Comparing rates and characteristics of ambulance attendances related to extramedical use of pharmaceutical opioids in Victoria, Australia from 2013 to 2018

Increased incidence of mixed drug toxicity deaths involving tapentadol - A forensic study

Tapentadol is a relatively new synthetic opioid analgesic prescribed for the management of moderate to severe pain. While tapentadol has been shown to be more effective than traditional opioid analgesics, it still carries the risk of addiction, abuse, and misuse. In Australia, tapentadol has become one of the top five most commonly prescribed opioid drugs, with prescriptions increasing by approximately 150,000 each year since it first became available. The rapid increase in tapentadol prescriptions has occurred in parallel to an increasing number of post-mortem tapentadol detections in South Australia (SA). While the number of deaths in SA related to tapentadol use was low in the current study, findings suggest that an increasing trend of deaths involving tapentadol will continue in parallel to a rapidly increasing number of prescriptions, mirroring trends associated with traditional opioids in SA. As a comparatively new opioid analgesic, monitoring future trends will be important to determine if additional prescribing education, intervention, or restrictions are required.

Tapentadol Versus Oxycodone for Opioid-Related Adverse Drug Events and Clinical Outcomes After Inpatient Surgery

Oxycodone is a commonly prescribed opioid for postoperative pain. However, there has been a marked increase in the use of tapentadol over the previous decade due to a perceived superior safety profile of tapentadol compared to oxycodone. There is limited real-world evidence on the safety of tapentadol compared to oxycodone after surgery. The primary objective was to examine the impact of tapentadol compared to oxycodone use on the incidence of opioid-related adverse drug events after surgery. Data for adult surgical patients receiving tapentadol or oxycodone during hospitalization between January 1, 2018, and December 31, 2021, were collected from electronic medical records of 3 tertiary metropolitan hospitals in Australia. The primary outcome was the incidence of opioid-related adverse events. Patients receiving tapentadol or oxycodone were matched using nearest-neighbour propensity score matching. In the matched cohorts (n = 1,530 vs n = 2,775; mean [standard deviation] age 62.3 [17.0] years vs 61.9 [standard deviation 17.9] years; 43% vs 45% male for the tapentadol vs oxycodone groups, respectively), patients given tapentadol experienced a similar incidence of adverse events overall (14.4%, 220/1,530 vs 12.6%, 349/2,775; P = .100; 95% CI -.35% to 3.95%). Secondary outcomes included an increased risk of delirium (2.7%, 41/1,530 vs 1.3%, 37/2,775), arrhythmias (3.4%, 52/1,530 vs 2.2%, 62/2,775), and length of hospital stay (5 [range 1-201] vs 4 [range 1-226] days) compared with oxycodone use. Further real-world studies are warranted to determine the impact of tapentadol use on a broad range of patient outcomes. PERSPECTIVE: This study provides an early signal that tapentadol use may be associated with an increased risk of some adverse events and a longer length of stay. Further research is needed to examine the impact of tapentadol use on a broad range of patient outcomes in clinical practice settings.

Effect of discharge opioid on persistent postoperative opioid use: a retrospective cohort study comparing tapentadol with oxycodone

Opioid harm can vary by opioid type. This observational study examined the effect of opioid type (oxycodone vs. tapentadol) on rates of persistent postoperative opioid use ('persistence'). We linked hospital and community pharmacy data for surgical patients who were dispensed discharge opioids between 1 January 2016 and 30 September 2021. Patients were grouped by opioid experience ('opioid-naive' having received no opioids in the 3 months before discharge) and formulation of discharge opioid (immediate release only or modified release ± immediate release). Mixed-effects logistic regression models predicted persistence (continued use of any opioid at 90 days after discharge), controlling for key persistence risk factors. Of the 122,836 patients, 2.31% opioid-naive and 27.24% opioid-experienced patients met the criteria for persistence. For opioid-naive patients receiving immediate release opioids, there was no significant effect of opioid type. Tapentadol modified release was associated with significantly lower odds of persistence compared with oxycodone modified release, OR (95%CI) 0.81 (0.69-0.94) for opioid-naive patients and 0.81 (0.71-0.93) for opioid-experienced patients. Among patients who underwent orthopaedic surgery (n = 19,832), regardless of opioid experience or opioid formulation, the odds of persistence were significantly lower for those who received tapentadol compared with oxycodone. This was one of the largest and most extensive studies of persistent postoperative opioid use, and the first that specifically examined persistence with tapentadol. There appeared to be lower odds of persistence for tapentadol compared with oxycodone among key subgroups, including patients prescribed modified release opioids and those undergoing orthopaedic surgery.

