In February the FDA approved Alli, an over-the-counter (OTC) version of orlistat (Xenical). Alli is expected to arrive in drugstores this month. The advent of America's first FDA-approved nonprescription diet pill likely will assist some people attempting to lose weight because of the medical risks associated with obesity. Yet because Alli will be readily available, some patients with eating disorders likely will abuse this medication and potentially incur dangerous medical side effects.
Research suggests that people with eating disorders regularly abuse OTC diet products to control weight and suppress appetite. Between 28%1 and 64%2 of eating disorder outpatients might use such products to control weight and appetite. The percentages of adult and adolescent eating disorder patients who abuse OTC products are similar. Eating disorder patients continue to use such products despite adverse side effects2 and despite the fact that no OTC diet product (until now) has FDA approval or established efficacy for weight loss or appetite suppression. Yet because Alli has FDA approval as a diet aid and because orlistat is known to increase weight loss among dieters by as much as 40%,3 it is possible that even greater percentages of eating disorder sufferers will misuse Alli.
In fact, several case studies have documented orlistat abuse among patients with eating disorders. Normal-weight patients with bulimia nervosa have abused orlistat as a purging mechanism.4-6 Patients who initially meet criteria for binge eating disorder but who misuse orlistat to purge may develop full-blown bulimia nervosa,5 a more serious illness.
Research has demonstrated that orlistat entails a range of side effects (table). Although Alli will be of reduced strength relative to prescription orlistat, when patients abuse diet products they typically take larger than recommended doses, perhaps as much as ten times more than recommended doses.7 Hence, the actual ingested dose of Alli for many eating disorder patients may exceed the strength of prescription orlistat. As a result, the known side effects of orlistat may be even more severe or more common in those who abuse Alli.
One of orlistat's unpleasant side effects is diarrhea, but this might not dissuade eating disorder patients from abusing Alli. As much as 26%8 of eating disorder patients abuse OTC laxatives, of which diarrhea is a side effect. Among college students who do not even have an eating disorder, 26% of those merely at risk for eating disorders may abuse laxatives for weight loss purposes.9 In fact, patients with eating disorders, particularly those with bulimia nervosa and binge-purge anorexia nervosa, are likely to abuse laxatives. If laxatives are abused concomitantly with orlistat, these patients may be at greater risk for fluid and electrolyte imbalances, making them vulnerable to a sudden cardiac event or sudden death.
And among inpatients with severe eating disorders treated at our facility, one of the largest inpatient eating disorder treatment systems in North America, 26% abuse OTC diet products and 15% abuse laxatives. Hence, as many as four in ten severe eating disorder patients may be willing to abuse an OTC product.
Other commonly observed side effects of orlistat include such gastrointestinal symptoms as flatulence with discharge, oily spotting of underwear, fecal urgency, fatty/oily stools, increased defecation, and fecal incontinence. These side effects result from orlistat's partial blockage of fat absorption in the intestine. Such blockage entails a significant reduction in the absorption of the fat soluble vitamins: A, D, E, and K. One pharmacokinetic interaction study showed a 30% reduction in beta-carotene supplement absorption when taken concomitantly with orlistat.10 Another study suggested that orlistat inhibits absorption of vitamin E by approximately 60%.11 In adolescents prescribed a multivitamin, three to six months of orlistat treatment diminished their vitamin D and K concentrations.12