Abuse and diversion of gabapentin among nonmedical prescription opioid users in Appalachian Kentucky

Characteristics of US Medicare Beneficiaries with Chronic Cough vs. Non-Chronic Cough: 2011-2018

Background: Chronic cough (CC), characterized as a cough lasting >8 weeks, is a common multi-factorial syndrome in the community, especially in older adults. Methods: Using a pre-existing algorithm to identify patients with CC within the 2011-2018 Medicare beneficiaries, we examined trends in gabapentinoid use through repeated cross-sectional analyses and identified distinct utilization trajectories using group-based trajectory modeling (GBTM) in a retrospective cohort study. Individuals without CC but with any respiratory conditions related to cough served as a comparator group. Results: Among patients with CC, gabapentinoid use increased from 18.6% in 2011 to 24.1% in 2018 (p = 0.002), with a similar upward trend observed in the non-CC cohort but with overall lower usage (14.7% to 18.4%; p < 0.001). Patients with CC had significantly higher burdens of respiratory and non-respiratory comorbidities, as well as greater healthcare service and medication use compared to the non-CC cohort. The GBTM analyses identified three distinct gabapentinoid utilization trajectories for CC and non-CC patients: no use (77.3% vs. 84.5%), low use (13.9% vs. 10.3%), and high use (8.8% vs. 5.2%). Conclusions: Future studies are needed to evaluate the safety and effectiveness of gabapentinoid use in patients with refractory or unexplained CC in real-world settings.

Patterns of Cough Medication Prescribing among Patients with Chronic Cough in Florida: 2012-2021

Among patients with chronic cough (CC) in the 2012-2021 statewide OneFlorida Clinical Research Consortium database, we examined trends in cough medication (CM) prescribing prevalence over time in repeated cross-sectional analyses and identified distinct CM utilization trajectories using group-based trajectory modeling (GBTM) in a retrospective cohort study. Among eligible adults (≥18 years) without cancer/benign respiratory tumor diagnoses, we identified CC patients and non-CC patients with any cough-related diagnosis. In the GBTM analysis, we calculated the number of monthly prescriptions for any CMs (excluding gabapentinoids) during the 12 months from the first qualifying cough event to identify distinct utilization trajectories. From 2012 to 2021, benzonatate (9.6% to 26.1%), dextromethorphan (5.2% to 8.6%), and gabapentinoid (5.3% to 14.4%) use increased among CC patients, while opioid antitussive use increased from 2012 to 2015 and decreased thereafter (8.4% in 2012, 14.7% in 2015, 6.7% in 2021; all p < 0.001). Of 15,566 CC patients and 655,250 non-CC patients identified in the GBTM analysis, CC patients had substantial burdens of respiratory/non-respiratory comorbidities and healthcare service and concomitant medication use compared to non-CC patients. Among CC patients, GBTM identified three distinct CM utilization trajectories: (1) no CM use (n = 11,222; 72.1%); (2) declining CM use (n = 4105; 26.4%); and (3) chronic CM use (n = 239; 1.5%). CC patients in Florida had limited CM use with increasing trends in use of benzonatate, dextromethorphan, and gabapentinoids and a decreasing trend in opioid antitussive use. CC patients, particularly with chronic prescription CM use, experienced substantial disease burden.

Trends in overdose deaths involving gabapentinoids and Z-drugs in the United States

INTRODUCTION

As policies have been implemented to limit access to prescription opioids, other drugs have been prescribed off-label, sometimes concurrently with opioids, to manage pain. There are concerns about the use of gabapentinoids and "Z-drugs" with opioids. As the opioid crisis transitions to illicit opioids and polysubstance use, little work quantifies the concurrent involvement of non-opioid prescription drugs and illicit opioids in overdose deaths.

METHODS

Data from the census of deaths in the United States for 1999-2020 were used to understand trends in deaths involving gabapentinoids/Z-drugs and opioid co-involvement. These trends were studied overall and by sex, race, age, and education.

RESULTS

Per capita overdose deaths involving gabapentinoids/Z-drugs increased almost continuously since 1999, averaging 15.8% annual growth. This rate increased to 32% in 2020, primarily due to overdoses involving synthetic opioids. Women typically had higher rates of overdose deaths involving both opioids and gabapentinoids/Z-drugs, though this disparity disappeared in 2020. White Americans and American Indians/Alaskan Natives historically had higher rates than other racial groups; however, Black Americans experienced over 60% annual growth in recent years. Low education groups have been disproportionately impacted. The age incidence tends to be older than overdoses involving opioids more generally.

CONCLUSION

Overdose deaths involving opioids and gabapentinoids/Z-drugs have tended to disproportionately affect women and older age groups compared to all opioid-involved overdoses. As deaths involving synthetic opioids likely reflect use of illicitly-obtained opioids, there may be less of a role for policies targeting the concurrent prescribing of gabapentinoids/Z-drugs with opioids to reduce these deaths.

Pharmacist, prescriber, and drug policy expert opinions on gabapentinoid misuse

BACKGROUND

Gabapentinoids (gabapentin and pregabalin) are widely used in clinical practice, but recent evidence indicates that they carry an increased risk of misuse. As healthcare professionals (HCPs) and policymakers plan different strategies to promote harm reduction, it is important to understand different interested party viewpoints.

OBJECTIVE

To explore prescriber, pharmacist, and drug policy expert (DPE) awareness, opinions, and experiences regarding gabapentinoid misuse.

METHODS

A qualitative description study using individual semi-structured virtual interviews was conducted between February and April 2021. Participants included prescribers (physicians, physician assistants [PA], or nurse practitioners [NP]) and pharmacists practicing in outpatient, ambulatory, or community-based healthcare settings; individuals with relevant drug policy expertise were also included. Qualtrics (Provo, Utah) and Zoom (San Jose, California) were used to facilitate quantitative (for initial screening and participant characteristics) and qualitative (interview) data collection. Data were coded and organized into themes in NVivo (QSR International; Burlington, Massachusetts) using thematic analysis steps.

RESULTS

A total of 43 individuals participated in this study, including 16 (37.2%) pharmacists, 13 (30.2%) physicians, seven (16.3%) NPs, four (9.3%) DPEs, two (4.7%) pharmacist/DPEs, and one (2.3%) PA. Results were organized along four themes: (1) challenges/opportunities in gabapentinoid use; (2) gabapentinoid misuse awareness; (3) solutions to gabapentinoid misuse and (4) contributing barriers in pain management. Participants invoked different opinions in their consideration of gabapentinoid misuse, including the desire for harm reduction, the limitations of the current healthcare and insurance system, the lack of options for pain and substance use disorder treatment, and the influence of patient expectations.

CONCLUSIONS

Gabapentinoid misuse was commonly framed in comparative fashion to ongoing concerns with opioids, and proposed solutions often focused less on regulatory control and more toward patient and HCP education and an overhaul of the health system approach to substance use and healthcare overall.

Effect of amoxicillin/clavulanic acid in attenuating pregabalin-induced condition place preference

Substance abuse is a worldwide problem with serious repercussions for patients and the communities where they live. Pregabalin (Lyrica), is a medication commonly used to treat neuropathic pain. Like other analgesic medications there has been concern about pregabalin abuse and misuse. Although it was initially suggested that pregabalin, like other gabapentinoids, has limited abuse liability, questions still remain concerning this inquiry. Changes in glutamate system homeostasis are a hallmark of adaptations underlying drug dependence, including down-regulation of the glutamate transporter 1 (GLT-1; SLC1A2) and the cystine/glutamate antiporter (xCT; SLC7A11). In this study, it was found that pregabalin (90 mg/kg) produces a conditioned place preference (CPP), indicative of reinforcing effects that suggest a potential for abuse liability. Moreover, like other drugs of abuse, pregabalin also produced alterations in glutamate homeostasis, reducing the mRNA expression of Slc1a2 and Slc7a11 in the nucleus accumbens (NAc) and medial prefrontal cortex (mPFC). Amoxicillin clavulanic acid, a β-lactam antibiotic, blocked the reinforcing effects of pregabalin and normalized glutamate homeostasis. These results suggest that pregabalin has abuse potential that should be examined more critically, and that, moreover, the mechanisms underlying these effects are similar to those of other drugs of abuse, such as heroin and cocaine. Additionally, these results support previous findings showing normalization of glutamate homeostasis by β-lactam drugs that provides a novel potential therapeutic approach for the treatment of drug abuse and dependence.