Endogenous opiates and behavior: 2020

This paper is the forty-third consecutive installment of the annual anthological review of research concerning the endogenous opioid system, summarizing articles published during 2020 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides and receptors as well as effects of opioid/opiate agonists and antagonists. The review is subdivided into the following specific topics: molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors (1), the roles of these opioid peptides and receptors in pain and analgesia in animals (2) and humans (3), opioid-sensitive and opioid-insensitive effects of nonopioid analgesics (4), opioid peptide and receptor involvement in tolerance and dependence (5), stress and social status (6), learning and memory (7), eating and drinking (8), drug abuse and alcohol (9), sexual activity and hormones, pregnancy, development and endocrinology (10), mental illness and mood (11), seizures and neurologic disorders (12), electrical-related activity and neurophysiology (13), general activity and locomotion (14), gastrointestinal, renal and hepatic functions (15), cardiovascular responses (16), respiration and thermoregulation (17), and immunological responses (18).

Comparing opioid types in the persistence of opioid use following surgical admission: a study protocol for a retrospective observational linkage study comparing tapentadol and oxycodone in Australia

INTRODUCTION

Each year, an estimated two million Australians commence opioids, with 50 000 developing longer-term (persistent) opioid use. An estimated 3%-10% of opioid-naïve patients prescribed opioids following surgery develop persistent opioid use. This study will compare rates of persistent opioid use between two commonly used postoperative opioids, oxycodone and tapentadol, to understand if initial postoperative opioid type is important in determining longer-term outcomes.

METHODS AND ANALYSIS

A retrospective data linkage study that analyses administrative data from hospital and community pharmacies. Data will be obtained from at least four pharmacies that service large hospitals with comparable supplies of oxycodone and tapentadol. The study will include at least 6000 patients who have been dispensed a supply of oxycodone or tapentadol to take home following their discharge from a surgical ward. The primary outcome measure will be persistent opioid use at 3 months postdischarge for opioid naïve people who receive either immediate release tapentadol or immediate release oxycodone. Hierarchical logistic regression models will be used to predict persistent opioid use, controlling for covariates including comorbidities.

ETHICS AND DISSEMINATION

Ethics approval has been obtained through the Monash University Human Research Ethics Committee (29977). We will present project findings in a peer-reviewed journal article, in accordance with the REporting of studies Conducted using Observational Routinely-collected health Data statement.

Pharmaceutical opioid poisonings in Victoria, Australia: Rates and characteristics of a decade of emergency department presentations among nine pharmaceutical opioids

BACKGROUND AND AIMS

Pharmaceutical opioids are a significant contributor to the global 'opioid crisis', yet few studies have comprehensively distinguished between opioid types. We measured whether a range of common pharmaceutical opioids varied in their contribution to the rates and characteristics of harm in a population-wide indicator of non-fatal overdose.

DESIGN

Retrospective observational study of emergency department (ED) patient care records in the Victorian Emergency Minimum Data set (VEMD), July 2009 to June 2019.

SETTING

Victoria, Australia.

CASES

ED presentations for non-fatal overdose related to pharmaceutical opioid use (n = 5403), where the specific pharmaceutical opioid was documented.

MEASUREMENTS

We compared harms across the nine individual pharmaceutical opioids most commonly sold, and considered where multiple opioids contributed to the overdose. We calculated supply-adjusted rates of ED presentations using Poisson regression and used multinomial logistic regression to compare demographic and clinical characteristics of presentations among nine distinct pharmaceutical opioids and a 10th category where multiple opioids were documented for the presentation.

FINDINGS

There were wide differences, up to 27-fold, between supply-adjusted rates of overdose. When considering presentations with sole opioids, the highest supply-adjusted overdose rates [per 100 000 oral morphine equivalents (OME); 95% confidence interval (CI)] were for codeine (OME = 0.078, 95% CI = 0.073-0.08) and oxycodone (OME =0.029, 95% CI = 0.027-0.030) and the lowest were for tapentadol (OME = 0.004, 95% CI = 0.003-0.006) and fentanyl (OME = 0.003, 95% CI = 0.002-0.004). These rates appeared related to availability rather than opioid potency. Most (62%) poisonings involved females. Codeine, oxycodone and tramadol were associated with younger presentations (respectively, 59.5%, 41.7% and 49.8% of presentations were 12-34 years old), and intentional self-harm (respectively 65.2%, 50.6%, and 52.8% of presentations). Relative to morphine, fentanyl [ 0.32 relative risk ratio (RRR)] and methadone ( 0.58 RRR) presentations were less likely to be coded as self-harm. Relative to morphine-buprenorphine, codeine, oxycodone and tramadol presentations were significantly more likely to be associated with the less urgent triage categories (respectively 2.18, 1.80, 1.52, 1.65 RRR).

