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Effect of restricting the legal supply of prescription opioids on buying through online illicit marketplaces: interrupted time series analysis

BMJ 2018; 361 doi: (Published 13 June 2018) Cite this as: BMJ 2018;361:k2270

Linked Editorial

Tighter prescribing regulations drive illicit opioid sales

  1. James Martin, associate professor of criminology1,
  2. Jack Cunliffe, lecturer in quantitative methods and criminology2,
  3. David Décary-Hétu, assistant professor of criminology3,
  4. Judith Aldridge, professor of criminology4
  1. 1Department of Social Sciences, Swinburne University, Melbourne, Australia
  2. 2School of Social Policy, Sociology and Social Research, University of Kent, Canterbury, Kent CT2 7NF, UK
  3. 3École de criminologie, Université de Montréal, Montréal, Canada
  4. 4School of Law, University of Manchester, Manchester, UK
  1. Correspondence to: J Cunliffe j.d.cunliffe{at}
  • Accepted 22 April 2018


Objective To examine the effect on the trade in opioids through online illicit markets (“cryptomarkets”) of the US Drug Enforcement Administration’s ruling in 2014 to reschedule hydrocodone combination products.

Design Interrupted time series analysis.

Setting 31 of the world’s largest cryptomarkets operating from October 2013 to July 2016.

Main outcome measures The proportion of total transactions, advertised and active listings for prescription opioids, prescription sedatives, prescription steroids, prescription stimulants, and illicit opioids, and the composition of the prescription opioid market between the US and elsewhere.

Results The sale of prescription opioids through US cryptomarkets increased after the schedule change, with no statistically significant changes in sales of prescription sedatives, prescription steroids, prescription stimulants, or illicit opioids. In July 2016 sales of opioids through US cryptomarkets represented 13.7% of all drug sales (95% confidence interval 11.5% to 16.0%) compared with a modelled estimate of 6.7% of all sales (3.7% to 9.6%) had the new schedule not been introduced. This corresponds to a 4 percentage point yearly increase in the amount of trade that prescription opioids represent in the US market, set against no corresponding changes for comparable products or for prescription opioids sold outside the US. This change was first observed for sales, and later observed for product availability. There was also a change in the composition of the prescription opioid market: fentanyl was the least purchased product during July to September 2014, then the second most frequently purchased by July 2016.

Conclusions The scheduling change in hydrocodone combination products coincided with a statistically significant, sustained increase in illicit trading of opioids through online US cryptomarkets. These changes were not observed for other drug groups or in other countries. A subsequent move was observed towards the purchase of more potent forms of prescription opioids, particularly oxycodone and fentanyl.


  • Contributors: JM conceived the study and is the guarantor. DD-H and JA collected the data. JC ran the analyses. All authors were involved in the design and writing of the paper. The corresponding author attests that all listed authors meet authorship criteria and that no others meeting the criteria have been omitted.

  • Funding: The data collection was funded in parts by the Social Sciences and Humanities Research Council of Canada (#430-2015-01089), Macquarie University internal grants, and the Wetenschappelijk Onderzoek-en Documentatiecentrum (WODC) from the Ministry of Justice and Security of the Netherlands. The researchers remained independent from the funders at all time. The funders were not consulted before or during the work.

  • Competing interests: All authors have completed the ICMJE uniform disclosure form at and declare: this research was funded by a Macquarie University research development grant; no financial relationships with any organisations that might have an interest in the submitted work in the previous three years, no other relationships or activities that could appear to have influenced the submitted work.

  • Ethical approval: Not required.

  • Data sharing: No additional data available.

  • Transparency: The lead author (JM) affirms that the manuscript is an honest, accurate, and transparent account of the study being reported; that no important aspects of the study have been omitted; and that any discrepancies from the study as planned have been explained.

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