The introduction of a potentially abuse deterrent oxycodone formulation: Early findings from the Australian National Opioid Medications Abuse Deterrence (NOMAD) study

Shifts in substance use patterns among a cohort of people who use opioids after delisting of OxyContin in BC, Canada: An interrupted time series study

BACKGROUND

OxyContin was delisted from Canadian provincial drug formularies in March 2012 and replaced with a reformulated tamper-resistant form of oxycodone (i.e., OxyNeo). We assessed if delisting of OxyContin was associated with changes in the use of unregulated opioids and other substances among people who use opioids (PWUO).

METHODS

Data were derived from two prospective cohort studies of people who use drugs in Vancouver, BC, Canada from 2006 to 2018. PWUO who had at least one follow-up visit before and after delisting of OxyContin were included. Outcomes of interest were self-reported regular (i.e., at least weekly) use of heroin, non-prescribed prescription opioids, cannabis, methamphetamine, crack cocaine, and powder cocaine during the previous six months. Using quasi-experimental interrupted time series, we fit generalized least squares models to assess participants' immediate and long-term substance use practices after the policy change.

RESULTS

We analyzed data from 1014 participants who contributed to 17457 visits during the study. Following the delisting of OxyContin, heroin use increased immediately by 5.17% (95% confidence intervals [CI]: 0.68 to 9.67) and over time by 0.47% (0.35 to 0.58) per month. Non-prescribed prescription opioid use increased immediately by 1.80% (0.10 to 3.50) and over time by 0.16% (0.12 to 0.19) per month. Cannabis use increased immediately by 4.37% (0.88 to 7.87) and over time by 0.11% (0.02 to 0.19) per month. Methamphetamine use did not increase immediately but increased over time by 0.10% (0.01 to 0.18) per month. Crack cocaine use decreased immediately by 6.13% (-10.94 to -1.69) but not significantly over time. Lastly, powder cocaine use did not increase immediately or over time.

CONCLUSIONS

Delisting of OxyContin in BC was not associated with a reduction in unregulated opioid use among PWUO. Our findings point to a shift in substance use patterns of PWUO post-intervention and further highlight the unintended consequences of supply-reduction interventions in addressing the opioid epidemic.

Trends in opioid prescribing in Australia: a systematic review

Objective This review systematically identified studies that estimated the prevalence of prescription opioid use in Australia, assessed the prevalence estimates for bias and identified areas for future research. Methods Literature published after 2000 containing a potentially representative estimate of prescription opioid use in adults, in the community setting, in Australia was included in this review. Studies that solely assessed opioid replacement, illicit opioid usage or acute hospital in-patient use were excluded. Databases searched included PubMed, EMBASE, Web of Science and the grey literature. Results The search identified 2253 peer-reviewed publications, with 34 requiring full-text review. Of these, 20 were included in the final qualitative analysis, in addition to four publications from the grey literature. Most studies included analysed prescription claims data for medicines dispensed via Australia's national medicines subsidy scheme (the Pharmaceutical Benefits Scheme). Although data sources were good quality, all prevalence estimates were at least at moderate risk of bias, predominantly due to incompleteness of data or potential confounding. Included publications demonstrated a significant rise in opioid use up to 2017 (including a 15-fold increase in prescriptions dispensed over the 20 years to 2015), predominantly driven by a sharp rise in oxycodone use. Although opioid prescription numbers continue to escalate, usage, as measured by oral morphine equivalent per capita, may have plateaued since 2014. Codeine remains the most prevalently obtained opioid, followed by oxycodone and tramadol. There was a substantial delay (median 30 months; interquartile range 20-37 months) to publication of opioid usage data from time of availability. Conclusions Australia has experienced a marked increase in opioid prescribing since the 1990s. Current published literature is restricted to incomplete, delayed and historical data, limiting the ability of clinicians and policy makers to intervene appropriately. What is known about the topic? Opioid prescriptions in Australia have continued to increase since the 1990s and may be mirroring the epidemic being seen in the US. What does this paper add? This paper systematically identifies all publications that have examined the prevalence of prescription opioid use in Australia since 2000, and only identified prevalence estimates that were at moderate or high risk of bias, and found significant delays to publication of these estimates. What are the implications for practitioners? Because published literature on the prevalence of prescription opioid consumption is restricted to incomplete, delayed and historical data, the ability of clinicians and policy makers to appropriately intervene to curb prescription opioid use is limited. A national policy of real-time monitoring and reporting of opioid prescribing may support improvements in practice.

