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. Author manuscript; available in PMC: 2021 Sep 11.
Published in final edited form as: Subst Use Misuse. 2020 Sep 11;55(14):2364–2370. doi: 10.1080/10826084.2020.1817082

Factors associated with gabapentin misuse among people who inject drugs in Appalachian Kentucky

Mance E Buttram 1, Hilary L Surratt 2
PMCID: PMC7643539  NIHMSID: NIHMS1641045  PMID: 32917119

Abstract

Aims:

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 misuse 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 moderate methamphetamine highs. Syringe service programs can educate PWID about the potential dangers of polydrug use involving gabapentin and to connect PWID with needed healthcare services.

Keywords: gabapentin, drug injection, PWID, opioid, syringe service program

Introduction

Gabapentin, a ɣ-aminobutyric acid (GABA)-analogue, received approval from the U.S. Food and Drug Administration for the treatment of post-herpetic neuralgia and epilepsy (Wallach and Ross 2018). Since that time, prescriptions for gabapentin have grown considerably (Quintiles IMS Institute 2017) and it is widely prescribed off-label for the treatment of substance use disorder and mental health problems, including bipolar disorder, posttraumatic stress disorder, and anxiety (Berlin, Butler, and Perloff 2005, Wallach and Ross 2018). Gabapentin requires a prescription, although historically it has been perceived to have low abuse potential because of its dose-limited absorption properties (Brockbrader et al. 2010). In recent years, however, growing reports of misuse led several states, including Kentucky, Tennessee, Michigan, North Dakota, West Virginia, Virginia, and Alabama, to reclassify gabapentin as a Schedule-V controlled substance and several additional states are considering similar legislation or increased surveillance by state prescription drug monitoring programs (Alabama State Board of Health 2019; North Dakota State Board of Pharmacy 2019; King 2020; Mincher 2018; Peckham, Ananickal, and Sclar 2018; Michigan Department of Licensing and Regulatory Affairs 2019). Notably in Kentucky one study documented a 2,950% increase in gabapentin misuse for the purpose of getting high between 2008 and 2014 (Smith, Lofwall, and Havens 2015).

A recent ethnographic study documented important motivations for gabapentin misuse among opioid dependent individuals, either alone or in combination with other substances, including achieving a desired central nervous system effect, moderating opioid withdrawal symptoms, self-detoxing from opioids, and treating physical pain or mental distress symptoms (Buttram, Kurtz, Cicero, et al. 2019). Furthermore, a small number of studies report that gabapentin and buprenorphine are used together for the purpose of getting high, and gabapentin is misused to potentiate the effects of methadone and other prescription opioids (Baird, Fox, and Colvin 2013; Reeves and Ladner 2014; Buttram, Kurtz, Cicero, et al. 2019; Vickers Smith, et al. 2018). Law enforcement agencies are seeing increasing rates of gabapentin diversion, with diverted gabapentin being combined and used in conjunction with heroin (Buttram et al. 2017).

Such combination use of gabapentin and opioids carries with it the risk for negative health consequences (Peckham and Sclar 2019). In fact, gabapentin and pregabalin can contribute to polysubstance-related fatalities, with the most significant risk being respiratory depression and overdose when these drugs are used in combination with opioids (Evoy et al. 2019). Additional adverse events associated with gabapentin include nausea, hypotension, sedation, ataxia, toxicity, increased drug tolerance, and symptoms of dependence and withdrawal (Evoy, Morrison, and Saklad 2017; Vickers-Smith et al. 2019).

The increasing visibility of adverse health consequences associated with gabapentin misuse has occurred in conjunction with the implementation of legislative actions and stewardship programs designed to limit high risk opioid prescribing, and the need for alternative therapies for the treatment of pain (Goodman and Brett 2017). In this regard, data from Kentucky’s prescription drug monitoring program shows that the rate of opioid prescriptions per 100 Kentucky residents peaked in 2011 and has dropped each year since (Centers for Disease Control and Prevention 2020). At the same time, an analysis of a national commercial insurance claims database indicates that the state of Kentucky recorded the highest prevalence of gabapentin prescribing among all states in 2016 and the state’s gabapentin prescribing rate per 1,000 population increased 85% from 2009 to 2016 (Pauly et al. 2020). This analysis also found that individuals who were prescribed gabapentin had higher rates of substance use disorder compared to those not prescribed. Increased exposure to gabapentin among vulnerable individuals with substance use disorder warrants additional examination given the emerging evidence of adverse consequences associated with its use.

