always an issue with drug therapy, however. Alcoholics often skip their medications "because their drinking interferes with their recall or because they may simply not want to change," Kranzler said. What's needed in cases like these is some type of slow-release mechanism, akin to a patch, that doesn't rely on patient recall or changes in mood.
In their study, Kranzler's team treated 315 alcoholic patients with either naltrexone in a special intramuscularly injected formulation or a placebo for three months. All of the patients received regular psychotherapy.
The naltrexone "depot" injection, given in the buttock once every month, consists of tiny microcapsules releasing a steady amount of the drug into the bloodstream over time. The study was funded by the product's manufacturer, DrugAbuse Sciences Inc.
According to Kranzler, "long-acting naltrexone depot doubled the rate of total abstinence over placebo, and it increased the number of abstinent days in the overall group."
Side effects were minor and the drug was "generally well tolerated," he added. "It hurts a little to get an injection in your butt, but people didn't seem to have a whole lot of difficulty with it."
In the United States, naltrexone is currently available for use only in pill form; this trial is part of an effort to win FDA approval of an injectable formulation.
Studies have shown that naltrexone doesn't work for everyone, however. "In general, for alcoholism, there's no one remedy that works for all," said Houtsmuller, who helped investigate acamprosate, an anti-alcoholism medication currently under FDA review. Her team's study was funded by a grant from the National Institute of Alcohol Abuse and Alcoholism.
Acamprosate's track record in Europe "has been fairly good," Houtsmuller said. "There have been a number of large clinical trials there, and they have more or less unanimously shown that acamprosate can help people abstain."
What's puzzling, though, is that scientists still don't know how the drug works to encourage sobriety.
In their six-week study, Houtsmuller's team closely monitored physiologic and behavioral changes in 10 heavy drinkers who were given daily acamprosate and were also provided the chance to drink at various points during the trial.
According to Houtsmuller, the study worked best at revealing what acamprosate doesn't do to keep folks from drinking. "It doesn't work by altering alcohol absorption or elimination," she said. "And it doesn't appear to work by changing alcohol's subjective effects -- the alcohol 'experience' that people have."
Individuals who drank while on acamprosate did seem to become more sedated than usual, but it's not clear whether this sedation is enough to turn them off repeat alcohol consumption.
One theory some experts share is that the drug works on the glutamate system, a neurochemical process within the brain. The glutamate system appears to play a role in spurring alcoholics' cravings, helping them achieve that feeling of "normalcy" that only drinking can bring. Acamprosate's effect -- if any -- on the glutamate system remains "speculation," however, Houtsmuller stressed.
These days medication, psychotherapy, and groups such as AA are all resources easily available to alcoholics committed to turning their lives around, Kranzler said.
"We see people getting better all the time," he said.
Still, for most alcoholics, the fight against their addiction requires a lifetime of vigilance. "Relapse is common," Kranzler said, "and there has to be a rededication to sobriety over time."
For more on alcoholism and ways to stay sober, visit the National Institute on Alcohol Abuse and Alcoholism.