Benefits and safety of gabapentinoids in chronic low back pain: A systematic review and meta-analysis of randomized controlled trials

Risk of adverse outcomes during gabapentinoid therapy and factors associated with increased risk in UK primary care using the clinical practice research datalink: a cohort study

ABSTRACT

Growing evidence from pharmacovigilance data and postmortem toxicology reports highlights the misuse potential of gabapentinoids. This study aimed to investigate the risk of serious adverse outcomes (drug misuse, overdose, major trauma), and their risk factors, in primary care patients who are prescribed gabapentinoids. Using the UK Clinical Practice Research Datalink, a matched cohort study calculated adverse event rates separately for gabapentinoid-exposed and unexposed cohorts. In the exposed cohort, event rates for exposure to a range of potential risk factors were calculated. Event rates were compared using Cox proportional hazards models, adjusted for age, sex, deprivation, previous mental health diagnosis, and coprescribing with potentially interacting medicines. Substance misuse (gabapentin adjusted hazard ratio [95% CI]: 2.40 [2.25-2.55]), overdose (2.99 [2.56-3.49]), and major trauma (0-2.5 years: 1.35 [1.28-1.42]; 2.5 to 10 years: 1.73 [1.56-1.95]) were more common among patients prescribed gabapentinoids than matched individuals who were not. The association with overdose was stronger for pregabalin than gabapentin. All adverse outcomes were significantly associated with smoking, history of substance misuse, overdose, or a mental health condition and prescription of opioids, benzodiazepines, antidepressants, and Z-drug hypnotics (eg, gabapentin hazard ratios for association of concurrent opioid use: misuse 1.49 [1.47-1.51]; overdose 1.87 [1.78-1.96]; major trauma 1.28 [1.26-1.30]). Our findings highlight the importance of careful patient selection when prescribing gabapentinoids and the need to educate prescribers about the risks of these drugs, particularly in combination with other central nervous system depressants.

Medication recommendations for treatment of lumbosacral radiculopathy: A systematic review of clinical practice guidelines

OBJECTIVE

The purpose of this systematic review was to ascertain guideline-recommended pharmaceutical approaches to lumbosacral radicular symptoms, assess the quality of the clinical practice guidelines (CPGs) with the Appraisal of Guidelines for Research and Evaluation II (AGREE II) tool, and qualitatively synthesize the guideline recommendations.

LITERATURE SURVEY

Literature searches were performed in PubMed, Cochrane Database of Systematic Reviews, Index to Chiropractic Literature, Allied and Complementary Medicine Database (AMED), Cumulative Index for Nursing and Allied Health Literature (CINAHL), and Physiotherapy Evidence Database (PEDro). We included guidelines published between January 1, 2017, and January 9, 2022, written in the English language, related to radiculopathy, sciatica, and/or low back pain with leg pain, and that provided recommendations on oral medication.

METHODOLOGY

The review was performed in accordance with Preferred Reporting Items for Systemic Reviews and Meta-Analyses (PRISMA) and the protocol was pre-registered with the International Prospective Register of Systematic Reviews (PROSPERO). Eligibility screening, full-text review, extraction of information pertaining to pharmacological management, and synthesis of results were performed independently by two authors and a third investigator was recruited to arbitrate any disagreements. The AGREE II tool was administered by four authors to appraise CPG quality.

SYNTHESIS

After screening 413 citations and assessing 37 full-text articles, 11 CPGs met the inclusion criteria. They represented seven countries (Belgium, Canada, England, France, Japan, Korea, and United States) and three continents (Asia, Europe, and North America), as well as the Global Spine Care Initiative aimed at a worldwide presence. The mean overall AGREE II score was 87.1% (standard deviation [SD] 12.6%), generally reflecting high-quality CPGs. The highest domain mean score was for Clarity of Presentation (96.7%, SD 4.4%), and the lowest was Applicability (75.6%, SD 22.8%). Five classes of medications were recommended by at least one CPG: anticonvulsants, antidepressants, oral corticosteroids, nonsteroidal anti-inflammatory drugs (NSAIDs), and opioids.

CONCLUSIONS

The most common medication class recommended by the CPGs for lumbar radiculopathy was antidepressants. No CPGs recommended prescribing acetaminophen, benzodiazepines, muscle relaxants, or antibiotics. There was very little agreement between the CPGs, and all the medication classes had at least one CPG recommended against its use. Three guidelines reviewed did not recommend any medications due to lack of supporting literature, and instead recommended nonpharmacologic therapy.

Rat Sympathetic Neuron Calcium Channels Are Insensitive to Gabapentin

The gabapentenoids such as gabapentin (GP) and pregabalin are approved for the treatment of chronic pain, but their utility is limited by persistent side effects. These adverse effects result from GPs affecting many types of neurons and muscle cells, not just the pain-sensing neurons that are the intended targets. We have recently discovered a type of peripheral neuron, rat sympathetic neurons from the superior cervical ganglion (SCG), that is uniquely insensitive to GP effects. Currents were measured using whole-cell patch-clamp electrophysiology from cells in primary culture from either the SCG or the Nodose Ganglion (NDG) as a positive control for the effects of GP. We find that the calcium current density was dramatically reduced by GP pretreatment in NDG neurons, but that neurons from the SCG were resistant. Further, when GP was cytoplasmically injected into these neurons, the resistance of SCG neurons to GP treatment persisted. These data demonstrate that rat sympathetic neurons appear to be uniquely resistant to GP treatment. These results may help us to better understand the mechanism of action of, and resistance to, GP in altering calcium channel current density, which may help to develop future treatments with fewer side effects.

The cost of potentially inappropriate medications for older adults in Canada: A comparative cross-sectional study

BACKGROUND

Potentially inappropriate medications (PIMs) are medications whereby the harms may outweigh the benefits for a given individual. Although overprescribed to older adults, their direct costs on the healthcare system are poorly described.

METHODS

This was a cross-sectional study of the cost of PIMs for Canadians aged 65 and older, using adapted criteria from the American Geriatrics Society. We examined prescription claims information from the National Prescription Drug Utilization Information System in 2021 and compared these with 2013. The overall levels of inflation-adjusted total annual expenditure on PIMs, average cost per quarterly exposure, and average quarterly exposures to PIMs were calculated in CAD$.

RESULTS

Exposure to most categories of PIMs decreased, aside from gabapentinoids, proton pump inhibitors, and antipsychotics, all of which increased. Canadians spent $1 billion on PIMs in 2021, a 33.6% reduction compared with 2013 ($1.5 billion). In 2021, the largest annual expenditures were on proton pump inhibitors ($211 million) and gabapentinoids ($126 million). The quarterly amount spent on PIMs per person exposed decreased from $95 to $57. In terms of mean cost per person, opioids and antipsychotics were highest ($138 and $118 per exposure). Some cost savings may have occurred secondary to an observed decline of 16.4% in the quarterly rate of exposure to PIMs (from 7301 per 10,000 in 2013 to 6106 per 10,000 in 2021).

CONCLUSIONS

While expenditures on PIMs have declined in Canada, the overall cost remains high. Prescribing of some seriously harmful classes of PIMs has increased and so directed, scalable interventions are needed.

Patterns of gabapentinoid use among long-term opioid users

OBJECTIVE

Understanding the clinical and demographic profile of patients on gabapentinoids can highlight areas of prescribing disparities, inform clinical practice, and guide future research to optimize effectiveness and safety of gabapentinoids for pain management. We used a national sample of Medicare beneficiaries to examine trends, patterns, and patient-level predictors of gabapentinoid use among long-term opioid users.

METHODS

Using a national Medicare sample between 2014 and 2020, we examined factors associated with gabapentinoid use among long-term opioid users. We included Medicare eligible long-term opioid users with no prior gabapentinoid use. The primary outcome was gabapentinoid use after the long-term opioid use episode. Logistic regression was used to test the association with gabapentinoid use for year, age, sex, race/ethnicity, region, Medicare entitlement, low-income status, frailty, pain locations, anxiety, depression, opioid use disorder, and opioid morphine milligrams equivalent.

RESULTS

Gabapentinoid use among long-term opioid users increased from 12.6% in 2014 to 16.8% in 2019 (p < .0001). Factors associated with increased gabapentinoid use were Hispanic ethnicity, back pain, nerve pain, and moderate or high opioid usage. Factors associated with decreased gabapentinoid use were older age and Medicare entitlement due to old age.