Application of gabapentinoids and novel compounds for the treatment of benzodiazepine dependence: the glutamatergic model

BACKGROUND

Current approaches for managing benzodiazepine (BZD) withdrawal symptoms are daunting for clinicians and patients, warranting novel treatment and management strategies. This review discusses the pharmacodynamic properties of BZDs, gabapentinoids (GBPs), endozepines, and novel GABAergic compounds associated with potential clinical benefits for BZD-dependent patients. The objective of this study was to review the complex neuromolecular changes occurring within the GABAergic and glutamatergic systems during the BZD tolerance and withdrawal periods while also examining the mechanism by which GBPs and alternative pharmacological therapies may attenuate withdrawal symptoms.

METHODS AND RESULTS

An elaborative literature review was conducted using multiple platforms, including the National Center for Biotechnology (NCBI), AccessMedicine, ScienceDirect, pharmacology textbooks, clinical trial data, case reports, and PubChem. Our literature analysis revealed that many distinctive neuroadaptive mechanisms are involved in the GABAergic and glutamatergic systems during BZD tolerance and withdrawal. Based on this data, we hypothesize that GBPs may attenuate the overactive glutamatergic system during the withdrawal phase by an indirect presynaptic glutamatergic mechanism dependent on the α₂δ₁ subunit expression.

CONCLUSIONS

GBPs may benefit individuals undergoing BZD withdrawal, given that the α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor current significantly increases during abrupt BZD withdrawal in animal studies. This may be a conceivable explanation for the effectiveness of GBPs in treating both alcohol withdrawal symptoms and BZD withdrawal symptoms in some recent studies. Finally, natural and synthetic GABAergic compounds with unique pharmacodynamic properties were found to exert potential clinical benefits as BZD substitutes in animal studies, though human studies are lacking.

Association of State-Imposed Restrictions on Gabapentin with Changes in Prescribing in Medicare

BACKGROUND

Between August 2016 and July 2018, three states classified gabapentin as a Schedule V drug and nine states implemented prescription drug monitoring program (PDMP) regulation for gabapentin. It is highly unusual for states to take drug regulation into their own hands. The impact of these changes on gabapentin prescribing is unclear.

OBJECTIVE

To determine the effect of state-imposed regulation on gabapentin prescribing for Medicare Part D enrollees from 2013 to 2018.

DESIGN

Population-based difference-in-difference(DID) analysis study utilizing the Medicare Part D Prescriber Public Use File.

PARTICIPANTS

All eligible Medicare Part D prescribers excluding those outside of the fifty states and the District of Columbia were included in our analysis. Prescriber data and key sociodemographic variables were organized by state and year. States with a gabapentin schedule change or PDMP regulation enacted before 2019 were included in the intervention group. For the Schedule V DID analysis, a control group of the ten highest opioid-prescribing states was used.

INTERVENTIONS

States with gabapentin schedule changes or PDMP regulation before January 1, 2019, were included and compared to control states that did not implement these policies.

MAIN MEASURES

Total days' supply of gabapentin per enrollee per year was the primary outcome variable.

KEY RESULTS

The mean total days' supply of gabapentin per enrollee increased 41% from 19.71 to 27.81 total days' supply per enrollee per year between 2013 and 2018. After adjustment, Schedule V gabapentin regulation resulted in a reduction of 8.37 total days of gabapentin prescribed per enrollee (95% confidence interval of - 10.34 to - 6.39). In contrast, PDMP regulation resulted in a reduction of 1.01 total days of gabapentin prescribed per enrollee (95% confidence interval of - 1.74 to - 0.29).

CONCLUSIONS

Classifying gabapentin as a Schedule V drug results in substantial reduction in total days prescribed whereas PDMP regulation results in modest reduction.

Psychiatric Uses of Gabapentin

OBJECTIVE

This article reviews evidence-based psychiatric uses of gabapentin, along with associated risks.

METHOD OF RESEARCH

An extensive literature review was conducted, primarily of articles searchable in PubMed, relating to psychiatric uses, safety, and adverse effects of gabapentin.

RESULTS

Evidence supports gabapentin as a treatment for alcohol withdrawal and alcohol use disorder. There is sufficient evidence to consider gabapentin as a third-line treatment for social anxiety disorder and severe panic disorder. Evidence does not support the use of gabapentin for bipolar disorder, major depressive disorder (MDD), posttraumatic stress disorder (PTSD), obsessive compulsive disorder (OCD), stimulant use disorder, or opioid withdrawal. Risks of gabapentin use are highest among those with a history of a substance use disorder and those concurrently taking opioids.

CONCLUSION

While gabapentin has a place in psychiatry for a select few indications, the literature does not support its use for many studied diagnoses.

Evaluation of Cough Medication Use Patterns in Ambulatory Care Settings in the United States: 2003-2018

Using 2003−2018 National Ambulatory Medical Care Survey data for office-based visits and 2003−2018 National Hospital Ambulatory Medical Care Survey data for emergency department (ED) visits, we conducted cross-sectional analyses to examine cough medication (CM) use trends in the United States (US) ambulatory care settings. We included adult (≥18 years) patient visits with respiratory-infection-related or non-infection-related cough as reason-for-visit or diagnosis without malignant cancer or benign respiratory tumor diagnoses. Using multivariable logistic regressions, we examined opioid antitussive, benzonatate, dextromethorphan-containing antitussive, and gabapentinoid use trends. From 2003−2005 to 2015−2018, opioid antitussive use decreased in office-based visits (8.8% to 6.4%, Ptrend = 0.03) but remained stable in ED visits (6.3% to 5.9%, Ptrend = 0.99). In both settings, hydrocodone-containing antitussive use declined over 50%. Benzonatate use more than tripled (office-based:1.6% to 4.8%; ED:1.5% to 8.0%; both Ptrend < 0.001). Dextromethorphan-containing antitussive use increased in ED visits (1.8% to 2.6%, Ptrend = 0.003) but stayed unchanged in office-based visits (3.8% to 2.7%; Ptrend = 0.60). Gabapentinoid use doubled in office-based visits (1.1% in 2006−2008 to 2.4% in 2015−2018, Ptrend < 0.001) but was negligible in ED visits. In US office-based and ED ambulatory care settings, hydrocodone-containing antitussive use substantially declined from 2003 to 2018, while benzonatate use more than tripled, and dextromethorphan-containing antitussive and gabapentinoid use remained low (<3%).

An algorithm to identify gabapentin misuse and/or abuse in administrative claims data

BACKGROUND

Despite gabapentin's misuse and abuse potential and associated adverse events, few algorithms are available to detect gabapentin misuse and/or abuse in claims data. This study aims to develop an algorithm to identify gabapentin misuse and/or abuse in administrative claims data.

METHODS

We developed an algorithm to identify gabapentin misuse and/or abuse over a 12-month period based on input from 21 clinical experts. We implemented the algorithm among 334,128 patients with at least one dispensed prescription of gabapentin between December 1, 2017 and December 1, 2018 in the IBM® MarketScan® Research Databases. We described the characteristics of patients who potentially misused and/or abused gabapentin and assessed factors associated with misuse and/or abuse using logistic regression.

RESULTS

The algorithm identified 17.6% of patients with gabapentin use who potentially misused and/or abused gabapentin. Factors associated with potential gabapentin misuse and/or abuse included men (adjusted odds ratio (aOR): 1.08; 95% confidence interval (CI): 1.06-1.10), comorbid conditions (e.g., drug and alcohol dependence (aOR: 1.31; 95% CI: 1.24-1.39); bipolar disorder (aOR: 1.34; 95% CI: 1.27-1.41)), and medication use (e.g., opioids (aOR: 1.23; 95% CI: 1.20-1.26), muscle relaxants (aOR: 1.24; 95% CI: 1.21-1.27), or serotonin-norepinephrine reuptake inhibitors (aOR: 1.33; 95% CI: 1.29-1.36)).

