Pregabalin prescribing patterns in Australian general practice, 2012-2018: a cross-sectional study

Secular trends in gabapentinoid dispensing by compensated workers with low back pain: a retrospective cohort study

OBJECTIVES

The increase in gabapentinoid prescribing is paralleling the increase in serious harms. To describe the low back pain workers compensation population whose management included a gabapentinoid between 2010 and 2017, and determine secular trends in, and factors associated with gabapentinoid use.

METHODS

We analysed claim-level and service-level data from the Victorian workers' compensation programme between 1 January 2010 and 31 December 2017 for workers with an accepted claim for a low back pain injury and who had programme-funded gabapentinoid dispensing. Secular trends were calculated as a proportion of gabapentinoid dispensings per year. Poisson, negative binomial and Cox hazards models were used to examine changes over time in incidence and time to first dispensing.

RESULTS

Of the 17 689 low back pain claimants, one in seven (14.7%) were dispensed at least one gabapentinoid during the first 2 years (n=2608). The proportion of workers who were dispensed a gabapentinoid significantly increased over time (7.9% in 2010 to 18.7% in 2017), despite a reduction in the number of claimants dispensed pain-related medicines. Gabapentinoid dispensing was significantly associated with an opioid analgesic or anti-depressant dispensing claim, but not claimant-level characteristics. The time to first gabapentinoid dispensing significantly decreased over time from 311.9 days (SD 200.7) in 2010 to 148.2 days (SD 183.1) in 2017.

CONCLUSIONS

The proportion of claimants dispensed a gabapentinoid more than doubled in the period 2010-2017; and the time to first dispensing halved during this period.

Opioid analgesics for nociceptive cancer pain: A comprehensive review

Pain is one of the most burdensome symptoms in people with cancer, and opioid analgesics are considered the mainstay of cancer pain management. For this review, the authors evaluated the efficacy and toxicities of opioid analgesics compared with placebo, other opioids, nonopioid analgesics, and nonpharmacologic treatments for background cancer pain (continuous and relatively constant pain present at rest), and breakthrough cancer pain (transient exacerbation of pain despite stable and adequately controlled background pain). They found a paucity of placebo-controlled trials for background cancer pain, although tapentadol or codeine may be more efficacious than placebo (moderate-certainty to low-certainty evidence). Nonsteroidal anti-inflammatory drugs including aspirin, piroxicam, diclofenac, ketorolac, and the antidepressant medicine imipramine, may be at least as efficacious as opioids for moderate-to-severe background cancer pain. For breakthrough cancer pain, oral transmucosal, buccal, sublingual, or intranasal fentanyl preparations were identified as more efficacious than placebo but were more commonly associated with toxicities, including constipation and nausea. Despite being recommended worldwide for the treatment of cancer pain, morphine was generally not superior to other opioids, nor did it have a more favorable toxicity profile. The interpretation of study results, however, was complicated by the heterogeneity in the study populations evaluated. Given the limited quality and quantity of research, there is a need to reappraise the clinical utility of opioids in people with cancer pain, particularly those who are not at the end of life, and to further explore the effects of opioids on immune system function and quality of life in these individuals.

Can General Practitioner Opioid Prescribing to Compensated Workers with Low Back Pain Be Detected Using Administrative Payments Data? An Exploratory Study

BACKGROUND

Approximately one third of Australians with accepted time loss workers' compensation claims for low back pain (LBP) are dispensed opioid analgesics. Structured administrative payments data is scalable but does not directly link opioids to prescribers. We sought to determine whether opioid prescribing by general practitioners (GPs) to workers with workers' compensation claims for LBP can be detected in structured administrative payments data.

METHODS

We used a sample of workers with accepted time loss workers' compensation claims for low back pain from 2011 to 2015 from the Australian states of Victoria and South Australia. We structured administrative data to test the assumption that opioid dispenses that occurred immediately after a GP encounter in sequence and occurred on the same date as the GP encounter are likely to be related. We measured the number and proportion of opioid dispenses with a GP encounter prior and the days between a GP encounter and opioid dispense.

