Prescribing Patterns in Fatal Intoxications Involving Zopiclone and Alprazolam: An Observational Register-Based Study.

BACKGROUND

Zopiclone was recently identified as a frequent contributor to fatal drug-intoxications in Sweden. However, characteristics of misuse and factors associated with prescribed use remain insufficiently described. Alprazolam has a more established misuse profile.

OBJECTIVE

The aim of the study was to describe and compare characteristics of fatal intoxications positive for zopiclone or alprazolam, focusing on prescription status and factors associated with prescribed drug use.

METHODS

Fatal intoxications between 2012 and 2020 with zopiclone and/or alprazolam in blood were identified using the Swedish Cause of Death Register and the Swedish forensic medicine database. Prescriptions within 1 year before death, and health and sociodemographic data were obtained from national registers.

RESULTS

Among 1270 zopiclone cases, 84% were prescribed users compared to 22% of 1532 alprazolam cases. For both substances, prescribed use was associated with female sex (zopiclone: aOR = 1.68, 95% CI = 1.22-2.30; alprazolam: aOR = 2.04, 95% CI = 1.54-2.71), suicide relative to accidental intoxication (zopiclone: aOR = 1.61, 95% CI = 1.11-2.33; alprazolam: aOR = 3.21, 95% CI = 2.16-4.75) and age ≥ 46 years (zopiclone: aOR = 2.26, 95% CI = 1.45-3.54; alprazolam: aOR = 3.20, 95% CI = 2.29-4.46). Psychiatry-contact and previous self-harm were associated with prescribed zopiclone use, but not alprazolam.

CONCLUSION

Fatal intoxications involving zopiclone differ from alprazolam. While factors associated with prescribed use were often shared, substance-specific preventative strategies could be beneficial.