Reprinted from Eating Disorders Review
September/October 2009 Volume 20, Number 5
©2009 Gürze Books
Topiramate, an anticonvulsant drug used for treating epilepsy, also has other effects, including reduction of impulsiveness and weight loss. The drug has been used for off-label uses such as smoking cessation and alcohol dependence. Its mechanism of action is still being debated.
Given all its effects, a group of Italian clinicians wondered if the drug might be helpful for treating obese patients with binge eating disorder (BED). Dr. Paolo Leombruni and colleagues at the Centre for Eating Disorders and Obesity, Turin, Italy, conducted a systematic literature research to determine the efficacy and safety of the anticonvulsant for treating obese patients with BED (Neuropsychiatr Dis Treatment 2009; 5:385).
What the authors found
The authors concluded that topiramate appears to be a relatively safe and effective treatment for obese persons with BED. The safest and most effective dosage schedule was starting the drug at 25 mg per day, then increasing the dosage by 25 mg per day every one to two weeks, to reach a dosage of 150 to 200 mg per day. For selected patients, the dosage can be increased to 400 mg per day or more.
Topiramate seems to produce greater weight loss than does other therapies, such as cognitive behavioral therapy, interpersonal therapy and the selective serotonin reuptake inhibitors, or SSRIs. While some authors expressed doubts about patients’ ability to tolerate the drug, considering the effects reported by epileptic patients, the authors note that the dosages in persons with BED produce milder adverse effects. While kidneys stones have been a concern, no case of this has been reported in patients with BED.
Other studies have shown less promising results. In one large international study, the drug was not useful for controlling bipolar disorder. In addition, a large Phase II trial of topiramate for binge eating disorder (BED) did not go on to Phase III clinical trials. The reasons for this are not completely clear, but the drug is not easy to use.
Some major limitations of the Italian study include lack of data on the long-term effects of the drug; the fairly high dropout rate reported in the studies analyzed, which was up to 30%; and the wide exclusion criteria among the randomized controlled clinical trials. Another concern was the lack of homogeneity among the psychological tests used to assess binge eating.
(Note: Dr. Yager has seen a patient with BED treated with topiramate and who had no prior history of kidney stones, but developed kidney stones for the first time during treatment with topiramate. In addition, the drug’s significant side effects, including memory problems, can be very disturbing to patients. Reducing the dosage or using small doses is helpful, but doesn’t always solve the problem.)