Reformulation of oxycodone 80 mg to prevent misuse: A cohort study assessing the impact of a supply-side intervention.

Background: In August 2010, extended-release OxyContin® products, including oxycodone 80 mg, were reformulated and released as abuse-deterrent medications. This paper describes changes in individual prescription filling patterns that followed the reformulation of oxycodone 80 mg.

Methods: Using New York State prescription monitoring program data, we conducted a retrospective analysis of a cohort of New York City residents who had filled at least three consecutive prescriptions for oxycodone 80 mg immediately prior to the reformulation. We classified cohort members into one of three groups (continuers, switchers, and discontinuers) based on prescription filling patterns post-reformulation. Descriptive analyses were conducted to identify prevalence of filling patterns. Differences in median morphine milligram equivalents (MME) pre- and post-reformulation were compared using the Wilcoxon signed-rank sum test. Analyses were completed in 2018.

Results: A cohort of 4,098 New York City residents filled continuous prescriptions for oxycodone 80 mg immediately prior to reformulation. Post-reformulation, 14% of the cohort discontinued filling opioid analgesic prescriptions; 46% continued to fill prescriptions for oxycodone 80 mg; and 40% switched to a different opioid analgesic, most commonly oxycodone 30 mg. Post-reformulation, the median MME dose decreased significantly among all three groups: 45 mg among continuers, 150 mg among switchers, and 360 mg among discontinuers.

Conclusion: Post-reformulation, more than half the cohort changed their filling patterns. Following reformulation, median MME dose decreased significantly among the cohort. We hypothesize that the dramatic decrease in MME dose prompted many to transition to heroin in order to avoid severe withdrawal.