Essential ("precursor") chemical control for heroin: Impact of acetic anhydride regulation on US heroin availability (2013)

Background: To reduce heroin availability, the United Nations (UN) has encouraged nations to control acetic anhydride, an essential ("precursor") chemical typically necessary to the drug's production. This effort, a major environmental prevention policy, has received little evaluation. The United States, per the UN's lead, implemented acetic anhydride regulation in 11/1989. The present study examines whether the US regulation impacted US heroin availability.
Methods: Monthly series of three heroin availability indicators - heroin purity, heroin price, and amount of heroin seized - were constructed for the conterminous United States, the US Southwest (supplied predominantly with Mexican-produced heroin), and the US Northeast (supplied predominantly, at the time, with Southeast Asian-produced heroin). Data came from the System to Retrieve Information from Drug Evidence (01/1987-04/2011). Impacts were assessed using ARIMA-intervention time series analysis.
Results: In each US area, heroin purity and amount seized rose and price decreased throughout the pre-intervention period. All of the indicators then reversed course at the time of the regulation. In the conterminous United States, the US Northeast, and the US Southwest, purity decreased (-40%, -25% and -50%, respectively); amount seized decreased (-27%, -37% and -39%, respectively); and price rose (+93%, +102% and +296%, respectively). Impacts lasted 2-5 years.
Conclusion: US heroin availability decreased in association with the US acetic anhydride regulation. The impacts in the US Southwest and US Northeast suggest that heroin production in Mexico and Southeast Asia, respectively, was constrained. This study lends support to the contention that essential ("precursor") chemical control can be used to help address heroin.