Alprazolam use among a sample of Australians who inject drugs: Trends up to six years post regulatory changes

INTRODUCTION

Alprazolam is a high potency triazolobenzodiazepine that is associated with a disproportionate amount of harm compared to other benzodiazepines. In Australia, amid growing concerns of extra-medical use and harms, alprazolam was up-scheduled from Schedule 4 (prescription only) to Schedule 8 (controlled drug) on 1 February 2014, with further restrictions introduced on 1 February 2017. This study aims to examine the impact of these regulatory changes among cross-sectional samples of people who inject drugs (PWID), from 2011-2019.

METHODS

Data were obtained from the 2011-2019 Illicit Drug Reporting System, comprising cross-sectional samples of PWID recruited annually from Australian capital cities (approximately ~900 per year).

RESULTS

By 2019, the proportion of PWID who reported past six-month use of non-prescribed (17%) and prescribed (4%) alprazolam had halved compared to 2011 (39% and 13%, respectively), with no evidence of an increase in use of other sedative substances. Following the up-scheduling of alprazolam in 2014, there was an increase in the median last price paid for 2 mg of diverted alprazolam ($5AUD pre-rescheduling versus $7AUD post rescheduling), with 61% of those able to answer reporting that diverted alprazolam had become 'more difficult' to obtain post versus pre-rescheduling. The correlates associated with non-prescribed alprazolam use remained relatively consistent pre- and post-regulatory change, with past-month criminal activity, past six-month opioid agonist therapy and past six-month use of non-prescribed other benzodiazepines associated with non-prescribed alprazolam use in both the 2013 and 2018 samples.

CONCLUSIONS

Regulatory changes appear to have resulted in sustained reductions in alprazolam use amongst our annual cross-sectional sentinel samples of PWID, although a considerable minority (17%) continued to report non-prescribed use in 2019. To achieve further reductions in non-prescribed use and associated harms, these regulatory changes need to be coupled with other interventions, such as direct consumer engagement and harm reduction messaging. Our findings suggest that people receiving opioid agonist therapy remain a key target population for such interventions.

Person-level changes in oxycodone use after the introduction of a tamper-resistant formulation in Australia

BACKGROUND

Australia introduced tamper-resistant controlled-release (CR) oxycodone in April 2014. We quantified the impact of the reformulation on dispensing, switching and poisonings.

METHODS

We performed interrupted time-series analyses using population-representative national dispensing data from 2012 to 2016. We measured dispensing of oxycodone CR (≥ 10 mg), discontinuation of use of strong opioids and switching to other strong opioids after the reformulation compared with a historical control period. Similarly, we compared calls about intentional opioid poisoning using data from a regional poisons information centre.

RESULTS

After the reformulation, dispensing decreased for 10-30 mg (total level shift -11.1%, 95% confidence interval [CI], -17.2% to -4.6%) and 40-80 mg oxycodone CR (total level shift -31.5%, 95% CI -37.5% to -24.9%) in participants less than 65 years of age but was unchanged in people 65 years of age or older. Compared with the previous year, discontinuation of use of strong opioids did not increase (adjusted hazard ratio [HR] 0.95, 95% CI 0.91 to 1.00), but switching to oxycodone/naloxone did increase (adjusted HR 1.54, 95% CI 1.32 to 1.79). Switching to morphine varied by age (p < 0.001), and the greatest increase was in participants less than 45 years of age (adjusted HR 4.33, 95% CI 2.13 to 8.80). Participants switching after the reformulation were more likely to be dispensed a tablet strength of 40 mg or more (adjusted odds ratio [OR] 1.40, 95% CI 1.09 to 1.79). Calls for intentional poisoning that involved oxycodone taken orally increased immediately after the reformulation (incidence rate ratio (IRR) 1.31, 95% CI 1.05-1.64), but there was no change for injected oxycodone.