CONCLUSIONS

Approximately one in six patients with gabapentin use potentially misused and/or abused gabapentin in a large commercial claims database. Multiple comorbidities and drug use were associated with gabapentin misuse and/or abuse. Monitoring requirements and individualized safety measures should be put in place for patients at elevated risks of gabapentin misuse and/or abuse.

How prevalent and severe is addiction on GABAmimetic drugs in an elderly German general hospital population? Focus on gabapentinoids, benzodiazepines, and z-hypnotic drugs

OBJECTIVE

Gabapentinoids (GPT) are reported to be increasingly misused by opioid- and polydrug-users, but the addictive potential of GPT outside of these populations remains understudied. Investigations comparing GPT abuse and dependence liability to that of other commonly prescribed Central Nervous System-acting medications are therefore warranted. We provide a comparison of GPT-abuse/dependence to that of other GABAmimetics within an elderly population.

DESIGN

DSM-IV-TR-based data (previously prospectively collected by SKID-I-interview) from a random sample of elderly patients admitted to a metropolitan German general hospital were reviewed. The prevalence and severity of GPT, benzodiazepine (BDZ), and z-hypnotic drug (ZD)-abuse and -dependence were compared, stratified also by mono-substance (no concurrent current or previous substance use) and de novo-substance (first)-abuse and -dependence states.

RESULTS

Among 400 patients (75 ± 6.4 years old; 63% females), neither current nor past abuse of BDZ, ZD or GPT, nor other illicit substances was observed. Dependence upon BDZ, ZD or GPT was observed among 55 (13.75%) individuals. The related lifetime/12-month prevalence-rates were: dependence condition (BDZ: 7%/2.45%; ZD: 4.25%/4.25%; GPT: 2.75/2.5%); mono-dependence condition (BDZ: 2.25%/0.75%; ZD: 1%/1%, GPT: 0%/0%); de novo-dependence condition (BDZ: 2.75%/1.75%; ZD: 1%/1%, GPT: 0.5%/0.5%). Opioid analgesic-dependence (N = 43/400) was significantly more frequently linked with BDZ than with GPT (p < 0.01) [Correction added on 29 December 2021, after first online publication: In the sentence 'Opioid analgesic-dependence…', the term 'and ZD' has been deleted]. For all three GABAmimetic classes, most mono- and de novo-dependence states were mild-to-moderate and lasted 2-6 years (median).

CONCLUSION

GABAmimetic-dependence was usually mixed with other substance-dependences. Every third to fourth instance of BDZ- or ZD-dependence was a mono-dependence condition, while a pure GPT-dependence was absent in this elderly (and illicit substance-naïve) population.

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

INTRODUCTION

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

METHODS

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

RESULTS

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

CONCLUSIONS

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

Development and validation of a rapid liquid chromatography/tandem mass spectrometry method to quantitate gabapentin and buprenorphine in human serum

RATIONALE

Gabapentin has shown initial promise as an opioid-sparing medication in pain patients as well as a treatment for opioid withdrawal and liquid chriomatography/tandem mass spectrometry (LC/MS/MS) is often used for clinical monitoring. Despite reports of validated tandem mass spectrometric methods for the determination of gabapentin and buprenorphine, mechanisms for the collision-induced fragmentation have not been adequetely described.

METHODS

A rapid analytical method has been developed to determine gabapentinoid, gabapentin, and the partial opioid agonist, buprenorphine, in 20 μL of human serum using LC/MS/MS with a chromatographic run time of 2 min. A simplified sample cleanup procedure using methanol precipitation of serum proteins/lipids followed by evaporation and reconstitution in mobile phase was demonstrated. Gabapentin and buprenorphine were detected following positive ion electrospray ionization using multiple-reaction monitoring. The internal standard approach was used for quantitation with labeled gabapentin-D10 and buprenorphine-D4 serving as internal standards. Using organic reaction principals and stable isotope labels, collision-induced fragmentation mechanisms for both gabapentin and buprenorphine are proposed. The method was validated according to the FDA Guidance for Industry - Bioanalytical Method Validation.

RESULTS

Accuracy was demonstrated by error values ≤15% for buprenorphine and ≤6% for gabapentin. The inter-day precision was ≤4.88% and 15.59% for gabapentin and buprenorphine and the intra-day precision was ≤5.20% and 11.65% for gabapentin and buprenorphine. The lower limit of quantitation corresponded to 10 ng/mL for gabapentin and 1 ng/mL for buprenorphine in serum. Recoveries were 104 ± 2.55% and 85 ± 2.03% for gabapentin and buprenorphine, respectively.

CONCLUSIONS

Concentrations of gabapentin and buprenorphine were determined for five authentic human serum samples to further validate the utility of the method and applicable to therapeutic drug monitoring beyond its use as a drug screening assay. Furthermore, new mechanisms for the collision-induced dissociation of gabapentin and buprenorphine have been proposed.

Sociodemographic and clinical correlates of gabapentin receipt with and without opioids among a national cohort of patients with HIV

Gabapentin is commonly prescribed for chronic pain, including to patients with HIV (PWH). There is growing concern regarding gabapentin's potential for harm, particularly in combination with opioids. Among PWH, we examined factors associated with higher doses of gabapentin receipt and determined if receipt varied by opioid use. We examined data from the Veterans Aging Cohort Study, a national prospective cohort including PWH, from 2002 through 2017. Covariates included prescribed opioid dose, self-reported past year opioid use, and other sociodemographic and clinical variables. We used multinomial logistic regression to determine independent predictors of gabapentin receipt. Among 3,702 PWH, 902 (24%) received any gabapentin during the study period at a mean daily dose of 1,469 mg. In the multinomial model, high-dose gabapentin receipt was associated with high-dose benzodiazepine receipt (adjusted odds ratio [aOR], 95% confidence interval [CI]= 1.53, [1.03-2.27]), pain interference (1.65 [1.39-1.95]), and hand or foot pain (1.81, [1.45-2.26]). High-dose gabapentin receipt was associated with prescribed high-dose opioids receipt (2.66 [1.95-3.62]) but not self-reported opioid use (1.03 [0.89-1.21]). PWH prescribed gabapentin at higher doses are more likely to receive high-dose opioids and high-dose benzodiazepines, raising safety concerns.

Patterns of Neonatal Co-Exposure to Gabapentin and Commonly Abused Drugs Observed in Umbilical Cord Tissue

Gabapentin was thought to have low abuse potential, but it is increasingly being abused by people with substance use disorder in an attempt to potentiate the euphoric effects from opioids and other CNS depressants. Additionally, infants co-exposed to gabapentin and opioids during pregnancy tend to exhibit prolonged and more severe neonatal abstinence syndrome. In this study, we describe positivity rates among commonly abused drugs and rates of co-medication with gabapentin in a large dataset of umbilical cord tissue specimens (n = 25,422) submitted for routine newborn drug testing at a national clinical reference laboratory (ARUP Laboratories, Salt Lake City, UT, USA). Detection of prenatal drug exposure in umbilical cord tissue specimens was accomplished using a semi-quantitative liquid chromatography-tandem mass spectrometry assay designed to detect 47 specific drugs and drug metabolites including opioids, stimulants, sedative-hypnotics and hallucinogens. A positive result for at least one of the measured drugs or drug metabolites was reported in 7,054 (28%) of the umbilical cord tissues analyzed. Gabapentin had a positivity rate of ~2% with 562 positive results. Of the 562 gabapentin-positive samples, 395 (70%) also had a positive result for at least one other drug or drug metabolite, with the highest co-positivity rate observed for norbuprenorphine (32%, n = 182) followed by amphetamine (15%, n = 84), buprenorphine (13%, n = 74), methamphetamine (12%, n = 68), morphine (11%, n = 64), fentanyl (10%, n = 54) and naloxone (10%, n = 54). Notably, the concentration of gabapentin in gabapentin-positive umbilical cord specimens was higher in buprenorphine-containing specimens as compared to specimens containing other opioids, stimulants or benzodiazepines. Identification of neonatal co-exposure to gabapentin and opioids, particularly buprenorphine, may guide clinicians in rapid initiation of monitoring and intervention for neonatal abstinence syndrome.

