Gabapentin for Off-Label Use: Evidence-Based or Cause for Concern?

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.

Efficacy of gabapentin and pregabalin for treatment of post refractive surgery pain: a systematic review and meta-analysis

INTRODUCTION

For ophthalmic patients, eye discomfort is a major problem that requires efficient pain treatment techniques. Pregabalin and gabapentin have surfaced as viable treatments for post-refractive surgery pain. To manage pain after refractive surgery, gabapentin and pregabalin were evaluated in this systematic review and meta-analysis.

METHODOLOGY

A thorough search of databases including PubMed, Embase, Cochrane Library, and CINAHL was performed until March 2024. Inclusion criteria were randomized controlled trials assessing pregabalin and/or gabapentin's effectiveness in treating pain post-PRK, LASIK, and LASEK surgeries.

RESULTS

Six studies met inclusion criteria, comprising a total of 391 patients undergoing various corneal surgeries. The meta-analysis revealed that pregabalin was significantly more effective than placebo in reducing pain on the first and second postoperative days (SMD day 1: -0.32, 95% CI -0.54, -0.09; SMD day 2: -0.55, 95% CI -0.85, -0.25), while gabapentin showed significant pain reduction on the second day only (SMD day 2: -0.42, 95% CI -0.71, -0.13). Combined analysis for both medications showed significant pain reduction on the first- and second-days post-surgery. No significant increase in adverse events was associated with either medication. Publication bias was minimal except for a slight asymmetry noted on day 1 effectiveness.

CONCLUSION

Pregabalin and gabapentin are effective in reducing postoperative pain following refractive surgeries, with pregabalin showing a greater effect. Both medications are safe, with no significant increase in adverse events. Further research with standardized methodologies and long-term follow-up is recommended to optimize postoperative pain management in ocular surgeries.

Assessing the feasibility of the GOTT (Gabapentinoid and Opioid Tapering Toolkit) in a primary care setting in North-East England

Objective

To assess the feasibility and possible impacts of implementation of systematic non-pharmacological interventions to reduce the level of prescribing of opioid and gabapentinoid analgesics for chronic non-cancer pain (CNCP), particularly high-dose prescriptions, through a proof-of-concept study in a deprived area (second lowest decile) primary care practice in North-East England.

Participant

Twenty-five primary care staff (clinical and non-clinical) of which 18 clinicians received the intervention.

Intervention used in this study practice known as GOTT Gabapentinoid and Opioid Toolkit

All clinicians received an educational skills programme to support patient pain self-management, tailored on the clinicians' self-assessment of their learning needs, embedding both clinician skill learning and patient self-care resources for rapid access within consultations into a GP clinical management computer system.

Outcome measures

Clinical staff completed questionnaires before and after the GOTT intervention to assess levels of knowledge and confidence in their own skills to support chronic pain self-management across several domains. Prescription data were used to measure changes in opioid and gabapentinoid prescribing at the practice across the 12-month intervention and 30-month follow-up period.

Results

Prescribing of opioid and gabapentinoid/pregabalin decreased substantially in the practice across the intervention period (c. 90% in high-dose opioid [p = .0118], and 15% gabapentin/pregabalin prescriptions, respectively), over a one-year period during the COVID-19 pandemic. Follow-up analysis showed 100% and c.50% reductions, respectively, in December 2022. The questionnaire data showed an increase in clinician confidence in skills to enable self-management over the intervention period, overall (p = .044) and, specifically across three of the five domains measured: supporting behavioural change (p = .028), supporting self-care (p = .008), and managing difficult consultations (p = .011).

Conclusion

The GOTT intervention program provided some initial evidence of a proof-of-concept for the implementation of a systematic non-pharmacological pain management skills and resources programme addressing lack of confidence in skills to introduce and support self-management and reduce use of strong opioids and gabapentinoids.

Assessing suicide risk in chronic pain management: a narrative review across drug classes

INTRODUCTION

Chronic pain presents a multifaceted challenge in clinical practice, necessitating a nuanced understanding of pharmacological interventions to optimize treatment outcomes. This review provides an outline of various pharmacological agents commonly used in chronic pain management and highlights their safety considerations, particularly regarding suicide risk.

AREAS COVERED

This review discusses the role of antidepressants, anticonvulsants, GABA receptor agonists, NMDA receptor antagonists, corticosteroids, cannabis and cannabinoids, bisphosphonates, calcitonin, and alpha-2 adrenergic receptor agonists in chronic pain management. It assesses their therapeutic benefits, potential for misuse, and psychiatric adverse effects, including the risk of suicide. Each pharmacological class is evaluated in terms of its efficacy, safety profile, and considerations for clinical practice. We searched peer-reviewed English literature on the topic using the MEDLINE database without time restrictions.

EXPERT OPINION

While pharmacological interventions offer promise in alleviating chronic pain, healthcare providers must carefully weigh their benefits against potential risks, including the risk of exacerbating psychiatric symptoms and increasing suicide risk. Individualized treatment approaches, close monitoring, and multidisciplinary collaboration are essential for optimizing pain management strategies while mitigating adverse effects. Ongoing research efforts are crucial for advancing our understanding of these pharmacological interventions and refining pain management practices.

The Association of Gabapentin Initiation with Cognitive and Behavioral Changes in Older Adults with Cognitive Impairment: A Retrospective Cohort Study

BACKGROUND

Although gabapentin has been increasingly prescribed to older adults, the relation between gabapentin initiation and longer-term neurocognitive changes is not well understood. Thus, this study aimed to examine the association of gabapentin initiation with cognitive and motor function decline in older adult participants with cognitive impairment.

