The prescription diet drug Xenical (orlistat) can safely help obese adolescents lose weight, according to a report by Canadian researchers presented at the International Congress on Obesity in Sydney, Australia.

In their study of obese adolescents aged 12-16 years, the researchers said the teens and preteens on Xenical for one year lost on average just over five pounds, compared to less than a pound for those taking a placebo.

Moreover, they said some adolescents responded more quickly than others to treatment with Xenical, and these obese teens and preteens lost on average more than 16 pounds and reduced their BMI by 3.7.

"The significant benefits seen in adolescents who respond early also provide a useful predictor for long-term treatment success," said Professor Jean-Pierre Chanoine, head of the Endocrinology and Diabetes Unit at British Columbia Children's Hospital in Vancouver.

"Xenical was shown to significantly improve quality of life with greater improvements in physical appearance, social acceptance, athletic competence and self-worth," the researchers added

"The problem of adolescent obesity has reached alarming levels, with dire health consequences," said Chanoine. "It's reassuring to know we have a safe and effective treatment option with Xenical.

Xenical is currently the only prescription only weight loss medication that has safety and efficacy data for use in adolescents 12 years and older included in its label.

A half-strength over-the-counter version of Xenical called Alli is currently awaiting approval by the U.S. Food and Drug Administration.