RESULTS

Nearly one third of workers (32.2%, N = 4,128) in our sample (n = 12,816) were dispensed opioids a median of five times (interquartile range 2, 17). There were 43,324 opioid dispenses to included workers. 30,263 (69.9%) of opioid dispenses were immediately preceded by a GP encounter. Of those dispenses, 51.0% (n = 15,443) occurred on the same day as the GP encounter.

CONCLUSION

At least one third of opioids dispensed to workers with claims for LBP can be potentially linked to GP prescribing using workers' compensation structured administrative payments data. This approach could have potential applications in supporting monitoring and audit and feedback systems. Future research should test this approach with a more diverse array of pain medicines and medical practitioners.

Trends in Pregabalin Use and Prescribing Patterns in the Adult Population: A 10-Year Pharmacoepidemiologic Study

BACKGROUND AND OBJECTIVE

Pregabalin is steadily gaining popularity worldwide, with epidemiological studies indicating an increase in labeled, off-labeled, and recreational uses. In Israel, pregabalin prescriptions are not regulated by the controlled substances legislations, prompting a need to examine its usage trends for potential policy adjustments. The objective of this study was to assess trends in pregabalin prescribing during a 10-year period, to characterize demographic and clinical characteristics of individuals prescribed pregabalin, and to identify risk factors associated with high-intensity pregabalin use.

METHODS

This retrospective, longitudinal study examined trends in pregabalin prescribing from 2010 to 2019 based on data extracted from the Clalit Health Services (CHS) electronic database. Annual pregabalin prescribing rate was calculated individually for each reporting year. A univariable analysis was conducted to compare the demographic and clinical characteristics of pregabalin users in 2019 with those in 2010. Multivariable regression analysis was performed to assess dose-related patterns by specific demographic and clinical characteristics.

RESULTS

Pregabalin prescription rate more than doubled over 10 years [odds ratio (OR) 2.3, p = 0.001], reaching 7.2 [95% confidence interval (CI) 7.18-7.28] prescriptions per 100 CHS members in 2019. The highest prescription rates were observed among the elderly population (13.2 and 24.1 prescriptions per 100 CHS members for those aged 55-74 and over 75 years old, respectively). Same-year administration of pregabalin with opioids, benzodiazepines, and Z-drugs was common; however, the percentage of patients using these drugs together declined in 2019 compared with 2010 (p < 0.001). Males, patients with low socioeconomic status, patients aged 35-54 years, and those who consumed opioids, benzodiazepines, and Z-drugs received higher pregabalin doses.

CONCLUSION

Pregabalin use has increased significantly in the Israeli adult-based CHS population, consistent with worldwide data. A growing use over time may indicate overprescription. More studies are needed on misuse patterns to identify populations most susceptible to high-dose and high-intensity pregabalin use.

Content and sentiment analysis of gabapentinoid-related tweets: An infodemiology study

INTRODUCTION

The increasing number of gabapentinoid (pregabalin and gabapentin) harms, including deaths observed across countries is concerning to health-care professionals and policy makers. However, it is unclear if the public shares these concerns. This study aimed to describe posts related to gabapentinoids, conduct a content analysis to identify common themes and describe adverse events or symptoms.

METHODS

Keywords of 'pregabalin' or 'Lyrica' or 'gabapentin' or 'Neurontin' were used to search for related tweets posted by people in the community between 8 March and 7 May 2021. Eligible tweets included a keyword in the post. We extracted de-identified data which included descriptive data of the total number of posts over time; and data on individual tweets including date, number of re-tweets and post content. Data were exported separately for pregabalin- and gabapentin-related tweets. A 20% random sample was used for the thematic analysis.

RESULTS

There were 2931 pregabalin-related tweets and 2736 gabapentin-related tweets. Thematic analysis revealed three themes (sharing positive experiences and benefits of taking gabapentinoids, people voicing their negative experiences, and people seeking opinions and sharing information). Positive experiences of gabapentinoids were related to sharing stories and giving advice. This was contrasted to negative experiences including ineffectiveness, withdrawals, side effects and frustration related to cost and insurance coverage. Brain fog was the most common adverse symptom reported. Gabapentinoid-related deaths were only mentioned in three tweets.

DISCUSSION

The increasing public health concern of gabapentinoid-related deaths was not translated to Twitter discussions.