CONCLUSIONS

In Victoria, Australia, rates and characteristics of emergency department presentations for pharmaceutical opioids show distinct variations by opioid type.

Treatment of opioid overdose: current approaches and recent advances

BACKGROUND

The USA has recently entered the third decade of the opioid epidemic. Opioid overdose deaths reached a new record of over 74,000 in a 12-month period ending April 2021. Naloxone is the primary opioid overdose reversal agent, but concern has been raised that naloxone is not efficacious against the pervasive illicit high potency opioids (i.e., fentanyl and fentanyl analogs).

METHODS

This narrative review provides a brief overview of naloxone, including its history and pharmacology, and the evidence regarding naloxone efficacy against fentanyl and fentanyl analogs. We also highlight current advances in overdose treatments and technologies that have been tested in humans.

RESULTS AND CONCLUSIONS

The argument that naloxone is not efficacious against fentanyl and fentanyl analogs rests on case studies, retrospective analyses of community outbreaks, pharmacokinetics, and pharmacodynamics. No well-controlled studies have been conducted to test this argument, and the current literature provides limited evidence to suggest that naloxone is ineffective against fentanyl or fentanyl analog overdose. Rather a central concern for treating fentanyl/fentanyl analog overdose is the rapidity of overdose onset and the narrow window for treatment. It is also difficult to determine if other non-opioid substances are contributing to a drug overdose, for which naloxone is not an effective treatment. Alternative pharmacological approaches that are currently being studied in humans include other opioid receptor antagonists (e.g., nalmefene), respiratory stimulants, and buprenorphine. None of these approaches target polysubstance overdose and only one novel approach (a wearable naloxone delivery device) would address the narrow treatment window.

Web-Based Discussion and Illicit Street Sales of Tapentadol and Oxycodone in Australia: Epidemiological Surveillance Study

Background

Opioid use disorder and its consequences are a persistent public health concern for Australians. Web activity has been used to understand the perception of drug safety and diversion of drugs in contexts outside of Australia. The anonymity of the internet offers several advantages for surveilling and inquiring about specific covert behaviors, such as diversion or discussion of sensitive subjects where traditional surveillance approaches might be limited.

Objective

This study aims to characterize the content of web posts and compare reports of illicit sales of tapentadol and oxycodone from sources originating in Australia. First, post content is evaluated to determine whether internet discussion encourages or discourages proper therapeutic use of the drugs. Second, we hypothesize that tapentadol would have lower street price and fewer illicit sales than oxycodone.

Methods

Web posts originating in Australia between 2017 and 2019 were collected using the Researched Abuse, Diversion, and Addiction-Related Surveillance System Web Monitoring Program. Using a manual coding process, unstructured post content from social media, blogs, and forums was categorized into topics of discussion related to the harms and behaviors that could lead to harm. Illicit sales data in a structured format were collected through a crowdsourcing website between 2016 and 2019 using the Researched Abuse, Diversion, and Addiction-Related Surveillance System StreetRx Program. In total, 2 multivariable regression models assessed the differences in illicit price and number of sales.

Results

A total of 4.7% (28/600) of tapentadol posts discussed an adverse event, whereas 10.27% (95% CI 9.32-11.21) of oxycodone posts discussed this topic. A total of 10% (60/600) of tapentadol posts discussed unsafe use or side effects, whereas 20.17% (95% CI 18.92-21.41) of oxycodone posts discussed unsafe use or side effects. There were 31 illicit sales reports for tapentadol (geometric mean price per milligram: Aus $0.12 [US $0.09]) and 756 illicit sales reports for oxycodone (Aus $1.28 [US $0.91]). Models detected no differences in the street price or number of sales between the drugs when covariates were included, although the potency of the pill significantly predicted the street price (P<.001) and availability predicted the number of sales (P=.03).

Conclusions

Australians searching the web for opinions could judge tapentadol as safer than oxycodone because of the web post content. The illicit sales market for tapentadol was smaller than that of oxycodone, and drug potency and licit availability are likely important factors influencing the illicit market.

Trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia (2003-2015)

INTRODUCTION

Fentanyl-related overdose is an ongoing concern among countries with high prescription opioid utilisation. This study examines trends in transdermal fentanyl utilisation and fatal fentanyl overdose across Australia between 2003 and 2015, overall, and by age/sex.

METHODS

This was a retrospective nationwide study of prescription dispensings and coronial records. Transdermal fentanyl utilisation was examined using Pharmaceutical Benefits Scheme dispensing records. Details of fatal fentanyl overdoses were extracted from the National Coronial Information System.

RESULTS

Transdermal fentanyl utilisation increased 5.1-fold between 2003 and 2015, from 0.28 to 1.39 mg/1000 population/day and was consistently higher among females and adults aged ≥85 years. The utilisation of higher strength patches (75 and 100 mcg/h) was more common among males aged 25-44 years. A total of 291 fatal fentanyl overdoses were recorded, increasing from no recorded deaths in 2003 to 2.23 deaths/1 000 000 population in 2015. Rates were higher among males (increasing from 0 to 3.72 deaths/1 000 000 population) and for adults aged 25-44 years (increasing from 0 to 5.34 deaths/1 000 000 population). The number of deaths/kg fentanyl dispensed was highest among males aged <25 years (45.45, 95% confidence interval 21.80-83.59). Most deaths (70.1%) involved the intravenous administration of fentanyl from transdermal patches.

DISCUSSION AND CONCLUSIONS

Rates of transdermal fentanyl utilisation and fatal fentanyl overdose across Australia increased between 2003 and 2015. Although transdermal fentanyl utilisation was consistently greater among females and older adults, rates of fatal fentanyl overdose were highest among younger males. Interventions to reduce extramedical use among this high-risk population group are necessary to minimise fentanyl-related harms.

Characteristics of oxycodone-related ambulance attendances: analysis of temporal trends and the effect of reformulation in Victoria, Australia from 2013 to 2018

BACKGROUND AND AIMS

In Australia, oxycodone has been associated with increasing rates of harm over time, despite reduced use, reformulation to a tamper-resistant form and in contrast to most prescription opioids. We explored characteristics of oxycodone-related ambulance attendances to understand whether presentation characteristics could explain increasing oxycodone harm.

DESIGN

Retrospective study of coded ambulance patient care records related to extramedical oxycodone use, January 2013 to September 2018.

SETTING

Victoria, Australia.

CASES

A total of 2788 oxycodone-related ambulance attendances.

MEASUREMENTS

Primary outcomes were temporal changes in characteristics of oxycodone presentations over time (from 2013 to 2018) and following reformulation. Covariates include demographic characteristics, presentation severity, mental health, substance use and poisoning intent.

FINDINGS

Average age was 41.3 (± 16.4) years with females comprising 56.4% of attendances (n = 2788). The proportion of females in oxycodone-related attendances increased over time [an average increase in the odds ratios of 5% per year (OR) = 1.05, 95% confidence interval (CI) = 1.01-1.10]. Other temporal trends included a reduced likelihood of naloxone administration (OR = 0.92, 95% CI = 0.85-1.00), heroin involvement (OR = 0.81, 95% CI = 0.66-0.99), comorbid mental health symptoms (OR = 0.87, 95% CI = 0.82-0.92) and unknown intent poisoning (OR = 0.91, 95% CI = 0.85-0.96); and a greater risk of alcohol involvement (OR = 1.06, 95% CI = 1.01-1.11), non-opioid extramedical pharmaceutical use (OR = 1.05, 95% CI = 1.01-1.10), comorbid suicidal thoughts or behaviours (OR = 1.10, 95% CI = 1.05-1.15) and past history of psychiatric issues (OR = 1.22, 95% CI = 1.16-1.27). Interrupted time-series analysis showed that reformulation was associated with an immediate effect on sex, severity, accidental poisoning and unknown intent poisoning, although these were not sustained over time. Alcohol involvement in the attendance (OR = 1.43, 95% CI = 1.17-1.74, i.e. an average increase in the odds of 43% per year), Glasgow Coma Scale (OR = 1.28, 95%CI 1.04 - 1.57), a previous history of psychiatric issues (OR = 0.80, 95% CI = 0.70-0.92, i.e. an average decrease in the odds of 20% per year, heroin involvement (OR = 0.22, 95% CI = 0.05 - 0.98) and illicit drug use (OR = 0.45, 95% CI = 0.23 - 0.87) showed statistically significant relative changes following the reformulation.

CONCLUSIONS

The characteristics of oxycodone presentations in Australian ambulances attendances appear to be changing over time, including more female presentations; increasing alcohol use, extramedical use of non-opioid pharmaceuticals and suicidal thoughts or behaviours and decreasing heroin and illicit drug involvement.

