A new study suggests that medication long used to treat obesity may also be able to help patients who are suffering from the eating disorder bulimia nervosa. Researchers have suspected that the medication could be effective at treating the disorder, but the new clinical study finally provides data that seems to back up the theory.

A New Use for an Old Treatment

The study looked at the effects of medication consisting of a combination of two drugs, phentermine, and topiramate. Topiramate has been used to treat binge-eating disorder, and phentermine is often used as a short-term appetite suppressant to treat obesity. The combination of the two drugs, which is marketed under the brand name Qsymia, is approved for the treatment of obese patients with high blood pressure, type 2 diabetes, or high cholesterol. It has been on the market since 2012.

Despite the medication’s effectiveness, no one knows exactly how it works. It’s thought that phentermine suppresses appetite by controlling the release of the brain chemical norepinephrine, whose primary function is to cause alertness and focus. Topiramate may work by inhibiting the effect of glutamate, a brain chemical that, among other things, seems to stimulate the appetite.

The effectiveness of the medication at suppressing appetite led scientists to believe it might also be able to control the unhealthy eating habits associated with binge-eating disorder and bulimia.

Hope for Bulimia

Bulimia nervosa is an eating disorder in which the patient, in an attempt to lose weight, engages in binge eating and then attempts to purge the extra calories in an unhealthy way, such as vomiting or using laxatives. The hope is that the phentermine/topiramate medication might control binge-eating behaviors and, as a consequence, help control the secondary unhealthy effects of bulimia.

In the study, some participants who had been diagnosed with bulimia nervosa or binge-eating disorder were given the phentermine/topiramate medication for 12 weeks. Others were given a placebo. The participants who took the medication showed a significant improvement in some key areas.

Those who took the medication reported a 75% reduction in the number of days in which they engaged in eating binges. Almost 64% of the non-placebo participants abstained entirely from binge eating. They also lost weight at a much higher rate than the placebo participants, and they reported a reduction in secondary symptoms such as depression.

The study is the first randomized, controlled trial aimed at assessing the effectiveness and safety of phentermine/topiramate in the treatment of bulimia nervosa and binge-eating disorder. Previous papers have noted that the medication seems to have worked in anecdotal cases, but no previous study has delivered objective, measurable data.

It should be noted that this research is preliminary, and more studies are needed to determine whether the medication is safe and effective for bulimia sufferers. Qsymia has also been linked to birth defects when used by pregnant women, and it is not recommended for use by all patients.

Vivus, New Clinical Data Demonstrate VIVUS’ Qsymia® is Effective at Reducing Binge Eating in Patients with Binge-Eating Disorder or Bulimia Nervosa
International Journal of Eating Disorders, A randomized, placebo‐controlled crossover trial of phentermine‐topiramate ER in patients with binge‐eating disorder and bulimia nervosa
Drug Design, Development and Therapy, Phentermine and topiramate for the management of obesity: a review

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