Dual-trajectories of opioid and gabapentinoid use and risk of subsequent drug overdose among Medicare beneficiaries in the United States: a retrospective cohort study

BACKGROUND AND AIMS

Little is known about opioid and gabapentinoid (OPI-GABA) use duration and dose patterns' associations with adverse outcome risks. We examined associations between OPI-GABA dose and duration trajectories and subsequent drug overdose.

DESIGN

Retrospective cohort study.

SETTING

US Medicare.

PARTICIPANTS

Using a 5% sample (2011-16), we identified 71 005 fee-for-service Medicare beneficiaries with fibromyalgia, low back pain, neuropathy and/or osteoarthritis initiating OPIs and/or GABAs [mean age ± standard deviation (SD) = 65.5 ± 14.5 years, female = 68.1%, white = 76.8%].

MEASUREMENTS

Group-based multi-trajectory models identified distinct OPI-GABA use patterns during the year of OPI and/or GABA initiation, based on weekly average standardized daily dose (i.e. OPIs = morphine milligram equivalent, GABAs = minimum effective daily dose). We estimated models with three to 12 trajectories and selected the best model based on Bayesian information criterion (BIC) and Nagin's criteria. We estimated risk of time to first drug overdose diagnosis within 12 months following the index year, adjusting for socio-demographic and health factors using inverse probability of treatment weighted multivariable Cox proportional hazards models.

FINDINGS

We identified 10 distinct trajectories (BIC = -1 176 954; OPI-only = 3, GABA-only = 3, OPI-GABA = 4). Compared with OPI-only early discontinuers (40.6% of the cohort), 1-year drug overdose risk varied by trajectory group: consistent low-dose OPI-only users [16.6%; hazard ratio (HR) = 1.47, 95% confidence interval (CI) = 1.19-1.82], consistent high-dose OPI-only users (1.8%; HR = 4.57, 95% CI = 2.99-6.98), GABA-only early discontinuers (12.5%; HR = 1.39, 95% CI = 1.09-1.77), consistent low-dose GABA-only users (11.0%; HR = 1.44, 95% CI = 1.12-1.85), consistent high-dose GABA-only users (3.1%; HR = 1.43, 95% CI = 0.94-2.17), early discontinuation of OPIs and consistent low-dose GABA users (6.9%; HR = 1.24, 95% CI = 0.90-1.69), consistent low-dose OPI-GABA users (3.4%; HR = 2.49, 95% CI = 1.76-3.52), consistent low-dose OPI and high-dose GABA users (3.2%; HR = 2.46, 95% CI = 1.71-3.53) and consistent high-dose OPI and moderate-dose GABA users (0.9%; HR = 7.22, 95% CI = 4.46-11.69).

CONCLUSIONS

Risk of drug overdose varied substantially among US Medicare beneficiaries on different use trajectories of opioids and gabapentinoids. High-dose opioid-only users and all consistent opioid and gabapentinoid users (regardless of doses) had more than double the risk of subsequent drug overdose compared with opioid-only early discontinuers.

Gabapentinoids for Pruritus in Older Adults: A Narrative Review

There is currently no standardized algorithm for the treatment of chronic pruritus (CP), or itch lasting more than 6 weeks, in adults aged ≥ 65 years. The antiepileptic agents gabapentin and pregabalin, however, are gaining popularity in the dermatologic community for their efficacy in treating CP of neuropathic origin. Yet the lack of literature specifically looking at the safety and efficacy of these medications in older adults results in limited guidance for providers in the safe use of gabapentinoids. In this paper we discuss special considerations and recommendations for treating older adults with gabapentin and pregabalin and explore the possibility for these drugs to ameliorate CP of multiple etiologies.

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.

Gabapentin controlled substance status

Gabapentin is approved to treat postherpetic neuralgia and epilepsy with partial-onset seizures. The large majority of gabapentin prescribing is off label. Gabapentin may be abused for euphoria, potentiating the high from opiates, reduction of alcohol cravings, a cocaine-like high, as well as sedation or sleep. Individuals at the highest risk for abusing gabapentin include those with opioid abuse, mental illness, or previous history of prescription drug abuse. States are now taking action to track gabapentin use through prescription monitoring programs, and some states have reclassified it as a Schedule V controlled substance. This commentary summarizes gabapentin's abuse potential, identifies state-level actions regarding gabapentin monitoring, and discusses possible clinical implications and ways to enhance patient safety when prescribing gabapentin.

Prevalence of and Factors Associated with Gabapentinoid Use and Misuse Among Texas Medicaid Recipients

BACKGROUND AND OBJECTIVES

Gabapentin and pregabalin have been considered relatively safe opioid-sparing adjuncts for pain management. However, rising prescribing trends, presence of gabapentinoids in opioid-related overdoses, and the growing body of evidence regarding gabapentinoid misuse and abuse, have caused gabapentinoids to emerge as a drug class of public health concern. This study aimed to assess the prevalence of, and factors associated with gabapentinoid use and misuse.

METHODS

This retrospective study of Texas Medicaid data from 1/1/2012 to 30/8/2016 included patients aged 18-63 years at index date, with ≥ 1 gabapentinoid prescription, and continuously enrolled 6 months pre-index and 12 months post-index. Gabapentinoid misuse was defined as ≥ 3 claims exceeding daily doses of 3600 mg for gabapentin and 600 mg for pregabalin. Age, gender, concurrent opioid use, neuropathic pain diagnoses and gabapentinoid type were independent variables. Descriptive and inferential statistics were used.

RESULTS

Of included subjects (N = 39,000), 0.2% (N = 81) met study criteria for gabapentinoid misuse. Overall, the majority (76.4%) of gabapentinoid users were aged 41-63 years with a mean ± SD age of 48.2 ± 10.7 years. Those patients meeting the study criteria for gabapentinoid misuse were significantly younger (45.1 ± 11.0 vs 48.2 ± 10.7, p = 0.0084). Majority of the study sample was female (68.1%). However, a significantly higher proportion of males met the study criteria for gabapentinoid misuse compared to females (0.3% vs 0.2%, p = 0.0079). Approximately one-half (51.9%) of the study sample had neuropathic pain, and gabapentinoid misuse was significantly higher in neuropathic pain patients compared to those without neuropathic pain (0.3% vs 0.1%, p = 0.0078). Over three-quarters (77.4%) of patients were using gabapentin; however, gabapentinoid misuse was significantly higher among pregabalin users (0.4% vs 0.2%, p = 0.0003). Approximately 20% (17.3%) of gabapentinoid users had ≥ 90 days of concurrent opioid use. However, there was no significant difference in gabapentinoid misuse among patients with concurrent opioid use compared to patients without (0.3% vs 0.2%, p = 0.1440). Factors significantly associated with misuse included: male sex (odds ratio [OR] 0.486; 95% confidence interval [CI] 0.313-0.756; p = 0.0013); neuropathic pain (OR 2.065; 95% CI 1.289-3.308; p = 0.0026); and pregabalin versus gabapentin use (OR 2.337, 95% CI 1.492-3.661; p = 0.0002). Concurrent opioid use was not significantly associated with gabapentinoid misuse (OR 1.542, 95% CI 0.920-2.586; p = 0.1006).

CONCLUSION

Prevalence of gabapentinoid misuse was low (0.2%) among Texas Medicaid recipients. Younger age, male gender, neuropathic pain diagnosis and pregabalin use were significantly associated with higher levels of gabapentinoid misuse.

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.