Gabapentinoids in Ireland 2010 to 2020: An observational study of trends in gabapentinoid prescribing, law enforcement drug seizures and postmortem toxicology

AIMS

We explored trends in gabapentinoid prescribing, drug seizures and postmortem toxicology using a national pharmacy claims database, law enforcement drug seizures data and a population-based postmortem toxicology database.

METHODS

Gabapentinoid prescribing rates per 100 000 eligible population (2010-2020), annual number of drug seizures involving gabapentinoids (2012-2020) and gabapentinoid detection (positive) rates per 100 postmortem toxicology case (2013-2020) were calculated. Negative binomial regression models were used to evaluate longitudinal trends for gabapentin and pregabalin separately.

RESULTS

Gabapentin (adjusted rate ratio [RR] 1.06, 95% confidence interval [CI] 1.05-1.06, P < .001) and pregabalin (adjusted RR 1.08, 95% CI 1.08-1.09, P < .001) prescribing increased annually, with higher rates of pregabalin (vs. gabapentin) observed every year. Drug seizures involving pregabalin also increased over time (RR 1.54 95% CI 1.25-1.90, P < .0001). Of the 26 317 postmortem toxicology cases, 0.92% tested positive for gabapentin, and 6.37% for pregabalin. Detection rates increased for both gabapentin (RR 1.28, 95% CI 1.11-1.48, P < .001) and pregabalin (RR 1.13, 95% CI 1.11-1.48, P < .001) between 2013 and 2020. A total of 1901 cases (7.2%) tested positive for heroin/methadone; this sub-group had a higher detection rate for pregabalin (n = 528, 27.8%) and gabapentin (n = 41, 2.2%) over the study period, with a high burden of codetections for pregabalin with benzodiazepines (peaking at 37.3% in 2018), and pregabalin with prescription opioids (peaking at 28.9% in 2020).

CONCLUSION

This study raises concerns regarding the wide availability of pregabalin in Ireland, including a growing illicit supply, and the potential for serious harm arising from poly drug use involving pregabalin among people who use heroin or methadone.

Experiences of misuse and symptoms of dependence among people who use gabapentinoids: a qualitative systematic review protocol

INTRODUCTION

Gabapentinoids are among the most widely prescribed pain medications. However, there is growing evidence to suggest that gabapentinoids may be associated with dependence and misuse. The aim of this systematic review is to synthesise the qualitative literature on gabapentinoid misuse and symptoms of dependence. The findings of this study will inform efforts to mitigate emerging harms.

METHODS AND ANALYSIS

A systematic review of qualitative research will explore lived experiences of misuse and symptoms of dependence among people who use gabapentinoids. Six databases (MEDLINE, Scopus, Web of Science, CINAHL, EMBASE and PsycINFO) and grey literature sources will be searched from inception to May 2023. Qualitative studies that include people with lived experiences of gabapentinoid misuse and symptoms of gabapentinoid dependence will be included. Reference lists of included studies will also be screened for additional studies. The methodological quality of included studies will be appraised using the Critical Appraisal Skills Programme qualitative checklist, and higher quality studies will be prioritised in the thematic synthesis. The GRADE-CERQual approach will be used to assess confidence in the overall findings of the review.

ETHICS AND DISSEMINATION

Ethical approval is not required for this systematic review. The findings of this review will be disseminated in peer-reviewed journals, at conferences and on social media.

PROSPERO REGISTRATION NUMBER

CRD42023401832.

Deprescribing interventions for gabapentinoids in adults: A scoping review

The emerging issue of rising gabapentinoid misuse is being recognized alongside the lack of current evidence supporting the safe and effective deprescribing of gabapentinoids. This scoping review aimed to assess the extent and nature of gabapentinoid deprescribing interventions in adults, either in reducing dosages, or prescribing of, gabapentinoids. Electronic databases were searched on 23 February 2022 without restrictions. Eligible studies included randomized, non-randomized and observational studies that assessed an intervention aimed at reducing/ceasing the prescription/use of a gabapentinoid in adults for any indication in a clinical setting. The research outcomes investigated the type of intervention, prescribing rates, cessations, patient outcomes and adverse events. Extracted outcome data were categorized as either short (≤3 months), intermediate (>3 but <12 months) or long (≥12 months) term. A narrative synthesis was conducted. The four included studies were conducted in primary and acute care settings. Interventions were of dose-reducing protocols, education and/or pharmacological-based approaches. In the randomized trials, gabapentinoid use could be ceased in at least one third of participants. In the two observational trials, gabapentinoid prescribing rates decreased by 9%. Serious adverse events and adverse events specifically related to gabapentinoids were reported in one trial. No study included patient-focused psychological interventions in the deprescribing process, nor provided any long-term follow-up. This review highlights the lack of existing evidence in this area. Due to limited available data, our review was unable to make any firm judgements on the most effective gabapentinoid deprescribing interventions in adults, highlighting the need for more research in this area.