METHODS

A retrospective cohort study was conducted using the National Alzheimer's Coordinating Center Uniform Data Set (2005-March 2023). Participants with cognitive impairment at the visit of gabapentin initiation (i.e., index visit) were included. Using the incidence density sampling method, up to nine non-users were randomly selected for each initiator. Cognitive decline over 1 year was defined as any increase in Clinical Dementia Rating global score (CDR®GLOB) or a 1-point increase in CDR® sum of boxes (CDR®SB). Functional status decline over 1 year was defined as at least a 3-point increase in the Functional Activities Questionnaire (FAQ) sum or a 0.3-point increase of mean of FAQ. Motoric decline over 1 year was defined as new clinician reports of gait disorder, falls, and slowness. To mitigate confounding and selection bias, joint stabilized inverse probability of treatment weights and censoring weights were used. Analyses compared index with index + 1 and index + 2 visits.

RESULTS

For the study of cognitive and functional status decline, we included 505 initiators (mean age [SD] 78.8 [7.4]; male = 45%) and 4545 non-users (79.2 [7.6]; 50.1%). For the study of motor decline, we included 353 initiators (78.3 [7.2]; 42.8%) and 3177 non-users (78.5 [7.4]; 48.1%). Gabapentin initiation was not statistically associated with decline on CDR®GLOB, CDR®SB, FAQ sum, or mean FAQ at the index + 1 or index + 2 visits. However, gabapentin initiation was significantly associated with increased odds of new falls at the index + 2 visit (odds ratio [95% confidence interval] 2.5 [1.3, 4.6]).

CONCLUSIONS

Over 1 or 2 years of follow-up, gabapentin initiation was not associated with decline in cognitive or functional status but was associated with increased odds of falling among research participants with cognitive impairment.

Gabapentinoids and Risk for Severe Exacerbation in Chronic Obstructive Pulmonary Disease : A Population-Based Cohort Study

BACKGROUND

North American and European health agencies recently warned of severe breathing problems associated with gabapentinoids, including in patients with chronic obstructive pulmonary disease (COPD), although supporting evidence is limited.

OBJECTIVE

To assess whether gabapentinoid use is associated with severe exacerbation in patients with COPD.

DESIGN

Time-conditional propensity score-matched, new-user cohort study.

SETTING

Health insurance databases from the Régie de l'assurance maladie du Québec in Canada.

PATIENTS

Within a base cohort of patients with COPD between 1994 and 2015, patients initiating gabapentinoid therapy with an indication (epilepsy, neuropathic pain, or other chronic pain) were matched 1:1 with nonusers on COPD duration, indication for gabapentinoids, age, sex, calendar year, and time-conditional propensity score.

MEASUREMENTS

The primary outcome was severe COPD exacerbation requiring hospitalization. Hazard ratios (HRs) associated with gabapentinoid use were estimated in subcohorts according to gabapentinoid indication and in the overall cohort.

RESULTS

The cohort included 356 gabapentinoid users with epilepsy, 9411 with neuropathic pain, and 3737 with other chronic pain, matched 1:1 to nonusers. Compared with nonuse, gabapentinoid use was associated with increased risk for severe COPD exacerbation across the indications of epilepsy (HR, 1.58 [95% CI, 1.08 to 2.30]), neuropathic pain (HR, 1.35 [CI, 1.24 to 1.48]), and other chronic pain (HR, 1.49 [CI, 1.27 to 1.73]) and overall (HR, 1.39 [CI, 1.29 to 1.50]).

LIMITATION

Residual confounding, including from lack of smoking information.

CONCLUSION

In patients with COPD, gabapentinoid use was associated with increased risk for severe exacerbation. This study supports the warnings from regulatory agencies and highlights the importance of considering this potential risk when prescribing gabapentin and pregabalin to patients with COPD.

PRIMARY FUNDING SOURCE

Canadian Institutes of Health Research and Canadian Lung Association.

Gabapentin Use Among Individuals Initiating Buprenorphine Treatment for Opioid Use Disorder

Importance

Gabapentin prescriptions have drastically increased in the US due to off-label prescribing in settings such as opioid use disorder (OUD) treatment to manage a range of comorbid conditions and withdrawal symptoms, despite a lack of evidence.

Objective

To assess the purpose and associated risks of off-label gabapentin use in OUD treatment.

Design, Setting, and Participants

This retrospective recurrent-event case-control study with a crossover design used administrative claims data from MarketScan Commercial and Multi-State Medicaid databases from January 1, 2006, to December 31, 2016. Individuals aged 12 to 64 years with an OUD diagnosis and filling buprenorphine prescriptions were included in the primary analysis conducted from July 1, 2022, through June 1, 2023. Unit of observation was the person-day.

Exposures

Days covered by filled gabapentin prescriptions.

Main Outcomes and Measures

Primary outcomes were receipt of gabapentin in the 90 days after initiation of buprenorphine treatment and drug-related poisoning. Drug-related poisonings were defined using codes from International Classification of Diseases, Ninth Revision, and International Statistical Classification of Diseases and Related Health Problems, Tenth Revision.

