Abase liability assessment of sibutramine, a novel weight control agent

Rationale: Sibutramine (Meridia) is a serotonin and norepinephrine reuptake inhibitor marketed for weight control. Previous studies demonstrated low a buse potential for 20 and 30 mg sibutramine (doses near the therapeutic ran ge). however, no data existed on supra-therapeutic doses. This study, there fore, examined 25 and 75 mg sibutramine in humans compared to d-amphetamine (20 mg) as a positive control and placebo as a negative control. Ojectives : The study examined the acute subjective, reinforcing, and physiological e ffects of sibutramine to assess its abuse liability. Methods: Twelve polydr ug abusers with no history of drug dependence participated in this double-b lind, inpatient/outpatient study. Volunteers participated in four drug sess ions, in which they completed subjective effects scales including the Profi le of Mood States (POMS), Visual Analog Scales (VAS), and the Addiction Res earch Center Inventory (ARCI). The Multiple Choice Procedure (MCP) was used to evaluate reinforcing efficacy. Results: Sibutramine 25 mg produced subj ective effects that were indistinguishable from placebo. Sibutramine 75 mg produced significant unpleasant effects, such as Anxiety, Confusion, and de creased Vigor. On the MCP, volunteers chose to give up an average of $4.04 from their study pay rather than receive the higher dose of sibutramine aga in. In contrast, d-amphetamine 20 mg produced positive mood changes and was well liked. Conclusions: These data indicate sibutramine lacks amphetamine -type abuse liability when administered acutely.