Prevalence of gabapentin in drug overdose postmortem toxicology testing results

Background: The goal of this study was to establish and compare baseline data on the prevalence of gabapentin identified through postmortem toxicology testing among drug overdose decedents in several geographically diverse states/jurisdictions with differing levels of drug overdose fatality burdens in 2015.

Methods: Death certificates and postmortem toxicology result reports from five U.S. jurisdictions were used to identify residents who died from drug overdoses in year 2015 and to calculate prevalence rates of gabapentin in postmortem toxicology by jurisdiction.

Results: On average, 22% of all drug overdose decedents in our study tested positive for gabapentin. The percentage of gabapentin-positive overdose deaths varied significantly among jurisdictions: 4% in Northeast Tennessee, 7% in Maricopa County, 15% in West Virginia, 20% in North Carolina, and 41% in Kentucky (p < 0.0001). Among the drug overdose decedents who tested positive for opioids (including heroin), 26% also tested positive for gabapentin, with significant variation among states/jurisdictions (p < 0.0001). There was a significant difference in the gender distribution among drug overdose decedents who tested positive for gabapentin (46% male) vs. those who tested negative for gabapentin (65% male) (p < 0.0001). In Kentucky, gabapentin was listed as a contributing drug on the death certificate in 40% of the overdose deaths with gabapentin-positive toxicology; in North Carolina this percentage was 57%.

Conclusions: Routine gabapentin postmortem testing and linking of death certificate, medical examiner, coroner, toxicology, and prescription history data will provide more reliable information on the extent of gabapentin misuse, diversion, and implications for clinical care.