Pregabalin prescriptions in the United Kingdom: a drug utilisation study of The Health Improvement Network (THIN) primary care database

Prenatal exposure to pregabalin, birth outcomes and neurodevelopment - a population-based cohort study in four Nordic countries

INTRODUCTION

Pregabalin is an antiepileptic drug frequently prescribed to pregnant women. Risks of adverse birth and postnatal neurodevelopmental outcomes following prenatal exposure to pregabalin are uncertain.

OBJECTIVE

To investigate the association between prenatal exposure to pregabalin and the risks of adverse birth and postnatal neurodevelopmental outcomes.

METHODS

This study was conducted using population-based registries in Denmark, Finland, Norway, and Sweden (2005-2016). We compared pregabalin exposure against no exposure to antiepileptics and against active comparators lamotrigine and duloxetine. We obtained pooled propensity score-adjusted estimates of association using fixed-effect and Mantel-Haenszel (MH) meta-analyses.

RESULTS

The total number of pregabalin-exposed births was 325/666,139 (0.05%) in Denmark, 965/643,088 (0.15%) in Finland, 307/657,451 (0.05%) in Norway, and 1275/1,152,002 (0.11%) in Sweden. The adjusted prevalence ratios (aPRs) with 95% confidence interval (CI) following pregabalin exposure versus no exposure were 1.14 (0.98-1.34) for major congenital malformations and 1.72 (1.02-2.91) for stillbirth, which attenuated to 1.25 (0.74-2.11) in MH meta-analysis. For the remaining birth outcomes, the aPRs were close to or attenuated toward unity in analyses using active comparators. Adjusted hazard ratios (95% CI) contrasting prenatal pregabalin exposure versus no exposure were 1.29 (1.03-1.63) for ADHD and attenuated when using active comparators, 0.98 (0.67-1.42) for autism spectrum disorders, and 1.00 (0.78-1.29) for intellectual disability.

CONCLUSIONS

Prenatal exposure to pregabalin was not associated with low birth weight, preterm birth, small for gestational age, low Apgar score, microcephaly, autism spectrum disorders, or intellectual disability. On the basis of the upper value of the 95% confidence interval, increased risks greater than 1.8 were unlikely for any major congenital malformation and ADHD. For stillbirth and most groups of specific major congenital malformations, the estimates attenuated in MH meta-analysis.

Opioid and gabapentinoid prescriptions in England from 2015 to 2020

PURPOSE

Concerns gradually arose about misuse of gabapentinoids (gabapentin and pregabalin), especially when used in combination with opioids. Because it can be a driver of usage, trends in prescribing habits may be interesting to analyse. The aim of this study is to examine the evolution of prescriptions of opioids and gabapentinoids in England from 2015 to 2020 at a regional level.

METHODS

This study included data from April 2015 to February 2020, focusing on prescribing data, extracted the OpenPrescribing database. We described the evolution of the prescriptions of opioids and gabapentinoids and calculated their ratios for each month. We used Analyses of Variance (ANOVAs) to compare data between and within regions (over time).

RESULTS

During this period, opioid prescriptions remained stable (from -3.3% to +2.2%/year) and increased for gabapentinoids generally (from +1.5% to +2.2%). The ratio between gabapentinoid to opioid prescriptions increased by more than 20% in 2020 compared to 2015, variably between regions (F(6,406) = [120.2]; P<0.001; LSD Test: P<0.001; ANOVA for repeated measures: P<0.05). In 2019, a decline in the ratio occurred in all regions, but only persisting in the London commissioning region in 2020 (-14.4% in comparison with 2018, 95%CI: -12.8 to -16.3).

CONCLUSIONS

Gabapentinoids are increasingly prescribed in England. The ratio of gabapentinoid to opioid prescriptions in England increased from 2015 to 2020. The reclassification of gabapentinoids as controlled drugs, in 2019, may have been associated with a significant reduction, although larger prescribers may have been less influenced.

Patterns of pregabalin prescribing in four German federal states: analysis of routine data to investigate potential misuse of pregabalin

OBJECTIVES

The objectives of this study were to investigate the utilisation patterns of pregabalin, to identify users potentially misusing pregabalin and to compare this group of patients to patients prescribed recommended doses of pregabalin concerning their personal characteristics and the coordination among their prescribers. Unintended coprescription of drugs with addictive potential might occur when care is insufficiently coordinated.

DESIGN

Secondary data analysis of linked data from three regional sickness funds in Germany (AOK) for the years 2014-2016.

