New Drug Curbs Pot Dependence

Topiramate significantly reduced marijuana use, but side effects were severe in some cases


For patients struggling with marijuana dependence, a new treatment option could be on the horizon.

A new study from Brown University found that, when used in combination with addiction counseling, the epilepsy drug topiramate (brand name Topamax) curbed marijuana use among young smokers significantly more than counseling alone. However, many of the study patients couldn't tolerate the medication's side effects.

"The positive news is it did seem to have some effect, and that effect seemed to really be focused on helping people reduce how much they smoke," said lead study author Robert Miranda, PhD, a professor of psychiatry and human behavior at Brown, in a press release. "It's promising in the sense that it suggests that medications can help, but it asks questions about for whom it might be most effective because many people can't tolerate the medication."

There is currently no FDA-approved medication for marijuana dependence or misuse. And the benefits of counseling, according to Dr. Miranda and colleagues, aren't always enough to help patients.

That's why Dr. Miranda and team conducted this trial — to find out whether topiramate could add to the benefits of addiction counseling for patients with marijuana dependence. Researchers including Dr. Miranda previously looked at topiramate as a potential treatment option for alcohol, cocaine and nicotine dependence.

For this study, Dr. Miranda and team recruited 66 volunteers ages 15 to 24 who smoked at least twice weekly and were interested in receiving treatment to reduce their marijuana use. Initial screening showed that more than half of these patients met clinical criteria for marijuana dependence or abuse.

Of the 66 volunteers, 40 received topiramate in doses that slowly scaled up from 25 to 200 milligrams. The remaining patients received a placebo. All received 50-minute counseling sessions every other week in addition to medication.

Through regular interviews, patients reported how often they smoked and how much. Urine tests were also used to show whether they were using marijuana.

Both groups reduced the number of days in which they used marijuana by similar amounts. However, the topiramate group used about 0.2 fewer grams of cannabis each time on average compared to the placebo group.

While Dr. Miranda said his team was encouraged by these results, it was clear that the treatment was not for everyone.

By the study's end, 21 of the 40 patients given topiramate had stopped taking the drug. Only 6 of the 26 patients given a placebo had done the same.

The most common side effects reported included depression, anxiety, coordination and balance problems, weight loss and unusual sensations.

This study was published Jan. 14 in the journal Addiction Biology.

The National Institute on Drug Abuse funded this research. No conflicts of interest were disclosed.