The announcement was made in a news release by the pharmaceutical companies Alkermes, which makes Vivitrol, and Cephalon, which markets the drug.
Vivitrol is the first and only injectable drug given once per month to treat alcohol dependence, the news release states.
Vivitrol is indicated for alcohol-dependent patients who are able to abstain from drinking in an outpatient setting and are not actively drinking when starting treatment. It's also intended for use in combination with psychosocial support, such as counseling or group therapy.
Vivitrol, which is nonaddictive, must be given by a health care provider as a shot. The companies expect the drug to be available in the U.S. to doctors and patients by the end of June as a single monthly dose.
"This is the first medication for the treatment of alcohol dependence that has ever been available which provides a full month of coverage with a single dose," Michael Bohn, MD, tells WebMD.
Bohn is a board-certified addiction psychiatrist. He's also the medical director of the adolescent substance abuse treatment program at Aurora Psychiatric Hospital near Milwaukee.
Bohn was one of the researchers who worked on a six-month study of Vivitrol in 624 patients. He received payment for that work and for serving as an advisor to Alkermes and Cephalon.
"Given the really significant rates of noncompliance with the existing medications, I think that this offers a really significant hope for people who may be ambivalent about medications, and it will allow them to continue on medication that's effective for so many weeks," Bohn says.
Heavy Drinking Down
At the start of the Vivitrol study, the selected patients had about 20 days per month of heavy drinking, which was defined as five or more drinks per day for men and four or more drinks per day for women.
Bohn and colleagues randomly assigned patients to either get a monthly shot of Vivitrol or a similar shot that lacked medicine (placebo). Nearly two-thirds of the patients completed the study, which lasted six months. All participants also got psychosocial support.
"If you look at the rate of heavy drinking in the individuals who got the active medication, it was significantly lower than in the group that got the placebo injection," Bohn says. "It's a very significant difference ... [about] 25%," he says.
Abstaining From Alcohol
Participants were asked to abstain from alcohol for a week before the first shots were given. "They were not required to abstain prior to starting treatment," Bohn says. "Some selected to, and others did not."
Those who abstained from alcohol for at least four days before their first Vivitrol shot "did even better," Bohn says. Those participants were "significantly more likely to remain abstinent, and they had a significant reduction in the rate at which they drank heavily if they did not abstain," Bohn says.
"So there were benefits both for those who were able to abstain altogether ... and even among those who did not abstain, they were much less likely to drink heavily," Bohn says.
How It Works
"We don't know exactly how opioid receptors are involved in alcohol dependence, but there's very good preclinical data that indicate that medications that bind to these receptors and block them reduce drinking and remove the incentive to drink," he explains.
About 18 million people in the U.S. are dependent upon alcohol or abuse alcohol, and more than 2 million of those people receive treatment each year, Bohn notes. He says Vivitrol offers "a new hope to a really significant number of them."
A once-per-month treatment could enhance compliance with medication, Bohn says, calling Vivitrol "a really significant advance to clinicians who are treating patients who want to stop their drinking."
Alkermes and Cephalon state that Vivitrol's active ingredient, naltrexone, may cause liver damage when given in excessive doses and that the drug shouldn't be taken by patients using opioid drugs or those in acute opioid withdrawal.
Vivitrol was "generally well tolerated" in clinical trials, the companies state, reporting mild to moderate side effects with the drug. In clinical trials, Vivitrol's most common side effects were nausea, vomiting, headache, dizziness, fatigue, and reactions at the injection site, according to the news release.
Participants who completed the Vivitrol study were allowed to keep taking Vivitrol (or switch to it, if they had previously taken the placebo); 85% accepted that offer, Bohn says.
"What this is says is that the acceptance rate for people who are on this medication is quite high," Bohn says. "Because there were relatively few side effects and the medication was well-tolerated, and because people liked coming in to get an injection, this type of treatment with Vivitrol offers a really exciting new opportunity, as far as I'm concerned."