INTERPRETATION

The reformulation had a greater impact on opioid access patterns of people less than 65 years of age who were using higher strengths of oxycodone CR. This group has been identified as having an increased risk of problematic opioid use and warrants closer monitoring in clinical practice.

Post-marketing studies of pharmaceutical opioid abuse-deterrent formulations: a framework for research design and reporting

BACKGROUND AND AIMS

Opioid formulations with properties to deter abuse (abuse-deterrent formulations; ADFs) have been developed as one response to the prescription opioid 'epidemic'. As for all medicines, ADFs undergo evaluation of safety and efficacy prior to registration for marketing. However, reduced extra-medical use (the primary intended outcome of ADFs and reason for their introduction) can only be established in post-marketing observational studies, comparing them to opioid formulations without abuse-deterrent properties. This has implications for various features of study design and analysis. We discuss proposals for the design, conduct, governance and reporting of post-marketing studies on the effectiveness of pharmaceutical and opioid ADFs.

METHODS

A review of current guidance documents, public work-shops and forums and our own experience with post-marketing studies of ADFs.

RESULTS AND CONCLUSIONS

Research questions for post-marketing studies on ADFs of opioids should reasonably be framed around detecting any probable intended or unintended clinical and/or meaningful changes in specific aspects of extra-medical use (e.g. injection use) and harms. Outcomes reported by prevalence and frequency of occurrence and disaggregated by specific product and route of administration can illustrate the magnitude of ADF impact. We argue that a multi-faceted approach is required, using data from both general population and sentinel high-risk cohorts and from primary and secondary data sources. The comparator (historical non-ADF formulation of that opioid, equivalent current generic or similar opioid product), duration of monitoring and analytical approach require justification and should be sufficient to add weight to conclusions of causality. To maximize transparency, we recommend explicit declarations of funding and conflict of interest, establishment of an advisory committee, publication of study protocol and access to study results.

Public Policy: An Analgesia for Opioid Diversion

Although opioids are a commonly prescribed form of analgesics among the armamentarium for their efficacy and safety when used responsibly, societal problems of drug diversion are highly prevalent. This review seeks to examine the importance of opioids and the extent of diversion and its impact, drawbacks, and controversies in law, public policies, and strategies. In particular, the law has skewed its focus toward the regulation of opioid suppliers (as compared to consumers), giving rise to a chilling effect where physicians are hesitant to prescribe opioids to patients with legitimate needs. This has downplayed the importance of medically treating pain, especially in the context of palliative care. This article recommends the intelligent use of public policy to alleviate the opioid diversion problem while acknowledging the importance of appropriate pain management. Concurrently, this article recommends providing continuous education and support for physicians, dispensers, and the like and adoption of soft law approaches by legislators and enforcement bodies to prevent relentless clamping down on opioid abusers. In conclusion, appropriate policies and guidelines are necessary to support the entire health care body in executing a coordinated approach and exercising vigilance to better manage the opioid diversion problem.

Combating escalating harms associated with pharmaceutical opioid use in Australia: the POPPY II study protocol

INTRODUCTION

Opioid prescribing has increased 15-fold in Australia in the past two decades, alongside increases in a range of opioid-related harms such as opioid dependence and overdose. However, despite concerns about increasing opioid use, extramedical use and harms, there is a lack of population-level evidence about the drivers of long-term prescribed opioid use, dependence, overdose and other harms.

METHODS AND ANALYSIS

We will form a cohort of all adult residents in New South Wales (NSW), Australia, who initiated prescribed opioids from 2002 using Pharmaceutical Benefits Scheme dispensing records. This cohort will be linked to a wide range of other datasets containing information on sociodemographic and clinical characteristics, health service use and adverse outcomes (eg, opioid dependence and non-fatal and fatal overdose). Analyses will initially examine patterns and predictors of prescribed opioid use and then apply regression and survival analysis to quantify the risks and risk factors of adverse outcomes associated with prescribed opioid use.