SETTING

Ambulatory and hospital care sector in four German federal states.

METHODS

On the basis of routine data, patients who received at least three prescriptions of pregabalin were identified and classified into patients prescribed pregabalin as recommended and those dispensed with a higher than recommended dose (>600 mg/day). Social network analysis was applied to identify prescription networks and to analyse cooperation among the prescribers. With descriptive statistics and univariate statistical tests, typical characteristics of the group of patients potentially misusing pregabalin were compared with the others.

RESULTS

Among the 53 049 patients prescribed pregabalin, about 2% (877) were classified as potentially misusing pregabalin. The majority of this group was male and aged between 30 and 60 years. Of the patients misusing pregabalin, 365 (42%) had a diagnosed history of substance use disorders and 359 (41%) had been prescribed another drug with addictive potential (opioids) before. The prescribers of those patients potentially misusing pregabalin were more loosely connected within networks compared with prescribers of patients prescribed pregabalin as recommended.

CONCLUSION

This study found that patients could exceed recommended doses of pregabalin by getting prescriptions from multiple physicians. Specific patients were at increased risk of potentially misusing pregabalin, and these patients sought to obtain their prescriptions from physicians who were as loosely connected as possible. Coordination and sharing a relevant number of patients seem to be levers to avoid these problems of unintended coprescribing.

Geographic Variation in the Use of Gabapentinoids and Opioids for Pain in a Commercially Insured Adult Population in the United States

Background

Gabapentinoids have been prescribed off-label for almost all types of pain. The geographic variation in the use of gabapentinoids as analgesics remains unknown.

Objective

To describe the geographic variation in gabapentinoids, opioids and concurrent use of both for pain by US state and metropolitan statistical area (MSA).

Methods

We conducted a cross-sectional study on December 1, 2018, among commercially insured adults aged 18–64 years without epilepsy or opioid use disorders using IBM^® MarketScan^® Research Databases. We described the geographic variation in the analgesic regimens (gabapentinoids, opioids and concurrent use of both) by state and MSA, and assessed factors associated with the geographic variation using multilevel logistic regression.

Results

We included 9,314,197 beneficiaries; 1.4% had gabapentinoids, 1.5% had opioids and 0.3% had concurrent use of both. The majority of gabapentinoid use lacked an FDA-approved indication. Use of the analgesic regimens varied across states (gabapentinoids (median (interquartile range)): 1.4% (1.2–1.7%); opioids: 1.5% (1.2–1.9%); both: 0.3% (0.2–0.4%)) and MSAs (gabapentinoids: 1.6% (1.3–2.0%); opioids: 1.8% (1.3–2.3%); both: 0.3% (0.2–0.5%)). Demographics explained the largest proportion of the between-state and between-MSA variation. The pattern of the geographic variation in gabapentinoids was similar to that of opioids across states and MSAs.

Conclusion

Gabapentinoids were as commonly used as opioids for pain in a commercially insured population (mostly off-label). The geographic variation in gabapentinoids was similar to that of opioids, which suggests that gabapentinoids may be widely used as alternatives or adjuvants to opioids across the US.

Current Evidence on Abuse and Misuse of Gabapentinoids

This review summarizes current evidence on the abuse and misuse of the gabapentinoids pregabalin and gabapentin. Pharmacovigilance studies, register-based studies, surveys, clinical toxicology studies, and forensic toxicology studies were identified and scrutinized with the goal to define the problem, identify risk factors, and discuss possible methods to reduce the potential for abuse and misuse. Studies found that gabapentinoids are abused and misused and that individuals with a history of psychiatric disorders or substance use disorder seem to be at high risk. Moreover, some evidence supports the notion that patients with opioid use disorders may be at an increased risk of abusing gabapentinoids. Available evidence also suggests that abuse and misuse are more frequent in users of pregabalin compared with users of gabapentin. Health professionals and prescribers should be aware of the risk for misuse of pregabalin and gabapentin, which eventually could lead to abuse, substance dependence, and intoxications. Prescribing to patients belonging to risk populations such as those with psychiatric disorders or substance use disorder should be avoided if possible and, if prescribed, signs of misuse and abuse should be monitored.

Investigating the prescribing trajectory and geographical drug utilisation patterns of gabapentinoids in primary care in England: An ecological study

AIMS

This study aimed to investigate the prescribing trajectory, geographical variation and population factors, including socioeconomic status (SES), related to prescribing gabapentinoids in primary care in England.

