Postmarketing surveillance of abuse liability of sibutramine

The abuse liability of medications is a growing concern as the number of newly approved psychoactive medications increases. Postmarketing surveillance can assist in determining abuse liability, but strategies are not well-defined for medications believed to be at low abuse risk. Using a newly approved medication (sibutramine--an anorectic drug), a novel approach to postmarketing abuse surveillance was introduced. A one-page anonymous questionnaire covering sibutramine, a scheduled anorectic drug (phentermine), and a fabricated name was added to the intake process of 58 treatment programs. From the 8780 completed questionnaires, 8.8% had heard of sibutramine and phentermine. For continued use to get high (a proxy for abuse), the rate for sibutramine was lower than for phentermine (0.6 vs. 2.2%, McNemar's chi(2) = 110.45, P < 0.001) but was higher than for the fabricated name (0.6 vs. 0.3%, McNemar's chi(2) = 11.86, P < 0.001). These results suggest the risk of abuse associated with sibutramine was lower than that associated with a known abused drug, one that itself is considered low risk despite decades of population exposure. The relatively high rate of hearing of sibutramine may be due to the direct-to-consumer advertisement. This approach is only one indicator in a surveillance framework but appears promising and validates findings from laboratory-based abuse liability studies that also indicate low abuse liability for sibutramine.