Within this context, PWID often experience serious health complications, including use disorder, mental distress, health problems and infections that interfere with daily activities, and physical pain (Anagnostopoulos et al. 2018; Dahlman et al. 2017; Staton et al. 2017). Difficulty in accessing formal healthcare services as well as experiences of stigma in healthcare settings exacerbate many of these health complications (Al-Tayyib et al., 2015; Paquette, Syvertsen, and Pollini, 2018). As a result, prescription drug misuse among PWID is associated with physical and mental distress as these individuals attempt to self-manage physical pain and cope with limited healthcare access by misusing prescription drugs, including opioids and benzodiazepines (Khosla et al., 2011; Voon et al., 2014). Despite the growing literature on gabapentin misuse, there are no apparent studies specifically examining gabapentin misuse among PWID.

The increasing misuse of gabapentin and associated negative consequences, combined with elevated risks related to injection and combination drug use, and a multitude of physical and mental health problems, indicate that PWID may be highly vulnerable to adverse impacts of gabapentin, particularly in a rural state with high background prescribing prevalence and medically underserved areas. To address this apparent gap in the literature, the present paper examines factors associated with gabapentin misuse among a sample of PWID in Appalachian Kentucky. Based on prior literature, the primary aims of this analysis are to assess recency of gabapentin misuse and to identify factors associated with gabapentin misuse (e.g., achieve a desired psychoactive effect, self-treat health problems; compensate for limited healthcare services) in an effort to improve potential prevention and intervention efforts and inform future research.

Methods

Study sample and recruitment

The data were collected as part of a National Institute on Drug Abuse-funded study of social environmental factors influencing the uptake of syringe service programs (SSPs) among PWID in Appalachian Kentucky. A total of 324 participants completed comprehensive baseline assessments between February 2018 and October 2019. As of March 2020, data collection is ongoing.

The initial sampling strategy was based on respondent-driven sampling (RDS) (Heckathorn 1997) in the SSPs and targeted community locations to engage PWID not currently utilizing the SSPs. The research team initially recruited a handful of seeds (index participants) in each of the three participating SSP locations. Each seed and subsequent study participant was provided with up to three recruitment coupons to give to other PWID in their social network. Many seeds proved to be insufficiently networked and were unable to refer any eligible recruits to the study. As a result of numerous unproductive seeds, the study team continued to recruit new seeds at each SSP location on an ongoing basis and provided all subsequent seeds with three referral coupons. Nevertheless, just 37% of the SSP sample was comprised of RDS coupon referrals, ranging from 34% to 41% across the three sites. Direct recruitment within the SSPs was utilized to enroll the balance of the sample.

For the non-SSP sample, we identified multiple starting points in community-based locations to recruit seeds, including local churches, grocery stores, housing complexes, and homeless services organizations, and located community key informants who permitted the team to post study advertisements. This community outreach process was successful in identifying initial eligible participants for enrollment and interview, however subsequent referrals through RDS were not robust. Several seeds reported trying to recruit their peers unsuccessfully, most often due to concerns about privacy, mistrust, and fear. Overall, 26% of the non-SSP sample were RDS coupon referrals; the remainder were direct recruits from community outreach efforts.

Study procedures

Enrollment occurred in the three county health department SSPs, as well as local faith community organizations. Research staff verified study eligibility, obtained informed consent, and administered a structured face to face interview lasting approximately 40 minutes to eligible participants. Participants were compensated with a $20 gift card upon interview completion. All study protocols were reviewed and approved by the university’s Institutional Review Board.

