February 04, 2019
The introduction of abuse-deterrent OxyContin in 2010 may have played a key role in the rapid increase in hepatitis C infections because some drug abusers switched from the prescription opioid to injectable heroin, new research suggests
While hepatitis C infection rates increased broadly across the United States in the years after reformulated OxyContin became available, investigators found that states with above-average rates of OxyContin misuse prior to the reformulation saw hepatitis C infections increase three times as fast as in other states.
The results suggest efforts to deter misuse of opioids can have "unintended, long-term public health consequences," David Powell, lead investigator and senior economist at RAND Corporation, told Medscape Medical News.
"Policies that limit the supply of opioids are a great idea but they may cause more problems than they actually solve. Supply-side interventions, which is kind of how we are currently attacking the opioid crisis, may have limited impact when you have a readily available substitute like heroin out there," Powell added.
The study was published online February 4 in the journal Health Affairs.
In the United States, acute new hepatitis C infections declined during the 1990s, plateaued starting around 2003, but have been rising at an "alarming" rate since 2010, the authors point out.
Prior studies suggest abuse-deterrent OxyContin may have led some nonmedical users of the drug to switch to injectable heroin, which then led to a sharp increase in heroin overdoses after 2010.
Because injection drug use is the predominant risk factor for hepatitis C, Powell and colleagues sought to determine whether the opioid epidemic might be one driver of the recent rise in new infections.
They examined rates of hepatitis C infections in each state from 2004 to 2015, examining differences between states based on the level of misuse of the drug before the reformulation occurred.
Results showed that states with above-median OxyContin misuse before the reformulation had a 222% increase in hepatitis C infections in the post-reformulation period, while states with below-median misuse of OxyContin had a 75% increase in hepatitis C infections over the same period.
Before the reformulation, there was almost no difference in hepatitis C infection rates across the two groups of states. The rise in hepatitis C infection rates was not associated with initial rates of abuse of other pain relievers, which suggests that the source of the differential rise in hepatitis C infection rates was unique to reformulated OxyContin, the authors say.
"It is important that strategies that limit the supply of abusable prescription opioids are paired with polices to ease the harms associated with switching to illicit drugs, such as improved access to drug treatment and increased efforts to identify and treat diseases associated with injection drug use," study co-author Rosalie Liccardo Pacula, co-director of the RAND Opioid Policy Tools and Information Center and the RAND Drug Policy Research Center, said in a news release.
Interpret With Caution
Reached for comment on the study, David Murray, PhD, senior fellow at the Hudson Institute, cautions against concluding that reformulation of OxyContin alone is to blame for the rise in hepatitis C infections.
"The issue is very complicated and teasing out what exactly the abuse-resistant formulary did against the backdrop of several major policy changes is very difficult," he noted in an interview with Medscape Medical News. "You will find a correlation, obviously, with an opioid crisis surging forward and increased injection drug use and therefore exposure to hepatitis C. The linkage to reformulation of Oxycontin, however, is a little weaker," said Murray.
"There is no clear signal that reformulation was sufficient to drive hepatitis C when you consider the policy changes happening at the time and the stunning rise in heroin availability and use itself. Reformulation of OxyContin is a factor, but it is not the factor when you consider all the other contributing factors. That is a bridge too far in my sense," Murray added.
Support for the study was provided by the National Institutes on Drug Abuse. The authors have disclosed no relevant financial relationships. Murray served as chief scientist at the Office of National Drug Control Policy (ONDCP) from 2006 to 2009 and as associate deputy for supply reduction in the ONDCP until 2014.
Health Aff. Published online February 4, 2019.