Estimation of adherence to urate-lowering therapy in people living with gout using Australia's Pharmaceutical Benefits Scheme and patient-reported dosing.

AIMS: The aim of this study was to estimate adherence to urate-lowering therapy (ULT), predominately allopurinol, from Australia's Pharmaceutical Benefits Scheme (PBS) claims database in association with (1) patient-reported doses and (2) World Health Organization's (WHO) defined daily doses (DDD), namely, allopurinol (400 mg/day) or febuxostat (80 mg/day). METHODS: Proportion of days covered (PDC) was calculated in 108 Gout App (Gout APP) trial participants with at least two recorded ULT dispensings in an approximately 12-month period before provision of intervention or control apps. Adherence was defined as PDC ≥80%. We measured the correlation between the two methods of calculating PDC using a Wilcoxon signed rank test. Agreement between ULT-taking status (self-reports) and ULT-dispensed status (PBS records) was tested with Cohen's kappa (κ), and positive and negative percent agreement. RESULTS: Allopurinol was prescribed in 93.5% of participants taking ULT. Their self-reported mean daily dose (SD) was 291 (167) mg/day. Mean PDC (SD) for allopurinol was 83% (21%) calculated using self-reported dose, and 63% (24%) using WHO's DDD. Sixty-three percent of allopurinol users were identified as adherent (PDC ≥80%) using self-reported dose. There was good agreement between self-reported ULT use and PBS dispensing claims (κ = 0.708, P < .001; positive percent agreement = 90%, negative percent agreement = 82%). CONCLUSIONS: Participant-reported allopurinol daily doses, in addition to PBS dispensing claims, may enhance confidence in estimating PDC and adherence compared to using DDD. This approach improves adherence estimations from pharmaceutical claims datasets for medications where daily doses vary between individuals or where there is a wide therapeutic dose range.

The impact of tightened prescribing restrictions for PBS-subsidised opioid medicines and the introduction of half-pack sizes, Australia, 2020-21: an interrupted time series analysis.

OBJECTIVES: To evaluate the impact of the tightened Pharmaceutical Benefits Scheme (PBS) prescribing rules for immediate release (IR) and controlled release (CR) opioid medicines (1 June 2020), which also eliminated repeat dispensing without authorisation for codeine/paracetamol and tramadol IR and introduced half-pack size item codes for IR formulations. DESIGN, SETTING: Population-based interrupted time series analysis of PBS dispensing data claims for a 10% sample of PBS-eligible residents and IQVIA national opioid medicine sales data (PBS-subsidised and private prescriptions), 28 May 2018 - 6 June 2021. MAIN OUTCOME MEASURES: Mean amount of PBS-subsidised opioid medicines dispensed per day and mean overall amount sold per day - each expressed as oral morphine equivalent milligrams (OME) - overall, by formulation type (IR, CR), and by specific formulation. RESULTS: During the twelve months following the PBS changes, daily PBS-subsidised opioid medicine dispensing was 81 565 OME lower (95% CI, -106 146 to -56 984 OME) than the mean daily level for 2018-20, a decline of 3.8% after adjusting for the pre-intervention trend; the relative reduction was greater for IR (8.4%) than CR formulations (2.6%). Total daily sales of all, IR formulation, and CR formulation opioid medicines did not change significantly after the PBS changes. Repeat dispensing of prescriptions comprised 7.4% of PBS-subsidised opioid dispensing before 1 June 2020, and 1.3% after the changes. Half-pack sizes comprised 8.4% of PBS-subsidised IR opioid medicine dispensing and 2.8% of all opioid medicines sold in the twelve months after the PBS changes. CONCLUSIONS: The introduction of new PBS rules for subsidised opioid medicines was followed by a decline in PBS-subsidised dispensing. Some people may have bypassed the new restrictions by switching to private prescriptions, but our findings suggest that opioid medicine use in Australia declined as a result of the new restrictions.

Quality use of publicly subsidised tapentadol in Australia: a population-based analysis.

