Characterization of gabapentin use in Kentucky after reclassification as a Schedule V controlled substance

Owing to increasing concern over the potential for gabapentin misuse, gabapentin was reclassified as a schedule V controlled substance in Kentucky (July 2017).

This study aimed to characterize gabapentin use among Kentucky residents in the first year after its scheduling.

This study used Kentucky All Schedule Prescription Electronic Reporting data (2018). Gabapentin use was defined as having at least 1 dispensed gabapentin prescription, and high-dose gabapentin use was defined as an average daily dose of more than 3600 mg at the patient level. The prevalence of gabapentin use, concurrent use of gabapentin with opioid analgesics (OAs) (gabapentin-OA), and gabapentin with OAs and benzodiazepines (BDZs) (gabapentin-OA-BDZ) were assessed. Estimated prevalence rate ratio and its 95% CI were reported to compare gabapentin use rates across different demographic groups.

A total of 16% of all 2018 controlled substance prescriptions were for gabapentin, and approximately 20% of Kentucky residents with controlled substance prescriptions received gabapentin at least once in 2018. The overall prevalence of gabapentin use was 63 per 1000 residents, with the highest rates among residents aged 55-64 years (126.9 per 1000). The prevalence of gabapentin use was higher in females (74.6 per 1000) versus males (50.6 per 1000) and in residents living in the Appalachian region (88.57 per 1000) versus Central (51.78 per 1000) and Delta (66.41 per 1000) regions. Among gabapentin users, 1% were high-dose users; 27.4% and 11.9% received gabapentin-OA or gabapentin-OA-BDZ concurrently, respectively. As the average daily dose increased from less than 900 mg to high-dose, the percentage of concurrent gabapentin-OA use increased from 13.4% to 50.7%.

Gabapentin is widely prescribed in Kentucky, with higher rates of use observed in females, those older than 55 years and individuals living in the Appalachian region. Concurrent use of gabapentin and OAs is common, especially in those receiving high-dose gabapentin. Future studies are needed to assess the risks associated with gabapentin use.