Objective: Behavioural treatment of children suffering from hypothalamic obesity or uncomplicated obesity in combination with syndromes that aggravate this condition has proven to be ineffective. The combination of co-morbidities and severe obesity lower the quality of these children's lives drastically. The present goal was to determine whether treatment with sibutramine has a beneficial effect on such children.

Design and subjects: A double-blind, placebo-controlled, cross-over study (20 + 20 weeks), followed by a 6-month open phase, was performed. The primary indicator of efficacy was the BMI SDS value, which was analysed employing an ANOVA repeated-measures design (ITT). The fifty children (7–20 years of age) involved included 22 with hypothalamic obesity and 28 with uncomplicated obesity plus aggravating syndromes. Forty-five patients completed the first phase and 42 participated in the entire study.

Results: The group that initially received the placebo demonstrated an insignificant decrease (-0.06) in BMI SDS during this treatment, but a significant decrease (-0.68; P < 0.001) when treated with sibutramine. The other group demonstrated a reduction in their BMI SDS of –0.72 during administration of sibutramine and a rebound of +0.43 when placed on the placebo (P < 0.001 in both cases). The response of children with hypothalamic obesity was also significant, but less pronounced than that of children with non-hypothalamic obesity. During the open phase a continuous reduction in weight was observed. The treatment was tolerated well.

Conclusion: The clinically and statistically significant weight reduction caused by sibutramine in this short-term study indicates that treatment of hypothalamic and syndromal obesity with this drug may be beneficial.