METHODS

This ecological study applied practice-level dispensing data and statistics from the UK National Health Service Digital and Office for National Statistics from 2013 to 2019. The prescribing of gabapentinoids (in defined daily doses [DDDs]/1000 people) was measured annually and quarterly. General practices were categorised according to the quarterly prescribing in a group-based trajectory model. The one-year prescribing in 2018/19 was associated with practice-level covariates in a mixed-effects multilevel regression, adjusted for the cluster-effects of Clinical Commissioning Groups (CCGs) and mapped geographically.

RESULTS

The annual national prescription rate increased by 70% from 2800 to 4773 DDDs/1000 people in the time period 2013/14 to 2018/19. General practices were stratified into six trajectory groups. Practices with the highest level and the greatest increase in prescribing (n = 789; 9.8%) are mainly located in the north of England and along the east and south coastline. Socioeconomic status, demographic characteristics and relevant disease conditions were significantly associated with the prescribing. For every decrease in the Index of Multiple Deprivation decile (becoming less affluent), prescribing of gabapentinoids increased significantly by 203 (95% CI: 183-222) DDDs/1000 registrants.

CONCLUSIONS

Gabapentinoid prescribing trajectories varied across geographical regions and are associated with socioeconomic status, CCG locality (geography) and other population characteristics. These factors should be considered in future studies investigating the determinants of gabapentinoid prescribing and the risk of harms associated with gabapentinoids.

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

BACKGROUND

In 2013 pregabalin was subsidised by Australia's Pharmaceutical Benefits Scheme (PBS) for neuropathic pain. Since the subsidy, pregabalin prescribing has been increasing in Australia and so has related harm. There are concerns it is being prescribed for indications other than neuropathic pain, which have little evidence of efficacy.

AIM

To describe pregabalin prescribing in Australian general practice.

DESIGN & SETTING

A cross-sectional study of patients attending 445 general practice sites in the national MedicineInsight database from March 2012-February 2018.

METHOD

The following aspects were calculated: the proportion of prescriptions that were for pregabalin per year; the prevalence of pain conditions in patients prescribed pregabalin; and same-day prescribing of pregabalin with opioids or benzodiazepines.

RESULTS

Prescribing increased from 13 per 10 000 to 104 per 10 000 prescriptions between 2012-2013 and 2017-2018. A total of 1 891 623 patients were identified of whom 114 123 (6.0%) were prescribed pregabalin; 49.7% (n = 56 772) had a recorded diagnosis of neuropathic pain. Among people prescribed pregabalin without a recorded diagnosis of neuropathic pain, 43.5% (n = 24 927) had a diagnosis of back problems, 8.8% (n = 5073) chronic pain, and 26.4% (n = 30 146) had no pain diagnosis. Pregabalin was prescribed the same day as an opioid to 38.1% of patients (95% confidence interval [CI] = 37.1% to 39.1%) and a benzodiazepine to 13.1% of patients (95% CI = 12.5% to 13.7%). Patients with a diagnosis of chronic pain had the highest rate of same-day prescribing of pregabalin with an opioid (70.4%, 95% CI = 68.9% to 71.9%) or a benzodiazepine (25.8%, 95% CI = 24.2% to 27.4%) CONCLUSION: Substantial increases in pregabalin prescribing were identified in Australian general practice, but only half of patients had a neuropathic pain diagnosis recorded, the only approved indication for subsidy. High rates of same-day prescribing with opioids and benzodiazepines may put patients at increased risk of harm.

Pregabalin for neuropathic pain in primary care settings: recommendations for dosing and titration

Pregabalin is one of the first-line treatments approved for the management of neuropathic pain (NeP). While many patients benefit from treatment with pregabalin, they are often treated with suboptimal doses, possibly due to unfamiliarity around prescribing the drug and/or side effects that can occur with up-titration. This narrative review discusses key aspects of initiating, titrating, and managing patients prescribed pregabalin therapy, and addresses concerns around driving and the potential for abuse, as well as when to seek specialist opinion. To ensure that patients derive maximum therapeutic benefit from the drug, we suggest a 'low and slow' dosing approach to limit common side effects and optimize tolerability alongside patients' expectations. When requiring titration to higher doses, we recommend initiating 'asymmetric dosing,' with the larger dose in the evening. Fully engaging patients in order for them to understand the expected timeline for efficacy and side effects (including their resolution), can also help determine the optimal titration tempo for each individual patient. The 'low and slow' approach also recognizes that patients with NeP are heterogeneous in terms of their optimal therapeutic dose of pregabalin. Hence, it is recommended that general practitioners closely monitor patients and up-titrate according to pain relief and side effects to limit suboptimal dosing or premature discontinuation.