CONCLUSIONS

Variation of gabapentinoid use by socio-demographics and insurance status indicates opportunities to improve pain management and a need for shared therapeutic decision making informed by discussion between pain patients and providers regarding safety and effectiveness of pain therapies. Our findings underscore the need for future research into the comparative effectiveness and safety of gabapentinoids for non-cancer chronic pain in various subpopulations.

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.

Gabapentinoid prescriptions for neuropathic and musculoskeletal pain in Lebanon

Aim: The purpose of this study is to analyze the different characteristics of gabapentinoids prescription by Lebanese orthopedics surgeons. Methods: This is an observational, cross-sectional study using a survey which was carried out in collaboration with the Lebanese Orthopedic Society over a 3-month period. Results: Forty-two orthopedic surgeons responded, most of them prescribing gabapentinoids in their daily practice with only half of the patients feeling relief after taking them. Furthermore, most of the surgeons prescribed these drugs for patients above 18 years old and for both acute and chronic pain. Conclusion: Even though almost half of the patients do not experience relief after taking gabapentinoids, these drugs are becoming more and more prescribed.

Anti-Stress and Anti-ROS Effects of MnOx-Functionalized Thermosensitive Nanohydrogel Protect BMSCs for Intervertebral Disc Degeneration Repair

Stem cell transplantation is proven to be a promising strategy for intervertebral disc degeneration (IDD) repair. However, replicative senescence of bone marrow-derived mesenchymal stem cells (BMSCs), shear damage during direct injection, mechanical stress, and the reactive oxygen species (ROS)-rich microenvironment in degenerative intervertebral discs (IVDs) cause significant cellular damage and limit the therapeutic efficacy. Here, an injectable manganese oxide (MnOx)-functionalized thermosensitive nanohydrogel is proposed for BMSC transplantation for IDD therapy. The MnOx-functionalized thermosensitive nanohydrogel not only successfully protects BMSCs from shear force and mechanical stress before and after injection, but also repairs the harsh high-ROS environment in degenerative IVDs, thus effectively increasing the viability of BMSCs and resident nucleus pulposus cells (NPCs). The MnOx-functionalized thermosensitive nanohydrogel provides mechanical protection for stem cells and helps to remove endogenous ROS, providing a promising stem cell delivery platform for the treatment of IDD.

Characterizing Gabapentinoid Use Among Patients With Isolated Low Back Pain

STUDY DESIGN

Retrospective cohort study.

OBJECTIVES

Gabapentinoids have been increasingly studied as a non-narcotic option for neuropathic and postoperative pain. However, there is evidence suggesting that off-label use of these medications for the treatment of isolated LBP is not effective. The purpose of the current study was to evaluate prescription patterns for gabapentinoids among patients with isolated low back pain.

METHODS

Adult patients with LBP were abstracted from the 2019 M91Ortho PearlDiver dataset using International Classification of Diseases (ICD-10) code M54.5. Patients were excluded if they had a diagnosis of neurologic symptoms, history of spinal surgery, spinal fracture, or conditions for which gabapentinoids are FDA approved. Gabapentinoid and narcotic prescriptions within one year of LBP diagnosis were identified. Patient characteristics and prescriber specialty were extracted from the dataset and predictors of gabapentinoid prescriptions were determined using univariate and multivariate analyses.

RESULTS

Among the 1,158,875 isolated LBP patients, gabapentinoids were prescribed for 11%, narcotics for 8%, and both for 3%. The most common prescriber specialties included: primary care physicians (45%), nurse practitioners (15%), and pain management physicians (5%). Independent predictors of gabapentinoid prescriptions included: female sex, region of the country, and insurance type (P-values <.001).

CONCLUSIONS

Of nearly 1.2 million patients with isolated LBP, 14.2% were prescribed gabapentinoids within one year of their LBP diagnosis. Patient characteristics predictive of receiving gabapentinoids were predominantly non-clinical factors.

A systematic review and network meta-analysis of pharmaceutical interventions used to manage chronic pain

It is estimated 1.5 billion of the global population suffer from chronic pain with prevalence increasing with demographics including age. It is suggested long-term exposure to chronic could cause further health challenges reducing people's quality of life. Therefore, it is imperative to use effective treatment options. We explored the current pharmaceutical treatments available for chronic pain management to better understand drug efficacy and pain reduction. A systematic methodology was developed and published in PROSPERO (CRD42021235384). Keywords of opioids, acute pain, pain management, chronic pain, opiods, NSAIDs, and analgesics were used across PubMed, Science direct, ProQuest, Web of science, Ovid Psych INFO, PROSPERO, EBSCOhost, MEDLINE, ClinicalTrials.gov and EMBASE. All randomised controlled clinical trials (RCTs), epidemiology and mixed-methods studies published in English between the 1st of January 1990 and 30th of April 2022 were included. A total of 119 studies were included. The data was synthesised using a tri-partied statistical methodology of a meta-analysis (24), pairwise meta-analysis (24) and network meta-analysis (34). Mean, median, standard deviation and confidence intervals for various pain assessments were used as the main outcomes for pre-treatment pain scores at baseline, post-treatment pain scores and pain score changes of each group. Our meta-analysis revealed the significant reduction in chronic pain scores of patients taking NSAID versus non-steroidal opioid drugs was comparative to patients given placebo under a random effects model. Pooled evidence also indicated significant drug efficiency with Botulinum Toxin Type-A (BTX-A) and Ketamine. Chronic pain is a public health problem that requires far more effective pharmaceutical interventions with minimal better side-effect profiles which will aid to develop better clinical guidelines. The importance of understanding ubiquity of pain by clinicians, policy makers, researchers and academic scholars is vital to prevent social determinant which aggravates issue.

How to treat chronic pain in rheumatic and musculoskeletal diseases (RMDs) - A pharmacological review

INTRODUCTION

Chronic pain is a common symptom of rheumatic diseases that impacts patients' quality of life. While non-pharmacological approaches are often recommended as first-line treatments, pharmacological interventions are important for pain management. However, the effectiveness and safety of different pharmacological treatments for chronic pain in rheumatic diseases are unclear.

METHODS

This review critically synthesizes the current evidence base to guide clinicians in selecting appropriate pharmacological treatments for their patients, considering the expected benefits and potential risks and side effects.

RESULTS

For osteoarthritis, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, opioids, and antidepressants are commonly used, with NSAIDs being the most recommended. In addition, topical agents, such as topical NSAIDs, are recommended for localized pain relief. For fibromyalgia, amitriptyline, serotonin and noradrenaline reuptake inhibitors (SNRIs), and gabapentinoids are commonly used, with SNRIs being the most recommended. For back pain, nonsteroidal anti-inflammatory drugs (NSAIDs), acetaminophen, opioids are used only for acute of flare-up pain, whereas neuropathic pain drugs are only used for chronic radicular pain. For inflammatory rheumatic diseases, disease-modifying antirheumatic drugs (DMARDs) and biological agents are recommended to slow disease progression and manage symptoms.

CONCLUSION

While DMARDs and biological agents are recommended for inflammatory rheumatic diseases, pharmacological treatments for other rheumatic diseases only alleviate symptoms and do not provide a cure for the underlying condition. The use of pharmacological treatments should be based on the expected benefits and evaluation of side effects, with non-pharmacological modalities also being considered, especially for fibromyalgia.

Safety and Efficacy of Gabapentin for Pain in Pediatric Patients: A Systematic Review

CONTEXT

Gabapentin has shown benefits for a variety of pain etiologies in adult patients, with off-label use as an adjunctive agent in pediatric patients occurring more frequently.

OBJECTIVES

To summarize the studies which evaluate safety and efficacy of gabapentin for the treatment of pediatric pain.

DATA SOURCES

A systematic review of the literature was conducted via PubMed query with controlled vocabulary and key terms using indexed medical subject heading.

STUDY SELECTION

Prospective studies published between January 1, 2000, and July 1, 2023, were selected utilizing a predetermined exclusion criteria independently by 2 authors, with a third independent author available for discrepancies.

DATA EXTRACTION

Data extraction was performed by 2 authors independently to include study design, patient population and characteristics, drug dosing, and outcomes. Studies were then assessed for their independent risk of bias utilizing the Grading of Recommendations, Assessment, Development, and Evaluations approach to risk of bias.

RESULTS

A total of 11 studies describing 195 pediatric patients who received gabapentin were included. Of the 11 studies, 9 were randomized controlled trials, 1 was a prospective multicenter study, and 1 was an open-label pilot study.