ETHICS AND DISSEMINATION

This study has received full ethical approval from the Australian Institute of Health and Welfare Ethics Committee, the NSW Population and Health Services Research Committee and the ACT Health Human Research Ethics Committee. This will be the largest postmarketing surveillance study of prescribed opioids undertaken in Australia, linking exposure and outcomes and examining risk factors for adverse outcomes of prescribed opioids. As such, this work has important translational promise, with direct relevance to regulatory authorities and agencies worldwide. Project findings will be disseminated at scientific conferences and in peer-reviewed journals. We will also conduct targeted dissemination with policy makers, professional bodies and peak bodies in the pain, medicine and addiction fields through stakeholder workshops and advisory groups. Results will be reported in accordance with the REporting of studies Conducted using Observational Routinely collected Data (RECORD) Statement.

Scoring the best deal: Quantity discounts and street price variation of diverted oxycodone and oxymorphone

PURPOSE

Diverted prescription opioids are significant contributors to drug overdose mortality. Street price has been suggested as an economic metric of the diverted prescription opioid black market. This study examined variables that may influence the street price of diverted oxycodone and oxymorphone.

METHODS

A cross-sectional study was conducted utilizing data from the previously validated, crowdsourcing website StreetRx. Street price reports of selected oxycodone and oxymorphone products, between August 22, 2014 and June 30, 2016, were considered for analysis. Geometric means and 95% confidence intervals were calculated comparing prices per milligram of drug in US dollars. Univariate and multivariable regressions were used to examine the influence of dosage strength, drug formulation, and bulk purchasing on street price.

RESULTS

A total of 5611 oxycodone and 1420 oxymorphone reports were analyzed. Across various dosages and formulations, geometric mean prices per milligram ranged between $0.12 and $1.07 for oxycodone and $0.73 and $2.90 for oxymorphone. For a 2-fold increase in dosage strength, there is a 24.0% (95% CI: -28.1%, -19.6%, P < 0.001) and a 22.5% (95% CI: -24.2%, -20.8%, P < 0.001) decrease on average in price per milligram for oxycodone and oxymorphone, respectively. Lower potency, high dosage strength, crush-resistant opioids, and those purchased in bulk were significantly cheaper.

CONCLUSION

Street prices for diverted oxycodone and oxymorphone are influenced by multiple factors including potency, dosage, formulation, and bulk purchasing. Buyers who purchase large quantities of low potency, large dosage, crush-resistant formulation prescription opioids can expect to achieve the lowest price.

Abuse-deterrent opioids: an update on current approaches and considerations

OBJECTIVE

Abuse and misuse of prescription opioids is a significant public health concern. This review examines the strategies used to confer abuse-deterrent properties on opioid abuse-deterrent formulations (ADFs), the characteristics and supporting data for each of the available ADFs, and the role of opioid ADFs as part of a comprehensive opioid risk management plan.

METHODS

A PubMed search was performed for articles published within the last 10 years using the search terms "abuse deterrent opioids". Articles were limited to clinical studies and reviews focusing on United States (US) Food and Drug Administration (FDA)-approved opioid ADFs in the US.

RESULTS

There are currently nine extended-release and one immediate-release opioid pain medications with US FDA-approved ADF labelling. All use either physical and chemical barriers or agonist/antagonist combinations to deter manipulation and abuse. Evidence is mounting that introduction of opioid ADFs has been associated with decreased rates of abuse and diversion of opioids in the US.

CONCLUSIONS

Although not sufficient by themselves to prevent prescription opioid abuse and misuse, opioid ADFs are an important component of a healthcare provider's comprehensive opioid risk management plan (along with utilization of prescription drug monitoring programs, clinical assessment tools, urine tests, co-prescribing of naloxone to patients at risk of an overdose, access to non-pharmacological treatments and addiction/mental health resources, among others). Adoption of opioid ADFs should be considered as part of an overall public health opioid risk management plan involving all stakeholders to balance legitimate safe and effective use of opioids against misuse and abuse.