BACKGROUND: Sustained-release (SR) tapentadol was listed on Australia's Pharmaceutical Benefits Scheme (PBS) in 2014 for chronic severe pain requiring long-term opioid treatment. Dispensings have increased since listing despite declining trends in other PBS-listed opioids. Preferential prescribing of SR opioids may increase the risk of dependence and accidental overdose, particularly when used to treat acute pain. AIMS: To explore the quality use of publicly subsidised tapentadol in Australia. METHODS: We examined annual initiation rates and patterns of use of tapentadol (SR) in the dispensing records of a 10% random sample of PBS-eligible Australians (2014-2021). We used national tapentadol sales data to assess the proportion of sales attributable to the PBS. RESULTS: Tapentadol initiation increased from 2014, peaking at 7.5/1000 adult population in 2019 before declining to 5.3/1000 in 2021. We identified 63 766 new users between 2014 and 2020, of whom 92.8% discontinued in the first year following initiation, 58.0% had only a single dispensing and 34.3% had no other opioids dispensed in the 3 months before or after initiation. 27.8% of new users were dispensed tapentadol on the same day as potentially interacting medicines. There was a sustained drop in the proportion of sales attributable to the PBS from June 2020 onwards, from an average of 69.1%, to 63.9% of pack sales. CONCLUSIONS: Patterns of use suggest tapentadol (SR) is generally used for short duration. Although most tapentadol sold in Australia is subsidised, there is evidence of a shift towards private sales.

Opioid analgesic exposure during the first trimester of pregnancy and the risk of major congenital malformations in infants: a systematic review and meta-analysis†.

BACKGROUND: Prescribed opioid analgesics are frequently used to manage pain in pregnancy. However, the available literature regarding the teratogenic potential of opioid use during pregnancy has not been systematically summarised. This systematic review and meta-analysis aimed to assess the quality of the evidence on these potential risks and calculate a pooled estimate of risk for any opioid analgesic and individual opioids. METHODS: We searched PubMed, Embase and CINAHL for published studies assessing the risk of major congenital malformations in infants following first-trimester exposure to opioid analgesics compared with a reference group, excluding studies examining opioid agonist therapy or illicit opioid use. We assessed the risk of bias using the Risk of Bias in Non-Randomised Studies of Intervention tool. We pooled adjusted risk estimates from studies rated at serious risk of bias or better in a random-effects meta-analysis. RESULTS: Of 12 identified studies, 11 were at high risk of bias (eight serious; three critical). Relative to unexposed infants, those exposed to any opioid use during the first trimester of pregnancy were not at an increased risk of major congenital malformations overall (relative risk 1.04, 95%CI 0.98-1.11); cardiovascular malformations (relative risk 1.07, 95%CI 0.96-1.20); or central nervous system malformations (relative risk 1.06, 95%CI 0.92-1.21). Raised risk estimates were observed for gastrointestinal malformations (relative risk 1.40, 95%CI 0.38-5.16) and cleft palate (relative risk 1.57, 95%CI 0.48-5.13) following any opioid exposure and atrial septal defects (relative risk 1.20, 95%CI 1.05-1.36) following codeine exposure. CONCLUSIONS: Although the meta-analysis did not indicate substantial increased risk for most malformations examined, this risk remains uncertain due to the methodological limitations of the included studies. Healthcare professionals and pharmaceutical regulators should be aware of the issues related to the quality of research in this field.

Drug dependence and prescribing ketamine for treatment-resistant depression in Australia and New Zealand.

Ketamine is a restricted and regulated medication in Australia and New Zealand, which has implications when considering treatment for patients with treatment-resistant depression and a history of illicit drug use, abuse or dependence. Regulations governing prescription of ketamine for treatment-resistant depression vary between jurisdictions in Australia and New Zealand, though most restrict use in those with drug dependence. There is substantial variation in definitions of drug dependence used in each jurisdiction, and between the legal and clinical definitions, with the latter specified in the current International Classification of Diseases, Eleventh Revision and Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition. This paper reviews the literature assessing the risk of ketamine misuse and dependence in patients with a history of illicit drug use, abuse or dependence and presents recommendations for psychiatrists who prescribe ketamine in such patients with treatment-resistant depression.

Measuring Objective and Subjective Sleep during Lisdexamfetamine Treatment of Acute Methamphetamine Withdrawal: A Feasibility Study.

