Objective: The reformulation of oxycodone hydrochloride controlled-release (CR) tablets in August 2010 created a natural experiment at a national scale, providing an opportunity to evaluate patterns of abuse of prescription opioids and other drugs before and after introduction of this abuse-deterrent formulation (ADF).
Design: Observational, cross-sectional study
Setting: Sentinel sample of adults assessed for substance abuse treatment within the NAVIPPRO® surveillance system
Subjects: Two hundred thirty-two thousand and eight hundred seventy-four adults at 437 facilities during January 1, 2008 through December 31, 2011.
Methods: Time-series analysis using logistic regression to estimate quarterly prevalence of past 30-day abuse (adjusted for covariates and prescription volume) and changes in abuse pre-and post-ADF introduction.
Results: Increases in abuse prevalence occurred for all prescription opioids as a class and for extended-release (ER) opioids. Significantly greater abuse of ER oxymorphone and buprenorphine occurred in the post-ADF period (relative risk [RR] = 2.91, 95% confidence interval [CI] = 2.59-3.27 and RR = 1.85, 95% CI = 1.74-1.96). Increases in abuse for these two compounds were significant among groups who reported abuse via preferential routes of administration (oral only, snorting only, injection only) post-ADF introduction.
Conclusions: Replacement of a widely prescribed opioid formulation known for its abuse potential alone may have had little impact on overall rates of prescription opioids as a class. However, changes in abuse levels of certain opioids coinciding with ADF introduction suggest possible switching of abuse among this study sample to specific long-acting opioid analgesics. Additional follow-up studies will be important to monitor changing abuse patterns and their public health impact as new opioid formulations are developed and introduced to market.
Keywords: Abuse Deterrent Formulation; NAVIPPRO; Oxycodone; Oxymorphone; Prescription Opioid Abuse; Tamper-Resistant Formulation.
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