Study Measures

The interview instrument was primarily based on the Global Appraisal of Individual Needs (GAIN; GAIN-I 2016), and it included abbreviated segments of the core domains: demographics, substance use, physical health, sexual risk behaviors, mental health, and environment. During the interview, participants were instructed that prescription drug misuse does not include use as instructed under the direction of a doctor, but misuse includes using prescription drugs to get high, for fun, to relax, or to come down.

Dependent variable

Recent (past 90 days) gabapentin misuse was assessed with the question, “When was the last time that you used gabapentin to get high, for fun, to relax or come down?” Responses of within the past 90 days were coded as “1”. All other responses, including, “ were coded as “0”.

Independent variables

We assessed gender, race/ethnicity, age, education, SSP utilization, and county. Participants were able to identify as male, female, transgender, or other. For analyses, this variable was dichotomized as “females” versus not. Race/ethnicity was assessed by asking participants whether they were Hispanic or Latino/a, followed by asking them what race/ethnicity they consider themselves to be. Years of education was assessed with the question, “What is the last grade or year that you completed in school?” SSP utilizer status was based on location of recruitment (within the SSP versus not); for those recruited outside of the SSP, a single screener item assessed recent use of the SSP. County indicates the location in which the participant was recruited.

Similar to the dependent variable described above, the GAIN also assesses recency of use of alcohol, marijuana, cocaine, crack, cocaine, heroin, ecstasy, methamphetamine, benzodiazepines, prescription stimulants, prescription opioids, buprenorphine, and fentanyl. For analyses, substance use measures were dichotomized into, “past 90 days,” versus not. Injection frequency was assessed by asking, “How many times (number of injections) did you inject drugs in the last 30 days?” Primary drug of injection was assessed with the question, “Which drug do you inject most often?”

Severe mental distress was assessed by the 6 item GAIN Internalizing Disorder Screener that included somatic complaints, depression, anxiety, trauma, psychosis, and suicide and recency of each symptom. The endorsement of symptoms experienced during the past 90 days were dichotomized into “severe” (three or more symptoms) versus not, with severe scores suggesting possible diagnosed mental illness and needing mental health interventions/services (Dennis, Feeney, and Titus 2013). Substance Use Disorder was assessed by the 11 item GAIN Substance Use Disorder scale that examined symptoms of substance abuse, dependence, and craving in alignment with the Diagnostic and Statistical Manual of Mental Disorders, 5th edition (GAIN-I 2016). The endorsement of symptoms experienced during the past 90 days were dichotomized into “severe” (three or more symptoms) versus not, with severe scores suggesting possible substance use disorder diagnosis and needing interventions/services (Dennis, Feeney, and Titus 2013). Overdose was assessed by asking participants if they have ever overdosed. Physical pain or discomfort was assessed with the question, “During the past 90 days have you had a lot of physical pain or discomfort?” with responses dichotomized into “yes” versus not.

Substance use treatment was assessed by asking participants, “when was the last time (if ever) you receive any counseling, treatment, medication, case management or aftercare for your use of alcohol or any drug?” Responses were dichotomized into “treatment” versus not. Unsuccessful treatment attempt was assessed with the question, “In the past 90 days, did you try but were unable to get treatment for alcohol or drug problems?” Participants also responded to additional dichotomous questions, including “Do you have a physician who you consider to be ‘your doctor’ or a clinic you consider ‘your regular source of medical care’?”, “Have you received care from a doctor in the past year?”, and “Are you currently prescribed buprenorphine?”

Analyses

All analyses were conducted using IBM SPSS Statistics version 25. Descriptive statistics were calculated for the variables of interest. Bivariate logistic regression models were constructed to examine associations with recent gabapentin misuse. Variables in the bivariate models included demographics, substance use, health problems, and healthcare activities. Those measures that exhibited significant associations (p≤.05) in the bivariate models were included in a multivariable logistic regression model. Collinearity diagnostics were examined among variables included in the multivariable model; all had variance inflation factors of 1.692 or lower.