CONCLUSIONS

Heterogeneity of pain type and gabapentin dosing regimens within the included studies made conclusions difficult to quantify. Efficacy likely depends significantly on etiology of pain; however, per these studies, gabapentin is likely safe to use for a variety of pediatric patient populations as a multimodal agent.

Comparative effectiveness of pain control between opioids and gabapentinoids in older patients with chronic pain

ABSTRACT

Gabapentinoid (GABA) prescribing has substantially increased while opioid prescribing has decreased since the 2016 Centers for Disease Control and Prevention Guidelines restricted opioid prescribing for chronic pain. The shift to GABA assumes equal analgesic effectiveness to opioids, but no comparative analgesic effectiveness data exist to support this assumption. We compared GABA to opioids by assessing changes in pain interfering with activities (activity-limiting pain) over time in patients with chronic pain. We used 2017 to 2019 data from a 20% national sample of Medicare beneficiaries diagnosed with chronic pain who initiated a GABA or opioid prescription for ≥30 continuous days and received home health care in the study year. The main outcome was the difference in reduction in pain score from pre- to post-prescription assessments between the 2 groups. Within a 60-day window before-and-after drug initiation, our sample comprised 3208 GABA users and 2846 opioid users. Reduction in post-prescription scores of pain-related interference with activities to less-than-daily pain was 48.1% in the GABA group and 41.7% in the opioid group; this remained significant (odds ratio = 1.29, 95% confidence interval: 1.17-1.43, P < 0.0001) after adjustment for patient demographics and comorbidities. The adjusted difference in reduced pain-related interference score between the 2 groups was -0.10 points on a 0 to 4 scale ( P = 0.01). Gabapentinoid use had greater odds of less-than-daily pain post-prescription, in a dose-dependent manner. Thus, GABA use was associated with a larger reduction in chronic pain than opioids, with a larger effect at higher GABA dosage. Future research is needed on functional outcomes in patients with chronic pain prescribed GABA or opioids.

Gabapentinoids: a therapeutic review

The Australian Therapeutic Goods Administration's approved indications for prescription of gabapentinoids are refractory focal epilepsy and neuropathic pain. Use of gabapentinoids outside of the approved indications is common, but evidence for this is limited, especially for chronic nonspecific back pain and nonradicular leg pain. Some effects of gabapentinoids encourage their nonmedical use (e.g. euphoria, sedation, disinhibition). Widespread nonmedical use has increased the incidence of accidental and deliberate poisonings. Dependence may develop with chronic use of gabapentinoids and abrupt cessation may induce withdrawal symptoms. If the indication for continued use is unclear, gradual dose tapering as a means of deprescribing is recommended. Clinicians should consider the indication, patient characteristics and harm-benefit profile when prescribing gabapentinoids. Some people, such as those with kidney disease, have an increased risk of harm when using these drugs.

Systematic Review to Identify Predictors of Treatment Response to Neuromodulation in Patients With Neuropathic Pain-Protocol

OBJECTIVES

Patients who suffer from long-term, neuropathic pain that proves refractory to conventional medical management are high consumers of health care resources and experience poorer physical and mental health than people with other forms of pain. Pharmacologic treatments have adverse effects; nonpharmacologic interventions have limitations. Spinal cord stimulation (SCS) is an effective treatment for neuropathic pain, although 30% to 40% of patients fail to achieve acceptable levels of pain relief. There are currently no objective methods to predict the success of SCS to treat neuropathic pain, and therefore, it is important to understand which patient factors may be predictive of a lack of response to SCS, to inform future patient treatment options. This study proposes a protocol for a systematic review and meta-analysis of published studies to examine these predictive factors.

MATERIALS AND METHODS

Several bibliographic databases will be searched to identify relevant studies published since 2012 that provide data on patient characteristics (eg, age, gender, pain severity) as predictors of SCS outcomes of pain, function, and health-related quality of life. Two independent reviewers will screen citations; data will be extracted after full-text screening. Risk of bias will be assessed using the Quality In Prognosis Studies tool.

RESULTS

A formal quantitative synthesis is planned in which data from studies with the same predictive factors are available; this will be considered for pooling into separate meta-analyses. In cases of high heterogeneity or inconsistency in the data, subgroup analysis will be conducted.

CONCLUSIONS

This study seeks to provide a contemporary review of patient predictors of success of neuromodulation for neuropathic pain. We anticipate that findings may guide the use of neuromodulation in patient subgroups and the design and reporting of future clinical studies in this field.

Concurrent Gabapentin and Opioid Use and Risk of Mortality in Medicare Recipients with Non-Cancer Pain

Gabapentin is prescribed for pain and is perceived as safe generally. However, gabapentin can cause respiratory depression, exacerbated by concomitant central nervous system depressants (e.g., opioids), a concern for vulnerable populations. We compared mortality rates among new users of either gabapentin or duloxetine with or without concurrent opioids in the 20% Medicare sample. We conducted a new-user design retrospective cohort study, in Medicare enrollees ages 65-89 years with noncancer chronic pain and no severe illness who filled prescriptions between 2015 and 2018 for gabapentin (n = 233,060) or duloxetine (n = 34,009). Daily opioid doses, estimated in morphine milligram equivalents (MMEs), were classified into none, low (0 < MME < 50), and high (≥ 50 MME), based on Centers for Disease Control and Prevention (CDC) recommendations. The outcomes were all-cause mortality (primary) and out-of-hospital mortality (secondary). We used inverse probability of treatment weighting to adjust for differences between gabapentin and duloxetine users. During 116,707 person-years of follow-up, 1,379 patients died. All-cause mortality rate in gabapentin users was 12.16 per 1,000 person-years vs. 9.94 per 1,000 in duloxetine users. Risks were similar for users with no concurrent opioids (adjusted hazard ratio (aHR) = 1.03, 95% confidence interval (CI): 0.80-1.31) or low-dose daily opioids (aHR = 1.06, 95% CI: 0.63-1.76). However, gabapentin users receiving concurrent high-dose daily opioids had an increased rate of all-cause mortality compared with duloxetine users on high-dose opioids (aHR = 2.03, 95% CI: 1.19-3.46). Out-of-hospital mortality yielded similar results. In this retrospective cohort study of Medicare beneficiaries, concurrent use of high-dose opioids and gabapentin was associated with a higher all-cause mortality risk than that for concurrent use of high-dose opioids and duloxetine.

"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.

Novel Drug Targets and Emerging Pharmacotherapies in Neuropathic Pain

Neuropathic pain is a debilitating condition characterized by abnormal signaling within the nervous system, resulting in persistent and often intense sensations of pain. It can arise from various causes, including traumatic nerve injury, neuropathy, and certain diseases. We present an overview of current and emerging pharmacotherapies for neuropathic pain, focusing on novel drug targets and potential therapeutic agents. Current pharmacotherapies, including tricyclic antidepressants, gabapentinoids, and serotonin norepinephrine re-uptake inhibitors, are discussed, as are emerging treatments, such as ambroxol, cannabidiol, and N-acetyl-L-cysteine. Additionally, the article highlights the need for further research in this field to identify new targets and develop more effective and targeted therapies for neuropathic pain management.

Pregabalin and gabapentin for chronic low back pain without radiculopathy: a systematic review

BACKGROUND

 Chronic low back pain (CLBP) is a global health problem, and gabapentin and pregabalin are often used in the treatment of patients without associated radiculopathy or neuropathy. Therefore, determining their efficacy and safety is of enormous value.

OBJECTIVE

To examine the efficacy and safety of using gabapentin and pregabalin for CLBP without radiculopathy or neuropathy.

METHODS

 We performed a search on the CENTRAL, MEDLINE, EMBASE, LILACS, and Web of Science data bases for clinical trials, cohorts, and case-control studies that evaluated patients with CLBP without radiculopathy or neuropathy for at least eight weeks. The data were extracted and inserted into a previously-prepared Microsoft Excel spreadsheet; the outcomes were evaluated using the Cochrane RoB 2 tool, and the quality of evidence, using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system.

RESULTS

 Of the 2,230 articles identified, only 5 were included, totaling 242 participants. In them, pregabalin was slightly less efficacious than amitriptyline, the combination of tramadol/acetaminophen, and celecoxib, and pregabalin added to celecoxib showed no benefit when compared to celecoxib alone (very low evidence for all). On the other hand, although one study with gabapentin did not support its use in a general sample of patients with low back pain, another found a reduction in the pain scale and improved mobility (moderate evidence). No serious adverse events were observed in any of the studies.