Trends in unintentional polysubstance overdose deaths and individual and community correlates of polysubstance overdose, North Carolina, 2009-2018

BACKGROUND

Polysubstance involvement is increasing among fatal drug overdoses. However, little is known about the epidemiology of polysubstance drug overdoses. This paper describes emerging trends in unintentional polysubstance overdose deaths in North Carolina (NC) and examines associations with individual and community factors.

METHODS

Using 2009-2018 NC death certificate data, we identified unintentional drug overdose deaths and commonly involved substances (opioids, stimulants, benzodiazepines, alcohol, and antiepileptics). We examined polysubstance combinations, comparing opioid and non-opioid involved deaths. We examined individual level correlates from death certificate data and community level correlates from the American Community Survey and Robert Wood Johnson Foundation County Health Rankings to quantify associations.

RESULTS

From 2009-2018, 53 % of opioid and 19 % of non-opioid overdose deaths involved multiple substances. During this period, polysubstance overdose death increased dramatically, from 2.9 to 12.1 per 100,000 persons, with the greatest increases among drug combinations involving stimulants. The most common polysubstance combinations were: opioids and stimulants (12.1 % of overdose deaths); opioids and benzodiazepines (9.0 %); opioids and alcohol (5.1 %); opioids, stimulants, and benzodiazepines (3.1 %); and opioids, benzodiazepines, and antiepileptics (2.2 %). Compared to overdoses involving opioids alone, overdoses involving combinations of opioids, stimulants, and benzodiazepines involved younger individuals (53.7 % in 15-34 years of age vs. 40.7 %). Men comprised two-thirds of overdoses involving opioids alone, however, overdoses involving opioids, benzodiazepines, and antiepileptics were predominantly among women (60.6 %).

CONCLUSIONS

Polysubstance involvement has increased among overdose deaths in NC. These findings can be used to inform public health interventions addressing polysubstance deaths and associated individual and community level factors.

Profile of Substance Misuse among Adolescent and Young Adult Gabapentinoid Users: A Register-Based Follow-up Study of Former Adolescent Psychiatric Inpatients

Our study examined characteristics of adolescent and young adult study participants using gabapentinoids (gabapentin, pregabalin), with previous history of adolescent psychiatric inpatient hospitalization. Particular focus was on temporal association of age, at first prescription for gabapentinoids, to age at tobacco smoking initiation, regular alcohol use, diagnosis of substance dependence and prescriptions for benzodiazepines and opioids. Methods: The initial study population contained 508 adolescents (300 females, 208 males) admitted to psychiatric inpatient care in Oulu University hospital between the ages 13-17 years. Register-based follow-up information on prescriptions for gabapentinoids, benzodiazepines and opioids, as well as ICD-10 diagnosis for hospital-treated substance dependence, was obtained from the Finnish national health care registers. Results: The users of gabapentinoids accounted for 9.1% of the initial study population. Of adolescence-related characteristics, suicidal ideation, suicide attempts and non-suicidal self-injury was emphasized in females using gabapentinoids. The majority of participants using gabapentinoids had benzodiazepines (80.4%) and opioids (71.7%) as comorbid drugs. Initiation of tobacco smoking and alcohol use and first prescriptions for of benzodiazepines and opioids, and a diagnosis of substance dependence commonly predated first prescriptions for gabapentinoids. Conclusions: In clinical practice, the decision to prescribe gabapentinoids to adolescents or young adults must be made with caution, particularly for those with substance use problems and/or without a clinically approved indication.

Current Evidence on Abuse and Misuse of Gabapentinoids

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

Longitudinal trends in nonmedical prescription opioid use in a cohort of rural Appalachian people who use drugs

Rural Appalachia remains an epicenter of the prescription opioid epidemic. In 2008, a cohort study was undertaken to examine longitudinal trends in nonmedical prescription opioid use (NMPOU). Eight waves of data (2008-2020) from the Social Networks among Appalachian People (SNAP) cohort were utilized for the current analysis. Only those who reported recent (past 6-month) NMPOU at baseline are included (n = 498, 99%). Mixed-effects logistic regression was used to model factors associated with NMPOU over time. Recent NMPOU declined significantly over the past decade (p < .001). However, 54.1% of participants still engaged in NMPOU at their most recent follow-up. Receipt of benefits for a physical or mental disability (adjusted odds ratio [aOR]: 3.11, 95% Confidence Interval [CI]: 1.98, 4.90) and self-described poor health status (aOR: 3.67, 95% CI: 1.61, 8.37) were both associated with NMPOU. All treatment modalities (methadone maintenance, residential, outpatient counseling) tested in the model, with the notable exception of detoxification, were associated with significantly lower odds of NMPOU. Although significant declines in prescription opioid misuse were observed in the cohort, more than half of all participants were engaged in NMPOU more than a decade after entering the study. Substance use disorder (SUD) treatment (excluding detoxification) was shown associated with reduced odds of continued NMPOU; therefore, increasing access to evidence-based treatments should be a priority in rural areas affected by the ongoing opioid epidemic.

Opioid-related overdose deaths among African Americans: Implications for research, practice and policy

Opioid-related overdose deaths among African Americans have only recently received national attention despite evidence of increase in death rates among this population spanning the past decade. Numerous authors have highlighted how the 'opioid epidemic' has largely been portrayed as a problem mostly affecting White America. The purpose of this commentary is to provide a synthesis spotlighting the unique structural and cultural considerations involved in research, practice and policy related to opioid use and treatment for opioid use disorders among African Americans. The commentary concludes with considerations for future research and practice intended to reduce deaths among this group.

Keeping the Pharmacology in Pharmacoepidemiology

The treatment of many medical conditions requires the use of multiple drugs. A study published recently in this journal nicely illustrates the need to consider the pharmacology of potentially interacting drugs when conducting pharmacoepidemiologic studies of patient safety outcomes associated with such interactions. By examining multiple streams of data, we can piece together the risks and the mechanisms of action underlying those risks, and provide useful information for clinicians and patients to use multiple pharmacotherapies safely.

Descriptions of Gabapentin Misuse and Associated Behaviors among a Sample of Opioid (Mis)users in South Florida

Gabapentin has received increased attention due to a growing number of reports of misuse and diversion. However, significant details about gabapentin misuse are scant. Data are drawn from a mixed-methods study examining gabapentin misuse in South Florida. The sample includes 49 respondents who were age 18 or over and reported past year use of illicit opioids and/or the misuse of prescription opioid medications, as well as, recent (past 90 days) gabapentin misuse. Respondents were female (40.8%), Hispanic (30.6%), Black (16.3%), white (49.0%), and other race/ethnicity (4.1%). Mean age was 37.6. Many respondents (43%) misused gabapentin without ever receiving a prescription and 14% misused prior to being prescribed. Mean frequency of recent misuse was 25.4 days and included a mean of 51.65 pills/doses. Prevalent routes of administration included swallowing (85.7%) and snorting (10.2%). Gabapentin misuse occurred concomitantly with any opioid (44.9%), benzodiazepines (38.8%), alcohol (24.5%), and powder cocaine (24.5), among others. Respondents' descriptions indicate that gabapentin produces feelings reminiscent of alcohol intoxication or opioid-induced euphoria, but for some it produces no noticeable effect or only alleviates pain. Greater understanding of gabapentin misuse, especially associated behaviors and concomitant use is needed to inform prevention and intervention efforts, and to guide policy approaches.

Use of promethazine, gabapentin and clonidine in combination with opioids or opioid agonist therapies among individuals attending a syringe service program

BACKGROUND

Clonidine, gabapentin, and promethazine are commonly used by people who use opioids, including heroin, raising concern for increased morbidity and mortality in a vulnerable population. We aimed to characterize how and why individuals use opioids in combination with these three psychoactive medications (PAMs).

METHODS

Participants (n = 103) were a convenience sample of adults attending a syringe service program who reported using a PAM in addition to opioids or opioid agonist therapies (buprenorphine or methadone). Face-to-face structured interviews consisted of closed and open-ended questions.

