Increasing availability of illicit and prescription opioids among people who inject drugs in a Canadian setting, 2010–2014

ABSTRACT

Background: Nonmedical use of prescription opioid and illicit opioid has been increasing at an alarming rate in North America over the past decade. Objective: We sought to examine the temporal trends and correlates of the availability of illicit and prescription opioids among people who inject drugs (PWID) in Vancouver, Canada. Methods: Data were derived from three prospective cohort studies of PWID in Vancouver between 2010 and 2014. In semiannual interviews, participants reported the availability of five sets of illicit and prescription opioids: (1) heroin; (2) Percocet (oxycodone/acetaminophen), Vicodin (hydrocodone/acetaminophen), or Demerol (meperidine); (3) Dilaudid (hydromorphone); (4) Morphine; (5) oxycontin/OxyNEO (controlled-release oxycodone). We defined perceived availability as immediate (e.g., available within 10 minutes) versus no availability/available after 10 minutes. The trend and correlation of immediate availability were identified by multivariable generalized estimating equations logistic regression. Results: Among 1584 participants, of which 564 (35.6%) were female, the immediate availability of all illicit and prescribed opioids (except for oxycontin/OxyNEO) increased over time, independent of potential confounders. The Adjusted Odds Ratios of immediate availability associated with every calendar year increase were between 1.09 (95% confidence interval 1.05–1.12) (morphine and Dilaudid) and 1.13 (95% confidence interval 1.09–1.17) (Percocet/Vicodin/Demerol) (all p-values <0.05). Conclusion: The availability of most prescription opioids had continued to increase in recent years among our sample of PWID in Vancouver. Concurrent increases in the availability of heroin were also observed, raising concerns regarding combination of both illicit and prescription opioid use among PWID that could potentially increase the risk of overdose.

KEYWORDS:

• Prescribed opioids
• illicit opioids
• availability
• injected drugs

Acknowledgments

The authors appreciate the study participants of ACCESS, VIDUS, and ARYS for their contribution to the research, as well as current and past researchers and staff.

Declaration of interest

All authors declare no conflict of interests.

Funding

The work was supported by the US National Institutes of Health (U01DA038886, R01DA021525) and the Canadian Institutes of Health Research (MOP–102742). This research was undertaken, in part, thanks to funding from the Canada Research Chairs program through a Tier 1 Canada Research Chair in Inner City Medicine which supports one of the authors, as well as a Canadian Institutes of Health Research Foundation grant supporting another author (FDN-148476). Dr. Kanna Hayashi is supported by a Canadian Institutes of Health Research (CIHR) New Investigator Award (MSH-141971). Dr. Kora DeBeck is supported by a Michael Smith Foundation for Health Research (MSFHR)/St. Paul’s Hospital Foundation-Providence Health Care Career Scholar Award and a CIHR New Investigator Award. Dr. M.-J. Milloy is supported by a CIHR New Investigator Award, a MSFHR Scholar Award, and the National Institutes of Drug Abuse (R01-DA0251525). His institution has received an unstructured gift from NG Biomed, Ltd., to support his research.

Additional information

Funding

The work was supported by the US National Institutes of Health (U01DA038886, R01DA021525) and the Canadian Institutes of Health Research (MOP–102742). This research was undertaken, in part, thanks to funding from the Canada Research Chairs program through a Tier 1 Canada Research Chair in Inner City Medicine which supports one of the authors, as well as a Canadian Institutes of Health Research Foundation grant supporting another author (FDN-148476). Dr. Kanna Hayashi is supported by a Canadian Institutes of Health Research (CIHR) New Investigator Award (MSH-141971). Dr. Kora DeBeck is supported by a Michael Smith Foundation for Health Research (MSFHR)/St. Paul’s Hospital Foundation-Providence Health Care Career Scholar Award and a CIHR New Investigator Award. Dr. M.-J. Milloy is supported by a CIHR New Investigator Award, a MSFHR Scholar Award, and the National Institutes of Drug Abuse (R01-DA0251525). His institution has received an unstructured gift from NG Biomed, Ltd., to support his research.