CONCLUSION

 Quality information to support the use of pregabalin or gabapentin in the treatment of CLBP without radiculopathy or neuropathy is lacking, although results may suggest gabapentin as a viable option. More data is needed to fill this current gap in knowledge.

The effect of skilled motor training on corticomotor control of back muscles in different presentations of low back pain

Transcranial magnetic stimulation (TMS) has revealed differences in the motor cortex (M1) between people with and without low back pain (LBP). There is potential to reverse these changes using motor skill training, but it remains unclear whether changes can be induced in people with LBP or whether this differs between LBP presentations. This study (1) compared TMS measures of M1 (single and paired-pulse) and performance of a motor task (lumbopelvic tilting) between individuals with LBP of predominant nociceptive (n = 9) or nociplastic presentation (n = 9) and pain-free individuals (n = 16); (2) compared these measures pre- and post-training; and (3) explored correlations between TMS measures, motor performance, and clinical features. TMS measures did not differ between groups at baseline. The nociplastic group undershot the target in the motor task. Despite improved motor performance for all groups, only MEP amplitudes increased across the recruitment curve and only for the pain-free and nociplastic groups. TMS measures did not correlate with motor performance or clinical features. Some elements of motor task performance and changes in corticomotor excitability differed between LBP groups. Absence of changes in intra-cortical TMS measures suggests regions other than M1 are likely to be involved in skill learning of back muscles.

Gabapentin-Friend or foe?

BACKGROUND

Gabapentin is a recommended first-line agent for treating neuropathic pain; however, its efficacy rate is reportedly low, and the risk of adverse events is high. A plausible explanation for this lies with its wide range of actions, the entirety of which have yet to be fully elucidated.

METHODS

A review of the literature was conducted on gabapentin's known and proposed analgesic mechanisms of action, as well as potentially opposing or detrimental actions.

RESULTS

Gabapentin's classical analgesic mechanisms involve direct attenuation of excitatory neurotransmission in the spinal cord via inhibition of neuronal ion channels, while indirect mechanisms include descending inhibition and block of injury-evoked synaptogenesis. Glial effects have also been reported; however, whether they are neuroprotective or detrimental is unknown. Furthermore, data from animal models do not reflect clinical outcomes.

CONCLUSIONS

Gabapentin's clinical use should be reconsidered according to the net effects of its numerous assumed actions, including the tripartite synapse and oligodendrocyte effects. Whether it is doing more harm than good, especially in the scenarios of incomplete or loss of response, warrants consideration when prescribing gabapentin.

Assessment and nonsurgical management of low back pain: a narrative review

Low back pain (LBP) is a common condition that affects people of all ages and income levels worldwide. The etiology of LBP may be mechanical, neuropathic, systemic, referred visceral, or secondary to other causes. Despite numerous studies, the diagnosis and management of LBP remain challenging due to the complex biomechanics of the spine and confounding factors, such as trivial degenerative imaging findings irrelevant to symptoms and psychological and emotional factors. However, it is imperative to identify the crucial signs ("red flags") indicating a serious underlying condition. While many recent guidelines emphasize non-pharmacologic management approaches, such as education, reassurance, and physical and psychological care, as the first option, LBP patients in many countries, including South Korea, are prescribed medications. Multidisciplinary rehabilitation combined with prudent use of medications is required in patients unresponsive to first-line therapy. The development of practical guidelines apposite for South Korea is needed with multidisciplinary discussion.

Functional Impairment and Cognitive Symptoms Among People with HIV Infection on Chronic Opioid Therapy for Pain: The Impact of Gabapentin and Other Sedating Medications

Gabapentin is associated with dizziness, falls, and somnolence yet commonly prescribed to people with HIV (PWH) treated with chronic opioid therapy (COT). Physical function and cognition are understudied when prescribed together. Among PWH on COT, we evaluated whether co-prescribed gabapentin is associated with (a) functional impairment; (b) trouble thinking clearly; and (c) difficulty controlling drowsiness using logistic regression models adjusted for prescribed opioid dose, other (non-gabapentin) sedating medication, substance use disorder, and mental/physical health indicators in a cross-sectional study. Among 166 participants, 40% were prescribed gabapentin, 41% reported functional impairment, 41% trouble thinking clearly, and 38% difficulty controlling drowsiness. Gabapentin co-prescribed with COT was significantly associated with trouble thinking clearly but not with functional impairment or difficulty controlling drowsiness. Clinicians should be cognizant of potential problems with thinking clearly when co-prescribing gabapentin and opioid medication.

Benefits and harms of treatments for chronic non-specific low back pain without radiculopathy: Systematic review and meta-analysis

BACKGROUND CONTEXT

Currently, there are no published studies that compare non-pharmacological, pharmacological and invasive treatments for chronic low back pain in adults and provide summary statistics for benefits and harms.

PURPOSE

The aim of this review was to compare the benefits and harms of treatments for the management of chronic low back pain without radiculopathy and to report the findings in a format that facilitates direct comparison (Benefit-Harm Scale: level 1 to 7).

DESIGN

Systematic review and meta-analysis of randomized controlled trials, including trial registries, from electronic databases up to 23^rd May 2022.

PATIENT SAMPLE

Adults with non-specific chronic low back pain, excluding radicular pain in any clinical setting.

OUTCOME MEASURES

Comparison of pain at immediate-term (≤2 weeks) and short-term (>2 weeks to ≤12 weeks) and serious adverse events using the Benefit-Harm Scale (level 1 to 7).

METHODS

This was a registered systematic review and meta-analysis of randomized controlled trials. Interventions included non-pharmacological (acupuncture, spinal manipulation), pharmacological and invasive treatments compared to placebo. Best evidence criteria was used. Two independent reviewers conducted eligibility assessment, data extraction and quality appraisal.

RESULTS

The search retrieved 17,362 records. Three studies provided data on the benefits of interventions, and 30 provided data on harms. Studies included interventions of acupuncture (n=8); manipulation (n=2); pharmacological therapies (n=9), including NSAIDs and opioid analgesics; surgery (n=8); and epidural corticosteroid injections (n=3). Acupuncture (standardized mean difference (SMD) -0.51, 95%CI -0.88 to -0.14, n=1 trial, moderate quality of evidence, benefit rating of 3) and manipulation (SMD -0.39, 95%CI -0.56 to -0.21, n=2 trials, moderate quality of evidence, benefit rating of 5) were effective in reducing pain intensity compared to sham. The benefit of the other interventions was scored as uncertain due to not being effective, statistical heterogeneity preventing pooling of effect sizes, or the absence of relevant trials. The harms level warnings were at the lowest (eg, indicating rarer risk of events) for acupuncture, spinal manipulation, NSAIDs, combination ingredient opioids, and steroid injections, while they were higher for single ingredient opioid analgesics (level 4) and surgery (level 6).

CONCLUSIONS

There is uncertainty about the benefits and harms of all the interventions reviewed due to the lack of trials conducted in patients with chronic non-specific low back pain without radiculopathy. From the limited trials conducted, non-pharmacological interventions of acupuncture and spinal manipulation provide safer benefits than pharmacological or invasive interventions. However, more research is needed. There were high harms ratings for opioids and surgery.

Placebo Response to Oral Administration in Osteoarthritis Clinical Trials and Its Associated Factors: A Model-Based Meta-analysis

Importance

In osteoarthritis (OA) clinical trials, a placebo is often used as control. Therefore, a thorough understanding of the placebo response is important for guiding drug development in OA.

Objective

To develop an oral placebo response model for OA.

Data Sources

PubMed, EMBASE, and Cochrane Library databases were searched systematically from January 1, 1991, to July 2, 2022.

Study Selection

Randomized double-blind placebo-controlled trials of patients with primary OA were included. The interventions and placebo were administered orally. A total of 3032 trials were identified; of these, 130 (4.3%) met the inclusion criteria.

Data Extraction and Synthesis

Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores, dosage form of the placebo, sample size, proportion of patients who previously used nonsteroidal anti-inflammatory drugs, publication year, intervention categories, Kellgren-Lawrence grades, proportion of White patients, duration of pain, funding source, and risk of bias were extracted. A model-based meta-analysis was used to evaluate the time course of the placebo response in OA treatment and estimate the influencing factors. For subgroup analyses, a meta-analysis with a random-effects model was used to summarize the typical values of the model parameters and their SEs.

Main Outcomes and Measures

The primary end point was the time course of the oral placebo response on the WOMAC pain, stiffness, and function subscale scores.