INTRODUCTION: Sleep disturbance is common during methamphetamine (MA) use and withdrawal; however, the feasibility of combined subjective-objective measurement of sleep-wake has not been shown in this population. Actigraphy is a well-established, non-invasive measure of sleep-wake cycles with good concordance with polysomnography. This study aimed to investigate the feasibility and utility of using actigraphy and sleep diaries to investigate sleep during MA withdrawal. METHODS: We conducted a feasibility and utility study of actigraphy and sleep diaries during a clinical trial of lisdexamfetamine for MA withdrawal. Participants were inpatients for 7 days, wore an actigraph (Philips Actiwatch 2) and completed a modified Consensus Sleep Diary each morning. Participants were interviewed between days 3-5. RESULTS: Ten participants (mean age 37 years, 90% male) were enrolled. No participant removed the device prematurely. Participants interviewed (n = 8) reported that the actigraph was not difficult or distracting to wear or completion of daily sleep diary onerous. Actigraphic average daily sleep duration over 7 days was 568 min, sleep onset latency 22.4 min, wake after sleep onset (WASO) 75.2 min, and sleep efficiency 83.6%. Sleep diaries underreported daily sleep compared with actigraphy (sleep duration was 56 min (p = 0.008) and WASO 47 min (p < 0.001) less). Overall sleep quality was 4.4 on a nine-point Likert scale within the diary. CONCLUSIONS: Continuous actigraphy is feasible to measure sleep-wake in people withdrawing from MA, with low participant burden. We found important differences in self-reported and actigraphic sleep, which need to be explored in more detail.

Patterns of suboptimal antipsychotic use and misuse in Australia: What can routinely collected data tell us?

AIMS: There are increasing concerns about harms related to suboptimal antipsychotic use. Here we describe recent population-based trends in antipsychotic use and harms in Australia and identify population groups exhibiting patterns of use likely to contribute to these harms. METHODS: Using population-based data from the Australian Pharmaceutical Benefits Scheme (2015-2020), poisoning calls to the New South Wales (NSW) Poisons Information Centre (2015-2020) and poisoning deaths in all coronial records (2005-2018) in Australia, we measured trends in the prevalence of antipsychotic use and related deaths and poisonings. We applied latent class analyses to identify patterns of antipsychotic use that may contribute to harms. RESULTS: Quetiapine and olanzapine had the highest prevalence of use between 2015 and 2020. Noteworthy trends included increases of 9.1% and 30.8% in quetiapine use and poisonings, while olanzapine use decreased by 4.5% but poisonings increased by 32.7%. Quetiapine and olanzapine poisonings and related deaths had the highest rates of co-ingestion of opioids, benzodiazepines and pregabalin compared to other antipsychotics. We identified six distinct population groups using antipsychotics: (i) ongoing high-dose use with sedatives (8%), (ii) ongoing use (42%), (iii) ongoing use with analgesics and sedatives (11%), (iv) long-term low-dose use (9%), (v) sporadic use (20%) and (vi) sporadic use with analgesics (10%). CONCLUSION: Ongoing potentially suboptimal antipsychotic use and associated harms highlight the need to monitor such patterns of use, for example through prescription monitoring systems.

Blood, dose recommendation reports and phone calls: Experiences of a therapeutic drug monitoring advisory service for vancomycin.

Dose-prediction software is recommended to enable area under the curve over 24 h (AUC24 )-guided dosing of the antibiotic vancomycin. However, uncertainty remains about how best to implement software in the clinic. We describe the activity, over 18 months, of a consultative therapeutic drug monitoring Advisory Service (the Service) for vancomycin that used dose-prediction software alongside clinical expertise, identifying factors that influence attainment of therapeutic targets. Of the 408 vancomycin dose reports provided for 182 courses of therapy, most (57%) recommended a dose change. The majority (82.8%, 193/233) of recommended dose adjustments were accepted by treating teams. A dose report was not published for 125 courses of therapy, with reasons including patient in intensive care unit or service error. An estimated 26.6 h of staff time was allocated to Service activities each month. Publication of a dose report facilitated attainment of therapeutic targets (P = .002). Software integration could improve Service outcomes, avoiding errors and reducing staff workload.

Can old drugs learn new tricks? Achieving registration and public subsidy listing for off-patent medicines with novel therapeutic applications.

With the increasing costs of drug development, repurposing of low-cost medicines for new indications has never been more important. However, there are multiple barriers to repurposing, particularly for off-patent medicines, and limited incentives for the pharmaceutical industry to sponsor registration and public subsidy listing. Here, we explore these barriers and their consequences and provide examples of successful repurposing strategies.

Patterns of attention deficit hyperactivity disorder medicine use in the era of new non-stimulant medicines: A population-based study among Australian children and adults (2013-2020).