Results

A total of 109 407 patients were included in the analysis (mean [SD] age, 34.0 [11.2] years; 60 112 [54.9%] male). Among the 29 967 patients with Medicaid coverage, 299 (1.0%) were Hispanic, 1330 (4.4%) were non-Hispanic Black, 23 112 (77.1%) were non-Hispanic White, and 3399 (11.3%) were other. Gabapentin was significantly less likely to be prescribed to Black or Hispanic patients, and more likely to be prescribed to female patients, those with co-occurring substance use or mood disorders, and those with comorbid physical conditions such as neuropathic pain. Nearly one-third of persons who received gabapentin (4336 [31.1%]) had at least 1 drug-related poisoning after initiating buprenorphine treatment, compared with 13 856 (14.5%) among persons who did not receive gabapentin. Adjusted analyses showed that days of gabapentin use were not associated with hospitalization for drug-related poisoning (odds ratio, 0.98 [95% CI, 0.85-1.13]). Drug-related poisoning risks did not vary based on dosage.

Conclusions and Relevance

Gabapentin is prescribed in the context of a myriad of comorbid conditions. Even though persons receiving gabapentin are more likely to have admissions for drug-related poisoning, these data suggest that gabapentin is not associated with an increased risk of drug-related poisoning alongside buprenorphine in adjusted analyses. More data on the safety profile of gabapentin in OUD settings are needed.

Delirium following pregabalin discontinuation in an individual with no psychiatric or substance use history

We report about a man in his mid-50s who was prescribed pregabalin (150 mg/day) for neuropathic pain due to a herniated intervertebral disc. Four weeks later, he presented to the emergency room with symptoms consistent with delirium. After ruling out acute intoxication with a substance and neurological causes, collateral information from the family and review of his medical chart indicated potential discontinuation syndrome owing to pregabalin. Following the successful treatment and resolution of delirium, the patient revealed he had been consistently consuming pregabalin doses upwards of 2 g/day over the past 2 weeks, leading to the premature exhaustion of his prescription and an abrupt cessation. The case findings underscore the necessity for physicians to recognise the potential for pregabalin misuse and the associated withdrawal risks, including delirium.

Gabapentin: Clinical Use and Pharmacokinetics in Dogs, Cats, and Horses

Gabapentin is an anticonvulsant drug, which presents an established clinical efficacy in human patients for the management of refractory partial seizures, secondarily generalized tonic-clonic seizures, and for the control of chronic neuropathic pain. Gabapentin was synthesized as a structural analogue of the inhibitory neurotransmitter GABA, with GABA-mimetic effects, able to cross the blood-brain barrier. In veterinary medicine, is extra-label used in combination with other treatments to control seizures when other drugs are no longer effective or become toxic or for neuropathic pain treatment and anxiety. This review aimed to clarify gabapentin use and pharmacokinetic aspects to promote conscious use in dogs, cats, and horses. In dogs, gabapentin was beneficial in the treatment of epilepsy, as well as chronic, neuropathic, and post-operative pain, as well as anxiety. In cats, it showed efficacy in post-ovariohysterectomy-related pain and in anxiety management. In horses, gabapentin has been administered as an analgesic for chronic pain management. In conclusion, when used in combination with other drugs, gabapentin can be considered an interesting therapeutic option for the treatment of neuropathic diseases and analgesia in postoperative and chronic pain. However, despite its beneficial use in different clinical settings, further trials and pharmacokinetic studies are needed for the definition of an effective dosage regimen through proper pharmacokinetic/pharmacodynamic correlation in dogs, cats, and horses.

Effects of Gabapentinoids on Heroin-Induced Ventilatory Depression and Reversal by Naloxone

Despite an increasing prevalence of gabapentinoids (gabapentin and pregabalin) in opioid overdose deaths, little research has evaluated potentially harmful interactions between gabapentinoids and opioids. This study sought to determine the effects of gabapentinoids on the ventilatory depressive effects of heroin and their reversal by naloxone. Rats were given gabapentin, pregabalin, or saline prior to receiving increasing doses of heroin while ventilation was monitored using whole-body plethysmography. In some sessions naloxone was administered following the largest dose of heroin. The primary outcomes of this study were minute volume and Pause. Heroin dose-dependently reduced minute volume and increased Pause. Administration of naloxone dose-dependently reversed the effects of heroin on ventilation. Gabapentinoids did not alter the ventilatory depressive effects of heroin alone but reduced the potency of naloxone to reverse heroin-induced ventilatory depression. These preliminary findings emphasize the need for further research evaluating interactions between gabapentinoids and opioids related to substance misuse and overdose.

Trends and correlates of concurrent opioid and benzodiazepine and/or gabapentinoid use among Ontario nursing home residents

BACKGROUND

A concern with long-term opioid use is the increased risk arising when opioids are used concurrently with drugs that can potentiate their associated adverse effects. The drugs most often encountered are benzodiazepines (BZDs) and gabapentinoids. Our study objectives were to examine trends in the concurrent use of opioids and BZDs, or gabapentinoids, in a Canadian nursing home population over an 11-year period, and current resident-level correlates of this concurrent use.

METHODS

We conducted a population-based, repeated cross-sectional study among Ontario nursing home residents (>65 years) dispensed opioids between April 2009 and February 2020. For the last study year, we examined cross-sectional associations between resident characteristics and concurrent use of opioids with BZDs or gabapentinoids. Linked data on nursing home residents from clinical and health administrative databases was used. The yearly proportions of residents who were dispensed an opioid concurrently with a BZD or gabapentinoid were plotted with percent change derived from log-binomial regression models. Separate modified Poisson regression models estimated resident-level correlates of concurrent use of opioids with BZDs or gabapentinoids.