Gabapentinoid misuse, abuse and non-prescribed obtainment in a United States general population sample

Background Reports of gabapentinoid (gabapentin and pregabalin) misuse are on the rise, but few studies have assessed this within the general US population. Objective Describe lifetime misuse/abuse/non-prescribed obtainment of gabapentinoids and descriptive characteristics associated with such actions in a US general population sample. Setting This cross-sectional questionnaire was administered online by Qualtrics^® research panel aggregator via quota-based sampling. Methods Data were collected from a sample of respondents that mirrored the general US population aged 18-59 years with regards to age, geographic region, ethnicity, income, and education level, based on most recent census data. Misuse/abuse/non-prescribed obtainment was collectively defined as use of a gabapentinoid for reasons other than a diagnosed medical condition, using with the intention of altering one's state of consciousness, or obtaining without a prescription. A multivariable logistic regression model was created to predict misuse/abuse/non-prescribed obtainment of gabapentinoids, incorporating relevant covariates. Main outcome measure Proportion of sample indicating lifetime misuse/abuse/non-prescribed obtainment of gabapentinoids. Results Among 1,843 respondents, 121 (6.6%) reported gabapentinoid misuse/abuse/non-prescribed obtainment. Specifically, 2.1% (n = 39) and 1.5% (n = 27) of respondents for gabapentin and pregabalin, respectively, met study criteria for abuse. Opioids were the most common medication co-administered with gabapentinoids (among 50-70% of respondents) for misuse/abuse. Previous treatment for addiction (OR: 2.61, 95% CI: 1.32-5.14, p = 0.005) and the total attitudinal risk score (OR: 1.14, 95% CI: 1.09-1.19, p < 0.001) were associated with gabapentinoid misuse/abuse/non-prescribed obtainment. Conclusion Among those surveyed, 6.6% reported previous gabapentinoid misuse/abuse/non-prescribed obtainment, providing one of the first estimates within a nationally distributed, US general population sample.

Influence of single nucleotide polymorphism of LAT1 on therapeutic response to gabapentinoids in Pakistani patients with neuropathic pain

Gabapentinoids are substrate of L-type amino acid transporter 1 (LAT1) for distribution across the blood-brain barrier. The present study aimed to evaluate the effect of LAT1 rs4240803 genetic polymorphism on the clinical efficacy and tolerability of gabapentinoids in Pakistani patients with neuropathic pain. Three-hundred and ninety-two patients were recruited, genotyped for SNP rs4240803, and followed up for eight weeks to evaluate the clinical response to gabapentinoids in terms of pain relief, inadequate response, and the emergence of adverse events. LAT1 rs4240803 GG, GA, and AA genotype frequency were 33.42%, 47.96% and 18.62%, respectively. Out of 392 patients, 323 responded to the treatment and 17.6% discontinued either due to insufficient response or intolerable adverse events (AEs). GA genotype was more frequent in non-responder group (P ˂ 0.001). Maximum pain responders (≥50%) in combination with the lowest incidence of AEs were observed in the GG group, whereas partial responders belonged to GA genotype and with the highest frequency of somnolence (83.6%) and dizziness (69.9%). Overall, 72.5% patients with GA genotype experienced AEs (P ˂ 0.001). In conclusion, clinical outcomes of gabapentinoids are influenced by LAT1 rs4240803 polymorphism and population pharmacogenetics should be considered to evaluate the maximum potential of gabapentinoids in the management of neuropathic pain.

Fibromyalgia: Recent Advances in Diagnosis, Classification, Pharmacotherapy and Alternative Remedies

Fibromyalgia (FM) is a syndrome that does not present a well-defined underlying organic disease. FM is a condition which has been associated with diseases such as infections, diabetes, psychiatric or neurological disorders, rheumatic pathologies, and is a disorder that rather than diagnosis of exclusion requires positive diagnosis. A multidimensional approach is required for the management of FM, including pain management, pharmacological therapies, behavioral therapy, patient education, and exercise. The purpose of this review is to summarize the recent advances in classification criteria and diagnostic criteria for FM as well as to explore pharmacotherapy and the use of alternative therapies including the use of plant bioactive molecules.

Evaluation of Treatment Patterns and Direct Costs Associated with the Management of Neuropathic Pain

Background

Neuropathic pain has a prevalence of 2-17% in the general population. Diagnosis and treatment of neuropathic pain are not fully described in different populations. The aim was to determine the treatment patterns and direct costs of care associated with the management of neuropathic pain from the onset of the first symptom to up to two years after diagnosis.