Results

The 130 trials selected for analysis included 12 673 participants (mean age, 59.9 years; 68.9% women). The baseline scores of WOMAC pain, stiffness, and function subscales were found to be significantly associated with the placebo response. The placebo response reached 90% of its maximum response between 5 and 7 weeks. The placebo responses on the WOMAC subscales were also associated with the sample size, proportion of patients who had previously used nonsteroidal anti-inflammatory drugs, intervention drugs, and publication year.

Conclusions and Relevance

In this study, an oral placebo response model of OA was developed that may quantitatively describe the placebo response at different baseline levels of symptoms. The findings may provide valuable references for future clinical trial design and decision-making.

Project rebuild the evidence base (REB): A method to interpret randomised clinical trials and their meta-analysis to present solid benefit-risk assessments to patients

Evidence-based medicine is the cornerstone of shared-decision making in healthcare today. The public deserves clear, transparent and trust-worthy information on drug efficacy. Yet today, many drugs are prescribed and used without solid evidence of efficacy. Clinical trials and randomised clinical trials (RCTs) are the best method to evaluate drug efficacy and side effects. In a shared medical decision-making approach, general practitioners need drug assessment based on patient-important outcomes. The aim of project rebuild the evidence base (REB) is to bridge the gap between the data needed in clinical practice and the data available from clinical research. The drugs will be assessed on clinical patient important outcomes and for a population. Using the Cochrane tools, we propose to analyse for each population and outcome: 1) a meta-analysis based on RCTs with a low risk of bias overall; 2) an evaluation of results of confirmatory RCTs; 3) a statistical analysis of heterrogeneity between RCTs and 4) an analysis of publication bias. Depending on the results of these analyses, the evidence will be categorized in 4 different levels: firm evidence, evidence (to be confirmed), signal or absence of evidence. Project REB proposes a method for reading and interpreting RCTs and their meta-analysis to produce quality data for general practitioners to focus on risk-benefit assessment in the interest of patients. If this data does not exist, it could enable clinical research to better its aim.

Long-term and serious harms of medical cannabis and cannabinoids for chronic pain: a systematic review of non-randomised studies

OBJECTIVE

To establish the prevalence of long-term and serious harms of medical cannabis for chronic pain.

DESIGN

Systematic review and meta-analysis.

DATA SOURCES

MEDLINE, EMBASE, PsycINFO and CENTRAL from inception to 1 April 2020.

STUDY SELECTION

Non-randomised studies reporting on harms of medical cannabis or cannabinoids in adults or children living with chronic pain with ≥4 weeks of follow-up.

DATA EXTRACTION AND SYNTHESIS

A parallel guideline panel provided input on the design and interpretation of the systematic review, including selection of adverse events for consideration. Two reviewers, working independently and in duplicate, screened the search results, extracted data and assessed risk of bias. We used random-effects models for all meta-analyses and the Grades of Recommendations, Assessment, Development and Evaluation approach to evaluate the certainty of evidence.

RESULTS

We identified 39 eligible studies that enrolled 12 143 adult patients with chronic pain. Very low certainty evidence suggests that adverse events are common (prevalence: 26.0%; 95% CI 13.2% to 41.2%) among users of medical cannabis for chronic pain, particularly any psychiatric adverse events (prevalence: 13.5%; 95% CI 2.6% to 30.6%). Very low certainty evidence, however, indicates serious adverse events, adverse events leading to discontinuation, cognitive adverse events, accidents and injuries, and dependence and withdrawal syndrome are less common and each typically occur in fewer than 1 in 20 patients. We compared studies with <24 weeks and ≥24 weeks of cannabis use and found more adverse events reported among studies with longer follow-up (test for interaction p<0.01). Palmitoylethanolamide was usually associated with few to no adverse events. We found insufficient evidence addressing the harms of medical cannabis compared with other pain management options, such as opioids.

CONCLUSIONS

There is very low certainty evidence that adverse events are common among people living with chronic pain who use medical cannabis or cannabinoids, but that few patients experience serious adverse events.

Patient empowerment brochures to increase gabapentinoid deprescribing: protocol for the prospective, controlled before-and-after GABA-WHY trial

BACKGROUND

Off-label use of gabapentinoids is common among patients admitted to hospital medical wards, who are at risk of adverse drug events. In this study, we will assess if educational brochures can increase rates of gabapentinoid deprescription among medical inpatients, compared with usual care.

METHODS

We describe the protocol for a prospective before-and-after trial that will take place on 5 medical wards of 2 tertiary care hospitals in Montréal, Canada. The study intervention will include distribution of educational brochures to users of gabapentinoids during hospital admission, as well as short educational sessions for medical staff on safe gabapentinoid prescribing practices. We will include patients with a gabapentinoid prescription before admission who are aged 60 years or older. Exclusion criteria are known seizure disorder, severe cognitive impairment, expected prognosis less than 3 months and inability to read English or French. The primary outcome is the rate of gabapentinoid deprescription at 8 weeks postdischarge. We aim to recruit 160 participants, with a 1:1 distribution between intervention and control groups.

INTERPRETATION

If successful, the use of educational brochures and staff education represents a scalable intervention to reduce gabapentinoid overuse by encouraging deprescription conversations between patients and their health care providers. Results of the study will be disseminated through publication in peer-reviewed journals and presentations at conferences.

TRIAL REGISTRATION

ClinicalTrials.gov, no. NCT04855578.

A snapshot on the usage pattern of gabapentinoids in Oman

Background

Since their introduction as adjunct anticonvulsants, the use of gabapentinoids (gabapentin and pregabalin) has increased substantially worldwide to include a wide range of clinical conditions. Various reports have demonstrated that they possess addiction liability and can produce effects similar to traditional recreational drugs, such as significant euphoric effects, enhanced sociability, and relaxation. However, there is limited information on the use of these agents in the Middle East.

Objectives

Here, we describe the usage pattern of gabapentinoids at Sultan Qaboos University Hospital, a tertiary care medical institution in Oman.

Methods

Adult patients (≥18 years) who were prescribed gabapentinoids for six months (March-August 2019) were included in this retrospective cross-sectional study. Indications and dosing regimens were reviewed according to the Food and Drug Administration labeling. Controlled and restricted drugs were reviewed using Oman National Formulary. Institutional ethical approval was obtained before conducting the study.

Results

We analyzed 291 prescriptions. The mean (standard deviation, SD) age was 60.5 years (SD = 13.0) with the age group of ≥60 years being the most common (190, 65.3%). Most of patients were females (178, 61.2%). The majority of prescriptions were for outpatients (85.8%). Drugs were prescribed as refill and follow-up in 116 (40.0%) and 97 (33.4%) of prescriptions, respectively. Diabetic peripheral neuropathy (50, 79.4%) was the most labeled indication for both. Off-label use was 128 (51.8%) and 31 (70.5%) for pregabalin and gabapentin, respectively, with lower back pain as being the most common indication for both drugs. A total of 54 (19.0%) patients were using at least one of the psychotropic drugs.

Conclusions

Our findings indicate that gabapentinoids are frequently prescribed for off-label use. Awareness programs and the establishment of policy for the use of these drugs are required to ensure their rational use and prevent misuse and/or abuse.

Gabapentin initiation in the inpatient setting: A characterization of prescribing

Disclaimer

In an effort to expedite the publication of articles related to the COVID-19 pandemic, AJHP is posting these manuscripts online as soon as possible after acceptance. Accepted manuscripts have been peer-reviewed and copyedited, but are posted online before technical formatting and author proofing. These manuscripts are not the final version of record and will be replaced with the final article (formatted per AJHP style and proofed by the authors) at a later time.

Purpose

Gabapentin is a widely prescribed analgesic with increased popularity over recent years. Previous studies have characterized use of gabapentin in the outpatient setting, but minimal data exist for its initiation in the inpatient setting. The objective of this study was to characterize the prescribing patterns of gabapentin when it was initiated in the inpatient setting.

Methods

This was a retrospective cohort study of a random sample of adult patients who received new-start gabapentin during hospital admission. Patients for whom gabapentin was prescribed as a home medication, with one-time, on-call, or as-needed orders, or who died during hospital admission were excluded. The primary outcome was characterization of the gabapentin indication; secondary outcomes included the starting and discharge doses, the number of dose titrations, the rate of concomitant opioid prescribing, and pain clinic follow-up. Patients were stratified by surgical vs nonsurgical status.