Results

Sample characteristics

The study includes 324 PWID, of which 193 reported recent gabapentin misuse. Sample characteristics are shown in Table 1. Half of the sample was female (50.0%) and participants identified as Hispanic (2.2%), African American/Black (1.5%), white (90.7%), and another race/ethnicity (4.6%). The mean age was 37.3 and mean years of education was 11.4. A majority of participants were utilizers of SSPs (58.3%). County residence included Clark (46.9%), Knox (40.4%), and Owsley (12.7%).

Table 1:

Sample Characteristics (N=324)

N %
Demographics and Background
Female 162 50.0%
Race/ethnicitya
 Hispanic 7 2.2%
 African American/Black 5 1.5%
 White 294 90.7%
 Other race/ethnicity 15 4.6%
Age (mean; SD) 37.31 (9.547)
Last grade completed in school (mean;SD) 11.40 (2.030)
SSP utilizer 189 58.3%
County of residence
 Clark 152 46.9%
 Knox 131 40.4%
 Owsley 41 12.7%
Substance Useb
 Alcohol 106 32.8%
 Marijuana 200 61.9%
 Cocainec 44 13.6%
 Crack cocainec 31 9.6%
 Heroinc 90 27.9%
 Ecstasyc 9 2.8%
 Methamphetamine 271 83.9%
 Benzodiazepinesc 98 30.3%
 Prescription stimulantsd 20 6.2%
 Prescription opioids 101 31.3%
 Buprenorphined 158 48.9%
 Fentanyld 45 13.9%
 Gabapentin 139 43.0%
Drug Injection
Injection frequencye,f (mean; SD) 91.33 (109.528)
Primary drug of injectiona
 Methamphetamine 169 52.2%
 Buprenorphine 67 20.7%
 Heroin 41 12.7%
 Prescription opioids 37 11.4%
 Other 7 2.2%
Health Problems
 Severe mental distressb 261 80.6%
 Severe substance use disorderb 208 64.2%
 Ever overdosed 119 36.7%
 A lot of physical pain or discomfortb 181 55.9%
Healthcare Service Utilization
 Ever substance use treatment 227 70.1%
 Unsuccessful treatment attemptb 45 13.9%
 Have a regular physician or clinic 160 49.4%
 Received care from a doctorg 225 69.4%
 Currently prescribed buprenorphine 48 14.8%
 Currently prescribed pain medication(s) 29 9.0%
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a

three cases missing;

b

past 90 days;

c

one case missing;

d

two cases missing;

e

past 30 days;

f

17 cases DK/Refused;

g

past year

The most frequently reported substance used during the past 90 days was methamphetamine (83.9%). Additional substances (mis)used included marijuana (61.9%), buprenorphine (48.9%), gabapentin (43.0%), alcohol (32.8%), prescription opioids (31.3%), benzodiazepines (30.3%), heroin (27.9%), fentanyl (13.9%), cocaine (13.6%), crack cocaine (9.6%), prescription stimulants (6.2%), and ecstasy (2.8%). On average, participants injected 91.33 times in the past 30 days and the most frequently injected drugs included methamphetamine (52.2%), buprenorphine (20.7%), and heroin (12.7%).

Recent health problems reported among the sample included severe mental distress (80.6%), severe substance use disorder (64.2%), history of drug overdose 36.7%, and experiencing a lot of physical pain or discomfort (55.9%). The majority of participants reported a history of substance use treatment (70.1%) while smaller numbers described an unsuccessful treatment attempt during the past 90 days (13.9%). Nearly half of participants have a regular physician or clinic (49.4%) and a majority received care from a doctor in the past year (69.4%). Few participants have current prescriptions for buprenorphine (14.8%) and pain medication(s) (9.0%).

Bivariate logistic regression models

Bivariate logistic regression models are shown in Table 2. Eight substance use measures were associated with higher odds of recent gabapentin misuse, including marijuana (OR=1.739; p=.019), cocaine (OR=1.933; p=.044), methamphetamine (OR=2.137; p=.021), benzodiazepines (OR=2.325; p=.001), prescription stimulants (OR=2.666; p=.042), prescription opioids (OR=3.054; p=.000), buprenorphine (OR=1.828; p=.008), and fentanyl (OR=1.002; p=.028). Past 90-day measures of severe substance use disorder (OR=2.781; p=.000) and having a lot of physical pain or discomfort (OR=2.022; p=.003) were also associated with higher odds of recent gabapentin misuse.