Methods

From a drug-claim database, a cohort of randomly selected outpatients diagnosed with neuropathic pain was obtained from an insurer in Colombia and followed up for two years after diagnosis. The clinical records were reviewed individually to identify the study variables, including the time needed to make the diagnosis, the medical and paraclinical resources used, the pharmacological therapy for pain management, and the direct costs associated with care.

Results

We identified 624 patients in 49 cities, with a mean age of 50.3 ± 14.1 years, of which 324 were men (51.9%). An average of 90 days passed from the initial consultation until the diagnosis of neuropathic pain, the most frequent being lumbosacral radiculopathy (57.9%). 34.5% of the cohort had at least one diagnostic imaging procedure, and 16% had an electromyography. On average, they were treated by a general practitioner twice. 91.7% received initial treatment with tramadol, carbamazepine, amitriptyline, imipramine, or pregabalin, and 60.4% received combined therapy. The mean cost of care for two years for each patient was US$246.3.

Conclusions

Patients with neuropathic pain in Colombia are being diagnosed late, are using therapeutic agents not recommended as first-line treatment by clinical practice guidelines, and are being treated for short periods of time.

Trends in gabapentinoid prescribing in patients with osteoarthritis: a United Kingdom national cohort study in primary care

OBJECTIVE

To investigate trends in gabapentinoid prescribing in patients with osteoarthritis (OA).

METHODS

Patients aged 40 years and over with a new OA diagnosis recorded between 1995 and 2015 were identified in the Clinical Practice Research Datalink (CPRD) and followed to first prescription of gabapentin or pregabalin, or other censoring event. We estimated the crude and age-standardised annual incidence rates of gabapentinoid prescribing, stratified by patient age, sex, geographical region, and time since OA diagnosis, and the proportion of prescriptions attributable to OA, or to other conditions representing licensed and unlicensed indications for a gabapentinoid prescription.

RESULTS

Of 383,680 newly diagnosed OA cases, 35,031 were prescribed at least one gabapentinoid. Irrespective of indication, the annual age-standardised incidence rate of first gabapentinoid prescriptions rose from 1.6 [95% confidence interval (CI): 1.3, 2.0] per 1000 person-years in 2000, to 27.6 (26.7, 28.4) in 2015, a trend seen across all ages and not explained by length of follow-up. Rates were higher among women, younger patients, and in Northern Ireland, Scotland and the North of England. Approximately 9% of first prescriptions could be attributed to OA, a further 13% to comorbid licensed or unlicensed indications.

CONCLUSION

Gabapentinoid prescribing in patients with OA increased dramatically between 1995 and 2015. In most cases, diagnostic codes for licensed or unlicensed indications were absent. Gabapentinoid prescribing may be attributable to OA in a significant proportion but evidence for their effectiveness in OA is lacking. Further research to investigate clinical decision making around prescribing these expensive and potentially harmful medicines is recommended.

Gabapentinoids for treatment of neuropathic pain: a medicines usage evaluation at the Groote Schuur Hospital Chronic Pain Management Clinic

Background: Neuropathic pain (NP), defined as pain caused by a lesion or disease of the somatosensory system, affects 6.9–10% of people worldwide. Pregabalin is currently recommended as a first line drug for NP in South Africa. Methods: A cross-sectional, retrospective, descriptive medicines usage evaluation (MUE) of pregabalin at Groote Schuur Hospital (GSH) Chronic Pain Management Clinic for the year 2017 was conducted. A MUE using a standardised data collection form was performed on 100 randomly selected patient folders. Data was summarised using descriptive statistics. Results: The majority of cases were women (76) with a mean age of 55.9 years (SD12.49). A diagnosis of NP was recorded in 58 folders and a “possible” diagnosis recorded in 7 folders. In 79 cases there was no mention of a tool/method used to diagnose NP. The most common condition diagnosed was chronic postsurgical pain with a neuropathic component (n = 16), followed by NP (n = 15). The most common initiating and current dose of pregabalin was 75 mg twice daily. In 56 patients, pregabalin was prescribed in conjunction with a tricyclic antidepressant (TCA) or selective noradrenaline reuptake inhibitor (SNRI). Patient education was documented as having taken place in 76 of cases. Conclusions: Based on this MUE we recommend the use of screening tools for the diagnosis of neuropathic pain, and a focus on the initiating dose of pregabalin. The use of a standardised assessment document and the interdisciplinary team input at this clinic appears to optimise prescribing of pregabalin in line with practice guidelines.

