Orlistat, a drug that decreases fat absorption, appears helpful for improving weight management in obese adolescents

Jun 14 2005

When combined with diet, exercise and behavioral therapy, orlistat, a drug that decreases fat absorption, appears helpful for improving weight management in obese adolescents, compared with placebo, according to an article in the June 15 issue of JAMA: The Journal of the American Medical Association.

Excess weight in adolescents is associated with increased risk of hyperlipidemia and type 2 diabetes, and its prevalence is increasing worldwide, according to background information in the article. In the United States, the proportion of adolescents with a body mass index (BMI) at or above the 95th percentile for age, a widely accepted definition of obesity in adolescents, has increased 15.5 percent to 23.4 percent in certain ethnic minorities. Overweight children are at a 15-fold greater risk of becoming overweight adults compared to children and adolescents not overweight. Pediatric obesity can be particularly difficult to treat, with long-term success depending on the type of therapy used. Orlistat is a gastrointestinal tract lipase (an enzyme) inhibitor which decreases intestinal fat absorption by up to 30 percent; in adults, the drug has a good safety profile and is generally well tolerated.

Jean-Pierre Chanoine, M.D., Ph.D., from the British Columbia Children's Hospital, Vancouver, and colleagues examined the effectiveness and safety of orlistat for weight management in adolescents, in this 54-week, randomized, double-blind study. Participants were aged 12 to 16 years and had a BMI (calculated as weight in kilograms divided by the square of height in meters) two units or more above the 95th percentile at baseline. Three hundred fifty-seven patients received 120 mg of orlistat three times daily and 182 participants received placebo three times daily for one year. Both groups were given instructions on how to maintain a reduced calorie diet, and received counseling for exercise and behavior modification (i.e., recording food intake, recognizing cues for overeating). The researchers also assessed the impact of orlistat treatment on waist circumference, lipid levels, blood pressure, and glucose and insulin.

The researchers found that both groups experienced a decrease in BMI up to week 12, thereafter stabilizing with orlistat but increasing beyond baseline with placebo. At the end of the study, BMI had decreased by 0.55 with orlistat, and had increased by 0.31 with placebo; weight had increased 0.53 kg. with orlistat and 3.14 kg. with placebo. At the study's end, 15.7 percent of the placebo group compared to 26.5 percent of orlistat patients had a five percent or higher decrease in BMI, and 4.5 percent of the placebo group and 13.3 percent of the orlistat group had a ten percent or higher decrease in BMI.

Waist circumference also decreased in the orlistat group by 1.33 cm (.52 inches) and increased by .12 cm (.047 inches) in the placebo group. Mild to moderate gastrointestinal tract adverse effects (such as nausea, fatty/oily stools, and abdominal pain) occurred in 9 percent to 50 percent of the orlistat group, and one percent to 13 percent of the placebo group.

"We conclude that treatment with 120 mg of orlistat three times daily for 52 weeks, in conjunction with a reduced-calorie diet, exercise, and behavioral modification, statistically significantly improves weight management in obese adolescent participants," the authors write. "This effect is probably due to the decrease in the absorption of fat and its associated calories."

In an accompanying editorial, Alain Joffe, M.D., M.P.H., from Johns Hopkins University, Baltimore, writes "Until public health efforts to prevent child and adolescent obesity are developed and successfully implemented on a broad scale, physicians are likely to encounter significant numbers of obese adolescents for the foreseeable future. … appropriate management of this chronic health condition is a pressing but daunting task for physicians."

"Obesity is by nature a chronic disease. Many obese individuals who lose weight regain it over time, often exceeding their original weight," Dr. Joffe writes. "What will be critical to determine is whether the weight loss (or slowing of weight gain) achieved by those treated with orlistat is sustainable over time. Once adolescents stop using orlistat, will they maintain their weight loss, or will maintenance required ongoing use of the medication?"

He concludes by saying "It would not be surprising that no single weight-loss medication will find favor with all adolescents; pharmacotherapy will need to be individualized following a comprehensive assessment of the adolescent including the presence or absence of various comorbidities [related disease]. … Until [more] data are available, use of orlistat should be limited to settings that offer comprehensive assessment and management of obese adolescents. There is no justification for using it as a stand-alone treatment.