Table 2:

Bivariate logistic regression models predicting recent gabapentin misuse (N=324)

p OR 95% CI
Demographics and background
 Female .313 .797 .513, 1.238
 Age .550 .993 .970, 1.016
 Non-white race/ethnicity .900 .951 .430, 2.102
 Clark County .344 .808 .519, 1.257
 Knox County .552 1.157 .740, 1.811
 Owsley County .634 1.173 .608, 2.264
 SSP utilizer .167 1.370 .877, 2.141
Substance Usea
 Alcohol .187 1.370 .858, 2.186
 Marijuana .019 1.739 1.095, 2.761
 Cocaine .044 1.933 1.017, 3.675
 Crack cocaine .635 .832 .390, 1.777
 Heroin .101 1.505 .923, 2.456
 Ecstasy .916 1.075 .283, 4.078
 Methamphetamine .021 2.137 1.123, 4.068
 Benzodiazepines .001 2.325 1.4348, 3.771
 Rx stimulants .042 2.666 1.034, 6.873
 Rx opioids .000 3.054 1.876, 4.971
 Buprenorphine .008 1.828 1.169, 2.857
 Fentanyl .028 2.046 1.081, 3.875
Drug injection frequencyb .141 1.002 .999, 1.005
Healt Problems
 Severe mental distressa .089 1.650 .926, 2.941
 Severe substance use disordera .000 2.781 1.704, 4.538
 Ever overdosed .633 .894 .566, 1.413
 A lot of physical pain or discomforta .003 2.022 1.279, 3.198
Healthcare Service Utilization
 Ever substance use treatment .218 1.360 .834, 2.218
 Unsuccessful treatment attempta .416 1.301 .691, 2.448
 Have a regular physician or clinic .136 .715 .460, 1.112
 Received care from a doctor (past year) .967 1.010 .618, 1.652
 Currently prescribed buprenorphine .429 .775 .412, 1.457
 Currently prescribed pain medication(s) .339 .677 .304, 1.507
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a

past 90 days;

b

past 30 days

Multivariable logistic regression model

In the multivariable model, recent prescription opioid and buprenorphine misuse, severe substance use disorder, and experiencing a lot of physical pain or discomfort demonstrated significant associations with recent gabapentin misuse. For individuals reporting prescription opioid misuse, the odds of recent gabapentin misuse were more than three times those of other participants in the sample (aOR=3.584; p<.000). Buprenorphine misuse was also significantly associated with recent gabapentin misuse (aOR=1.880; p=.038). Participants with severe substance use disorder had 2.185 times higher odds of reporting recent gabapentin misuse, compared with others in the sample (p=.022). Similarly, physical pain also displayed a strong association with recent gabapentin misuse (aOR=2.148; p=.016).

Discussion

Among this sample of PWID in Appalachian Kentucky, 43% reported recent gabapentin misuse, which exceeds prior reports indicating that 15%−26% of prescription opioid misusers report gabapentin misuse (Bastiaens, Galus, and Mazur 2016; Smith, Lofwall, and Havens 2015; Wilens et al. 2015). Gabapentin prescribing has increased in Kentucky since 2009 and the state reports the highest state prevalence of gabapentin prescribing in 2016 (Pauly et al. 2020). As a result, the increased availability of gabapentin, likely contributes to growing gabapentin diversion and misuse.