RESULTS

Over the study period, among residents dispensed an opioid there was a 53.2% relative decrease (30.7% to 14.4%) in concurrent BZD and a 505.4% relative increase (4.4% to 26.6%) in concurrent gabapentinoid use. In adjusted models, increasing age and worsening cognition were inversely associated with the concurrent use of both classes, but most other significantly related covariates were unique to each drug class (e.g., sex and anxiety disorders for BZD, pain severity and presence of pain-related conditions for gabapentinoids).

CONCLUSIONS

Co-administration of BZDs or gabapentinoids in Ontario nursing home residents dispensed opioids remains common, but the pattern of co-use has changed over time. Observed covariates of concurrent use in 2019/20 suggest distinct but overlapping resident populations requiring consideration of the relative risks versus benefits of this co-use and monitoring for potential harm.

Gabapentin utilization among older adults with different cognitive statuses enrolled in the National Alzheimer's Coordinating Center (2006-2019)

This study aimed to examine gabapentin utilization trends among older adults with different cognitive statuses and investigate concurrent medication use of potentially inappropriate medications. Data were extracted from the National Alzheimer's Coordinating Center Uniform Data Set (2006-2019). We estimated the yearly prevalence of gabapentin use, both overall and within subgroups defined by cognitive status (normal, mild cognitive impairment and dementia) and demographics (age and sex) for participants aged 65+. Additionally, we assessed the prevalence of concurrent use of gabapentin with opioids, combined opioids and benzodiazepine, antidepressant and antipsychotic. From 35 205 eligible older adults (mean age [SD]: 75.7 [7.0]; male: 43.1%), gabapentin use increased from 2006 to 2019 in both overall and every participant subgroup. About 10%-30% of gabapentin users reported to concurrently use opioids, and the concurrent use of gabapentin, opioid and benzodiazepine was up to 7.5% throughout the study period. The frequency of concurrent use with antipsychotics or antidepressants was higher in participants with dementia than those with normal cognition or those who were mildly cognitively impaired. Given increasing use among older adults, rigorous studies are needed to examine the safety of gabapentin in this population.

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.

Assessing the impact of a national clinical guideline for the management of chronic pain on opioid prescribing rates: a controlled interrupted time series analysis

BACKGROUND

Opioids can be effective analgesics, but long-term use may be associated with harms. In 2013, the first national, comprehensive, evidence-based pain management guideline was published, from the Scottish Intercollegiate Guideline Network (SIGN 136: Management of Chronic Pain) with key recommendations on analgesic prescribing. This study aimed to examine the potential impact on national opioid prescribing rates in Scotland.

METHODS

Trends in national and regional community opioid prescribing data for Scotland were analysed from quarter one (Q1) 2005 to Q2 2020. Interrupted time series regression examined the association of SIGN 136 publication with prescribing rates for opioid-containing drugs. Gabapentinoid prescribing was used as a comparison drug.

RESULTS

After a positive prescribing trend pre-publication, the timing of SIGN 136 publication was associated with a negative change in the trend of opioid prescribing rates (-2.82 items per 1000 population per quarter [PTPPQ]; P < 0.01). By Q2 2020, the relative reduction in the opioid prescribing rate was -20.67% (95% CI: -23.61, -17.76). This persisted after correcting for gabapentinoid prescribing and was mainly driven by the reduction in weak opioids, whereas strong opioid prescribing rates continued to rise. Gabapentinoid prescribing showed a significant rise in level (8.00 items per 1000 population; P = 0.01) and trend (0.27 items PTPPQ; P = 0.01) following SIGN 136 publication.

CONCLUSIONS

The publication of SIGN 136 was associated with a reduction in opioid prescribing rates. This suggests that changes in clinical policy through evidence-based national clinical guidelines may affect community opioid prescribing, though this may be partially replaced by gabapentinoids, and other factors may also contribute.

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.

Using Named Entity Recognition to Identify Substances Used in the Self-medication of Opioid Withdrawal: Natural Language Processing Study of Reddit Data

BACKGROUND

The cessation of opioid use can cause withdrawal symptoms. People often continue opioid misuse to avoid these symptoms. Many people who use opioids self-treat withdrawal symptoms with a range of substances. Little is known about the substances that people use or their effects.

OBJECTIVE

The aim of this study is to validate a methodology for identifying the substances used to treat symptoms of opioid withdrawal by a community of people who use opioids on the social media site Reddit.

METHODS

We developed a named entity recognition model to extract substances and effects from nearly 4 million comments from the r/opiates and r/OpiatesRecovery subreddits. To identify effects that are symptoms of opioid withdrawal and substances that are potential remedies for these symptoms, we deduplicated substances and effects by using clustering and manual review, then built a network of substance and effect co-occurrence. For each of the 16 effects identified as symptoms of opioid withdrawal in the Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, we identified the 10 most strongly associated substances. We classified these pairs as follows: substance is a Food and Drug Administration-approved or commonly used treatment for the symptom, substance is not often used to treat the symptom but could be potentially useful given its pharmacological profile, substance is a home or natural remedy for the symptom, substance can cause the symptom, or other or unclear. We developed the Withdrawal Remedy Explorer application to facilitate the further exploration of the data.

