| Nalmefene May Reduce Relapse | |
Researchers at the University of Miami have found that nalmefene, a drug normally used to reverse the effects of anethesia, significantly reduces cravings and therefore relapse for alcoholics. The pharmalogical treatment of alcoholism is not new, but until 1994 there were no Food and Drug Administration-approved medications for the treatment of alcoholism other than disulfiram (Antabuse). There were specific problems with the adverse effects associated with disulfiram and controversy regarding the use of any medication. Many believed "you can't treat a drug/ alcohol problem with a drug."
In 1994 the use of naltrexone was approved for treatment of alcoholism and now, as a result of the recent Miami findings, scientist are pushing for the approval of nalmefene, which is not currently available in the oral medication form used in the study.
How Does it Work?
Normally endogenous opioid activation results in release of dopamine in reward systems of the brain. Opiate receptor antagonists such as naltrexone and nalmefene block the endogenous opioid circuit, thus blocking dopamine-mediated euphoria.In laymen's terms that means if you take the drugs, drinking no longer gives you a buzz, therefore reducing the "craving" for alcohol.
Naltrexone has been most recently used in the procedure known as "rapid detox" for narcotic addicts. In the procedure, patients are put to sleep and given large doses of opiate blockers. The patient goes through withdrawal, but does so while asleep (sedated). During the sedation, a pellet of naltrexone is surgically implanted into the patient's abdomen -- deep enough that it cannot be removed easily -- which releases the medication into the blood stream for six to eight weeks.
Nalmefene Study
In the new alcohol study, patients were given daily doses of nalmefene orally. The main difference between naltrexone and nalmefene is that the latter lasts longer and is more potent in blocking dopamine. The newer nalmefene is a "universal" opioid antagonist that works on all opioid receptors.In the Miami study patients who received nalmefene were 2.4 times less likely to relapse to heavy drinking than those who received a placebo.
Although one-third of the nalmefene patients relapsed to heavy drinking at least once during the 12-week trial, significantly more nalmefene than placebo patients altogether avoided relapse. Of patients who relapsed, those on nalmefene had fewer subsequent heavy-drinking episodes.
Magic Pill?
"This study again demonstrates the promise of pharmacologic agents to work with standard behavioral treatments in the treatment of alcoholism. Prospects for improving treatment outcome have never been better," said Enoch Gordis, M.D., Director, National Institute on Alcohol Abuse and Alcoholism, a component of the National Institutes of Health."Alcohol consumption is mediated by multiple neurotransmitters and neuromodulators, including nonopioid systems, so that an opioid antagonist alone would not necessarily eliminate alcohol drinking in all alcohol dependent persons," said Barbara J. Mason, Ph.D, author of the study. "But any agent that can reduce relapse would be a useful addition in treating alcoholic patients, approximately one-half of whom relapse within the first few months of most behavioral treatments."
Several pharmaceutical companies have approached the University of Miami to review the nalmefene data in support of a new drug application to the FDA, Dr. Mason said.
