Background: Sibutramine is an anti-obesity agent that inhibits reuptake of serotonin and norepinephrine. The aim of this study is to compare the efficacy and safety of sibutramine mesilate with sibutramine hydrochloride for evaluating efficacy and safety in obese patients.
Methods: This study was a 12-week, double blind, multi-center, comparative clinical trial following a 2 week screening period. Eligible subjects had a body mass index greater than 30kg/m2orbetween27and30kg/m2withcontrolledhypertension,diabetesorhyperlipidemia.Among275subjects,218subjectswererandomizedeithertosibutraminemesilateorsibutraminehydrochloridein6centers.
Results: After 12 weeks of treatment, 55.8% of sibutramine mesilate group and 53.5% of sibutramine hydrochloride group lost 5% or more of their body weight. Mean weight reduction at 12 weeks was 5.1±3.2kg in sibutramine mesilate group and 5.0±4.1kg in sibutramine hydrochloride group (P>0.05). There were no significant differences in changes of weight, waist circumference, percent body fat and lipid profiles between the two groups (P>0.05). Changes of blood pressure and pulse rate were not different in either groups. The drop out rate was not significantly different. Reported adverse events were similar in both groups with constipation as a highest frequency, 13.9% in sibutramine mesilate group and 10.0% in sibutramine hydrochloride group (P>0.05).
Conclusion: A 12-week clinical trial showed evidence that efficacy and safety of sibutramine mesilate as an anti-obesity agent was not significantly different compared to those of sibutramine hydrochloride in obese subjects.

Keywords: Obesity, Efficacy, Safety, Clinical trial