RESULTS

Our named entity recognition model achieved F1 scores of 92.1 (substances) and 81.7 (effects) on hold-out data. We identified 458 unique substances and 235 unique effects. Of the 130 potential remedies strongly associated with withdrawal symptoms, 54 (41.5%) were Food and Drug Administration-approved or commonly used treatments for the symptom, 17 (13.1%) were not often used to treat the symptom but could be potentially useful given their pharmacological profile, 13 (10%) were natural or home remedies, 7 (5.4%) were causes of the symptom, and 39 (30%) were other or unclear. We identified both potentially promising remedies (eg, gabapentin for body aches) and potentially common but harmful remedies (eg, antihistamines for restless leg syndrome).

CONCLUSIONS

Many of the withdrawal remedies discussed by Reddit users are either clinically proven or potentially useful. These results suggest that this methodology is a valid way to study the self-treatment behavior of a web-based community of people who use opioids. Our Withdrawal Remedy Explorer application provides a platform for using these data for pharmacovigilance, the identification of new treatments, and the better understanding of the needs of people undergoing opioid withdrawal. Furthermore, this approach could be applied to many other disease states for which people self-manage their symptoms and discuss their experiences on the web.

Gabapentin prevalence: clinical and forensic experience in St. Louis, Missouri, USA

Gabapentin (Neurontin) is an anti-epileptic drug that has had wide off-label prescription use since market release due to presumed negligible abuse potential. However, trends in drug misuse have demonstrated that gabapentin misuse is occurring, particularly in those with a history of opioid misuse. This is concerning, because although gabapentin has no direct ligand activity at opioid receptors, it does potentiate the analgesic effect of opioids, and concurrent use of gabapentin and opioids may increase the risk of respiratory depressive effects of opioids. This study investigates the incidence of gabapentin detected in urine samples collected for clinical drug screening purposes in a local hospital emergency department and in postmortem samples submitted by medical examiners in the St. Louis metropolitan area. The prevalence of gabapentin and co-detected drugs in both populations is contrasted, compared, and discussed. This study found that 30% of urine samples collected from patients with suspected drug intoxication presenting to SSM Health Saint Louis University Hospital, a quaternary care medical center, were positive for gabapentin, and nearly two thirds of those were also positive for oxycodone. Over a 6-month period, the incidence of gabapentin positive postmortem cases increased from 18% to 20%. Nearly all gabapentin positive postmortem cases were also positive for an opioid, the most significant being fentanyl, suggesting that gabapentin misuse may be due to its potentiating effect of opioid drug action. This study also highlights the limited utility of immunoassay-based urine drug screens.

Trends in prescribing pattern of opioid and benzodiazepine substitutes among Medicare part D beneficiaries from 2013 to 2018: a retrospective study

OBJECTIVE

Opioid and benzodiazepine co-prescribing is associated with a substantial increase in opioid overdose deaths. In this study, we examine the prescribing trends of substitutes of opioids and benzodiazepines alone or in combination, compared with opioids and benzodiazepines.

DESIGN

Retrospective cohort study.

SETTING

Data were collected using a 20% national sample of Medicare beneficiaries from 2013 to 2018.

PARTICIPANTS

4.1-4.3 million enrollees each year from 2013 to 2018.

INTERVENTION

None.

PRIMARY OUTCOME

We employ a generalised linear mixed models to calculate ORs for opioid use, benzodiazepine or Z-drug (benzos/Z-drugs) use, opioid/benzos/Z-drugs 30-day use, gabapentinoid use and (selective serotonin reuptake inhibitors (SSRI) and serotonin norepinephrine reuptake inhibitors (SNRIs)) use, adjusted for the repeated measure of patient. We then created two models to calculate the ORs for each year and comparing to 2013.

RESULTS

Opioid and benzos/Z-drugs use decreased by 2018 (aOR 0.626; 95% CI 0.622 to 0.630) comparing to 2013. We demonstrate a 36.3% and 9.9% increase rate of gabapentinoid and SSRI/SNRI use, respectively. Furthermore, combined gabapentinoid and SSRI/SNRI use increased in 2018 (aOR 1.422; 95% CI 1.412 to 1.431).

CONCLUSION

Little is known about the prescribing pattern and trend of opioid and benzodiazepine alternatives as analgesics. There is a modest shift from prescribing opioid and benzos/Z-drugs (alone or in combination) towards prescribing non-opioid analgesics-gabapentinoids with and without non-benzos/Z-drugs that are indicated for anxiety. It is unclear if this trend towards opioid/benzos/Z-drugs alternatives is associated with fewer drug overdose death, better control of pain and comorbid anxiety, and improved quality of life.

Outpatient Off-Label Gabapentin Use for Psychiatric Indications Among U.S. Adults, 2011-2016

OBJECTIVE

Gabapentin is widely prescribed off label in medical practice, including psychiatry. The U.S. Food and Drug Administration (FDA) warned of risks associated with gabapentin combined with central nervous system depressant (CNS-D) drugs, which are commonly prescribed in psychiatric treatment. This study examined off-label outpatient gabapentin use for psychiatric indications and concomitant CNS-D medication use.

METHODS

National Ambulatory Care Medical Survey data (2011-2016) were used to identify encounters involving gabapentin (gabapentin visits) for adults (ages ≥18) (N=5,732). FDA-approved uses and off-label psychiatric use indications were identified with ICD-9-CM and ICD-10-CM diagnosis codes. CNS-D drugs examined were opioids, benzodiazepines, sedatives-hypnotics, antidepressants, antipsychotics, first-generation antihistamines, and skeletal muscle relaxants. Concomitance was prescription of one or more CNS-D medications at the same visit. Visits were stratified by provider type and specialty.