The effect of a potentially tamper-resistant oxycodone formulation on opioid use and harm: main findings of the National Opioid Medications Abuse Deterrence (NOMAD) study

BACKGROUND

Escalation of pharmaceutical opioid use and harm in North America is well-documented, with similar issues emerging in Australia. One response is the development of tamper-resistant formulations of opioids. A potentially tamper-resistant formulation of controlled-release oxycodone was introduced in Australia in April, 2014, rapidly replacing the non-tamper-resistant formulation. Our study is the most systematic and comprehensive examination of the impact of a new opioid formulation to date, assessing the effect of tamper-resistant formulation of controlled-release oxycodone on population-level opioid use and opioid-related harm (ie, overdose, help-seeking, and treatment-seeking); and opioid use, tampering, and preference for the tamper-resistant formulation of controlled-release oxycodone compared with other drugs or formulations among sentinel populations likely to tamper with pharmaceutical opioids.

METHODS

We conducted interrupted time-series analyses of opioid sales data and multiple routinely collected health datasets, followed up a cohort of people who tamper with pharmaceutical opioids before and after the introduction of the tamper-resistant formulation of controlled-release oxycodone, and analysed annual surveys of people who inject drugs. Data were collected from several Australian states: New South Wales, South Australia, and Tasmania. Meta-analyses (weighted Z tests) were conducted to synthesise across data sources providing evidence for a given indicator.

FINDINGS

At the population level, we found reduced sales of higher strengths of controlled-release oxycodone and increased sales of other oxycodone formulations. No significant effect was observed among population-level indicators of opioid overdose, or help or treatment-seeking. Mortality data were not available for inclusion at the time of our study. Meta-analyses across sentinel populations (ie, prospective cohort, surveys of people who inject drugs, and clients of supervised injecting facilities or needle and syringe programmes) indicated reduced controlled-release oxycodone use via tampering (mainly injection), with no evidence of switching to heroin or other drug use.

INTERPRETATION

This formulation of controlled-release oxycodone reduced tampering with pharmaceutical opioids among people who inject drugs, but did not affect population-level opioid use or harm.

FUNDING

Mundipharma Australia, the Australian Government, and the National Health and Medical Research Council.

Heroin and pharmaceutical opioid overdose events: Emergency medical response characteristics

BACKGROUND

Emergency Medical Services (EMS) data may provide insight into opioid overdose incidence, clinical characteristics, and medical response. This analysis describes patient characteristics, clinical features, and EMS response to opioid overdoses, comparing heroin and pharmaceutical opioid (PO) overdoses, using a structured opioid overdose case criteria definition.

METHODS

A case series study was conducted. EMS medical staff screened cases for possible overdoses and study staff categorized the likelihood of opioid overdose. Medical form data were abstracted. Patient characteristics, clinical presentation, and medical response to heroin and PO-involved overdoses were compared with bi-variate test statistics.

RESULTS

We identified 229 definite or probable opioid overdose cases over six months: heroin in 98 (43%) cases (10 also involved PO), PO without heroin in 85 (37%) cases, and 46 (20%) that could not be categorized and were excluded from analyses. Heroin overdose patients were younger than PO (median age 33 v 41 (p<0.05)), more often male (80% v 61% (p=<0.01)), intubated less (8% v 22%, p<0.01) and more likely to be administered naloxone (72% v 51%, p<0.01). No significant differences were found between heroin and PO overdoses for initial respiratory rate, Glasgow Coma Scale score, or co-ingestants, but heroin users were more likely to have miotic pupils (p<0.01).

CONCLUSIONS

While heroin and PO events presented similarly, heroin-involved cases were more likely to receive naloxone and less likely to be intubated. Standardized case definitions and data documentation could aid opioid overdose surveillance as well as provide data for measuring the impact of professional and lay interventions.

Sustained reduction of diversion and abuse after introduction of an abuse deterrent formulation of extended release oxycodone

BACKGROUND

The development of abuse deterrent formulations is one strategy for reducing prescription opioid misuse and abuse. A putative abuse deterrent formulation of oxycodone extended release (OxyContin^®) was introduced in 2010. Early reports demonstrated reduced abuse and diversion, however, an analysis of social media found 32 feasible methods to circumvent the abuse deterrent mechanism. We measured trends of diversion, abuse and street price of OxyContin to assess the durability of the initial reduction in abuse.