"We were all looking for the magic pill": A qualitative study of patient experiences using gabapentinoids for chronic pain

BACKGROUND

Gabapentinoid medications are increasingly being used in chronic pain management, yet very little is known about the experiences of those using them. The aim of this study was to address this gap in the literature by qualitatively exploring the lived experiences of patients using gabapentinoids for chronic pain.

METHODS

Semi-structured interviews were conducted with 12 adults prescribed a gabapentinoid medication - either pregabalin or gabapentin - for chronic pain in Australia. Interviews were conducted in May 2022 via telephone or online video chat. Audio recordings of the interviews were transcribed verbatim, and data were analysed using reflexive thematic analysis. The Medication Adherence Model was used as a framework for synthesising the data and organising themes.

RESULTS

For participants in this study, the initial decision to use gabapentinoids for chronic pain was driven by a level of desperation for pain relief, a perceived lack of pain management alternatives, and a belief that the medication was safer and easier to access than opioids. However, once using gabapentinoids, experiences varied considerably with some viewing the medication as effective and safe, and others viewing it as useless or harmful. Some participants expressed concern that they were not adequately informed by their prescribers about the risks of gabapentinoid use.

CONCLUSION

These findings emphasise the importance of patient-provider communication and taking a patient-centred approach to gabapentinoid prescribing and de-prescribing. Future qualitative research in this area should involve primary care providers to gain a better understanding of factors driving increased gabapentinoid prescribing in chronic pain management as well as barriers to patient education.

Gabapentinoid consumption in 65 countries and regions from 2008 to 2018: a longitudinal trend study

Recent studies raised concerns about the increasing use of gabapentinoids in different countries. With their potential for misuse and addiction, understanding the global consumption of gabapentinoids will offer us a platform to examine the need for any interventional policies. This longitudinal trend study utilised pharmaceutical sales data from 65 countries and regions across the world to evaluate the global trends in gabapentinoid consumption between 2008-2018. The multinational average annual percentage change of gabapentinoid consumption was +17.20%, increased from 4.17 defined daily dose per ten thousand inhabitants per day (DDD/TID) in 2008 to 18.26 DDD/TID in 2018. High-income countries had the highest pooled gabapentinoid consumption rate (39.92 DDD/TID) in 2018, which was more than six times higher than the lower-middle income countries (6.11 DDD/TID). The study shows that despite differences in healthcare system and culture, a consistent increase in gabapentinoid consumption is observed worldwide, with high-income countries remaining the largest consumers.

Gabapentinoid detection in coronial casework in Gold Coast, Australia: a 5-year retrospective study

Gabapentinoids is a class of drug with analgesic, anxiolytic, and anticonvulsant properties and has a reported increase in prescription, use, and adverse outcomes. Regional studies are scant, and postmortem toxicological data may characterise patterns of regional use and inform local interventions. Characterising drug and non-drug-related deaths with gabapentinoid detection may also aid in toxicology interpretation. A 5-year retrospective study on all deaths admitted to the Gold Coast University Hospital under where toxicological analysis was performed. Of the gabapentinoids, only pregabalin was detected over the study period, and annual rates of detection did not differ significantly over the period (7.4-12.4%). In cases where pregabalin was detected, it was 15 times more likely to be a drug-related death. Drug-related deaths where pregabalin was detected have higher levels of pregabalin, are younger, and had a greater proportion of concurrent opioid detection. Postmortem detection of pregabalin was associated with drug-related deaths. Higher levels, younger decedents, and concurrent use of opioids were found in drug-related deaths. Public health interventions and regulated prescribing to target concurrent pregabalin and opioid use may address the burden of pregabalin drug-related deaths.