RESULTS

Between 2011 and 2016, 2.8% of visits listed gabapentin prescriptions (weighted estimate of 129.6 million visits). A small proportion (<1%) listed an FDA-approved indication. Among off-label gabapentin visits, 5.3% listed a depressive disorder, 3.5% an anxiety disorder, and 1.8% bipolar disorder. Over 6 years, 58.4% of off-label gabapentin visits listed one or more concomitant CNS-D medications, most frequently antidepressants (24.3%), opioids (22.9%), and benzodiazepines (17.3%). Most gabapentin visits were with primary care providers (34.9%) and other provider specialties (i.e., not primary care, neurology, or psychiatry) (48.1%).

CONCLUSION

In this nationally representative sample, <1% of outpatient gabapentin use was for approved indications. High concomitant use of CNS-D drugs and off-label gabapentin for psychiatric diagnoses underlines the need for improved communication about safety.

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.

Gabapentinoid Pharmacology in the Context of Emerging Misuse Liability

This article will review the epidemiology and pharmacology of gabapentinoids (gabapentin and pregabalin) relevant to their emerging misuse potential and provide guidance for clinical and regulatory management. Gabapentinoids are γ-aminobutyric acid analogues that produce their therapeutic effects by inhibiting voltage-gated calcium channels and decreasing neurotransmitter release. Recently gabapentinoid prescribing and use have increased tremendously. Although traditionally thought to possess a favorable safety profile, gabapentinoid misuse has also risen significantly. Gabapentinoid misuse generally occurs in combination with other substances, most notably opioids, and may be for purposes of eliciting euphoric effects, enhancing the effects of other substances, or self-treating conditions such as withdrawal, pain, anxiety, or insomnia. Given its faster onset, increased bioavailability and potency, and nonsaturable absorption, pregabalin's pharmacokinetics theoretically enhance its misuse liability versus gabapentin. However, gabapentin can produce similar euphoric effects, and epidemiologic studies have identified higher rates of gabapentin misuse in the United States, likely because of greater availability and less regulated prescribing. Although adverse events of gabapentinoid-only ingestion are relatively benign, a growing body of evidence indicates that gabapentinoids significantly increase opioid-related morbidity and mortality when used concomitantly. In addition, significant withdrawal effects may occur on abrupt discontinuation. As a result of these trends, several US states have begun to further regulate gabapentinoid prescribing, reclassifying it as a controlled substance or mandating reporting to local prescription drug-monitoring programs. Although increased regulation of gabapentin prescribing may be warranted, harm reduction efforts and increased patient and provider education are necessary to mitigate this concerning gabapentinoid misuse trend.

Characterization of hospitalized patients who received naloxone while receiving opioids with or without gabapentinoids

Introduction

Gabapentin and pregabalin (gabapentinoids) can be given with opioids for opioid-sparing and adjuvant analgesic effects. In the context of certain comorbidities and high dosages, coadministration of these agents can lead to respiratory depression or oversedation, necessitating naloxone administration.

Methods

A retrospective chart review from January 2015 to December 2017 was conducted to include patients who received naloxone and opioids with or without gabapentinoids. Exclusion criteria included pregnancy or having received naloxone in the emergency department, intensive care, or pediatrics units. The primary outcome was to characterize differences between groups regarding comorbidities, history of renal or hepatic dysfunction, history of SUD, opioid tolerance, initiation and dose appropriateness of gabapentinoids, and dose intensity of gabapentinoids and opioids. Secondary outcomes were concomitant CNS depressant use and naloxone episodes for documented respiratory depression.

Results

Of 126 patients who met inclusion criteria, 36 received opioids and gabapentinoids (gabapentinoid group) and 90 received opioids alone (nongabapentinoid group). There were 136 naloxone episodes between the 2 groups. More than 50% of the naloxone episodes in the gabapentinoid group involved opioids of at least 90 oral morphine mg equivalents. Respiratory depression accounted for 39% and 15.8% of the naloxone episodes in the gabapentinoid and nongabapentinoid groups, respectively.

Discussion

There may be increased naloxone episodes among patients receiving opioids and gabapentinoids. Future studies are needed to evaluate the incremental risk of respiratory depression and oversedation as it pertains to concomitant medication administration and patient-specific factors.

Assessment of gabapentin misuse using prescription drug monitoring program data

BACKGROUND

Gabapentin is an anticonvulsant medication with potential misuse reported in case reports and population studies, highlighting the need to reexamine its abuse liability. The purpose of this study was to describe gabapentin dispensing patterns and assess potential misuse. Methods: We used data from Ohio's Prescription Drug Monitoring Program (PDMP) from December 1, 2016 to March 31, 2017 and restricted the population to adults who filled at least one gabapentin prescription (N = 379,372). Gabapentin dispensing patterns are described and multiple strategies were used to assess potential misuse, including Lorenz-1 curve analysis. Supratherapeutic dosing, number of prescribers and number of pharmacies used were compared for individuals who were co-dispensed medications for opioid use disorder (MOUD) and those who were not. Results: More than one million gabapentin prescriptions were dispensed during the 4-month period, with a mean dose of 1103.8 mg. While few individuals received supratherapeutic dosing, exceptionally high doses were observed. Half of the individuals (50.9%) were co-dispensed gabapentin and opioids. The Lorenz-1 value for gabapentin (5.5%) did not exceed the threshold for misuse potential. Individuals co-dispensed MOUD were more likely to have supratherapeutic dosing; however, they had a lower Lorenz-1 value compared to individuals not co-dispensed MOUD. Conclusions: Among Ohio residents dispensed gabapentin, there was no evidence of misuse using PDMP data based on the Lorenz-1 value, yet supratherapeutic dosing of gabapentin was observed and was associated with OUD. New strategies may be needed to identify the non-medical use of gabapentin.