METHODS

Data from the Poison Center Program, Drug Diversion Program, Opioid Treatment Program, Survey of Key Informant Patients Program and StreetRx program of the Researched Abuse, Diversion, and Addiction-Related Surveillance (RADARS^®) System were used. The average quarterly rates of abuse and diversion for OxyContin were compared from before reformulation to the rate in second quarter 2015. Rates were adjusted for population using US Census data and drug availability.

RESULTS

OxyContin abuse and diversion declined significantly each quarter after reformulation and persisted for 5 years. The rate of abuse of other opioid analgesics increased initially and then decreased, but to lesser extent than OxyContin. Abuse through both oral and non-oral routes of self-administration declined following the reformulation. The geometric mean difference in the street price of reformulated OxyContin was 36% lower than the reformulated product in the year after reformulation.

DISCUSSION

Despite methods to circumvent the abuse deterrent mechanism, abuse and diversion of OxyContin decreased promptly following the introduction of a crush- and solubility- resistant formulation and continued to decrease over the subsequent 5 years.

Abuse-deterrent formulations of prescription opioid analgesics in the management of chronic noncancer pain

Misuse, abuse and diversion of prescription opioid analgesics represent a global public health concern. The development of abuse-deterrent formulations (ADFs) of prescription opioid analgesics is an important step toward reducing abuse and diversion of these medications, as well as potentially limiting medical consequences when misused or administered in error. ADFs aim to hinder extraction of the active ingredient, prevent administration through alternative routes and/or make abuse of the manipulated product less attractive, less rewarding or aversive. However, opioid ADFs may still be abused via the intended route of administration by increasing the dose and/or dosing frequency. The science of abuse deterrence and the regulatory landscape are still relatively new and evolving. This paper reviews the current status of opioid ADFs, with particular focus on different approaches that can be used to deter abuse, regulatory considerations and implications for clinical management.

A typology of people who tamper with pharmaceutical opioids: responses to introduction of a tamper-resistant formulation of controlled-release oxycodone

PURPOSE

In April 2014, a tamper-resistant controlled-release oxycodone formulation was released in Australia. We aimed to determine whether there are latent classes of people who tamper with pharmaceutical opioids based on frequency of opioid and illicit drug use, the demographic and clinical profiles of these groups, and if there were changes in use and harms following the introduction.

METHODS

A prospective cohort of 606 people who regularly tamper with pharmaceutical opioids was interviewed January to March 2014 (Wave 1) and May to August 2014 (Wave 2). Latent class analysis identified groups based on non-prescribed opioid, illicit drug and prescribed opioid substitution therapy (OST) use at Wave 1. Regression models examined whether group membership predicted use and harms at Wave 2.

RESULTS

Four groups were identified: frequent OST group (39%), mixed OST/heroin group (7%), infrequent pharmaceutical opioid and heroin group (44%) and frequent oxycodone group (25%). Compared with the frequent OST group, the infrequent pharmaceutical opioid/heroin group was more likely to report non-everyday pain and risky alcohol use, and the frequent oxycodone group had higher odds of homelessness. At Wave 2, oxycodone use decreased across groups (odds ratios (OR) ≤ 0.18, p < 0.001, particularly for the frequent oxycodone group: OR ≤ 0.05, p < 0.001), with reductions in days of use (g ≥ 0.35, p < 0.050). Non-prescribed pharmaceutical opioid use, illicit drug use and harms remained stable or decreased.

CONCLUSIONS

Despite heterogeneity among people who tamper with pharmaceutical opioids, the tamper-resistant formulation was followed by reductions in oxycodone tampering among high-frequency and low-frequency users. There was no evidence of increased use of other opioids or illicit drugs.

Drug diversion

Prescription drug diversion has significant health, legal and social implications. Deaths from misuse of prescription drugs account for a significant proportion of overdose deaths. The drugs most commonly involved are analgesics, particularly opioids, and psychoactive drugs, particularly benzodiazepines. Diverted drugs are most often sourced from a family member or friend, but are also sourced from overseas pharmacies or laboratories, or bought from drug dealers. Drug diversion can be mitigated by good prescribing practices. Systems for monitoring the prescribing and dispensing of medicines are being instituted across Australia.