BACKGROUND AND AIMS: New therapeutic options such as lisdexamfetamine and guanfacine have recently become available for the treatment of attention deficit hyperactivity disorder. We described contemporary patterns of attention deficit hyperactivity disorder medicine use among children, adolescents and adults in Australia. METHODS: This population-based study used dispensing data for a 10% random sample of Australian residents between July 2012 and December 2020. We estimated the annual prevalence and incidence of attention deficit hyperactivity disorder medicines, second-line guanfacine use and examined concurrent medicine use of both stimulants and non-stimulants. We followed incident users for up to 5 years and analysed treatment persistence using a novel proportion of people covered method. Analyses were stratified by attention deficit hyperactivity disorder medicine, sex and age group; young children (0-5 years), children (6-12 years), adolescents (13-17 years), young adults (18-24 years) and adults (⩾25 years). RESULTS: We observed a twofold increase in the overall prevalence of attention deficit hyperactivity disorder medicine use between 2013 and 2020, from 4.9 to 9.7 per 1000 persons. Incident use also increased across all age groups and both sexes, with the most pronounced increases among adolescent females (from 1.4 to 5.3 per 1000 persons). Stimulant treatment persistence after 5 years was highest among those initiating treatment as young children (64%) and children (69%) and lowest among those initiating treatment in adolescence (19%). Concurrent use of stimulants and non-stimulants was more common among males and younger age groups. Most children (87%) initiating guanfacine had prior dispensings of attention deficit hyperactivity disorder medicines. CONCLUSION: We observed increasing attention deficit hyperactivity disorder medicine use in Australia, especially among young females. Nevertheless, treatment rates remain lower than the estimated prevalence of attention deficit hyperactivity disorder across all subpopulations. Poor long-term treatment persistence in adolescence may warrant improved clinical monitoring of attention deficit hyperactivity disorder in patients transitioning from paediatric to adult care. Reassuringly, use of newly approved guanfacine appeared to be in accordance with guidelines among children.

Understandings, attitudes, practices and responses to GHB overdose among GHB consumers.

BACKGROUND: Gamma-hydroxybutyrate (GHB) is used at disproportionately high rates within sexuality and gender diverse communities and carries a high risk of overdose. GHB overdose can result in death. Internationally, recent increases in GHB overdoses have been observed. Coronial reviews of GHB-related death highlight the pivotal roles that bystanders to GHB overdose play in preventing fatality. No research has examined, in detail, how bystanders respond to GHB overdose. This qualitative study was conducted among people who use GHB and explored how they responded upon witnessing a GHB overdose experienced by someone else. METHODS: Interviews were conducted with 31 sexuality and gender diverse Australian residents reporting three or more occasions of GHB use in the previous 12 months. Participants were asked questions about witnessed GHB overdose, their actions and decision-making processes throughout overdose. Data were analysed thematically. RESULTS: Participants described witnessing GHB overdose, commonly in private settings involving sexualized GHB use. Variable definitions of GHB overdose were reported, ranging from GHB-induced symptoms of distress to comatose intoxication. Drastic actions to keep someone alert and responsive post-GHB ingestion were reported; these included the administration of stimulant substances and citrus. Decisions to call or not call for emergency medical services (EMS) were influenced by many circumstantial variables. In most instances, an EMS call was resisted and response practices deviated from established first aid protocols. CONCLUSIONS: GHB overdose prevention and response training programs targeting people who use GHB are urgently required. These education interventions ought to address inaccuracies that inform street remedies for GHB overdose, teach people how to safely check breathing and response, promote basic first aid principles and address barriers to contacting EMS.

An exploratory ergonomic evaluation of musculoskeletal risks for ophthalmic photographers who use ophthalmic imaging equipment plus user equipment trials.

PURPOSE: An evaluation of musculoskeletal risks for users of ophthalmic imaging equipment and subsequent trials based on recommendations by an Ergonomist. METHODS: An advertisement was posted on ophthalmic imaging social media sites, requesting photographers, who are experiencing pain or discomfort when using the imaging equipment, to contact the author. Responders received a questionnaire that created a profile of the working habits, equipment used, and location of discomfort using diagrams of the torso and hands. The author contacted the Centre for Occupational Health and Wellbeing in Oxford for recommendations and assessment of the imaging equipment. Trials were conducted at the Oxford Eye Hospital imaging department following recommendations by an Ergonomist. DISCUSSION: Our research has indicated that the number of imaging procedures carried out by a photographer over the duration of their career, may be the key to calculating the risk factors for developing Musculoskeletal Disorders. Ergonomist recommendations include increasing awareness of wrist and hand pain, so it can be treated early with implementation of risk assessment for working practices, as trials carried out at the imaging department in Oxford have shown that small changes contribute to reducing identified risks.