Lack of correlation between the activity of the mesolimbic dopaminergic system and the rewarding properties of pregabalin in mouse

RATIONALE

Pregabalin is a psychoactive drug indicated in the treatment of epilepsy, neuropathic pain, and generalized anxiety disorders. Pregabalin acts on different neurotransmission systems by inactivating the alpha2-delta subunit of voltage-gated calcium channels. In light of this pharmacological property, the hypothesis has been raised that pregabalin may regulate the mesolimbic dopamine pathway and thereby display a potential for misuse or abuse as recently observed in humans. Although some preclinical data support this possibility, the rewarding properties of gabapentinoid are still a matter for debate.

OBJECTIVE

The aim of this work was to evaluate the rewarding properties of pregabalin and to determine its putative mechanism of action in healthy mice.

RESULTS

Pregabalin alone (60 mg/kg; s.c.) produced a rewarding effect in the conditioned place preference (CPP) test albeit to a lower extent than cocaine (30 mg/kg; s.c.). Interestingly, when assessing locomotor activity in the CPP, the PGB60 group, similarly to the cocaine group, showed an increased locomotor activity. In vivo single unit extracellular recording showed that pregabalin had mixed effects on dopamine (DA) neuronal activity in the ventral tegmental area since it decreased the activity of 50% of neurons and increased 28.5% of them. In contrast, cocaine decreased 75% of VTA DA neuronal activity whereas none of the neurons were activated. Intracerebal microdialysis was then conducted in awake freely mice to determine to what extent such electrophysiological parameters influence the extracellular DA concentrations ([DA]ext) in the nucleus accumbens. Although pregabalin failed to modify this parameter, cocaine produced a robust increase (800%) in [DA]ext.

CONCLUSIONS

Collectively, these electrophysiological and neurochemical experiments suggest that the rewarding properties of pregabalin result from a different mode of action than that observed with cocaine. Further experiments are warranted to determine whether such undesirable effects can be potentiated under pathological conditions such as neuropathic pain, mood disorders, or addiction and to identify the key neurotransmitter system involved.

Rising pregabalin use and misuse in Australia: trends in utilization and intentional poisonings

BACKGROUND AND AIMS

Pregabalin is a gamma-aminobutyric acid (GABA) analogue, used to treat neuropathic pain and epilepsy. Pregabalin was registered in Australia in 2005, and subsidized publically in 2013. We aimed to describe Australian patterns of pregabalin use and intentional poisoning, and identify people potentially at high risk of misuse.

DESIGN AND SETTING

Population-based retrospective cohort study of dispensings in the 10% sample of Australian Pharmaceutical Benefits Scheme (July 2012-February 2017); intentional poisoning calls to New South Wales Poisons Information Centre (NSWPIC) (2004-2016); intentional poisonings in two Australian toxicology service databases; and poisoning fatalities in NSW coronial records (2005-2016).

PARTICIPANTS

A total of 122 572 people dispensed pregabalin, people with intentional pregabalin overdoses managed by NSWPIC and the toxicology services and pregabalin-associated deaths referred to the NSW coroner.

MEASUREMENTS

Trends in dispensing, poisoning, death; demographics and patient characteristics, proportion of users at high risk of misuse (latent class analysis, LCA) and characteristics of high-risk users.

FINDINGS

Pregabalin dispensing increased by 73 424 per year [95% confidence interval (CI) = 61726-85 121 P < 0.001] between 2013 and 2016. NSWPIC received 1158 reports of intentional pregabalin poisonings, with a 53.8% increase per year, 2005-2016 (95% CI = 44.0-64.2%, P < 0.001). We identified 88 pregabalin-associated deaths, 57.8% yearly increase (95% CI = 30.0-91.6%, P < 0.001). Patients overdosing on pregabalin commonly co-ingested opioids, benzodiazepines and illicit drugs, and had high rates of psychiatric and substance use comorbidities; 14.7% of pregabalin users were classed by the LCA as at high risk of misuse, and were more likely to be younger, male, co-prescribed benzodiazepines or opioids, have more individual prescribers and higher pregabalin strengths dispensed.

CONCLUSIONS

There has been a dramatic increase in pregabalin use, poisonings and deaths in Australia since it became subsidized publicly in 2013. One in seven Australians dispensed pregabalin appears to be at high risk of misuse.

