Eating disorders may be treated by Topamax

Last updated: May 2011

Contrary to popular belief, eating disorders affect men and women of all ages, not just the stereotypical teenage girl. Rates have risen sharply among boys during the last few decades, and experts estimate that up to 14 percent of Americans now have at least some signs of an eating disorder, which include:

  • Anorexia nervosa, characterized by self-starvation, low body-fat content and weight, feeling "fat" despite profound weight loss, and irregular periods in girls and women, or an absence of them.
  • Bulimia nervosa, a secretive cycle of binge eating followed by purging through self-induced vomiting, laxative abuse, excessive exercise, or fasting.
  • Binge eating, the most common eating disorder, marked by repeated episodes of uncontrolled overeating (but not followed by purging); about 65 percent of people with the disorder are obese.
  • Some combination of the symptoms above.

Treatment for eating disorders includes cognitive behavioral therapy, nutritional counseling, and medication, frequently in combination. But many patients don't respond adequately, and those treated for binge eating disorder often fail to lose weight. The Food and Drug Administration has approved only one drug—the antidepressant fluoxetine (Prozac and generic)—for the treatment of an eating disorder (bulimia nervosa). Consequently there is particular interest in topiramate (Topamax and generic), a drug approved to treat certain types of seizures and prevent migraine headaches, but is used off-label to control binging and purging, and to promote weight loss in people with eating disorders. (Doctors can legally prescribe any medication they deem appropriate to treat a patient's condition.)

Experts aren't sure why topiramate helps, but they think it enhances networks in the brain that have a calming effect and inhibits networks that are overstimulating. "That seems to reduce food cravings," says Joel Yager, M.D., a professor of psychiatry at the University of Colorado in Denver, who notes that the drug is also used to combat cravings for alcohol and cigarettes. "Topiramate is most effective for people who are overweight or obese with binge-eating disorder or bulimia nervosa, and the additional benefit is that they can lose some weight," he says. "But it's not a first-line drug because a significant minority of patients will have bothersome, and sometimes serious, side effects. Also, many people with bulimia nervosa are flirting with anorexia nervosa, and topiramate may cause unwanted additional weight loss."

What is the evidence?

There have been studies focused on topiramate for binge-eating disorder, and a few have examined its use in treating bulimia nervosa. Most were lasted a short period of time (12 to 24 weeks), included primarily women, and excluded people with psychiatric problems, which are common among people with eating disorders. That makes it difficult to draw conclusions about topiramate's long-term effectiveness or its benefits for a broader population. Most studies also noted a high placebo response. In addition, pharmaceutical companies that market topiramate sponsored nearly all of the significant published trials, raising the possibility of a conflict of interest.

According to guidelines from the American Psychiatric Association (APA), small controlled trials demonstrate topiramate's effectiveness as a treatment for bulimia nervosa. But the drug is recommended only when other medications have been ineffective, and is problematic for bulimic people of normal or low body weight. "It could be used by women with normal-weight bulimia nervosa who don't have menstrual irregularities and for whom the risk of losing a few pounds won't cause health concerns," says Yager, chairman of the group that wrote the guidelines. For those with binge-eating disorder, the APA finds topiramate effective for binge reduction and weight loss, but the side effects might limit its usefulness for many people.

In the medication trials reviewed, the Agency for Healthcare Research and Quality found topiramate to be superior to placebos in reducing the number of binge and purge days and easing obsessions related to body weight, food preoccupation, anxiety, and body dissatisfaction in people with bulimia nervosa. The agency reported that topiramate reduced binge frequency and body weight and eating-related obsessions and compulsions in people with binge-eating disorder. But a number of people withdrew from the trials due to side effects.

In a 2007 study by Brazilian researchers, 73 obese binge eaters were randomly assigned to take topiramate or a placebo in addition to participating in cognitive behavioral therapy (CBT). The ones who took topiramate plus CBT experienced greater weight loss and a higher rate of abstention from binging during treatment.

What are the risks and warnings?

Eye problems can lead to permanent loss of vision if not treated. Tell your doctor beforehand if you've had glaucoma and report eye pain, redness, or vision changes during treatment.

Decreased sweating makes it more difficult for your body to cool down when it gets very hot and might make you more vulnerable to heat-stroke. Avoid exposure to heat, drink plenty of fluids, and notify your doctor if you have a fever.

Suicidal thoughts or actions should be reported immediately to your doctor, including panic attacks, agitation, irritability, anxiety, depression, sleep problems, talking or thinking about suicide, and any other changes in behavior or mood.

Excess acid in the blood (acidosis) can cause tiredness, loss of appetite, irregular heartbeat, and impaired consciousness, and is more likely if you consume a high-fat, low-carbohydrate diet or have kidney disease, respiratory problems, or diarrhea. Tell your doctor if you have any of those conditions before or during treatment, and don't follow a high-fat, low-carb diet while taking the medication.

Kidney stones might develop. Drink six to eight glasses of water a day and tell your doctor beforehand if you've ever had kidney stones.

Cognitive problems involving thinking, concentration, attention, memory or speech might occur. Topiramate has also been found to cause confusion, dizziness, and sleepiness. Don't drive a car or operate machinery until you know how the drug affects you, and avoid alcohol and sedating drugs.

Other side effects include headaches, tingling in the hands or feet, dry mouth, nausea, taste disturbance, diarrhea, upset stomach, and menstrual problems. Additionally, the FDA recently announced that Topamax can cause birth defects in humans.

Drug interactions include reduced effectiveness of birth-control pills. Tell your doctor what prescription and over-the-counter medications and supplements you are taking or plan to take.

Sudden withdrawal from topiramate can cause serious problems. Don't stop taking it without first talking to a doctor.

Tell your doctor before treatment if you've ever had liver problems, osteoporosis, or mood disorders, or if you're pregnant, planning to become pregnant or breast-feeding.

What steps should you try first?

Eating disorders require professional help that includes some form of psychotherapy as well as nutritional counseling. For the treatment of bulimia nervosa and binge eating, substantial evidence supports the effectiveness of cognitive behavioral therapy and SSRI (selective serotonin reuptake inhibitor) antidepressants such as fluoxetine or sertraline (Zoloft and generic).

Bottom line. Small, short-term, controlled trials suggest that topiramate might reduce binges and purges and promote weight loss in overweight or obese people with binge-eating disorder. But our medical experts say that troublesome side effects, many serious and some life-threatening, preclude its usefulness in all but the most severe cases of binge eating—and then only when all other efforts have failed.

This off-label drug use report is made possible through a collaboration between Consumer Reports Best Buy Drugs and the American Society of Health-System Pharmacists. This is the 23rd in a series based on professional reports prepared by ASHP.

These materials were made possible by a grant from the state Attorney General Consumer and Prescriber Education Grant Program, which is funded by a multistate settlement of consumer fraud claims regarding the marketing of the prescription drug Neurontin (gabapentin).

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