Drug eases alcohol cravings and anxiety in rats addicted to alcohol.
A drug used to treat epilepsy could also ease cravings in alcoholics, say researchers who have investigated the effect in rats.
The drug, called gabapentin, is approved for the treatment of epileptic seizures and for some conditions that cause chronic pain. And now, researchers led by Marisa Roberto, of the Scripps Research Institute in La Jolla, California, have shown that alcohol-dependent rats given gabapentin drink less alcohol and are less anxious than those not given the drug1.
Preliminary small clinical trials have suggested that gabapentin could also be useful in the treatment of drug addiction, and trials are now under way to determine whether the drug can ease alcoholism in people.
The current results are promising, says Robert Swift, a researcher at the Center for Alcohol and Addiction Studies at Brown University in Rhode Island. “This paper really suggests that gabapentin may be efficacious in reducing drinking [in alcoholics],” he says.
Gabapentin is structurally similar to a neurotransmitter called γ-aminobutyric acid, or GABA, which can slow communication between neurons in the brain. Although the drug does not function in precisely the same way as GABA, it can prevent the chaotic electrical activity in the brain that triggers a seizure.
Alcohol affects the GABA system by mimicking GABA's activity in the brain, which contributes to alcohol’s sedative effect. But chronic drinking can lead to tolerance: a condition in which more and more alcohol is required to produce the same GABA response. Without an increasing supply of alcohol, alcoholics can begin to feel agitated.
There has been a lot of interest in whether epilepsy drugs might also be useful for treating alcoholism, says Swift. The drugs could help an alcoholic during the early stages of abstinence, until normal GABA tolerance has been restored, he adds.
No easy answer
Roberto and her colleagues investigated this possibility by testing the effects of gabapentin in rats. They modelled alcoholism in the rodents by exposing them to ethanol vapour for two to four weeks. By that time, the rats had become dependent on the alcohol and drank more ethanol than rats that had never previously been exposed to it.
But alcohol-dependent rats that were given gabapentin drank less ethanol and seemed less anxious than those that received the placebo. The drug had no effect on the drinking habits of rats that were not dependent on ethanol.
Although the results look promising, Roberto warns against perceiving gabapentin as a cure for alcoholism. No one drug is likely to be able to handle the disease, she says. “Alcohol is a very dirty drug,” says Roberto. “It affects so many neural systems.”
As with most behavioural disorders, counselling will remain an important component of treatment, says Swift. “You can’t just treat alcoholics with a pill,” he says. “You need to treat both the psychological component and the biological component.”
Roberto, M. et al. J. Neurosci. 28, 5762–5771 (2008).