Nearly half the sample reported buprenorphine misuse, yet only 14.8% reported a current buprenorphine prescription. Such findings suggest that users may have limited availability and access to buprenorphine for treatment of opioid use disorder and are therefore misusing diverted buprenorphine to manage withdrawal symptoms. Similar findings have been reported elsewhere (Cicero et al. 2014). However, findings from the multivariable model demonstrated a strong association between reports of prescription opioid and buprenorphine misuse, as well as severe substance use disorder, and recent gabapentin misuse. Recent studies found that gabapentin is used in combination with opioids for the purpose of getting high (Buttram, Kurtz, Cicero, et al. 2019; Vickers Smith, et al. 2018), and although buprenorphine is rarely misused for its euphoric properties (Cicero et al. 2014), limited reports suggest that gabapentin and burprenorphine may be misused in combination for the purpose of getting high (Reeves and Ladner 2014; Vickers Smith, et al. 2018). At the same time, it is conceivable that participants with severe substance use disorder may misuse gabapentin to self-treat withdrawal symptoms when opioids or other drugs of choice are unavailable, similar to other gabapentin misusers (Buttram, Kurtz, Cicero, et al. 2019). Investigations of the relationship between gabapentin, buprenorphine, and other prescription opioids, including concomitant use, are needed.

Among this sample of PWID, individuals reporting recent gabapentin misuse were more likely to report having a lot of physical pain or discomfort. Physical pain among PWID has been reported elsewhere (Bicket et al. 2020; Dahlman et al. 2017) and self-management of pain among vulnerable PWID includes the use of heroin and diverted prescription opioids (Bicket et al. 2020; Voon et al. 2014). Ethnographic data from South Florida indicate that misusing gabapentin to self-treat physical pain symptoms is common (Buttram, Kurtz, Cicero, et al. 2019). Thus, obtaining and misusing gabapentin may be a direct response to experiencing pain. Off-label prescribing of gabapentin includes treatment of physical pain (Peckham et al. 2018); however, questions remain as to whether gabapentin is an appropriate medication to prescribe for pain treatment, including among individuals with substance abuse histories (Buttram, Kurtz, Ellis, et al. 2019; Goodman and Brett 2017). Future research must continue to examine gabapentin’s role in the treatment of pain among people who use drugs and related consequences, as well as the misuse of gabapentin for this purpose.

Findings from this study may offer guidance on recruitment of PWID in rural locations. As described above, the sampling strategy was based on RDS (Heckathorn 1997), however many challenges to implementation were encountered. Many “seeds” were unable to recruit additional study participants in large numbers, and as a result, the majority of participants in this study were recruited directly from SSPs or through community outreach. Although RDS is an appropriate method for recruiting hidden or hard-to-reach populations, previous research has reported small social networks among PWID and the difficulty in using RDS for recruitment (Paquette, Bryant, & de Wit 2012). Moreover, the study sites were small population and rural counties, which likely contributed to the limited social networks of participants, and exacerbated fear of disclosing injection drug use through study participation. Future research among rural PWID may need to include a relatively large number of seeds to yield a successful RDS sample (Bryant 2014).

These findings illustrate the need for additional research. This is the first apparent study of gabapentin misuse conducted among a sample of primarily methamphetamine using PWID. While these data add considerably to the growing literature on gabapentin misuse, future studies are needed to examine the context of gabapentin misuse among methamphetamine users. Based on the present findings and current literature describing gabapentin misuse within the context of illicit and prescription opioid use and misuse, future research should examine the misuse of gabapentin to potentiate the effects of methamphetamine, moderate methamphetamine withdrawal symptoms, or to cease methamphetamine use. Additional characteristics of participants in this study, including drug injection and rural geography may influence gabapentin misuse behaviors. These unique factors and context should also be examined.

In spite of the need for additional research, the findings have several implications for health and social services for PWID. As of 2019, the U.S. Food and Drug Administration requires new warnings about respiratory depression for gabapentin, especially when used in combination with opioids (U.S. Food and Drug Administration, 2019) and reports of negative consequences of polydrug use involving gabapentinoids are severe (Evoy, Morrison, and Saklad 2017). As a result, prescribers should use additional caution when prescribing gabapentin and outreach to people who use drugs is needed. Syringe service programs and safe injection sites offer opportunities to educate PWID about the potential dangers of polydrug use involving gabapentin. Moreover, these locations may be able to assess motivations for gabapentin misuse, including drug use detoxification and cessation, and to connect these individuals with necessary health, social, or substance use treatment services.

