Illicit online sales of opioids increased significantly following a 2014 regulatory decision that restricted the legal supply of opioids in the United States, results of a recent analysis show.
Opioid sales in the so-called cryptomarkets also shifted toward more potent drugs, including fentanyl, after the U.S. Drug Enforcement Administration rescheduled hydrocodone combination products, making them harder to access, authors of the analysis reported.
Those results suggest “the possibility of a causal relation” between the schedule change and sales trends on cryptomarket sites, according to James Martin, PhD, of Swinburne University, Melbourne, Australia, and co-authors.
“Our analysis cannot rule out other possible causal explanatory factors, but our results are consistent with the possibility that the schedule change might have directly contributed to the changes we observed in the supply of illicit opioids,” Dr. Martin and colleagues wrote in the BMJ.
Cryptomarkets outside the United States had no such uptick in opioid traffic over time, reinforcing the possibility that the 2014 DEA decision caused an increase in the illicit opioid supply. The analysis included 31 online illicit markets operating between October 2013 and July 2016.
Investigators collected data using web crawling software that downloaded HTML pages on the cryptomarket sites and extracted relevant information such as listing titles and drug types for later analysis. Generally, each market was fully crawled every 2 weeks. After data was scraped and extracted, they conducted an interrupted time series analysis of drug sales for each day of the data collection period.
Opioids represented 13.7% of all drug sales through U.S. cryptomarkets in July 2016, they found, compared with a modeled estimate of 6.7% of sales that would have occurred in the absence of the new schedule introduction.
“This represents an approximate doubling of the percentage of the total drug sales through cryptomarkets within the United States,” the authors wrote.
Fentanyl was the least purchased product at the beginning of the analysis, but by July 2016 it was the second most frequently purchased. No other drug category had any meaningful changes in the proportion of sales over time.
There was no way for researchers to confirm that U.S.-based cryptomarket sites were selling to customers in the United States or elsewhere. However, they said, cryptomarket buyers often use sites in the same country to avoid shipment losses and increased delivery time.
Part of the study were funded by the Social Sciences and Humanities Research Council of Canada, Macquarie University internal grants, and the Ministry of Justice and Security of the Netherlands. Study authors had no current financial relationships relevant to the study.
SOURCE: Martin J, et al. BMJ. 2018 Jun 13. doi: 10.1136/bmj.k2270.