RESULTS

Patterns of PAM use varied. Risky use, including use of high doses and with other sedating medications, was common. Most individuals reported multiple medical reasons for use, even while reporting the PAM had mind-altering effects. Use of high doses of PAMs was associated with a history of overdose. Among those with a history of overdose, 32% reported that a PAM was involved.

CONCLUSION

The use of clonidine, gabapentin and promethazine among individuals who use opioids is complex. Providers should take individualized approaches to PAM prescribing, recognizing both the risks of PAMs and the potential unintended consequences of supply-side interventions in the era of the overdose crisis. Harm reduction interventions are needed to prevent PAM-involved overdoses.

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.

Characteristics Associated With U.S. Outpatient Opioid Analgesic Prescribing and Gabapentinoid Co-Prescribing

INTRODUCTION

A considerable burden of prescription and illicit opioid-related mortality and morbidity in the U.S. is attributable to potentially unnecessary or excessive opioid prescribing, and co-prescribing gabapentinoids may increase risk of harm. Data are needed regarding physician and patient characteristics associated with opioid analgesic and opioid analgesic-gabapentinoid co-prescriptions to elucidate targets for reducing preventable harm.

METHODS

Multiple logistic regression was utilized to examine patient and physician predictors of opioid analgesic prescriptions and opioid analgesic-gabapentinoid co-prescriptions in adult noncancer patients using the National Ambulatory Medical Care Survey 2015 public use data set. Potential predictors were selected based on literature review, clinical relevance, and random forest machine learning algorithms.

RESULTS

Among the 11.8% (95% CI=9.8%, 13.9%) of medical encounters with an opioid prescription, 16.2% (95% CI=12.6%, 19.8%) had a gabapentinoid co-prescription. Among all gabapentinoid encounters, 40.7% (95% CI=32.6%, 48.7%) had an opioid co-prescription. Predictors of opioid prescription included arthritis (OR=1.87, 95% CI=1.30, 2.69). Predictors of new opioid prescription included physician status as an independent contractor (OR=3.67, 95% CI=1.38, 9.81) or part owner of the practice (OR=3.34, 95% CI=1.74, 6.42). Predictors of opioid-gabapentinoid co-prescription included patient age (peaking at age 55-64 years; OR=35.67, 95% CI=4.32, 294.43).

CONCLUSIONS

Predictors of opioid analgesic prescriptions with and without gabapentinoid co-prescriptions were identified. These predictors can help inform and reinforce (e.g., educational) interventions seeking to reduce preventable harm, help identify populations for elucidating opioid-gabapentinoid risk-benefit profiles, and provide a baseline for evaluating subsequent public health measures.

Gabapentin drug misuse signals: A pharmacovigilance assessment using the FDA adverse event reporting system

BACKGROUND

Although there have been increasing reports of intentional gabapentin misuse, epidemiological evidence for the phenomenon is limited. The purpose of this study was to determine whether there are pharmacovigilance abuse signals for gabapentin.

METHODS

Using FDA Adverse Events Reporting System reports from January 1, 2005 to December 31, 2015, we calculated pharmacovigilance signal measures (i.e., reporting odds ratio, proportional reporting ratio, information component, and empirical Bayes geometric mean) for abuse-related adverse event (AR-AE)-gabapentin pairs. Loglinear modeling assessed the frequency of concurrent reporting of abuse-related and abuse-specific AEs (AS-AEs) associated with gabapentin. Findings were compared to a positive (pregabalin) and negative (duloxetine) control.

RESULTS

From 2005-2015 there were 5,951,229 unique AE reports submitted to the FDA including 99,977 for gabapentin, 73,977 for duloxetine, and 97,813 for pregabalin. Significant drug-AR-AE pair signals involving gabapentin included: drug abuser, multiple drug overdose, and substance-induced psychotic disorder. Significant drug AR-AE signals involving gabapentin and pregabalin, but not duloxetine, were: ataxia, dependence, drug abuse, increased drug tolerance, and overdose. Compared to duloxetine, gabapentin had significantly greater odds of a co-report for an AS-AE with drug withdrawal syndrome (OR: 6.55), auditory hallucinations (OR: 4.57), delusions (OR: 2.36), euphoric mood (OR: 5.45), ataxia (OR: 2.85), drug abuser (OR: 3.01), aggression (OR: 1.98), psychotic disorder (OR: 1.96), and feeling abnormal (OR: 1.31).

CONCLUSIONS

We identified abuse-related signals for gabapentin and highlighted several CNS effects that may be associated with its abuse. Gabapentin prescribers should be aware of the drug's abuse liability and effects that may accompany its use.

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.

An ethnographic decision model of the initiation of gabapentin misuse among prescription and/or illicit opioid (mis)user

AIMS

Gabapentin is used in the treatment of seizures and neuralgia, and it is prescribed off-label to treat substance use disorders and withdrawal symptoms. Recent research documents misuse of gabapentin, especially among prescription opioid misusers. The present study contributes to this literature by examining the initiation of gabapentin misuse.

METHODS

Qualitative interviews were conducted with prescription and/or illicit opioid (mis)users who reported a history of gabapentin misuse (N = 62) and who did not (N = 29). During semi-structured interviews, respondents provided descriptions of the first time they misused gabapentin. An ethnographic decision model was constructed to illustrate the factors that influence the initiation decision.

RESULTS

Multiple individual, social, and environmental factors influence the decision to initiate gabapentin misuse. Respondents described the initiation decision related to: a) wanting to feel a psychoactive high during times of limited access to one's preferred drug because of institutional barriers (e.g., substance abuse treatment; jail; transitional living facility; N = 18); b) the desire to use multiple drugs, including for experimentation or to potentiate another substance (N = 18); and c) the need to self-treat withdrawal symptoms during periods of opioid nonuse or when opioids were unavailable (N = 16). Respondents also initiated gabapentin misuse to self-treat physical pain (N = 10).

CONCLUSIONS

Multiple approaches are needed to mitigate gabapentin misuse, including limiting availability in institutional settings and informal channels as well as addressing the needs of drug users who experience physical pain and withdrawal symptoms. Continued research is needed to examine therapeutic uses of gabapentin and behaviors related to misuse.

Trends in prior receipt of prescription opioid or adjuvant analgesics among patients with incident opioid use disorder or opioid-related overdose from 2006 to 2016

BACKGROUND

With increasing efforts to scrutinize and reduce opioid prescribing, limited data exist on the recent trend in receipt of prescription pain medications before diagnosis of opioid use disorder (OUD) or opioid-related overdose (OD).

METHODS

Using 2005-2016 Truven MarketScan Commercial Claims databases, we assessed trends in annual 1) incidence of OUD or OD and 2) prevalence of receipt of prescription opioids or four commonly-prescribed adjuvant analgesics among patients newly diagnosed with OUD/OD. Trends were examined in the overall sample and by 3 age groups, including youths (≤18 years), adults (19-64 years), and older adults (≥65 years).

RESULTS

The incidence of diagnosed OUD or OD increased more than 3-fold from 4.99 to 23.81 per 10,000 persons from 2006 to 2016, with the highest increase (14.18-fold) seen in older adults, followed by adults (3.53-fold), and youths (0.16-fold). Between 2006 and 2016, the proportion of patients with incident OUD/OD who received anticonvulsant adjuvant analgesics in the year before diagnosis increased (from 23.4% to 34.3% [P-trend = .005]) whereas the proportion receiving high-dose prescriptions opioids decreased (from 45.5% to 34.8% [P-trend =< .001]). A decreasing trend was observed in general for tricyclic antidepressants and serotonin and norepinephrine reuptake inhibitors.

DISCUSSION

In US commercially insured patients newly diagnosed with OUD/OD, receipt of high-dose opioid prescriptions preceding the diagnosis decreased over time, paralleled by increased use of anticonvulsants commonly prescribed for pain conditions. Further investigations are warranted to understand how prescribed and anticonvulsants contribute to the development of OUD/OD.