Regional, national and international datasets: How they improve our understanding of the acute harms associated with prescription medicine misuse

Prescription medicine misuse is a significant problem in many areas of the world. Understanding the acute and chronic harms related to misuse of prescription medicines allows healthcare professionals, drug addiction treatment services and legislative authorities to determine what interventions may be beneficial to reduce these harms and protect individuals and society. However, it is difficult to obtain systematic data on the harms associated with prescription medicine misuse because of how patient visits to clinics and hospitals are recorded and coded in regional or national databases. In this review, we discuss how regional, national and international sources of information can help develop a greater understanding of the prevalence and pattern of acute harms related to prescription medicine misuse using data from ambulance attendances, emergency department presentations and poisons information services.

Comparing rates and characteristics of emergency department presentations related to pharmaceutical opioid poisoning in Australia: a study protocol for a retrospective observational study

INTRODUCTION AND AIMS

Pharmaceutical opioids are an important contributor to the global 'opioid crisis', and are implicated in 70% of Australia's opioid-related mortality. However, there have been few studies which consider the relative contribution of different pharmaceutical opioids to harm.We aim to compare commonly used pharmaceutical opioids in terms of (1) rates of harm, and (2) demographic and clinical characteristics associated with that harm.

METHOD AND ANALYSIS

Observational study of emergency department presentations for non-fatal poisoning related to pharmaceutical opioid use. Data from 2009 to 2019 will be extracted from the Victorian Emergency Minimum Dataset which contains data from public hospitals with dedicated emergency departments in Victoria, Australia's second most populous state. A combination of free-text and International Classification of Diseases 10th Revision codes will be used to identify relevant cases, with manual screening of each case to confirm relevance. We will calculate supply-adjusted rates of presentations using Poisson regression for all pharmaceutical opioid cases identified, separately for nine commonly prescribed pharmaceutical opioids (buprenorphine, codeine, fentanyl, methadone, morphine, oxycodone, oxycodone-naloxone, tapentadol, tramadol), and for a multiple opioid category. We will use multinomial logistic regression to compare demographic and clinical characteristics, such as triage category, across opioid types.

ETHICS AND DISSEMINATION

This work is conducted under approval 21427 from the Monash University Human Research Ethics Committee for ongoing injury surveillance. As per conditions of approval, cells of <5 will not be reported, though zeroes will be preserved. We will present project findings in a peer-reviewed journal article as well as at relevant scientific conferences.

Comparing rates and characteristics of ambulance attendances related to extramedical use of pharmaceutical opioids in Victoria, Australia from 2013 to 2018

BACKGROUND AND AIMS

Despite increases in opioid prescribing and related morbidity and mortality, few studies have comprehensively documented harms across opioid types. We examined a population-wide indicator of extramedical pharmaceutical opioid-related harm to determine if the supply-adjusted rates of ambulance presentations, the severity of presentations or other attendance characteristics differed by opioid type.

DESIGN

Retrospective observational study of coded ambulance patient care records related to extramedical pharmaceutical opioid use, January 2013 to September 2018.

SETTING

Australia CASES: Primary analyses used Victorian data (n = 9823), with available data from other Australian jurisdictions (n = 4338) used to determine generalizability.

MEASUREMENTS

We calculated supply-adjusted rates of attendances using Poisson regression, and used multinomial logistic regression to compare demographic, presentation severity, mental health, substance use and other characteristics of attendances associated with seven pharmaceutical opioids.

FINDINGS

In Victoria, the highest rates of attendance [per 100 000 oral morphine equivalent mg (OME)] were for codeine (0.273/100 000) and oxycodone (0.113/100 000). The lowest rates were for fentanyl (0.019/100 000) and tapentadol (0.005/100 000). Oxycodone-naloxone rates (0.031/100 000) were lower than for oxycodone as a single ingredient (0.113/100 000). Fentanyl-related attendances were associated with the most severe characteristics, most likely to be an accidental overdose, most likely to have naloxone administered and least likely to be transferred to hospital. In contrast, codeine-related attendances were more likely to involve suicidal thoughts/behaviours, younger females and be transported to hospital. Supply-adjusted attendance rates for individual opioids were stable over time. Victorian states were broadly consistent with non-Victorian states.

CONCLUSIONS

In Australia, rates and characteristics of opioid-related harm vary by opioid type. Supply-adjusted ambulance attendance rates appear to be both stable over time and unaffected by large changes in supply.