Tamper-resistant controlled-release oxycodone reduces use among individuals who inject drugs
A tamper-resistant controlled-release oxycodone formulation reduced tampering with pharmaceutical opioids among people who inject drugs, but had no effect on population-level opioid use or harm, results of the NOMAD study showed.
The study, conducted from December 2013 to August 2015 in Australia, showed that the introduction of a tamper-resistant formulation of controlled-release oxycodone caused reductions in injection of pharmaceutical opioids among individuals who inject drugs (Z score for any opioid injection, -5.23; oxycodone injection, -16.41; both p<0.0001). [Lancet Psychiatry 2018, doi, 10.1016/S2215-0366(18)30003-8]
However, the effect on opioid use or harm at the population level was not significant (Z score for overall opioid use, -0.28, p=0.78; oxycodone use, -1.67, p=0.095).
Analysis of data also did not suggest any switch to increased injection of heroin, methamphetamine or other drugs.
“The NOMAD study is the most systematic, comprehensive and transparent post-marketing surveillance of a new opioid formulation to date. Apart from studying opioid use and tampering among sentinel populations likely to tamper with pharmaceutical opioids, we also studied the impact of the new formulation on population-level use and harm,” the authors of the study said.
The time series analysis included opioid sales data, health datasets and a cohort of 606 individuals who used pharmaceutical opioids at least monthly and who reported that they regularly tampered with pharmaceutical opioids.
Interviews were conducted with individual members of the cohort at baseline from December 2013 to March 2014 (n=606), a month after the introduction of the tamper-resistant formulation of controlled-release oxycodone from May to August 2014 (n=547), and 1 year after treatment from April to August 2015.
The follow-up rate of 90 percent excluded participants ineligible for follow-up, namely those who were deceased or incarcerated or individuals who underwent drug rehabilitation.
The tamper-resistant formulation was shown to be less attractive for diversion (ie, sharing, selling, trading, or giving away of prescription medication to unintended recipients). Furthermore, participants of the study reported lower interest in tampering with and less pleasure in using the tamper-resistant formulation.
Attempts to tamper increased with time from 18 percent 1–4 months after the start of treatment to 27 percent 1 year after treatment.
There were no changes in population trends in opioid and other drug overdoses via multiple sources. The researchers also found no changes in indicators of help-seeking, including calls to telephone helplines and numbers of people receiving opioid treatment.
“The results of the study show that tamper-resistant formulations should be considered part of a multifaceted response, including increased availability of non-medication approaches to chronic non-cancer pain treatment, good clinical practice in long-term opioid treatment and implementation of strategies to minimize harm among people who use opioids outside the recommendations of their prescriber,” the authors commented.
Despite research highlighting the associations between increased pharmaceutical opioid use and harm in Australia in the past, no changes took place in terms of regulatory systems for pharmaceutical opioids, opioid prescription guidelines, limits on doctors’ prescribing of opioids and monitoring of patient or doctor access to opioids.