AIM We explored trends in gabapentinoid prescribing, drug seizures and post mortem toxicology using a national pharmacy claims database, law enforcement drug seizures data and a population based post mortem toxicology database.

METHODS Gabapentinoid prescribing rates per 100,000 eligible population (2010-2020), annual number of drug seizures involving gabapentinoids (2012-2020), and gabapentinoid detection (positive) rates per 100 post mortem toxicology case (2013-2020) were calculated. Negative binomial regression models were used to evaluate longitudinal trends for gabapentin and pregabalin separately.

RESULTS Gabapentin (Adjusted Rate Ratio (ARR) 1.06, 95% CI 1.05-1.06, p <0.001) and pregabalin (ARR 1.08, 95% CI 1.08-1.09, p<0.001) prescribing increased annually, with higher rates of pregabalin (vs gabapentin) observed every year. Drug seizures involving pregabalin also increased over time (RR 1.54 95% CI 1.25-1.90, p<0.0001). Of the 26,317 post mortem toxicology cases, 0.92% tested positive for gabapentin, 6.37% for pregabalin. Detection rates increased for both gabapentin (RR 1.28, 95% CI 1.11 - 1.48, p<0.001) and pregabalin (RR 1.13, 95% CI 1.11-1.48, p<0.001) between 2013 and 2020. A total of 1,901 cases (7.2%) tested positive for heroin/methadone; this sub-group had a higher detection rate for pregabalin (n=528, 27.8%) and gabapentin (n=41, 2.2%) over study period, with a high burden of co-detections for pregabalin with benzodiazepines (peaking at 37.3% in 2018), and pregabalin with prescription opioids (peaking at 28.9% in 2020) CONCLUSIONS: This study raises concerns regarding the wide availability of pregabalin in Ireland, including a growing illicit supply, and the potential for serious harm arising from poly drug use involving pregabalin among people who use heroin or methadone.