Prescription opioid use in Australian women of reproductive age: Implications for unplanned pregnancies.

AIMS: To examine trends in the prevalence and incidence of prescription opioid analgesic use in Australian women of reproductive age and to estimate the number of calendar months each year that women were dispensed opioids. METHODS: We conducted a retrospective cross-sectional study involving women aged 15-44 years using pharmaceutical dispensing claims for a 10% random sample of Australians. For the period 2013-2020, we calculated the annual prevalence and incidence of opioid analgesic dispensing per 100 (%) population by opioid type and age group. We also estimated the total number of calendar months that women were dispensed at least 1 opioid each year. RESULTS: The prevalence of opioid use decreased from 12.8% in 2013 to 11.3% in 2020, representing a relative decrease of 11.6% (95% confidence interval 10.7, 12.6%). The incidence of opioid use decreased from 10.3% in 2014 to 8.3% in 2020, representing a relative decrease of 18.6% (95% confidence interval 17.6, 19.6%). Codeine in combination products, followed by oxycodone and tramadol, were the most prevalent opioids. Prevalence and incidence of opioid use were lowest in women aged 15-19 years and the highest in women 30 years and above. Among all women dispensed opioids, 72.7% were dispensed an opioid in only 1 month each year. CONCLUSION: Prescription opioid use remains common, although decreasing, among women of reproductive age in Australia. However, it is reassuring that the majority of opioid use in this population is short term.

Just 'nanging' around - harmful nitrous oxide use: a retrospective case series and review of Internet searches, social media posts and the coroner's database.

BACKGROUND: The chronic recreational inhalation of nitrous oxide (N2 O) 'nanging', can have adverse neurological and psychiatric effects. AIM: To evaluate cases of chronic N2 O use presenting to two hospitals, as well as to evaluate nationally N2 O deaths reported to the coroner and trends in Internet searches and social media posts related to N2 O. METHODS: Retrospective review of two toxicology units, from July 2017 to October 2020, of patients presenting with chronic N2 O use and neurological and/or psychiatric symptoms. We evaluated 10 years (2010-2019) of Internet search and social media trends involving N2 O and the National Coronial Information System (NCIS) database for deaths across Australia. RESULTS: Twenty-two patients were identified: median age 22 years, half female, 17 Asian background and 15 students. Presentations included decreased mobility or unsteady gait (n = 15) and psychiatric symptoms (n = 5). The median reported bulb use/day was 300 (interquartile range (IQR): 200-370), for a median of 6 months (IQR: 3-24). On magnetic resonance imaging, 10/18 had subacute combined degeneration of the spinal cord and 7/7 sensorimotor neuropathy on nerve conduction studies. All received high-dose intramuscular vitamin B12 and 11 methionine. Despite prolonged rehabilitation, nine required walking aids on discharge. Since 2017, social media posts and Internet searches for N2 O increased rapidly, the latter mostly directed at obtaining N2 O canisters. From the NCIS, 36 deaths were identified, 12 unintentional (recreational drug use), 20 intentional self-harm and 4 traumatic. CONCLUSION: We report a case series of symptomatic chronic N2 O use, many with ongoing neurological sequelae. Furthermore, a sharp increase in Internet searches to obtain N2 O cannisters was noted. Education of high-risk student groups on the long-term sequelae is important.

A cross sectional study of psychotropic medicine use in Australia in 2018: A focus on polypharmacy.