Limitations

This study has some limitations which must be noted. Participants in the sample are broadly representative of the racial/ethnic and gender composition of the region, it is unclear where these findings can be generalized to gabapentin misusers or PWID in other locations or contexts. Due to limited success with recruitment through RDS, the sample cannot be considered representative and resembles a convenience sample. All data are based on self-report; drug use biomarkers were not included in assessments. However, the high levels of substance use and other risk behaviors suggest that underreporting of these behaviors appears to be minimal. The survey did not assess the source(s) of misused gabapentin and thus it is unknown whether participants misused their own prescribed medication or obtained diverted medication. Furthermore, diagnostic measures of severe mental distress and substance use disorder were not clinician-administered. Thus, caution is warranted when comparing these measures to other studies. Finally, the cross-sectional data presented do not permit attributions of causality to the observed relationships.

Conclusions

This is one of the first studies to examine gabapentin misuse among PWID. It is possible that individuals reporting recent gabapentin misuse are doing so to supplement for limited sources of healthcare and to self-treat physical pain. In addition, gabapentin may also be misused to achieve desired central nervous system effects and to potentiate the central nervous system effect of prescription opioids and buprenorphine. However, comprehensive research is needed to further examine gabapentin misuse within the contexts of self-treating physical pain, as well as drug injection. Moreover, the augmentation of educational and harm reduction messaging at SSPs to include polysubstance use and gabapentin appears warranted.

Table 3:

Multivariable logistic regression models predicting recent gabapentin misuse (N=324)

p aOR 95% CI
Demographics and background
 Female .140 .645 .360, 1.155
 Age .442 .987 .956, 1.019
 Non-white race/ethnicity .994 .996 .341, 2.909
 SSP utilizer .334 1.347 .736, 2.468
County (ref = Owsley)
 Clark County .208 .503 .173, 1.465
 Knox County .844 1.106 .404, 3.029
Substance Usea
 Alcohol .416 1.302 .690, 2.459
 Marijuana .858 1.058 .569, 1.966
 Cocaine .094 2.253 .870, 5.831
 Crack cocaine .150 .434 .139, 1.354
 Heroin .838 1.088 .483, 2.451
 Ecstasy .328 .392 .060, 2.560
 Methamphetamine .158 1.881 .782, 4.525
 Benzodiazepines .754 1.120 .553, 2.268
 Rx stimulants .389 1.962 .423, 9.102
 Rx opioids .000 3.584 1.769, 7.260
 Buprenorphine .038 1.880 1.034, 3.418
 Fentanyl .080 2.431 .900, 6.567
Drug injection frequencyb .747 1.000 .998, 1.003
Health Problems
 Severe mental distressa .846 1.081 .493, 2.368
 Severe substance use disordera .022 2.185 1.120, 4.263
 Ever overdosed .164 .633 .333, 1.205
 A lot of physical pain or discomforta .016 2.148 1.154, 3.997
Healthcare Service Utilization
 Ever substance use treatment .748 1.121 .560, 2.245
 Unsuccessful treatment attempta .871 1.068 .483, 2.361
 Have a regular physician or clinic .079 .553 .286, 1.071
 Received care from a doctor (past year) .600 .833 .422, 1.647
 Currently prescribed buprenorphine .428 1.439 .585, 3.539
 Currently prescribed pain medication(s) .876 .923 .338, 2.521
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Acknowledgements

This research was supported by Grant R21 DA044251 from the National Institute on Drug Abuse. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute on Drug Abuse or the National Institutes of Health.

Funding:

This research was supported by DHHS Grant Number R21 DA044251 from the National Institute on Drug Abuse. The content is solely the responsibility of the author and does not necessarily represent the official views of the National Institute on Drug Abuse or the National Institutes of Health.

Footnotes

Declaration of Interest

No conflicts declared.

Contributor Information

Mance E. Buttram, Center for Applied Research on Substance Use and Health Disparities, Nova Southeastern University, Miami, FL

Hilary L. Surratt, Department of Behavioral Science, College of Medicine, University of Kentucky, Lexington, KY

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