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Zyprexa to Treat Anorexia

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Zyprexa® is a drug that is marketed to treat psychosis. However, as with many other drugs, doctors noticed a side effect and thought it may be useful for other conditions.

In the case of Zyprexa (generic: Olanzapine), the side effect seen in some patients was weight gain.

The “other” condition was anorexia nervosa.

How does it help anorexics gain weight?

Studies have not been able to show precisely why. Since the drug is not marketed for this use, the manufacturer has not presented evidence, nor a specific mechanism, and the FDA has not approved it specifically for anorexia nervosa. The short answer is that no one knows exactly.

This doesn’t mean there aren’t some ideas. Zyprexa finds use in bipolar disorder and in treating delusions as well as depression. These are thought to be part of the disease of anorexia, especially body image disorder – where the anorexic sees themselves as fat when they are actually normal or even quite thin.

Does it really work?

Research continues, but the short answer is “sometimes.” Studies have shown conflicting results, some showing promise and others no effect. This doesn’t come as a complete surprise. Even for its labeled use, Zyprexa doesn’t help everyone. Mental health treatment is not an exact science and sometimes many different agents are tried in the hopes of finding something useful for a particular patient.

Can doctors prescribe it for anorexia?

Legally, yes. Prescribing Olanzapine for anorexia is an “off-label” use. That means the drug is legally marketed and prescribed, but not for the condition the doctor wants to use it for. Some doctors are more willing to try off-label uses, some less so.

It is illegal for the manufacturer to tell doctors to use it for anorexia. In fact, the company that manufactures Zyprexa has already been fined for saying it was useful for dementia – another off-label use. They paid a $1.4 billion fine for doing so in 2009.

Is it safe?

No prescription medication is completely safe. Zyprexa comes with a list of warnings and cautions, among them an increased risk for diabetes. An excellent monograph on this can be found here.

The proper way to evaluate risk vs. benefits is with the advice of a physician familiar with the patient. Treatment for eating disorders can be complex. When used for anorexia, Olanzapine is combined with other treatments, including behavioral therapy and counseling.