The combination of topiramate drug counseling slowed marijuana among young smokers significantly more than did counseling alone, according to the recently published results of a small randomized controlled trial at Brown University. The results come with a warning, however: many study volunteers were unable to tolerate the side effects of the drug.
There is no medication approved by the FDA for treatment of cannabis dependence and abuse. Meanwhile, the benefits of treatment counseling, and motivational enhancement therapy (MET), are not enough to help many patients, said Robert Miranda Jr., associate professor (research) of psychiatry and human behavior at the School of Medicine Alpert.
Miranda and his co-authors conducted the trial as the first test to determine whether topiramate an epilepsy drug marketed as Topamax, could add to the benefits of the market economy. Previously, researchers have studied including Miranda topiramate as a potential treatment for alcohol and nicotine dependence and cocaine addiction .
The results show the drug provides a statistically significant benefit. While topiramate did not reduce smoking frequency significantly more than therapy alone, the study participants who received medication and MET used less marijuana each time on average than participants who received counseling and a placebo.
“The positive news is that it seemed to have some effect and that the effect seemed to be really focused on helping people reduce the amount they smoke when they smoke,” Miranda, lead author of the study in the journal said Addiction Biology and member of the Center for Alcohol and addiction studies at the School of Public Health at Brown University. “It is promising in the sense that suggests that medications can help, but asks questions about who might be more effective because many people can not tolerate the medication.”
Users seeking help
To carry out the pilot study, the first to test topiramate for cannabis dependence, Miranda’s team recruited 66 volunteers, aged 15-24 years, who had smoked at least twice a week, but they were interested to receive psychological treatment and medication to reduce marijuana use. Intensive use is associated with impaired memory and executive cognitive function, difficulty maintaining attention and filtering irrelevant information. The initial screening showed that more than half of the participants met the clinical criteria for marijuana dependence or abuse.
Whether they were assigned to placebo or to receive topiramate, all participants received MET sessions of 50 minutes at weeks 1, 3 and 5 of the six-week study. MET professionally guided discussion involves motivation to stop smoking or reduce their use.
Of the 66 volunteers, 40 received topiramate at doses climb slowly up from 25 in the first week milligrams to 200 milligrams per week five before being edged out a few days after the end of the study.
Through interviews and other means consistent during the study, volunteers remembered how often they smoked and how much (urinalysis allow see if they were using marijuana and taking either the drug or the placebo). Both groups reduced the number of days that marijuana statistically similar amounts were used, but those who took the drug also used on average about 0.2 grams of cannabis less each time.
difficult side effects
While Miranda said he was encouraged by the results showing a significant additional effect of medication, it was clear that the treatment was not for everyone. At the end of the six-week study, 21 of the 40 subjects who received the drug had dropped compared with only 6 of the 26 people who took the placebo. Two thirds of those who left the study after using topiramate side effects cite as their reason for leaving. They complained of problems such as depression anxiety , problems with coordination and balance, weight loss and unusual sensations.
A next step in the investigation, Miranda said, would be to perform a larger and perhaps more testing. Another useful experiment would determine whether genetic markers or other factors may help predict who will have less difficulty with side effects of topiramate. That knowledge would allow any future clinical treatment to be applied to patients who will benefit.
In a small clinical trial, topiramate reduces the amount of smoked marijuana users (solid line) compared to placebo (dotted line). Both groups received MET counesling.
Robert Miranda University Jr./Brown