Results

A total of 464 patients were included, 283 (61.0%) of whom were surgical and 181 (39.0%) of whom were nonsurgical. The cohort was 60% male with a mean (SD) age of 56 (18) years; surgical patients were younger and included more women. The most common indications for surgical patients were multimodal analgesia (161; 56.9%), postoperative pain (53; 18.7%), and neuropathic pain (26; 9.2%), while those for nonsurgical patients were neuropathic pain (72; 39.8%) and multimodal analgesia (53; 29.3%). The mean starting dose was similar between the subgroups (613 mg for surgical patients vs 560 mg for nonsurgical patients; P = 0.196). A total of 51.6% vs 81.8% of patients received gabapentin at discharge (P &lt; 0.0001), while referral/follow-up to a pain clinic was minimal and similar between the subgroups (1.1% vs 3.9%; P = 0.210).

Conclusion

Inpatients were commonly initiated on gabapentin for generalized indications, with approximately half discharged on gabapentin. Further studies are needed to assess the impact of this prescribing on chronic utilization.

Pregabalin vs placebo to prevent chronic pain after whiplash injury in at-risk individuals: results of a feasibility study for a large randomised controlled trial

ABSTRACT

There are few effective treatments for acute whiplash-associated disorders (WADs). Early features of central sensitisation predict poor recovery. The effect of pregabalin on central sensitisation might prevent chronic pain after acute whiplash injury. This double blind, placebo-controlled randomised controlled trial examined feasibility and potential effectiveness of pregabalin compared with placebo for people with acute WAD. Twenty-four participants with acute WAD (<48 hours) and at risk of poor recovery (pain ≥5/10) were recruited from hospital emergency departments in Queensland, Australia, and randomly assigned by concealed allocation to either pregabalin (n = 10) or placebo (n = 14). Pregabalin was commenced at 75 mg bd, titrated to 300 mg bd for 4 weeks, and then weaned over 1 week. Participants were assessed at 5 weeks and 3, 6, and 12 months. Feasibility issues included recruitment difficulties and greater attrition in the placebo group. For the primary clinical outcome of neck pain intensity, attrition at 5 weeks was pregabalin: 10% and placebo: 36% and at 12 months was pregabalin: 10% and placebo: 43%. Pregabalin may be more effective than placebo for the primary clinical outcome of neck pain intensity at 3 months (mean difference: -4.0 [95% confidence interval -6.2 to -1.7]) on an 11-point Numerical Rating Scale. Effects were maintained at 6 months but not 12 months. There were no serious adverse events. Minor adverse events were more common in the pregabalin group. A definitive large randomised controlled trial of pregabalin for acute whiplash injury is warranted. Feasibility issues would need to be addressed with modifications to the protocol.

Non-operative treatment for lumbar spinal stenosis with neurogenic claudication: an updated systematic review

OBJECTIVES

Neurogenic claudication due to lumbar spinal stenosis (LSS) is a growing health problem in older adults. We updated our previous Cochrane review (2013) to determine the effectiveness of non-operative treatment of LSS with neurogenic claudication.

DESIGN

A systematic review.

DATA SOURCES

CENTRAL, MEDLINE, EMBASE, CINAHL and Index to Chiropractic Literature databases were searched and updated up to 22 July 2020.

ELIGIBILITY CRITERIA

We only included randomised controlled trials published in English where at least one arm provided data on non-operative treatment and included participants diagnosed with neurogenic claudication with imaging confirmed LSS.

DATA EXTRACTION AND SYNTHESIS

Two independent reviewers extracted data and assessed risk of bias using the Cochrane Risk of Bias Tool 1. Grading of Recommendations Assessment, Development and Evaluation was used for evidence synthesis.

RESULTS

Of 15 200 citations screened, 156 were assessed and 23 new trials were identified. There is moderate-quality evidence from three trials that: Manual therapy and exercise provides superior and clinically important short-term improvement in symptoms and function compared with medical care or community-based group exercise; manual therapy, education and exercise delivered using a cognitive-behavioural approach demonstrates superior and clinically important improvements in walking distance in the immediate to long term compared with self-directed home exercises and glucocorticoid plus lidocaine injection is more effective than lidocaine alone in improving statistical, but not clinically important improvements in pain and function in the short term. The remaining 20 new trials demonstrated low-quality or very low-quality evidence for all comparisons and outcomes, like the findings of our original review.

CONCLUSIONS

There is moderate-quality evidence that a multimodal approach which includes manual therapy and exercise, with or without education, is an effective treatment and that epidural steroids are not effective for the management of LSS with neurogenic claudication. All other non-operative interventions provided insufficient quality evidence to make conclusions on their effectiveness.

PROSPERO REGISTRATION NUMBER

CRD42020191860.

Higher-Dose Gabapentinoids and the Risk of Adverse Events in Older Adults With CKD: A Population-Based Cohort Study

RATIONALE & OBJECTIVE

Gabapentinoids are an opioid substitute whose elimination by the kidneys is reduced as kidney function declines. To inform their safe prescribing in older adults with chronic kidney disease (CKD), we examined the 30-day risk of serious adverse events according to the prescribed starting dose.

STUDY DESIGN

Population-based cohort study.

SETTING & PARTICIPANTS

74,084 older adults (64% women; median age 79 [interquartile range 73-85]) with CKD (defined as an estimated glomerular filtration rate [eGFR] <60 mL/min/1.73m2 while not receiving dialysis) and a newly prescribed a gabapentinoid between 2008-2020 in Ontario, Canada.

EXPOSURE

Higher-dose gabapentinoids (gabapentin >300 mg/day or pregabalin >75 mg/day) vs lower-dose gabapentinoids (gabapentin ≤300 mg/day or pregabalin ≤75 mg/day).

OUTCOMES

The primary composite outcome was the 30-day risk of a hospital visit with encephalopathy, a fall, a fracture, or a hospitalization with respiratory depression.

ANALYTICAL APPROACH

Comparison groups were balanced on indicators of baseline health using inverse probability of treatment weighting using propensity score analysis that generated a pseudo-sample for the reference group with a distribution of measured covariates similar to the exposed group. Weighted risk ratios (RR) were estimated using modified Poisson regression, and weighted risk differences (RD) estimated using binomial regression. Pre-specified subgroup analyses were conducted by eGFR category and type of gabapentinoid.

RESULTS

Among 74,084 patients were identified with CKD and a new prescription for gabapentin or pregabalin 41% started at >300 mg/day and >75 mg/day, respectively. From this set of patients a weighted study population with a size of 61,367 was generated. Patients who started at a higher dose had a 30-day risk of the primary outcome higher than the risk among with patients who started at lower dose. Within the weighted population, the numbers of events for higher vs. lower dose were 585/30,660 [1.9%] vs 462/30,707 [1.5%], respectively. The weighted RR was 1.27 [95% CI, 1.13 to 1.42] and the weighted RD was 0.40% [95% CI, 0.21% to 0.60%]). In subgroup analyses, neither multiplicative nor additive interactions were statistically significant.

LIMITATIONS

Residual confounding.

CONCLUSIONS

In this population-based study, starting a gabapentinoid at a higher vs lower dose was associated with a slightly higher risk of a hospital stay with encephalopathy, a fall, or a fracture, or hospitalization with respiratory depression. If verified, these risks should be balanced against the benefits of using a higher-dose gabapentinoid.

A systematic review and meta-analysis of the effectiveness and adverse events of gabapentin and pregabalin for sciatica pain

Aim

This SR aims to assess the effectiveness of pregabalin and gabapentin on pain and disability caused by acute sciatica and the adverse events associated with their clinical use.

Design

Systematic review.

Databases

Electronic databases of Cochrane Central Register of Controlled Trials, MEDLINE, EMBASE, and Clinical Trials.gov were searched from their inception until March 1st of 2021.

Selection criteria

Randomized trials (RCT) with adults > 18 years old with acute sciatica for a minimum of 1 week and a maximum of 1 year (at least moderate pain).

Data treatment

The outcomes were pain, disability and adverse events. Data was summarized using odds ratio and mean difference. GRADE was used to calculate the level of evidence.

Results

Eight RCT involving 747 participants were included. The effect of pregabalin was assessed in 3 RCT and in one three-arm trial (pregabalin vs limaprost vs a combination of limaprost and pregabalin). Two trials assessed the effect of gabapentin compared with placebo and one compared with tramadol. One study assessed the effect of gabapentin vs pregabalin in a crossover head-to-head trial.