Stress Allostasis in Substance Use Disorders: Promise, Progress, and Emerging Priorities in Clinical Research

Clinicians and researchers alike have long believed that stressors play a pivotal etiologic role in risk, maintenance, and/or relapse of alcohol and other substance use disorders (SUDs). Numerous seminal and contemporary theories on SUD etiology posit that stressors may motivate drug use and that individuals who use drugs chronically may display altered responses to stressors. We use foundational basic stress biology research as a lens through which to evaluate critically the available evidence to support these key stress-SUD theses in humans. Additionally, we examine the field's success to date in targeting stressors and stress allostasis in treatments for SUDs. We conclude with our recommendations for how best to advance our understanding of the relationship between stressors and drug use, and we discuss clinical implications for treatment development.

Trends in Gabapentin Prescribing in a Commercially Insured U.S. Adult Population, 2009-2016

BACKGROUND

Gabapentin is prescribed for a variety of conditions and is often used off label. It is important to understand the prevalence of gabapentin prescribing and the characteristics of individuals who are prescribed gabapentin, given increasing concern regarding its potential for misuse.

OBJECTIVES

To (a) examine state- and region-level prevalence and trends in gabapentin prescribing from 2009 to 2016 and (b) characterize demographic and clinical characteristics of individuals prescribed gabapentin in a nationwide population of commercially insured adults.

METHODS

This retrospective, longitudinal study examined trends in gabapentin prescribing from 2009 to 2016. The study population included individuals aged 18-64 years who were enrolled in a commercial insurance plan at any point from 2009 to 2016. Individuals who were prescribed gabapentin were defined as beneficiaries with at least 1 gabapentin prescription claim in a calendar year (CY). A cross-sectional descriptive analysis was performed to examine differences in demographic and clinical characteristics of individuals prescribed or not prescribed gabapentin in CY 2016.

RESULTS

The prevalence of gabapentin prescribing nearly doubled from 2009 to 2016. During this time, gabapentin prescribing increased in every state (range: 44%-179%). State-specific prevalence rates in 2016 varied from 12.7 to 43.9 per 1,000 beneficiaries. Overall, 2.7% of beneficiaries filled ≥ 1 gabapentin prescription in 2016. Individuals prescribed gabapentin were more likely to fill opioid prescriptions (60.8% vs. 16.5%, P < 0.01); reside in the South (53.7% vs. 47%, P < 0.01); be female (62.5% vs. 52.3%, P < 0.01); and be aged 55-64 years (41.7% vs. 21.2%, P < 0.01) compared with the comparator. Individuals who were prescribed gabapentin also had significantly higher rates of seizure disorders, neuropathic pain, mental health disorders, substance use disorders, and diabetes.

CONCLUSIONS

The prevalence of gabapentin prescribing among a U.S. privately insured population has increased steadily in recent years. Additional research should examine coprescribing of gabapentin in the context of the opioid epidemic.

DISCLOSURES

The project described in this study was supported by the NIH National Center for Advancing Translational Sciences through grant number UL1TR001998. This study was also partially supported by grant number 2017-PM-BX-K026 (Data-Driven Responses to Prescription Drug Misuse in Kentucky) awarded by the Bureau of Justice Assistance. Viewpoints or opinions in this document are those of the authors and do not necessarily represent the official position or policies of the U.S. Department of Justice or the official views of the NIH. The authors do not have any conflicts of interest to report. Portions of this study have been previously presented in poster presentations at the 2019 Academy Health Annual Research Meeting; June 2-4, 2019; Washington, DC, and the 2019 University of Kentucky Substance Use Research Day; March 3, 2019; Lexington, KY.

Factors Associated with Gabapentin Misuse among People Who Inject Drugs in Appalachian Kentucky

Gabapentin is misused to potentiate the euphoric effects of opioids, self-treat physical pain, and moderate opioid withdrawal symptoms. Because examinations of gabapentin misuse among people who inject drugs (PWID) are scant, the aim of this study is to identify factors associated with gabapentin misuse among this population. Methods: Data are drawn from a study examining the uptake of syringe service programs (SSPs) in Appalachian Kentucky. The sample includes 324 PWID who were age 18 and over and reported past month drug injection. Logistic regression models were constructed to examine recent (past 90 days) gabapentin misuse. Results: Participants are female (50.0%); Hispanic (2.2%), Black (1.5%), white (90.7%), and other race/ethnicity (4.6%). Mean age is 37. Participants reporting gabapentin misuse had higher odds of reporting (mis)use of marijuana, cocaine, methamphetamine, prescription opioids, benzodiazepines, prescription stimulants, fentanyl, and buprenorphine (p < .042); severe substance use disorder (p < .000); and recent physical pain (p < .003). In multivariable models, findings related to misuse of prescription opioids and buprenorphine; severe substance use disorder; and recent physical pain or discomfort, remained significant (p < .042). Conclusions: This is one of the first studies to examine gabapentin misuse among PWID. It is possible that individuals reporting recent gabapentin misuse are attempting to self-treat physical pain when healthcare is limited. Gabapentin may also be misused to achieve desired central nervous system effects and to potentiate opioid highs. Syringe service programs can educate PWID about the potential dangers of polydrug use involving gabapentin and to connect PWID with needed healthcare services.

