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

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.