Validation of a High-throughput Screening and Quantification Method for the Determination of Gabapentinoids in Blood Using a Combination of LC-TOF-MS and LC-MS-MS

Gabapentinoids such as gabapentin (GP) and pregabalin (PGL) have been used to treat a wide range of neurological and psychiatric disorders. In recent years, there has been an increasing awareness of GP and PGL misuse among individuals with a history of polysubstance use. Both GP and PGL are understood to potentiate the effects of opioids, with fatalities involving GP and PGL being reported with increasing frequency. An efficient procedure was developed to screen and quantitate GP and PGL in blood samples using a combination of liquid chromatography time-of-flight mass spectrometry (LC-TOF-MS) and liquid chromatography tandem mass spectrometry (LC-MS-MS). The developed LC-MS-MS method was linear from 0.5-50 mg/L, with a limit of detection (LOD) of 0.1 mg/L for GP and PGL. An LOD of 0.5 mg/L was determined for both analytes on the LC-TOF-MS screen. A total of 1,091 blood specimens were subjected to a protein crash with methanol, in the presence of deuterated internal standards, PGL-d6 and GP-d10, to minimize the effects of varying matrix conditions. Specimens tested included both post-mortem blood and preserved blood specimens collected for the purposes of investigating drug-impaired driving and suspected drug-facilitated crimes. Of the total of specimens tested, 101 (9.3%) screened positive using the developed LC-TOF-MS method for GP while only 13 (1.2%) blood specimens screened positive for PGL. All (100%) of the cases that screened positive for GP and PGL were confirmed positive by LC-MS-MS. Blood concentrations of GP and PGL ranged from <0.5 to 215 mg/L and from <0.5 to 32 mg/L, respectively. Of the blood specimens that had previously screened negative by LC-TOF-MS, 10% (N = 100) were randomly selected and tested by LC-MS-MS with 100% confirmed negative for GP and PGL. The developed methods provide a fast and reliable high-throughput screening and confirmation testing strategy for the detection of GP and PGL in blood specimens.

Gabapentin prescribed during substance abuse treatment: The perspective of treatment providers

BACKGROUND

Gabapentin, a prescription medication approved for the treatment of seizures and neuralgia, is often prescribed off-label for substance use treatment, mental health problems, and pain. Emerging reports also suggest it is misused for the purpose of getting high. The present study examines substance abuse treatment provider key informants' experiences with gabapentin prescribed to clients in treatment. The focus of this exploratory study is to ascertain how gabapentin is used in these settings and the benefits and risks for clients.

METHODS

Key informants from South Florida participated in confidential, in-depth interviews (N = 12). Data analyses included descriptive and in vivo coding schemes and employed a descriptive qualitative approach.

RESULTS

All key informants recognized the benefits of prescribing gabapentin to clients in treatment for problems related to withdrawal symptoms, mental distress and pain. At the same time, half of participants described gabapentin misuse among clients and four key informants described such misuse as a first marker of relapse. Key informants also stated that more research must be done about how to use gabapentin effectively in treatment settings.

CONCLUSIONS

These findings illustrate the lack of clarity about the efficacy of administration of gabapentin in treatment settings. Additional research about how to best use gabapentin, for whom it may be beneficial, and the effect of prescribed gabapentin on addiction recovery is needed.

Pharmacologic Treatment of Opioid Use Disorder: a Review of Pharmacotherapy, Adjuncts, and Toxicity

Opioid use disorder continues to be a significant source of morbidity and mortality in the USA and the world. Pharmacologic treatment with methadone and buprenorphine has been shown to be effective at retaining people in treatment programs, decreasing illicit opioid use, decreasing rates of hepatitis B, and reducing all cause and overdose mortality. Unfortunately, barriers exist in accessing these lifesaving medications: users wishing to start buprenorphine therapy require a waivered provider to prescribe the medication, while some states have no methadone clinics. As such, users looking to wean themselves from opioids or treat their opioid dependence will turn to alternative agents. These agents include using prescription medications, like clonidine or gabapentin, off-label, or over the counter drugs, like loperamide, in supratherapeutic doses. This review provides information on the pharmacology and the toxic effects of pharmacologic agents that are used to treat opioid use disorder. The xenobiotics reviewed in depth include buprenorphine, clonidine, kratom, loperamide, and methadone, with additional information provided on lofexidine, akuamma seeds, kava, and gabapentin.

Gabapentin-related suicide: Myth or fact?

Background:

The opioid epidemic in America is real and is estimated to be the number one cause of death in adults under 50 years of age. Finding alternative analgesic medications is part of the effort to decrease the prescription of narcotics, with gabapentin being at the top of the list.

Case Description:

In the present case, we discuss the side-effects of gabapentin, used as part of the multimodal treatment approach of painful spinal degenerative disease. The patient stated that he had noticed personality changes after gabapentin was initiated, and that he had become more depressed, frustrated, and aggressive. His uncontrolled pain and acute mood changes led him to attempt suicide by hanging himself. Gabapentin was discontinued and the patient's suicidal ideation completely subsided.

Conclusion:

It is imperative to screen, identify, and appropriately manage patients with underlying psychiatric disorders prior to initiating pain management with gabapentin. Therefore, it is crucial to raise awareness of gabapentin as a potential cause of depression, aggressive behavior, and suicidal ideation.

The Toxicology Investigators Consortium Case Registry-the 2017 Annual Report

The Toxicology Investigators Consortium (ToxIC) Case Registry was established by the American College of Medical Toxicology in 2010. The Registry collects data from participating sites with the agreement that all bedside medical toxicology consultations will be entered. The objective of this eighth annual report is to summarize the Registry's 2017 data and activity with its additional 7577 cases. Cases were identified for inclusion in this report by a query of the ToxIC database for any case entered from 1 January to 31 December 2017. Detailed data was collected from these cases and aggregated to provide information which includes demographics (e.g., age, gender, race, ethnicity), reason for medical toxicology evaluation (e.g., intentional pharmaceutical exposure, envenomation, withdrawal from a substance), agent and agent class, clinical signs and symptoms (e.g., vital sign abnormalities, organ system dysfunction), treatments and antidotes administered, fatality, and life support withdrawal data. Females were involved in 50.4% of cases. Transgender demographic information collection was initiated in 2017 to better represent the population and there were 36 cases involving transgender patients. Adults aged 19-65 were the most commonly reported age group. Non-opioid analgesics were the most commonly reported agent class, with acetaminophen again the most common agent reported. There were 93 fatalities reported in 2017. Treatment interventions were frequently reported with 30.6% receiving specific antidotal therapy. Major trends in demographics and exposure characteristics remained similar to past years' reports. While treatment interventions were commonly required, fatalities were rare.

Opportunities to Prevent Overdose Deaths Involving Prescription and Illicit Opioids, 11 States, July 2016-June 2017

In 2016, 63,632 drug overdose deaths occurred in the United States, 42,249 (66.4%) of which involved opioids (1). The development of prevention programs are hampered by a lack of timely data on specific substances contributing to and circumstances associated with fatal overdoses. This report describes opioid overdose deaths (referred to as opioid deaths) for decedents testing positive for prescription opioids (e.g., oxycodone and hydrocodone), illicit opioids (e.g., heroin, illicitly manufactured fentanyl, and fentanyl analogs), or both prescription and illicit opioids, and describes circumstances surrounding the overdoses, in 11 states participating in CDC’s Enhanced State Opioid Overdose Surveillance (ESOOS) program.* During July 2016–June 2017, among 11,884 opioid overdose deaths, 17.4% of decedents tested positive for prescription opioids only, 58.7% for illicit opioids only, and 18.5% for both prescription and illicit opioids (type of opioid could not be classified in 649 [5.5%] deaths). Approximately one in 10 decedents had been released from an institutional setting in the month preceding the fatal overdose. Bystanders were reportedly present in approximately 40% of deaths; however, naloxone was rarely administered by a layperson. Enhanced surveillance data from 11 states provided more complete information on the substances involved in and circumstances surrounding opioid overdose deaths. Consistent with other emerging evidence and recommendations,^† these data suggest prevention efforts should prioritize naloxone distribution to persons misusing opioids or using high dosage prescription opioids and to their family members and friends. In addition, these data suggest a need to expand treatment and support for persons who have experienced a nonfatal overdose and to expand treatment in detention facilities and upon release.

