Variability in the unregulated opioid market in the context of extreme rates of overdose

Abstract

Background: Drug checking uses analytical chemistry technologies to report on the composition of drugs from the unregulated market to reduce substance use-related risks, while additionally allowing for monitoring and reporting of the supply. In the context of an overdose crisis linked to fentanyl, we used drug checking data to examine variability within the illicit opioid supply. Methods: In this time-series analysis, data was collected from a drug checking service in Victoria, Canada from November 2020 to July 2021. Drugs reported as opioids by participants of the service (N = 454) were analyzed to determine sample composition and paper spray mass spectroscopy was used to quantify low-concentration actives. Interquartile and statistical process control (SPC) analysis, namely standard deviation control charts, were used to examine the degree of variability among samples. Results: Fentanyl was found in 96% of samples reported to be opioids, with a median concentration of 9%. Concentrations varied significantly, with a standard deviation of 7% for fentanyl and where nearly 20% of data points fell outside the control limits. Over half of the samples contained an additional and unexpected active, most commonly etizolam (43% of samples). Etizolam also showed a large level of variability, uncorrelated to that of fentanyl. Conclusions: Based on our chemical quantification and SPC analysis, a high degree of variability was found in opioid samples from the unregulated market in both the drugs detected and the concentrations of those drugs. This demonstrated the opioid crisis to be less attributable to a bad batch of drugs but rather the general variability found in the unregulated market.