Trends and psychosocial correlates of same day polysubstance use among people who inject drugs in Australia, 2012-2022

BACKGROUND

Polysubstance use is associated with negative health and social outcomes among people who inject drugs. We aimed to describe trends in polysubstance use and identify psychosocial correlates and associated drug use risk behaviours. We defined polysubstance use as intentional same day use of more than one of three drug classes: opioids, other non-opioid depressants (hereafter 'depressants'), and stimulants.

METHODS

We used 10 years (2012-2022, excluding 2020) of data from annual surveys in Australian capital cities with people who inject drugs (N=5657) to construct five mutually exclusive polysubstance use profiles: opioid-depressant, opioid-stimulant, stimulant-depressant, opioid-stimulant-depressant, and single drug class use. We examined time trends using the Mann Kendall test and identified correlates using multinomial logistic regression.

RESULTS

Same day polysubstance use was relatively common among this sample (43.6%). Opioid-depressant use was the most frequent polysubstance use profile, but this decreased over the study period (32.6% to 13.3%, p<0.001). This aligned with observed decreases in use of pharmaceutical opioids (p<0.001), opioid agonist treatment (p=0.007), and benzodiazepines (p=0.001). There was no evidence for any trend in the other polysubstance use profiles, although single drug class use increased (51.9% to 64.7%, p=0.031). The different polysubstance use profiles were variously associated with psychosocial factors, including unstable housing and very high psychological distress, and other drug use risk behaviours, including non-fatal overdose, receptive and/or distributive needle sharing, and reusing one's own needles.

CONCLUSION

Same day polysubstance use has remained relatively common among this sample over time, although the typology has changed. Collectively, our findings point to diverse drug use patterns among people who inject drugs and reiterate the need for a range of harm reduction, treatment, and support options.

Safety of mirogabalin and pregabalin in Japanese patients with neuropathic pain: a retrospective cohort study

BACKGROUND

Few studies have compared the safety risks between the gabapentinoids, pregabalin, and mirogabalin in post-marketing clinical settings. We assessed reported events associated with gabapentinoid use in patients with neuropathic pain.

RESEARCH DESIGN AND METHODS

We conducted a retrospective cohort study between September 2020 and December 2020 using the community pharmacies records in Japan. The pharmacists identified new vs. prevalent users of mirogabalin and pregabalin in September 2020 and reported data regarding baseline and adverse events to the Japan Pharmaceutical Association using web-based questionnaires. The incidence of events and hazard ratio (HR) were consequently compared.

RESULTS

New users of mirogabalin and pregabalin were identified (n = 1,650 and 2,244; mean age (SD): 69 (15) and 68 (16) years; women: 59% and 56%, respectively). Although serious events were not reported, a marked difference in HRs of common adverse events, including somnolence (1.6), dizziness (1.3), nausea (2.8), edema (3.1), and acetaminophen (2.0)/antidepressant (2.4) addition, was observed.

CONCLUSION

No new serious safety concerns were found for mirogabalin and pregabalin use in patients with neuropathic pain, although the HR of some events indicated increased risk among mirogabalin users. However, further studies are needed as estimates for events occurring in small numbers with wide confidence intervals.

Trends in gabapentinoid prescribing in UK primary care using the Clinical Practice Research Datalink: an observational study

Background

The UK government reclassified gabapentin and pregabalin as 'controlled drugs' from April 2019. This study aimed to describe the trends in gabapentinoid prescribing before and immediately after reclassification, in the UK Clinical Practice Research Datalink, an electronic primary care health record broadly representative of the UK.

Methods

Separately for gabapentin and pregabalin, we calculated annual incident and prevalent prescribing rates from year of UK approval (April 1997 and 2004 respectively) to September 2019, and monthly incident and prevalent prescribing rates (October 2017-September 2019). Significant changes in temporal trends were determined using joinpoint regression. We also described potential prescribing indications, prior pain-related prescribing, and co-prescribing with potentially interacting medicines.

Findings

Incident gabapentin prescribing increased annually, peaking in 2016-17, at 625/100,000 patient years before falling steadily to 2019. Incident pregabalin prescribing peaked at 329/100,000 patient years in 2017-18 and did not fall significantly until 2019. Prevalent gabapentin and pregabalin prescribing increased annually to 2017-18 and 2018-19 respectively, before plateauing. Gabapentinoids were commonly co-prescribed with opioids (60%), antidepressants (52%), benzodiazepines (19%), and Z-drugs (10%).