AIMS: To examine prescribed psychotropic medicine use on a given day in Australia (25 September 2018; World Pharmacists Day), with a focus on psychotropic polypharmacy. METHODS: We used a 10% sample of individual-level nationwide dispensing claims to examine psychotropic medicine use on a given day. We estimated the prevalence of psychotropic medicine use in all ages stratified by age and sex. We also calculated the observed vs expected (had medicines been randomly combined) prevalence of psychotropic combinations used. We focused on combinations of clinical significance as well combinations of psychotropics with medicines prescribed to manage cardiovascular risk and disease. RESULTS: Serotonin reuptake inhibitors, serotonin-noradrenalin reuptake inhibitors/noradrenaline reuptake inhibitors, tricyclic antidepressants and gabapentinoids dominated psychotropic use. The use of any psychotropic as a proportion of people in the Australian population increased with age, peaking at the 85-89 year age group and declining thereafter. Combinations of medicines from the same subclass generally occurred at lower than expected frequencies. However, combinations including atypical antipsychotics occurred more frequently than expected; e.g. 7.4× with anticonvulsants and 2.2× with other atypical antipsychotics. This was also the case for combinations of sedatives, e.g. anxiolytic with hypnotic benzodiazepines (3.8×). Lipid-lowering drugs and antidiabetic medicines were combined with psychotropics at frequencies close to those expected had they been randomly combined. CONCLUSION: Psychotropic use in older adults and certain psychotropic combinations that are not well supported with evidence remain prevalent and greater consideration of the drivers of this potentially inappropriate prescribing is required.

Patterns of pregabalin initiation and discontinuation after its subsidy in Australia.

Following the 2013 public subsidy of pregabalin in Australia for neuropathic pain not responding to other medicines, use and misuse increased substantially. We used pharmaceutical dispensing claims for a 10% sample of Australians to quantify initiation, discontinuation and dispensing of other analgesics before and after initiation. We identified 130 770 people initiating pregabalin between 2013/14 and 2017/18 (median age: 61 years; 56.8% female). Discontinuation rates at 1-year increased from 77.0% in 2013/14 to 85.9% in 2017/18; 38% only had 1 dispensing. Approximately 1/3 (37.5%) initiated on the lowest strength capsule (25 mg) with only 31.2% later up-titrating to a higher strength. 47.4% and 53.0% were dispensed opioids within 180 days before and after pregabalin initiation, respectively. Many individuals are using pregabalin for short treatment durations and low dose ranges not consistent with treatment of neuropathic pain, which is generally a chronic condition. This may suggest poorer tolerability than observed in clinical trials, or use for other conditions, some of which may be for indications where the balance of benefits and risk is less clear.

A national study on prescribed medicine use in Australia on a typical day.

PURPOSE: To describe Australians' prescribed medicine use on a typical day (September 25, 2018). METHODS: We conducted a cross-sectional study using nationally representative dispensing claims data using the Australian Government Department of Human Services random 10% sample of all Australians eligible for prescription medicines subsidised through the Australian Pharmaceutical Benefits Scheme (PBS). Our main outcome measures were the number and proportion of people using at least one prescribed medicine and the specific medicine groups and classes on the day. We estimated the proportion of Australians using these medicines using the mid-year Australian population as the denominator. We quantified multiple medicine use by calculating the number and proportion of people experiencing polypharmacy (the use of 5 or more unique medicines) and hyper-polypharmacy (the use of 10 or more unique medicines). RESULTS: We found that 9.0 million Australians used at least one PBS medicine on September 25, 2018; equating to 27.5 million medicines in use across Australia. "Cardiovascular system", "nervous system" and "alimentary tract and metabolism" medicines comprised the top three medicine groups. Over 1.8 million people experienced polypharmacy on the day, accounting for 13.6 million dispensed medicines. 1 022 590 (45%) people aged ≥70 years old experienced polypharmacy and 188 930 (8%) experienced hyper-polypharmacy. CONCLUSIONS: Rates of polypharmacy were high, particularly in the people most susceptible to polypharmacy-related harm. Strategies to optimise the risk-benefit ratio of medicines and to reduce polypharmacy through "choosing wisely" and "de-prescribing" in this age group are needed. Australia's national data provides a benchmark to inform global medicine utilisation practices.

The relative lethal toxicity of pharmaceutical and illicit substances: A 16-year study of the Greater Newcastle Hunter Area, Australia.

