Prevalence of Gabapentin Abuse: Comparison with Agents with Known Abuse Potential in a Commercially Insured US Population

Abstract

Background: Despite international calls to make gabapentin a controlled substance, studies of gabapentin use/abuse patterns are limited to small/high-risk samples and adverse event reports.

Objective: The aim of this study was to conduct a systematic assessment of the abuse potential/prevalence of gabapentin in a large sample.

Data source: Truven Health MarketScan^® Commercial Claims and Encounters database, years 2013-2015.

Eligibility criteria: Patients with two or more claims for one or more abusable drugs and ≥12 months' continuous enrollment were sampled for Lorenz curve analysis. Prevalence analysis was limited to those with ≥120 days of therapy.

Methods: Abuse potential was measured as Lorenz-1 (consumption of drug supply by top 1% of users) of ≥15%. Dose thresholds were morphine milligram equivalent (MME) standards for opioids, and maximum labeled doses in milligrams (mg) for other drugs.

Results: Lorenz-1 values were 37% opioids, 19% gabapentin, 15% pregabalin, 14% alprazolam, and 13% zolpidem. The top 1% gabapentin users filled prescriptions for a mean (median) 11,274 (9534) mg/day, more than three times the recommended maximum (3600 mg). Of these, one-quarter used or diverted ≥12,822 mg/day. The top 1% opioid and pregabalin users filled prescriptions for a mean (median) 180 (127) MMEs and 2474 (2219) mg/day, respectively. Of patients using opioids + gabapentin simultaneously, 24% had three or more claims exceeding the dose threshold within 12 months.

Limitations: Established threshold criteria for gabapentinoid abuse are uncertain. Indications for gabapentinoid use (e.g. hot flashes, restless legs syndrome) were not measured.

Conclusion: Gabapentin use patterns are similar to those of other abusable medications. High daily doses pose safety and/or diversion concerns, and investigation of the medical consequences of gabapentin abuse is needed.