A statistically significant improvement on leg pain at 2 weeks and leg pain with movement at 3 and 4 months was found in a RCT comparing gabapentin with placebo. There were no statistically differences on the remaining time periods assessed for leg pain, low back pain and functional disability.

Conclusions

This SR provides clear evidence for lack of effectiveness of pregabalin and gabapentin for sciatica pain management. In view of this, its routine clinical use cannot be supported.

Opioids and Gabapentinoids Utilisation and Their Related-Mortality Trends in the United Kingdom Primary Care Setting, 2010-2019: A Cross-National, Population-Based Comparison Study

Background: There is growing concern over the increasing utilisation trends of opioids and gabapentinoids across but there is lack of data assessing and comparing the utilisation trends across the four United Kingdom countries. We assessed/compared opioids and gabapentinoids utilisation trends across the four United Kingdom countries then evaluated the correlation between their utilisation with related mortality.

Methods: This repeated cross-national study used Prescription Cost Analysis (PCA) datasets (2010–2019). Opioids and gabapentinoids utilisation were measured using number of items dispensed/1,000 inhabitants and defined daily doses (DDDs)/1,000 inhabitant/day. Number of Opioids and gabapentinoids-related mortality were extracted from the United Kingdom Office for National Statistics (2010–2018). Data were analysed using descriptive statistics including linear trend analysis; correlation between the Opioids and gabapentinoids utilisation and their related mortality using Pearson correlation coefficient.

Results: The results illustrated an overall significant increasing trend in the utilisation of opioids (12.5–14%) and gabapentinoids (205–207%) with substantial variations among the four United Kingdom countries. For opioids, Scotland had the highest level of number of items dispensed/1,000 inhabitant (156.6% higher compared to the lowest level in England), whereas in terms of DDD/1,000 inhabitant/day, NI had the highest level. Utilisation trends increased significantly across the four countries ranging from 7.7% in Scotland to 20.5% in NI (p < 0.001). Similarly, for gabapentinoids, there were significant increasing trends ranging from 126.5 to 114.9% in NI to 285.8–299.6% in Wales (p < 0.001) for number of items/1,000 inhabitants and DDD/1,000 inhabitant/day, respectively. Although the utilisation trends levelled off after 2016, this was not translated into comparable reduction in opioids and gabapentinoids-related mortality as the latter continued to increase with the highest level in Scotland (3.5 times more deaths in 2018 compared to England- 280.1 vs. 79.3 deaths/million inhabitants). There were significant moderate-strong positive correlations between opioids and gabapentinoids utilisation trends and their related mortality.

Conclusion: The utilisation trends of opioids and gabapentinoids have increased significantly with substantial variations among the four United Kingdom countries. This coincided with significant increase in their related mortality. Our findings support the call for immediate actions including radical changes in official United Kingdom policies on drug use and effective strategies to promote best clinical practice in opioids and gabapentinoids prescribing.

Trends in the Utilization and Dose of Gabapentinoids in Combination With Opioids in an Injured Worker Population Between 2008 and 2018

OBJECTIVE

To determine long term (11 year) trends in gabapentin and pregabalin prescribing among workers' compensation claimants at various opioid dose combinations (low, medium, high, and very high) in Louisiana.

METHOD

A longitudinal study of 18,737 claimants who filled any prescriptions between 2008 and 2018.

RESULTS

The proportion of claimants prescribed opioids alone at all dose levels decreased dramatically. The proportion claimants prescribed the combination of low dose opioids and low dose gabapentinoids increased (7.7% to 10.9%). Prescribing higher daily doses of gabapentinoids was associated with higher daily doses of opioids. Gabapentinoid prescribing was associated with continued prescribing of medium and high dose opioids as claims matured.

CONCLUSIONS

Overall opioid prescribing decreased over time, while prescribing low dose opioids with gabapentinoids, increased.

Non-Surgical Interventions for Lumbar Spinal Stenosis Leading To Neurogenic Claudication: A Clinical Practice Guideline

Lumbar spinal stenosis (LSS) causing neurogenic claudication (NC) is increasingly common with an aging population and can be associated with significant symptoms and functional limitations. We developed this guideline to present the evidence and provide clinical recommendations on nonsurgical management of patients with LSS causing NC. Using the GRADE approach, a multidisciplinary guidelines panel based recommendations on evidence from a systematic review of randomized controlled trials and systematic reviews published through June 2019, or expert consensus. The literature monitored up to October 2020. Clinical outcomes evaluated included pain, disability, quality of life, and walking capacity. The target audience for this guideline includes all clinicians, and the target patient population includes adults with LSS (congenital and/or acquired, lateral recess or central canal, with or without low back pain, with or without spondylolisthesis) causing NC. The guidelines panel developed 6 recommendations based on randomized controlled trials and 5 others based on professional consensus, summarized in 3 overarching recommendations: (Grade: statements are all conditional/weak recommendations) Recommendation 1. For patients with LSS causing NC, clinicians and patients may initially select multimodal care nonpharmacological therapies with education, advice and lifestyle changes, behavioral change techniques in conjunction with home exercise, manual therapy, and/or rehabilitation (moderate-quality evidence), traditional acupuncture on a trial basis (very low-quality evidence), and postoperative rehabilitation (supervised program of exercises and/or educational materials encouraging activity) with cognitive-behavioral therapy 12 weeks postsurgery (low-quality evidence). Recommendation 2. In patients LSS causing NC, clinicians and patients may consider a trial of serotonin-norepinephrine reuptake inhibitors or tricyclic antidepressants. (very low-quality evidence). Recommendation 3. For patients LSS causing NC, we recommend against the use of the following pharmacological therapies: nonsteroidal anti-inflammatory drugs, methylcobalamin, calcitonin, paracetamol, opioids, muscle relaxants, pregabalin (consensus-based), gabapentin (very low-quality), and epidural steroidal injections (high-quality evidence). PERSPECTIVE: This guideline, on the basis of a systematic review of the evidence on the nonsurgical management of lumbar spine stenosis, provides recommendations developed by a multidisciplinary expert panel. Safe and effective non-surgical management of lumbar spine stenosis should be on the basis of a plan of care tailored to the individual and the type of treatment involved, and multimodal care is recommended in most situations.

Evidence of a gabapentinoid and diuretic prescribing cascade among older adults with lower back pain

BACKGROUND/OBJECTIVES

Gabapentinoids are commonly prescribed to relieve pain. The development of edema, an established adverse effect of gabapentinoids, may lead to a potentially harmful prescribing cascade whereby individuals are subsequently prescribed diuretics and exposed to diuretic-induced adverse events. The frequency of this prescribing cascade is unknown. Our objective was to measure the association between new dispensing of a gabapentinoid and the subsequent dispensing of a diuretic in older adults with new low back pain.

DESIGN

Population-based cohort study.

SETTING

Ontario, Canada.

PARTICIPANTS

A total of 260,344 community-dwelling adults aged 66 years or older, newly diagnosed with low back pain between April 1, 2011, and March 31, 2019.

MEASUREMENTS

Exposure status was assigned using dispensed medications in the 1 week after low back pain diagnosis. Older adults newly dispensed a gabapentinoid (N = 7867) were compared with older adults who were not newly dispensed a gabapentinoid (N = 252,477). Hazard ratios (HRs) with 95% confidence intervals (CIs) for dispensing of a diuretic within 90 days of follow-up among older adults prescribed gabapentin relative to those who were not.

RESULTS

Older adults newly dispensed a gabapentinoid had a higher risk of being subsequently dispensed a diuretic within 90 days compared with older adults who were not prescribed a gabapentinoid (2.0% vs. 1.3%). After covariate adjustment, new gabapentinoid users had a higher rate of being dispensed a diuretic compared with those not prescribed a gabapentinoid (HR: 1.44, 95% CI: 1.23, 1.70). The rate of diuretic prescription among new gabapentinoid users increased with increasing gabapentinoid dosages.

CONCLUSIONS

We have demonstrated the presence of a potentially inappropriate and harmful prescribing cascade. Given the widespread use of gabapentinoids, the population-based scale of this problem may be substantial. Increased awareness of this prescribing cascade is required to reduce the unnecessary use of diuretics and the exposure of patients to additional adverse drug events.

Effectiveness of acupuncture therapy for postherpetic neuralgia: an umbrella review protocol

INTRODUCTION

Several systematic reviews and meta-analysis indicate that acupuncture and related therapies may be a valuable adjunctive technique to pharmacological interventions for pain management of postherpetic neuralgia (PHN). However, the robustness of the results of these studies has not been evaluated. The aim of this proposed umbrella review is to provide more reliable evidence of the effectiveness of acupuncture therapy for PHN based on medical references for healthcare decision makers.

