Orlistat and Weight Loss in Adolescents

Orlistat, an inhibitor of gastrointestinal fat absorption used for promoting weight loss in adults, was approved for use in adolescents in 2003, partly based on results from this randomized trial. The manufacturer of orlistat contributed to the study design, data analysis, and manuscript preparation.

Researchers randomized 539 obese adolescents (age range, 12–16) to receive orlistat (120 mg, 3 times daily) or placebo for 1 year. All participants received instruction in maintaining hypocaloric diets and regular exercise; behavioral modification techniques were used to change eating habits. About 65% of each group completed the trial, but all 533 subjects who had at least one follow-up assessment were included in the analyses.

At 12 weeks, mean body-mass index had decreased by 1 unit among orlistat recipients and by 0.5 units among controls. At 1 year, mean BMI was roughly 0.6 units lower than baseline among orlistat subjects and about 0.2 units higher than baseline among controls, and BMI had decreased by 5% among significantly more orlistat subjects than controls (27% vs. 16%). Gastrointestinal adverse events were more common in the orlistat group, ranging from 9% with fecal incontinence to 50% with fatty/oily stool.

These findings are intriguing, but they are difficult to translate into routine practice for many reasons: A large proportion of subjects did not complete the study; the behavioral interventions were intense (as suggested by the impressive weight loss in one sixth of controls); the side effects were considerable; and the medication is expensive (US$170/month wholesale, according to an editorialist) and would have to be taken during school.

References:

1. Chanoine J-P et al. Effect of orlistat on weight and body composition in obese adolescents: A randomized controlled trial. JAMA 2005 Jun 15; 293:2873-83.

2. Joffe A. Pharmacotherapy for adolescent obesity: A weighty issue. JAMA 2005 Jun 15; 293:2932-4.