In 2018 the Washington State Legislature passed the first statewide Drug Take-Back program in the United States. This program was implemented in November 2020 with the placement of easily accessible kiosks in locations for residents to dispose of their unwanted prescription drugs. Prior to the Drug Take-Back Program, the national recommended method for disposing of prescription opioids was by flushing them down the toilet. The State will determine effectiveness of the program by weighing, but not identifying, the returned contents of the kiosks. A complementary method to track the efficacy of this Take-Back program proposed here is direct, efficient, and timely. A wastewater-based (WB) approach uses sewage samples from water treatment plants to determine community use/exposure by quantifying the parent compound and/or metabolite of certain compounds. Hydrocodone and its metabolite (norhydrocodone) were identified as ideal efficacy indicators to monitor changes in flushed drugs due to having a unique metabolite, being on the FDA flush list, and its high prescription and waste rate (35 million annual daily doses in Washington State with a waste rate of 60%). This longitudinal study covers a period 6 months before the deployment of kiosks to 30 months after. Daily wastewater samples are collected in April and August from seven wastewater treatment plants across Washington State. Samples are extracted using solid phase (SPE) and analyzed with ultra-performance liquid chromatography-quadrupole time of flight mass spectrometry. Initial results from April 2020 – August 2021 show hydrocodone/nor-hydrocodone and oxycodone/nor-oxycodone ratios ranging from 0.65-1.00 and 0.20-0.70, respectively. These ratios compare well to other wastewater studies where there are presumably no Drug Take-Back programs in place.

Analyzing the use and disposal of opioids in Washington State through wastewater-based-epidemiology

ACS Spring 2022

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.