Addition of Naltrexone to Fluoxetine in the Treatment of Binge Eating Disorder
To the Editor: Binge eating disorder is characterized by the presence of recurrent binge eating episodes and the absence of inappropriate compensatory behaviors to avoid weight gain (DSM-IV). Serotonergic agents, e.g., fluoxetine, may be effective to reduce binge frequency and induce weight loss (1). In humans, opiate antagonists, e.g., naltrexone, have proven to have robust short-term effects on food intake and eating behavior, but the value of naltrexone alone for long-term treatment of eating disorders is limited (2).
Ms. A was a 16-year-old girl who was hospitalized because of binge eating disorder with a complete loss of control of food intake and a severe major depressive episode including suicidal ideation and self-harming behavior (cutting herself). At hospitalization, her weight was 57.6 kg. Binges occurred at least once a day, and the amount of calories per day was about 5,000. Given the evidence that fluoxetine may be effective in reducing weight, Ms. A was treated with a regimen of fluoxetine, up to 60 mg/day, cognitive behavioral therapy, and dietary management. After several weeks, the depressive symptoms improved, but episodes of bingeing remained unchanged. Thus, we decided to administer, in addition to the described treatment schedule, the opiate antagonist naltrexone, at a daily dose of 100 mg. Within 14 days, we found a robust reduction in binge frequency and the amount of food consumed by Ms. A and weight loss. After discharge, Ms. A was treated with a regimen of fluoxetine (at 60 mg/day), naltrexone (at 100 mg/day), and psychotherapy. Follow-up data after 1 year showed that Ms. A’s weight (49 kg) had remained stable, and she never reported more than 2 binges/month. No side effects were documented. After 1 year, the daily dose of naltrexone was reduced to 50 mg/day, which was followed within 2 weeks by an increase in binge frequency. When we increased the dose of naltrexone to 100 mg/day, the symptoms disappeared again.
The present study is in line with controlled trials proving the efficacy of fluoxetine in the treatment of adolescent depression (3).Fluoxetine and psychotherapy alone did not reduce weight or binge frequency in Ms. A. The efficacy of naltrexone to reduce binge frequency supports hypotheses that endogenous opioid systems may play a role in binge eating disorder. It is interesting that the binge frequency was only reduced at a higher dose of naltrexone but not at a lower dose, arguing for a dose-dependent effect. The treatment combination of fluoxetine and naltrexone could possibly be a new strategy in the treatment of binge eating disorder in adolescents. Clearly, our findings have to be considered preliminary and must be confirmed in placebo-controlled, double-blind trials.
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