The drug Topamax (topiramate), typically used to treat epilepsy and more recently weight loss, may also help people addicted to both cocaine and alcohol use less cocaine, according to a new study.
Results from the double-blind, placebo-controlled trial add to the growing evidence supporting topiramate as a promising medication to treat addiction, say researchers at the University of Pennsylvania School of Medicine.
Previous separate studies have shown that topiramate can reduce alcohol dependence, as well as reduce relapse to cocaine. But using it to treat both alcohol- and cocaine-dependent people has not been explored in a clinical trial, the researchers said.
Since cocaine and alcohol addictions often go hand in hand, therapies targeting both may be the best strategy for treatment, they note.
Results of the 13-week clinical trial of 170 alcohol and cocaine-dependent people produced mixed results, the researchers report. The drug reduced alcohol cravings, but did not reduce drinking, and was not better at reducing cocaine cravings.
Addicts on topiramate, however, versus those on a placebo, were more likely to stay in treatment and abstain from cocaine during the last three weeks of the trial. People with more severe cocaine withdrawal symptoms — agitation, restless behavior, and depressed mood — appeared to have benefited most from topiramate, according to the researchers.
“Cocaine dependence continues to be a significant public health concern in the United States and Europe. Drug counseling remains the treatment of choice, but many patients do not respond completely to it, so developing effective medications for treatment is a research priority,” said first author Kyle M. Kampman, M.D., professor of psychiatry and medical director at the Charles O’Brien Center for Addiction Treatment.
Topiramate is an anticonvulsant drug that increases the brain levels of GABA, or gamma-Aminobutyric acid, which is a primary inhibitory neurotransmitter in the central nervous system. It is FDA approved for the treatment of epilepsy, migraines and, more recently, for weight loss in combination with phentermine.
It is speculated that the increase of GABA may reduce the dopamine release associated with cocaine and alcohol use, which would reduce the reinforcing euphoric effects of the two. A small pilot study in 2005 found that topiramate helped cocaine addicts stay off the drug for three weeks or more.
Given prior studies, it’s puzzling that topiramate did not reduce alcohol dependence, but could be explained by the severity of the group’s addiction to it, according to the researchers. The percent days of heavy drinking for participants in this trial were much lower than past studies (12 percent vs 48 percent in some cases).
Topiramate may have a greater effect in those who drink more heavily, the researchers suggested.
The double-blind, placebo-controlled trial included addicts whose average age was 45 and were mainly African-American males who smoked crack cocaine.
There was no significant difference, with respect to demographics, drug and alcohol use and amount of money spent on substances, between the two groups. Drug and alcohol tests were performed three times a week.
During the last three weeks of the trial, 20 percent of users on topiramate abstained from cocaine, compared to just 7 percent on the placebo. Heavy users also had significantly more negative cocaine drug tests during the trial compared to placebo-treated subjects (17.6 percent vs. 8.8 percent.) The drug likely had a more positive impact on heavy users because they experience higher levels of cocaine euphoria, said Kampman.
He noted that 65 percent of those who were on topiramate stayed in the trial, while 59 percent of subjects on the placebo stayed — a statistically significant difference.
“This study further supports topiramate as a promising medication for people who are both alcohol- and cocaine-dependent,” he said.
“Future studies are planned in which topiramate will be combined with other promising medications for the treatment of cocaine dependence in the hope of achieving even higher levels of cocaine abstinence than were achieved with topiramate alone.”
The study was published in Drug and Alcohol Dependence.