METHODS AND ANALYSIS

PubMed, EMBASE, The Cochrane Library, Web of Science, Chinese BioMedical Literature Database, VIP Database for Chinese Technical Periodicals, China National Knowledge Infrastructure and Wan fang Database will be used to retrieve reviews. The time of publication will be limited from inception to March 2021. Two reviewers will screen all retrieved articles independently to identify their eligibility and extract the data. The quality will be assessed independently by two trained reviewers using Assessment of Multiple Systematic Reviews-2 for methodological quality, Risk of Bias in Systematic Review for level of bias, Preferred Reporting Items for Systematic Reviews and Meta-Analysis for reporting quality and Grading of Recommendations Assessment, Development and Evaluation for the quality of evidence. Any disagreements will be settled by discussion or the involvement of a third reviewer.

ETHICS AND DISSEMINATION

The protocol of this review does not require ethical approval because the research will be based on publicly available data. The findings will be disseminated through publication in peer-reviewed international journals or presentation in academic conference.

PROSPERO REGISTRATION NUMBER

CRD42020173341.

REPORTING CHECKLIST

PRISMA-P, 2015.

Comparative safety review of current treatment options for chronic low back pain and unmet needs: a narrative review

Introduction: The healthcare expenditures in the United States are substantial for the management of refractory, chronic low back pain (CLBP). The objective of this review is to summarize and evaluate the safety profiles of different pharmacological treatment options used in the management of CLBP.Areas covered: The authors conducted a search of randomized controlled trials (RCTs) assessing the safety profiles of different pharmacological agents used in the management of CLBP. This narrative review covered corticosteroids, opioids, antidepressants, gabapentinoids, nonsteroidal anti-inflammatory drugs, muscle relaxants, anti-nerve growth factor antibodies and topical agents, as monotherapy or in combination.Expert opinion: The risk-benefit ratio of a particular treatment is a subject driving the ongoing development of pharmaceuticals. The most commonly reported AEs across all drug classes are of gastrointestinal nature, followed by neurological and skin-related. These AEs include nausea, dizziness, constipation, arthralgia, headache, dry mouth, pruritus, etc. The majority of the AEs reported are not life-threatening, although they may lower patients' quality of life, thus, affecting their compliance. One of the biggest limitations of our review stems from the paucity of safety assessments in published RCTs. Advances in our understanding of the neurobiology of pain will promote development of new therapeutic strategies.

The Efficacy, Adverse Events & Withdrawal Rates of the Pharmacological Management of Chronic Spinal Cord Injury Pain: A Systematic Review & Meta-Analysis

OBJECTIVE

To establish the efficacy of medications, incidence of adverse events (AE) and withdrawal rates (WR) of the pharmacological management of chronic spinal cord injury (SCI) pain.

METHODOLOGY

PubMed, MEDLINE, Embase, CINAHL, Web of Science, CENTRAL and PsycINFO were searched (November 2017) and updated (January 2020). Two independent review authors screened and identified papers for inclusion.

RESULTS

Twenty-one studies met inclusion for efficacy analysis and 17 for AEs and WR analysis; no additional paper were included from the up dated 2020 search. Treatments were divided into 6 categories: anticonvulsants (n = 6), antidepressants (n = 3), analgesics (n = 8), anti-spasticity (n = 2), cannabinoids (n = 1) and other (n = 2). Trials of anticonvulsants, antidepressants, and cannabinoids included long-term follow-up trials (2 weeks- 4 months), and analgesics, anti-spasticity, among others were short term trials (0-2 days). Effectiveness for NP was found for Pregabalin (3/3 studies) and Lidocaine (2/3 studies). Studies using Ketamine also reported effectiveness (2/2) but the quality of these papers was rated as poor. Most frequently reported AEs included dizziness, dry mouth, nausea and constipation. Pregabalin had a higher risk of somnolence (RR 3.15, 95% CI 2.00-4.98) and dizziness (RR 2.9, 95% CI 1.58-5.30). Ketamine had a higher risk of reduced vision (RR 9.00, 95% CI 0.05-146.11), dizziness (RR 8.33, 95% CI 1.73-40.10) and somnolence (RR 7.00, 95% CI 1.73-40.1). WRs ranged from: 18.4% (antidepressants), 0-30% (anticonvulsants), 0-10% (anti-spasticity), 0-48% (analgesics), 28.6% (cannabinoids) and 0-22.2% (other).

CONCLUSION

Pregabalin was found to be effective for NP versus placebo. Cannabinoids was ineffective for NP. AEs are a common cause for withdrawal. The nature of AEs was poorly reported and should be improved in future RCT's.

Pain: Integration of Sensory and Affective Aspects of Pain

Painful stimuli are detected by peripheral nociceptors, and the brain processes this nociceptive input into an unpleasant sensation. A new study identifies a brain circuit that integrates sensory and affective aspects of inflammatory and neuropathic pain.

Pharmacological and non-pharmacological treatment approaches to chronic lumbar back pain

Low back pain is a common and important cause of disability. Chronic pain increases disability and cost. In this review, we discuss pharmacological and non-pharmacological treatment approaches for chronic low back pain in the light of current data and guidelines.

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.

Association Between Dual Trajectories of Opioid and Gabapentinoid Use and Healthcare Expenditures Among US Medicare Beneficiaries

OBJECTIVES

Little is known about relationships between opioid- and gabapentinoid-use patterns and healthcare expenditures that may be affected by pain management and risk of adverse outcomes. This study examined the association between patients' opioid and gabapentinoid prescription filling/refilling trajectories and direct medical expenditures in US Medicare.

METHODS

This cross-sectional study included a 5% national sample (2011-2016) of fee-for-service beneficiaries with fibromyalgia, low back pain, neuropathy, or osteoarthritis newly initiating opioids or gabapentinoids. Using group-based multitrajectory modeling, this study identified patients' distinct opioid and gabapentinoid (OPI-GABA) dose and duration patterns, based on standardized daily doses, within a year of initiating opioids and/or gabapentinoids. Concurrent direct medical expenditures within the same year were estimated using inverse probability of treatment weighted multivariable generalized linear regression, adjusting for sociodemographic and health status factors.

RESULTS

Among 67 827 eligible beneficiaries (mean age ± SD = 63.6 ± 14.8 years, female = 65.8%, white = 77.1%), 11 distinct trajectories were identified (3 opioid-only, 4 gabapentinoid-only, and 4 concurrent OPI-GABA trajectories). Compared with opioid-only early discontinuers ($13 830, 95% confidence interval = $13 643-14 019), gabapentinoid-only early discontinuers and consistent low-dose and moderate-dose gabapentinoid-only users were associated with 11% to 23% lower health expenditures (adjusted mean expenditure = $10 607-$11 713). Consistent low-dose opioid-only users, consistent high-dose opioid-only users, consistent low-dose OPI-GABA users, consistent low-dose opioid and high-dose gabapentinoid users, and consistent high-dose opioid and moderate-dose gabapentinoid users were associated with 14% to 106% higher healthcare expenditures (adjusted mean expenditure = $15 721-$28 464).

CONCLUSIONS

Dose and duration patterns of concurrent OPI-GABA varied substantially among fee-for-service Medicare beneficiaries. Consistent opioid-only users and all concurrent OPI-GABA users were associated with higher healthcare expenditures compared to opioid-only discontinuers.

Gabapentinoid and Opioid Utilization and Cost Trends Among Injured Workers

OBJECTIVE

To characterize changes in opioid, gabapentin, and pregabalin utilization patterns and cost trends between 2008 and 2018 in a Louisiana workers' compensation claims population and explore the role of gabapentinoids as alternative analgesics during the opioid epidemic.

METHOD

Filled prescriptions for gabapentinoids and opioids were studied for 11 years in a cohort of 18,737 claimants.

RESULTS

The proportion of claimants prescribed gabapentin increased 2-fold (8.9% to 18.9%) and average drug cost per claimant decreased 22% ($612 to $480). The proportion of claimants prescribed pregabalin decreased approximately 80% (11.7% to 2.5%) and average drug cost per claim increased 224% ($911 to $2952). Proportion of claimants prescribed opioids decreased 20% (80% to 64.2%) and average drug cost per claim decreased 46% ($691 to $371).

CONCLUSIONS

Utilization increased substantially for gabapentin and decreased for pregabalin and opioids.