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Eating disorders: Pharmacotherapy

Anorexia nervosa

For anorexia nervosa, the treatment drug of choice is food. In sufficient quantities over enough time, food will reverse virtually all of the numerous laboratory and physical anomalies associated with the anorexia nervosa. Eating will also reverse some of the psychiatric symptoms, such as mood instability, anxiety, impaired concentration and sleep disturbance.

Resist the temptation to use antidepressants for the mood disturbance because there is no evidence for their effectiveness in the underweight state.

For some patients, the anticipatory anxiety before an appropriate meal can be so overwhelming that short-acting benzodiazepines such as lorazepam are used, but there is no high-quality evidence beyond clinical experience to support the use of benzodiazepines.

The seemingly delusional body image distortion evident in anorexia nervosa does not respond to antipsychotic medication. Drugs that induce weight gain as a side-effect or drugs that stimulate appetite should not be used because evidence shows they do not work. However, weight-recovered people with anorexia nervosa, given their long-term vulnerability to mood and anxiety disorders, may require pharmacotherapy.

Bulimia nervosa and binge eating disorder

There is significant evidence about the efficacy of antidepressants in bulimia nervosa. However, fluoxetine is the only such drug approved by Health Canada for treating the disorder, and the dose at which people typically respond is 60 mg per day in a single dose (versus 20 mg for people with depression only). There is no published evidence of increased suicidality with fluoxetine for this disorder. Common side-effects include sleep disturbance and decreased sexual desire and function.

For binge eating disorder, moderate evidence exists for the efficacy of various SSRIs (fluoxetine, fluvoxamine, sertraline, citalopram), with greater reductions in binge eating and other psychiatric symptoms than placebo. However, clinical trials had high dropout rates and placebo response rates.

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Frequently asked questions

Clinical guidelines

Eating disorders in over 8s: management (NICE guideline CG9, 2004)