AIMS: We aim to calculate 2 metrics of relative lethal toxicity; the fatal toxicity index (FTI; number of deaths per year of a daily dose) and the case fatality (CF; number of deaths per overdose) with a focus on opioids, antidepressants, antipsychotics, benzodiazepines and illicit drugs. METHODS: This descriptive cohort study used the Australian National Coronial Information System (NCIS) to identify a population of individuals with drug-associated deaths in the Greater Newcastle Hunter Area between January 2002 and December 2016. This was combined with Australian medicine dispensing data and corresponding data from the Hunter Area Toxicology Service to calculate FTI and CF. RESULTS: There were 444 drug-related deaths and 21,296 overdoses during the study period. FTI and CF were well correlated (Spearman's rho 0.64, P < .001). Of the classes of interest, opioids had the highest FTI (40.3 95% confidence interval [CI] 35.2-45.4 deaths per 100 years of use at the defined daily dose or deaths/DDD/100 years) and CF (12.4% 95%CI 11.0-13.9). Fentanyl, methadone and morphine had the highest relative fatal toxicity within this class. Tricyclic antidepressants had the highest relative fatal toxicity of all antidepressants (FTI 14.5 95%CI 9.7-19.3 deaths/DDD/100 years and CF 7.1% [95%CI 4.8-9.3]) and benzodiazepines appeared to be more associated with multiple agent deaths than single. Of the illicit drugs, heroin had the highest CF (26.4%, 95%CI 19.1-33.7). CONCLUSION: Knowledge of relative lethal toxicity is useful to prescribers and medicines and public health policy makers in restricting access to more toxic drugs and may also assist coroners in determining cause of death.

The impact of permissive and restrictive pharmaceutical policies on quetiapine dispensing: Evaluating a policy pendulum using interrupted time series analysis.

PURPOSE: To evaluate the impact of 2 policy changes on quetiapine dispensing in Australia: removal of prior authorisation for prescribing (policy 1: July 2007) and removal of repeat prescriptions for 25-mg quetiapine (policy 2: January 2014). METHODS: We performed an interrupted time series analysis using Pharmaceutical Benefits Scheme claims data (July 2005 to December 2015). We assessed the impact of both policies on monthly quetiapine dispensing (25 mg and >25 mg) and the impact of policy change 2 on monthly rates of 25-mg discontinuation and switching from 25 mg to other quetiapine strengths. We also estimated the impact of both policies on the proportion of people with potentially inappropriate therapy (no evidence of dose escalation) following 25-mg initiation. RESULTS: Following removal of prior authorisation, 25-mg and >25-mg quetiapine dispensing in the Pharmaceutical Benefits Scheme 10% sample increased by 11/month (95% CI: 2-21) and 14/month (95% CI: 8-20), respectively. After removing 25-mg repeats, there was a permanent decrease of 1072 (95% CI 773-1371) dispensings and an increase in discontinuation of this strength; 48% of people dispensed the 25-mg strength that discontinued, discontinued quetiapine completely; the remainder continued to use higher quetiapine strengths. We observed minimal switching to other quetiapine strengths. There was no change in inappropriate 25-mg therapy following policy change 1 and a small decrease (79% to 76%, P = 0.05) following policy change 2. CONCLUSION: More nuanced policies are needed to ensure the appropriate access to 25-mg quetiapine for dose escalation while discouraging use for indications where the evidence of risk and benefit is unclear.

Trends in opioid utilisation in Australia, 2006-2015: Insights from multiple metrics.

PURPOSE: Population-based observational studies have documented global increases in opioid analgesic use. Many studies have used a single population-adjusted metric (number of dispensings, defined daily doses [DDDs], or oral morphine equivalents [OMEs]). We combine these volume-based metrics with a measure of the number of persons dispensed opioids to gain insights into Australian trends in prescribed opioid use. METHODS: We obtained records of prescribed opioid dispensings (2006-2015) subsidised under Australia's Pharmaceutical Benefits Scheme. We used dispensing claims to quantify annual changes in use according to 3 volume-based metrics: DDD/1000 pop/day, OME/1000 pop/day, and dispensings/1000 pop. We estimated the number of persons dispensed at least one opioid in a given year (persons)/1000 pop using data from a 10% random sample of Pharmaceutical Benefits Scheme-eligible Australians. RESULTS: Total opioid use increased according to all metrics, especially OME/1000 pop/day (51% increase) and dispensings/1000 pop (44%). Weaker opioid use remained stable or declined; strong opioid use increased. The rate of persons accessing weaker opioids only decreased 31%, and there was a 238% increase in persons dispensed only strong opioids. Strong opioid use also increased according to dispensings/1000 pop (140%), OME/1000 pop/day (80%), and DDD/1000 pop/day (71% increase). CONCLUSIONS: Our results suggest that the increases in total opioid use between 2006 and 2015 were predominantly driven by a growing number of people treated with strong opioids at lower medicine strengths/doses. This method can be used with or without person-level data to provide insights into factors driving changes in medicine use over time.