Prescribed and non-prescribed gabapentin use among persons seeking inpatient opioid detoxification

BACKGROUND

Persons with opioid use disorder (OUD) are at increased risk for gabapentin misuse. Rising rates of concomitant gabapentin-opioid use in the U.S. are concerning given heightened risk of fatal overdose.

OBJECTIVE

To examine predictors of ever using gabapentin among persons seeking treatment for opioid use and to assess if reasons for gabapentin use differed by gender and how gabapentin was procured (prescribed, non-prescribed, or both).

METHOD

Persons with OUD were recruited from a managed withdrawal program. t-Tests and Pearson χ2 tests of independence were used to compare reasons for gabapentin use by gender and source of acquisition.

RESULTS

Among participants (n = 401; 69.1% male, 84.5% White, 86.8% sought treatment for heroin use, 90.0% insured), female gender, higher educational attainment, injection drug use (IDU), history of overdose, and chronic pain were associated with gabapentin use. Overall, reasons for use were similar across genders among those reporting a history of gabapentin use (65.8%), although males were more likely to use to get high than females. About half (47.0%) reported only using gabapentin that was not prescribed, 20.5% had only used prescribed gabapentin, and 32.5% reported prescribed and non-prescribed use. Persons prescribed gabapentin were most likely to use it to control pain (81.5%); for those using diverted gabapentin only and those reporting both prescribed and non-prescribed gabapentin use, the most common reasons for intake were to: get high, increase effects of heroin, substitute for opioids, and help with opioid withdrawal.

CONCLUSIONS

In this sample of people with OUD entering inpatient detoxification program, a majority reported a history of gabapentin use, with most using diverted gabapentin. The range of reasons for gabapentin use point to the need to better understand why co-use is common.

Intranasal Pregabalin Administration: A Review of the Literature and the Worldwide Spontaneous Reporting System of Adverse Drug Reactions

Background: It is repeatedly reported that pregabalin (PRG) and gabapentin feature a potential for abuse/misuse, predominantly in patients with former or active substance use disorder. The most common route of use is oral, though reports of sublingual, intravenous, rectal, and smoking administration also exist. A narrative review was performed to provide an overview of current knowledge about nasal PRG use. Methods: A narrative review of the currently available literature of nasal PRG use was performed by searching the MEDLINE, EMBASE, and Web of Science databases. The abstracts and articles identified were reviewed and examined for relevance. Secondly, a request regarding reports of cases of nasal PRG administration was performed in the worldwide spontaneous reporting system of adverse drug reactions of the European Medicines Agency (EMA, EudraVigilance database). Results: The literature search resulted in two reported cases of nasal PRG use. In the analysis of the EMA-database, 13 reported cases of nasal PRG use (11 male (two not specified), mean age of users = 34.2 years (four not specified)) were found. In two cases fatalities occurred related to PRG nasal use. Conclusions: Even if only little evidence can be found in current literature, the potential for misuse/abuse of PRG via nasal route might be of particular importance in the near future in PRG users who misuse it. Physicians should be aware of these alternative routes of administration.

A case of gabapentin overdose induced rhabdomyolysis requiring renal replacement therapy

We report a rare case with gabapentin overdose that caused severe rhabdomyolysis and acute tubular necrosis which required renal replacement therapy. A better awareness of its adverse effect and a close follow-up of laboratory tests are recommended. Prescribers should also be aware of high-risk population and monitor for signs of abuse.

Gabapentin Use for Hospitalized Neonates

BACKGROUND

Despite some clinician advocacy for the use of gabapentin to treat neonatal irritability of presumed neurological origin, the extent of gabapentin administration to hospitalized neonates is unknown. We aimed to identify trends in gabapentin utilization among infants hospitalized in neonatal intensive care units (NICUs) across the United States and to evaluate the associations between clinical diagnoses and gabapentin treatment.

METHODS

We analyzed neonates admitted to the NICU using the Pediatric Health Information System (2005 to 2016) to measure treatment timing, duration, and frequency. We used modified Poisson regression with a robust between-cluster variance estimator to calculate a probability (adjusted relative risk) for gabapentin administration.

RESULTS

Of 278,403 neonates, 374 were administered gabapentin (0.13%). The median treatment duration was 16 days (25th to 75th percentile: 8; 40). Gabapentin use increased from 0% in 2005 to 0.39% in 2016. Treatment was prescribed to neonates at 31 of 48 studied hospitals; 73% of total treated infants localized to five neonatal intensive care units. Term (0.16%) and ≤28 weeks' gestation preterm infants (0.22%) were most likely to receive gabapentin. Varying by gestational age, a diagnosis of chromosomal abnormalities, severe bronchopulmonary dysplasia, hemorrhagic stroke, and neonatal abstinence syndrome were associated with higher treatment with gabapentin. The majority (88.8%) of treated infants did not have a seizure diagnosis.

CONCLUSION

Gabapentin use in NICU in the United States increased in recent years and varies markedly between institutions. Term infants, ≤28 weeks' gestation preterm infants, and neonates with chronic genetic, neurological, and gastrointestinal diagnoses were more likely to receive gabapentin.