Abuse and Diversion of Gabapentin Among Nonmedical Prescription Opioid Users in Appalachian Kentucky
To the Editor: Gabapentin is approved by the Food and Drug Administration as an adjunctive antiepileptic for refractory partial seizures and as an analgesic for postherpetic neuralgia. It is presumed to interact with calcium channels to regulate various neurotransmitter release (1) and is commonly prescribed off-label for other pain syndromes, as well as mood and anxiety disorders (2), with few reports of abuse (2–5). However, with decreasing availability of commonly abused prescription opioids, it has been suggested that nonmedical users of prescription opioids are substituting other licit (6) and illicit (7) drugs for abuse.
For example, in a cohort of 503 adults reporting current, nonmedical use of diverted prescription opioids in Appalachian Kentucky (and not presently in substance abuse treatment; study details are described elsewhere [8]), 15% of participants identified using gabapentin specifically “to get high” in the past 6 months. This represents a 165% increase in use compared with reports from 1 year prior and a 2,950% increase since 2008 within this cohort. Participants reported using gabapentin an average of 25 of the past 30 days and were more likely than nonusers to be abusing immediate-release oxycodone (64.8% compared with 46.5%; difference in percentages [d]=18.3%; 95% Wald continuity corrected confidence interval [CI]=3.1%–31.5%), buprenorphine (44.4% compared with 26.0%; d=18.4%; 95% CI=4.3%–33.1%), and benzodiazepines (42.6% compared with 21.6%; d=21.0%; 95% CI=7.1%–35.7%) in the prior 30 days “to get high.” There were no differences in past 30-day use of heroin, cocaine, and methamphetamine. Females (77.8%; d=17.3%; 95% CI=10.4%–24.6%) and participants reporting chronic medical conditions (48.2%; d=16.3%; 95% CI=1.8%–31.0%) were also significantly more likely to report gabapentin use. The two major sources of gabapentin were physicians (52%) and drug dealers (36%), and street costs were reported to be less than $1.00 per pill. Several volunteers reported use of dosages outside the range of standard medical care.
To our knowledge, this is the first prospective report of gabapentin abuse in an epidemiologic study of drug users. While gabapentin may be an appropriate treatment for some individuals (e.g., those with alcohol withdrawal, chronic pain), use for these reasons was not queried. Further systematic research (e.g., amount used, route of and motivations for use) is necessary to more fully understand the patient, provider, and public health implications of this new trend. Psychiatrists prescribing gabapentin should be aware of its abuse potential.
1 : Pharmacology and mechanism of action of pregabalin: the calcium channel alpha2-delta (alpha2-delta) subunit as a target for antiepileptic drug discovery. Epilepsy Res 2007; 73:137–150Crossref, Medline, Google Scholar
2 : Gabapentin abuse, and delirium tremens upon gabapentin withdrawal. J Clin Psychiatry 2007; 68:483–484Crossref, Medline, Google Scholar
3 : Gabapentinoid abuse in order to potentiate the effect of methadone: a survey among substance misusers. Eur Addict Res 2014; 20:115–118Crossref, Medline, Google Scholar
4 : Potentiation of the effect of buprenorphine/naloxone with gabapentin or quetiapine. Am J Psychiatry 2014; 171:691Link, Google Scholar
5 : Misuse and abuse of pregabalin and gabapentin: cause for concern? CNS Drugs 2014; 28:491–496Crossref, Medline, Google Scholar
6 : The impact of a reformulation of extended-release oxycodone designed to deter abuse in a sample of prescription opioid abusers. Drug Alcohol Depend 2014; 139:9–17Crossref, Medline, Google Scholar
7 : Effect of abuse-deterrent formulation of OxyContin. N Engl J Med 2012; 367:187–189Crossref, Medline, Google Scholar
8 : Individual and network factors associated with prevalent hepatitis C infection among rural Appalachian injection drug users. Am J Public Health 2013; 103:e44–e52Crossref, Medline, Google Scholar