Effect of scheduling tramadol as a controlled substance on poison center exposures to tramadol.

Background: There is limited information on the effect of scheduling a drug as a controlled substance with comparable data from both a pre-scheduling and post-scheduling time period.

Objective: To investigate the temporal changes on poisoning cases involving tramadol in 4 states: 2 states where it has been scheduled and 2 where it is not scheduled.

Methods: Databases were searched for all cases involving tramadol reported from 2003 through 2009 at 6 regional poison centers that served Arkansas, Kentucky, Ohio, and West Virginia. To allow for comparison based on population, state population estimates were obtained from the US Census Bureau.

Results: Over the 7-year study period, the number of tramadol cases increased from 401 per year to 1009 cases per year. The mean annual increase in tramadol cases for all 4 states ranged from 8.8% to 14.1%. Post-scheduling in Arkansas and Kentucky, there was a mean decrease in cases of 4% and 31%, respectively. During this same period, the comparison states of West Virginia and Ohio showed a continued increase of 14% and 23%, respectively. The mean annual increase in tramadol cases per 100,000 population for all 4 states ranged from 16% to 31%. Post-scheduling of tramadol, there was an annual decrease in tramadol human exposures of 5% to 31% in Arkansas and Kentucky, respectively. During this same period, West Virginia and Ohio showed a continued annual increase of 14%.

Conclusions: The decrease in the number of cases of tramadol exposure following its addition to the schedule of controlled substances in Kentucky and Arkansas suggests that adding a drug to the schedule of controlled substances may result in a decrease in poisoning exposures related to that drug.