The drug, gabapentin, gives doctors a new option that is not only inexpensive, but is at least as effective as drugs already approved for alcoholism, said study leader Barbara J. Mason.
Moreover, gabapentin is the only drug that improves sleep and mood in those trying to quit or reduce drinking, Mason said. She is co-director of the Pearson Center for Alcoholism and Addiction Research at Scripps, based in La Jolla.
The study was published Monday in the journal JAMA Internal Medicine.
Gabapentin, sold under the trade name Neurontin, is now off-patent and available generically. While the drug is not approved to treat alcohol dependence, doctors can use their own medical judgment to prescribe it for that use. Mason said she hopes the study will prompt doctors to do so.
The study examined 150 men and women older than 18 trying to quite alcohol dependence. Participants were either given a placebo or gabapentin, in daily doses of 900 or 1,800 milligrams, over a 12-week period. The trial was double-blinded, meaning that neither patients nor researchers knew who was taking a placebo or the drug.
When the study was unblinded, patients receiving the highest dose of gabapentin were found most likely to avoid heavy drinking, or to quit completely. Of the high-dose group, 45 percent refrained from heavy drinking, compared to 23 percent of those getting a placebo. Total abstinence was achieved by 17 percent of the high-dose group compared to 4 percent of the placebo group. The low-dose group scored in the middle in both instances.
The study is well-done and provides convincing evidence of gabapentin’s efficacy, said Dr. Michael Plopper, chief medical officer of Sharp Behavioral Health Services. The unit of Sharp HealthCare oversees psychiatric services at Sharp Mesa Vista Hospital and Sharp Grossmont Hospital.
“This is the first placebo-controlled, double-blind study that I’m aware of, of gabapentin for alcohol dependence,” said Plopper, a psychiatrist. “The results are very positive.”
Gabapentin is a good choice because it’s safe, especially in the doses tested, and doctors are familiar with it, Plopper said.
The drug produces a calming effect, which helps those withdrawing from alcohol, Mason said. The brain adapts to constant exposure to alcohol, so withdrawal produces stress. Gabapentin appears to relieve stress by normalizing levels of the neurotransmitter GABA, which soothes the nervous system.
Gabapentin is also useful in treating marijuana dependence, said Mason. She led a study that found effectiveness in treating 50 cannabis users. The study was published in June 2012 in the journal Neuropsychopharmacology.
Gabapentin’s side effects are mild, and even advantageous, Mason said. The drug can cause sleepiness; however, those withdrawing from alcohol have trouble sleeping.
The study said “participants reported experiencing sleep disturbance and related daytime dysfunction that significantly improved with gabapentin relative to placebo.”
A commentary on the study appearing in the journal said gabapentin has a “strong potential” for treating alcohol dependence, but lack of FDA approval hinders its use. A clinical trial might be needed to get approval.
“Since gabapentin is off-patent, there is limited financial incentive for a pharmaceutical firm to assume sponsorship, and government support would probably be needed to make this happen,” said the commentary.
Mason said study researchers are “actively discussing” getting support for such a trial from the National Institutes of Health.
About 18 million Americans have an alcohol use disorder, according to the National Institute of Alcohol Abuse and Alcoholism, part of the National Institutes of Health. These either have alcohol dependence, also called alcoholism, or abuse alcohol.
More Americans are dependent on or abuse alcohol than all illicit drugs combined, according to the 2006 National Survey on Drug Use and Health. The survey found that 22.6 million people had drug or alcohol problems; of those 15.6 million had problems with alcohol but not illegal drugs.
Gabapentin’s effectiveness in relieving alcohol withdrawal has long been suspected. However, it’s illegal for drugmakers to advertise or promote drugs for so-called “off-label uses,” whether or not the information they provide is accurate. The Warner-Lambert unit of Pfizer, which sold the drug as Neurontin, got into trouble for off-label promotion. In 2004, the unit pleaded guilty to two felonies and agreed to pay $430 million for the unapproved promotions.
Warner-Lambert admitted illegally marketing the drug for alcohol withdrawal, along with bipolar disorder, pain and migraines.
The study, “Gabapentin Treatment for Alcohol Dependence: A Randomized Controlled Trial,” was funded by National Institute on Alcohol Abuse and Alcoholism and a grant to Mason from the National Institutes of Health.
Other contributors to the study were Susan Quello and Vivian Goodell of TSRI; and physicians Farhad Shadan, Mark Kyle and Adnan Begovic of Scripps Clinic and Scripps Green Hospital.