Interpretation

Following a dramatic rise, incident gabapentinoid prescribing has started to fall but the specific impact of reclassification on prescribing rates remains unclear. Limited change in prevalent gabapentinoid prescribing during the 6 months following their reclassification as controlled drugs suggests little immediate impact on continued gabapentinoid prescribing for existing users.

Funding

National Institute for Health and Care Research (NIHR) Research for Patient Benefit Programme. NIHR Applied Research Collaboration West Midlands. NIHR School for Primary Care Research.

Trajectories of pregabalin use and their association with longitudinal changes in opioid and benzodiazepine use

ABSTRACT

Concomitant use of pregabalin with opioids and/or benzodiazepines is common, despite the increased risks. However, clinical trials suggest pregabalin can have an opioid-sparing effect when treating acute postoperative pain. We explored how opioid and benzodiazepine use changed over time in people initiating pregabalin, using dispensing claims data for a 10% sample of Australians (2013-19). Among 142,776 people initiating pregabalin (median age = 61 years, 57% female), we used group-based trajectory modelling to identify 6 pregabalin dose trajectories in the first year postinitiation. Two trajectories involved discontinuation: after one dispensing (49%), and after 6 months of treatment (14%). Four trajectories involved persistent use with variable estimated median daily doses of 39 mg (16%), 127 mg (14%), 276 mg (5%), and 541 mg (2%). We quantified opioid and benzodiazepine use in the year before and after pregabalin initiation using generalised linear models. Over the study period, 71% were dispensed opioids and 34% benzodiazepines, with people on the highest pregabalin dose having highest rates of use. Opioid use increased postpregabalin initiation. Among people using both opioids and pregabalin, the geometric mean daily dose in oral morphine equivalents increased after pregabalin initiation in all trajectories, ranging from +5.9% (99% confidence interval 4.8%-7.0%) to +39.8% (99% confidence interval 38.3%-41.5%) in people on the highest daily pregabalin dose. Among people using both pregabalin and benzodiazepines, the dose remained constant over time for people in all trajectories. Notwithstanding its reputation as opioid-sparing, in this outpatient setting, we observed that people using opioids tended to use higher opioid daily doses after pregabalin initiation, especially those on high pregabalin doses.

Prevalence of Gabapentinoids and Central Nervous System Depressant Drugs, and Their Association with Risk Factors for Respiratory Depression in Primary Care Patients

BACKGROUND AND OBJECTIVES

Warnings have been published regarding an increased risk of severe respiratory depression in patients receiving gabapentinoids either alone or in combination with opioids and/or anxiolytics/hypnotics, especially in individuals with a respiratory risk factor. The aim is to report the prevalence of the use of gabapentinoids alone and associated with central nervous system depressant drugs, and possible associated risk factors for respiratory depression, in order to identify the most fragile population and establish intervention strategies.

METHODS

We performed a cross-sectional study using computerized prescription records from the northern area of Barcelona at Catalan Institute of Health for 363,007 inhabitants registered during 2021. Patients aged ≥ 18 years with one or more gabapentinoid prescription were included. Age, gender, polypharmacy, adjusted morbidity groups, quantity of chronic diseases, and the number of consultations per year were independent variables. Four age categories were defined (18-64 years, then 64-74, 75-84, and those aged 85 years or older). Descriptive and inferential statistics were employed. Level of statistical significance was 5% (p ≤ 0.05). For the analysis, the SPSS program (version 22) was employed.