Pregabalin Prescription for Neuropathic Pain and Fibromyalgia: A Descriptive Study Using Administrative Database in Japan

Objective

To assess dose, characteristics, and coprescribed analgesics in patients newly prescribed pregabalin for neuropathic pain and fibromyalgia in Japan.

Methods

Based on the medical and prescription information present in the Medical Data Vision database, we analyzed the initial and maximum daily doses, prescription period, coprescribed analgesics, and neuropathic pain-related disorders of patients newly prescribed pregabalin between 01 July 2010 and 31 December 2013.

Results

A total of 45,331 patients (mean age 66.8 years, 48.7% men) were newly prescribed pregabalin during this period. The mean initial and maximum daily doses were 97.3 mg and 127.8 mg, respectively, and decreased yearly. The duration of the prescription period was 111.9 (mean) and 53 (median) days, and the frequently coprescribed analgesics included NSAIDs, opioids, and Neurotropin®. About one half of the patients had spinal disorders.

Conclusion

In Japan during the period examined, the number of newly prescribed pregabalin users increased, but the initial and maximum daily doses decreased yearly after pregabalin went on the market. The maximum daily dose in Japan was lower than those reported in the USA and Europe. These differences might be associated with patient age and physical status and with anxiety about possible adverse events.

Pregabalin Misuse and Abuse: A Scoping Review of Extant Literature

Prescribing of pregabalin is increasing worldwide with public health concerns centering on misuse and abuse of prescribed and diverted pregabalin. To describe and map what is known about misuse and abuse of pregabalin, a scoping review of available published literature was undertaken. A scoping review methodology was used to identify and map available literature on misuse and abuse of prescribed and diverted pregabalin. Four themes emerged on the misuse and abuse of pregabalin: (a) abuse potential, (b) prevalence of abuse, (c) risk and predisposition, and (d) consequences of abuse. Fifty-four records were reviewed and charted. Of note was the dearth of research on the topic prior to 2005, with increased interest in pregabalin abuse potential from 2010 onward. Available literature supports concern around abuse potential of pregabalin, especially among patients with a history of substance abuse. Prescribers should adopt more rational prescribing.

How addictive are gabapentin and pregabalin? A systematic review

In the last ten years, gabapentin and pregabalin have been becoming dispensed broadly and sold on black markets, thereby, exposing millions to potential side-effects. Meanwhile, several pharmacovigilance-databases have warned for potential abuse liabilities and overdose fatalities in association with both gabapentinoids. To evaluate their addiction risk in more detail, we conducted a systematic review on PubMed/Scopus and included 106 studies. We did not find convincing evidence of a vigorous addictive power of gabapentinoids which is primarily suggested from their limited rewarding properties, marginal notes on relapses, and the very few cases with gabapentinoid-related behavioral dependence symptoms (ICD-10) in patients without a prior abuse history (N=4). In support, there was no publication about people who sought treatment for the use of gabapentinoids. Pregabalin appeared to be somewhat more addictive than gabapentin regarding the magnitude of behavioral dependence symptoms, transitions from prescription to self-administration, and the durability of the self-administrations. The principal population at risk for addiction of gabapentinoids consists of patients with other current or past substance use disorders (SUD), mostly opioid and multi-drug users, who preferred pregabalin. Pure overdoses of gabapentinoids appeared to be relative safe but can become lethal (pregabalin > gabapentin) in mixture with other psychoactive drugs, especially opioids again and sedatives. Based upon these results, we compared the addiction risks of gabapentin and pregabalin with those of traditional psychoactive substances and recommend that in patients with a history of SUD, gabapentinoids should be avoided or if indispensable, administered with caution by using a strict therapeutic and prescription monitoring.

Neuropathic pain responds better to increased doses of pregabalin: an in-depth analysis of flexible-dose clinical trials

Background

Pregabalin is an effective treatment option for many patients with neuropathic pain. Higher doses of pregabalin have been shown to be more effective in improving pain outcomes but, in practice, failing to appropriately increase the dose can leave patients under-treated.

Methods

This was a pooled analysis of 6 flexible-dose clinical trials of pregabalin in patients with neuropathic pain (diabetic peripheral neuropathy, peripheral herpetic neuralgia, posttraumatic pain, or postsurgical pain). Patients were divided into “dose pathway” groups based on their weekly pregabalin dose from the start of their trial to the first week of their maintenance phase. These were: 150 mg/day only; 150 to 300 mg/day; 150 to 300 to 450 mg/day; 150 to 300 to 450 to 600 mg/day; 150 to 300 to 600 mg/day; 300 to 600 mg/day. Pain outcomes assessed for each group at each new dose were proportion of 30% and 50% responders (≥30% or ≥50% reduction in mean pain score from baseline) and mean change in pain score. Percent change in mean pain score from baseline was assessed using a marginal structural model.

