Use of gabapentin with or without a prescription in substance use treatment settings: A national analysis of urine drug testing data, 2016–2023

BACKGROUND: Gabapentin prescriptions have increased due to off-label use, including managing withdrawal/comorbidities in substance use disorder (SUD) treatment, despite gaps in evidence bases and corresponding increases in nonmedical use. This study sought to identify trends in gabapentin use with and without a prescription in SUD treatment settings. METHODS: This retrospective, serial cross-sectional study analyzed urine drug tests (UDT) (n = 206,161) ordered from 2053 SUD settings in all 50 U.S. states, from 2016 to 2023. Specimens were analyzed by liquid chromatography-tandem mass spectrometry to assess positivity for gabapentin and other prescription and illicit drugs, with prescribed medications documented in requisitions. Multivariable regression assessed characteristics/diagnoses associated with gabapentin use with and without a prescription. RESULTS: Gabapentin was prescribed to 5.9 % of the sample, increasing from 3.9 % in 2016-7.6 % in 2023. Use of gabapentin without a prescription was identified in 11.3 % of the sample, decreasing from 15.2 % to 9.9 %. Gabapentin prescribing was associated with anxiety/mood disorders, insomnia, pain, and sedative, alcohol, or stimulant SUDs. Use without a prescription was associated with anxiety/mood disorders, and sedative or opioid SUDs. Detection was higher across all illicit substances among those engaged in gabapentin use without a prescription. CONCLUSIONS: Gabapentin prescribing significantly increased in SUD treatment settings despite a lack of strong evidence bases for its utility. While rates of gabapentin use outside a prescription were nearly double than for prescribed use, this appears to be decreasing over time. Polysubstance use and potential gaps in multimorbidity care may contribute to the use of gabapentin without a prescription.