RESULTS

Of the study sample, 9218 were prescribed gabapentidoids. Overall prevalence of use was 3.0% (women 3.6%, men 2.4%). On the whole, women used more drugs than men. In contrast to their younger counterparts, consumption increased 2.6 times, 3.8 times, and 4.0 times in the 65-74 age group, 75-84 age group, and those aged ≥ 85 years, respectively. Mean age was 65.59 (±15.80) years. Polypharmacy (5-9 drugs) was present in 41.7% of the patients and extreme polypharmacy (≥ 10 drugs) was present in 39.3% of the patients. Regarding renal function, 2396 patients (25.9%) had glomerular filtration that required dose adjustment (76.1% with gabapentin and 23.8% with pregabalin). In 141 patients (5.9%), a total daily dose higher than that authorized (109 with gabapentin, 29 with pregabalin) had been prescribed. The prescription of gabapentinoids combined with opioids and/or anxiolytics/hypnotics was significantly associated with (i) polypharmacy (5-9 drugs, OR: 3.42 [95% CI 3.00-3.88]; ≥ 10 drugs, OR 8.72 [95% CI 7.42-10.25]); (ii) quantity of chronic diseases, OR: 1.14 (95% CI 1.11-1.17); (iii) augmented number of consultations/year, OR: 1.01 (95% CI 1.00-1.01); (iv) female gender, OR: <  1 for men, OR: 0.66 (95% CI 0.60-0.73); (v) being elderly: 65-74 years, OR: 0.71 (95% CI 0.62-0.81); 75-84 years, OR: 0.62 (95% CI 0.54-0.71); ≥85 years, OR: 0.68 (95% CI 0.58-0.81); and (vi) adjusted morbidity groups, OR: 0.90 (95% CI 0.88-0.92), (p <  0.0001).

CONCLUSION

Exposure to gabapentinoids occurs in a non-negligible percentage of the population. Greater numbers of combinations of gabapentinoids and opioids and/or anxiolytics/hypnotics were associated with polypharmacy, quantity of chronic diseases, and augmented number of consultations, but not with male gender, older age, and adjusted morbidity groups.

Characteristics of fatal gabapentinoid-related poisoning in Australia, 2000-2020

INTRODUCTION

Gabapentinoids are centrally active GABA agonists whose use has increased substantially in the past decade. The current study aimed to provide a comprehensive clinical profile of a national case series of fatal poisonings related to gabapentinoids.

METHODS

Retrospective study of all deaths due to drug toxicity in Australia in which gabapentinoids were a contributory mechanism, retrieved from the National Coronial Information System (2000-2020). Information was collected on case characteristics, toxicology and major organ pathology.

RESULTS

A total of 887 cases were identified, with a mean age of 45.7 years and 55.2% being male. Death was due to accidental toxicity in 81.3% of cases and intentional in 18.7%. Pre-existing disease was co-contributory to drug toxicity in 19.5%. Pregabalin was present in 92.9% of cases, with a median blood concentration of 7.6 mg/L (range 0.1-850.0 mg/L). Gabapentin was present in 7.2%, with a median blood concentration of 9.5 mg/L (range 0.5-1940.0 mg/L). Both pregabalin and gabapentin were present in five cases. No other gabapentinoids were detected. Drugs other than gabapentinoids were present in 99.8%, most frequently opioids (90.1%), hypnosedatives (76.9%) and antidepressants (60.5%). A body mass index in the obese range was seen in 45.4%. Clinically significant pre-existing disease was common, notably cardiomegaly (24.9%), emphysema (20.2%), nephrosclerosis (18.7%) and severe hepatic steatosis (11.7%).

CONCLUSIONS

The concomitant use of other drugs was close to universal, with CNS depressants predominating. Mental health problems, chronic pain and substance misuse were prominent.

Trigeminal neuralgia management after microvascular decompression surgery: two case reports

Trigeminal neuralgia (TN) involves chronic neuropathic pain, characterized by attacks of repeating short episodes of unilateral shock-like pain, which are abrupt in onset and termination. Anticonvulsants, such as carbamazepine, are the gold standard first-line drugs for pharmacological treatment. Microvascular decompression (MVD) surgery is often the course of action if pharmacological management with anticonvulsants is unsuccessful. MVD surgery is an effective therapy in approximately 83% of cases. However, persistent neuropathic pain after MVD surgery may require reintroduction of pharmacotherapy. This case report presents two patients with persistent pain after MVD requiring reintroduction of pharmacological therapy. Although MVD is successful for patients with failed pharmacological management, it is an invasive procedure and requires hospitalization of the patient. About one-third of patients suffer from recurrent TN after MVD. Often, alternative treatment protocols, including the reintroduction of medications, may be necessary to achieve improvement. This case report presents two cases of post-MVD recurrent pain. Further research is lacking on the success rates of subsequent medication therapy after MVD has proven less effective in managing TN.