Results

Seven hundred and sixty-one patients treated with flexible-dose pregabalin were included in the analysis. For each dose pathway group, there was a notably greater proportion of 30% and 50% responders and change in pain score, at each escalating dose. As assessed by the marginal structural model, higher doses of pregabalin were estimated to result in a significantly greater change in mean pain score at each week. This dose response with flexible-dose pregabalin was consistent with that previously observed with fixed-dose pregabalin.

Conclusion

Many patients who do not respond to lower doses of pregabalin will respond with notable improvements in pain outcomes when the dose is escalated. These data should encourage physicians treating patients with neuropathic pain to escalate pregabalin to the dose that delivers optimal analgesia and tolerable side effects.

Trial of Pregabalin for Acute and Chronic Sciatica

BACKGROUND

Sciatica can be disabling, and evidence regarding medical treatments is limited. Pregabalin is effective in the treatment of some types of neuropathic pain. This study examined whether pregabalin may reduce the intensity of sciatica.

METHODS

We conducted a randomized, double-blind, placebo-controlled trial of pregabalin in patients with sciatica. Patients were randomly assigned to receive either pregabalin at a dose of 150 mg per day that was adjusted to a maximum dose of 600 mg per day or matching placebo for up to 8 weeks. The primary outcome was the leg-pain intensity score on a 10-point scale (with 0 indicating no pain and 10 the worst possible pain) at week 8; the leg-pain intensity score was also evaluated at week 52, a secondary time point for the primary outcome. Secondary outcomes included the extent of disability, back-pain intensity, and quality-of-life measures at prespecified time points over the course of 1 year.

RESULTS

A total of 209 patients underwent randomization, of whom 108 received pregabalin and 101 received placebo; after randomization, 2 patients in the pregabalin group were determined to be ineligible and were excluded from the analyses. At week 8, the mean unadjusted leg-pain intensity score was 3.7 in the pregabalin group and 3.1 in the placebo group (adjusted mean difference, 0.5; 95% confidence interval [CI], -0.2 to 1.2; P=0.19). At week 52, the mean unadjusted leg-pain intensity score was 3.4 in the pregabalin group and 3.0 in the placebo group (adjusted mean difference, 0.3; 95% CI, -0.5 to 1.0; P=0.46). No significant between-group differences were observed with respect to any secondary outcome at either week 8 or week 52. A total of 227 adverse events were reported in the pregabalin group and 124 in the placebo group. Dizziness was more common in the pregabalin group than in the placebo group.

CONCLUSIONS

Treatment with pregabalin did not significantly reduce the intensity of leg pain associated with sciatica and did not significantly improve other outcomes, as compared with placebo, over the course of 8 weeks. The incidence of adverse events was significantly higher in the pregabalin group than in the placebo group. (Funded by the National Health and Medical Research Council of Australia; PRECISE Australian and New Zealand Clinical Trials Registry number, ACTRN12613000530729 .).

Pregabalin for the Treatment of Drug and Alcohol Withdrawal Symptoms: A Comprehensive Review

Treatments for physical dependence and associated withdrawal symptoms following the abrupt discontinuation of prescription drugs (such as opioids and benzodiazepines), nicotine, alcohol, and cannabinoids are available, but there is still a need for new and more effective therapies. This review examines evidence supporting the potential use of pregabalin, an α2δ voltage-gated calcium channel subunit ligand, for the treatment of physical dependence and associated withdrawal symptoms. A literature search of the MEDLINE and Cochrane Library databases up to and including 11 December 2015 was conducted. The search term used was '(dependence OR withdrawal) AND pregabalin'. No other date limits were set and no language restrictions were applied. Works cited in identified articles were cross-referenced and personal archives of references also searched. Articles were included based on the expert opinions of the authors. There is limited evidence supporting the role of pregabalin for the treatment of physical dependence and accompanying withdrawal symptoms associated with opioids, benzodiazepines, nicotine, cannabinoids, and alcohol, although data from randomized controlled studies are sparse. However, the current evidence is promising and provides a platform for future studies, including appropriate randomized, placebo- and/or comparator-controlled studies, to further explore the efficacy and safety of pregabalin for the treatment of withdrawal symptoms. Given the potential for pregabalin misuse or abuse, particularly in individuals with a previous history of substance abuse, clinicians should exercise caution when using pregabalin in this patient population.