The Evolving Landscape of Acute Pain Management in the Era of the Opioid Crisis

PURPOSE OF REVIEW

The purpose of the study is to evaluate and analyze the role of both opioid and non-opioid analgesics in the emergency department (ED).

RECENT FINDINGS

Studies have shown that the implementation of opioid-prescribing policies in the ED has the potential to reduce the opioid addiction burden. Clinical studies point to inconsistencies in providers' approach to pain treatment. In this review, we discuss specific aspects of opioid utilization and explore alternative non-opioid approaches to pain management. Pain is the most common reason patients present to the ED. As such, emergency medicine (EM) providers must be well versed in treating pain. EM providers must be comfortable using a wide variety of analgesic medications. Opioid analgesics, while effective for some indications, are associated with significant adverse effects and abuse potential. EM providers should utilize opioid analgesics in a safe and rational manner in an effort to combat the opioid epidemic and to avoid therapeutic misadventures. EM providers should be aware of all of their therapeutic options, e.g., opioid and non-opioid, in order to provide effective analgesia for their patients, while avoiding adverse effects and minimizing the potential for misuse.

Reports of gabapentin and pregabalin abuse, misuse, dependence, or overdose: An analysis of the Food And Drug Administration Adverse Events Reporting System (FAERS)

BACKGROUND

Reports of gabapentinoid (gabapentin and pregabalin) misuse have increased in recent years. Pharmacovigilance data from the Food and Drug Administration Adverse Event Reporting System (FAERS) provides a useful examination of adverse drug event (ADE) reporting for safety signal detection.

OBJECTIVE

This study was conducted to analyze epidemiological information on the nature and extent of gabapentin/pregabalin abuse utilizing the FAERS database.

METHODS

A query was designed utilizing SafeRx, an indexed, searchable database of FAERS data from October 2012-December 2016. All-cause and abuse-related (including abuse/misuse/dependence/overdose events) ADE reports for gabapentin and pregabalin were isolated, as well as limited demographic data. The proportional reporting ratio (PRR) was calculated to compare signal detection.

RESULTS

A total of 10,038 all-cause ADEs were reported to FAERS for gabapentin, including 576 (5.7%) abuse-related events. For pregabalin, 571 all-cause ADEs were identified, including 58 (10.2%) related to abuse. Compared to all-cause ADEs, those involved in abuse-related events were younger and more likely to be male. The PRR of pregabalin versus gabapentin abuse-related events was 1.77.

CONCLUSION

Though not traditionally thought of as drugs of abuse, over 600 cases of gabapentinoid abuse were reported in the time frame analyzed, prompting the need for further study and regulatory investigation.

Oxycodone-induced tolerance to respiratory depression: reversal by ethanol, pregabalin and protein kinase C inhibition

BACKGROUND AND PURPOSE

Oxycodone, a prescription opioid, is a major drug of abuse, especially in the USA, and contributes significantly to opioid overdose deaths each year. Overdose deaths result primarily from respiratory depression. We have studied respiratory depression by oxycodone and have characterized how tolerance develops on prolonged exposure to the drug. We have investigated the role of PKC in maintaining tolerance and have examined whether ethanol or pregabalin reverses oxycodone-induced tolerance.

EXPERIMENTAL APPROACH

Respiration was measured in male CD-1 mice by whole-body plethysmography. Mice were preinjected with oxycodone then implanted with mini-pumps (s.c.) delivering 20, 45 or 120 mg·kg-1 ·day-1 oxycodone for 6 days and subsequently challenged with oxycodone (3 mg·kg-1 , i.p.) or morphine (10 mg·kg-1 , i.p.) to assess the level of tolerance.

KEY RESULTS

Oxycodone-treated mice developed tolerance to oxycodone and cross tolerance to morphine-induced respiratory depression. Tolerance was less with 20 mg·kg-1 ·day-1 than with 45 or 120 mg·kg-1 ·day-1 oxycodone treatment. At doses that do not depress respiration, ethanol (0.3 g·kg-1 ), pregabalin (20 mg·kg-1 ) and calphostin C (45 μg·kg-1 ) all reversed oxycodone-induced tolerance resulting in significant respiratory depression. Reversal of tolerance was less in mice treated with oxycodone (120 mg·kg-1 ·day-1 ). In mice receiving ethanol and calphostin C or ethanol and pregabalin, there was no greater reversal of tolerance than seen with either drug alone.

CONCLUSION AND IMPLICATIONS

These data suggest that oxycodone-induced tolerance is mediated by PKC and that reversal of tolerance by ethanol or pregabalin may be a contributory factor in oxycodone overdose deaths.

Prevalence of gabapentin in drug overdose postmortem toxicology testing results

BACKGROUND

The goal of this study was to establish and compare baseline data on the prevalence of gabapentin identified through postmortem toxicology testing among drug overdose decedents in several geographically diverse states/jurisdictions with differing levels of drug overdose fatality burdens in 2015.

METHODS

Death certificates and postmortem toxicology result reports from five U.S. jurisdictions were used to identify residents who died from drug overdoses in year 2015 and to calculate prevalence rates of gabapentin in postmortem toxicology by jurisdiction.

RESULTS

On average, 22% of all drug overdose decedents in our study tested positive for gabapentin. The percentage of gabapentin-positive overdose deaths varied significantly among jurisdictions: 4% in Northeast Tennessee, 7% in Maricopa County, 15% in West Virginia, 20% in North Carolina, and 41% in Kentucky (p < 0.0001). Among the drug overdose decedents who tested positive for opioids (including heroin), 26% also tested positive for gabapentin, with significant variation among states/jurisdictions (p < 0.0001). There was a significant difference in the gender distribution among drug overdose decedents who tested positive for gabapentin (46% male) vs. those who tested negative for gabapentin (65% male) (p < 0.0001). In Kentucky, gabapentin was listed as a contributing drug on the death certificate in 40% of the overdose deaths with gabapentin-positive toxicology; in North Carolina this percentage was 57%.

CONCLUSIONS

Routine gabapentin postmortem testing and linking of death certificate, medical examiner, coroner, toxicology, and prescription history data will provide more reliable information on the extent of gabapentin misuse, diversion, and implications for clinical care.

A qualitative analysis of gabapentin misuse and diversion among people who use drugs in Appalachian Kentucky

Gabapentin, an anticonvulsant and analgesic for postherpetic neuralgia, has been thought to have no abuse potential despite numerous published reports to the contrary. Gabapentin has been linked with impaired driving and opioid use, highlighting the need to more fully understand its risk profile. Thirty-three individuals reporting recent nonmedical use of gabapentin were recruited from two ongoing longitudinal studies of drug users in Appalachian Kentucky to participate in focus groups. Four sessions were held (two in the community and two in jail settings), during which participants responded to questions regarding their personal experiences with gabapentin misuse. Focus group participants were similar to other gabapentin users in the larger cohort studies with respect to demographics and drug use behaviors. Overall, the sample reported having initiated gabapentin more than 10 years earlier after having it prescribed for a legitimate, though generally off-label, medical indication (e.g., pain, anxiety, opioid detoxification). Participants reported use of gabapentin in combination with buprenorphine, other opioids, cocaine, and caffeine to produce sought-after central nervous system effects (e.g., muscle relaxation, pain reduction, sleep induction, feeling drunk, and feeling "high"). Focus group responses highlighted the low cost of gabapentin for the purpose of getting high and noted increasing popularity in the community, particularly over the last 2 years. Gabapentin was a prominent drug of abuse in two cohorts of the primarily opioid-using individuals. Providers should be aware of gabapentin's abuse potential, and a reexamination of the need for scheduling is warranted. (PsycINFO Database Record