HONOLULU, HI—Abuse of oxycodone HCl controlled release (OxyContin) declined by 49% among individuals being assessed for substance abuse problems in the first 11 months after introduction of reformulated tablets (ORF), a study presented during the American Pain Society’s 31st Annual Scientific Meeting has shown.

Ryan A. Black, PhD, and colleagues from Inflexxion, Newton, MA, conducted an observational study to assess changes in abuse of oxycodone HCl controlled release, ER oxymorphone, and ER morphine from “before” (June 2009 to August 8, 2010) to “after” (August 9, 2010, through June 2011) introduction of ORF. Original oxycodone HCl controlled release shipments were stopped in August 2010 when ORF shipments began. The reformulated tablets have physiochemical barriers to crushing and dissolving intended to reduce abuse, especially by nonoral routes of administration that require tampering.

Changes in abuse were measured using ASI-MV, a computer-administered interview for treatment planning for adults that collects self-report data on past 30 day substance abuse, including prescription opioids, on the NAVIPPRO sentinel surveillance network system.

A total of 67,165 assessments were collected in the “before” period, 12,035 of which reported abusing prescription opioids and 2,835 reported oxycodone HCl controlled release abuse. In the “after” period, of 37,465 assessments, 7,233 reported prescription opioid abuse and 786 reported ORF abuse.

The majority of all respondents was male, Caucasian, and had never married; mean age was 33.9 years. The largest percentage of individuals was employed in occupations that involved skilled or semi-skilled labor, the investigators reported. “More than half of all respondents and 40.9% of subjects who reported abusing any opioid in the past 30 days were prompted to enter substance abuse treatment by the criminal justice system,” Dr. Black noted.

When the “before” and “after” periods were compared, a 49% (95% CI: 46% to 53%) decline in individuals who abused oxycodone HCl controlled release among prescription opioid abusers was observed, from 24% to 12% (P<0.0001). The number of individuals abusing oxycodone HCl controlled release orally declined by 30% (95% CI: 23% to 36%), from 14% to 10% (P<0.0001). Nonoral abuse (i.e., injecting, snorting, and smoking) declined by 73% (95% CI: 70% to 76%) from 18% to 5% of opioid abusers (P<0.0001).

During the same time period, a 139% increase (95% CI: 102% to 183%) in ER oxymorphone abuse (P<0.0001) and a 12% decline (95% CI: 19% to 23%) in ER morphine abuse (P=0.053) among opioid abusers was reported, the investigators noted.

“While the prevalence of abuse of reformulated oxycodone HCl controlled release appears to have stabilized, longer term follow-up is needed to assess whether the reduction in abuse is sustained over an extended period of time,” they concluded.