Introduction: Drug poisoning (overdose) deaths are a leading cause of avoidable death with rates increasing globally. According to the European Monitoring Centre for Drugs and Drug Addiction (EMCDDA), the mortality rate due to drug poisoning in the European Union in 2019 is estimated at 14.8 deaths per million population aged 15–64 years, with over three-quarters (77%) of these deaths among men.1 Consequently, as drug poisoning deaths are dominated by men, specific circumstances associated with drug poisoning deaths among women may be masked by combining trends for men and women. A 2021 publication examined differences by sex in the rates of overall drug poisoning deaths and deaths involving specific drugs implicated in drug poisoning deaths in Ireland between 2004 and 2017.2

Methods: Data for this study were extracted from the National Drug-Related Deaths Index (NDRDI) and the Health Service Executive’s Primary Care Reimbursement Service (PCRS). The NDRDI’s definition of a poisoning death is a death directly due to the toxic effect of one or more substances on the body. Joinpoint Regression Program was used to examine any changes in trends in age-standardised rates (ASR) from 2004 to 2017, expressed as annual percentage changes, with a summary of the overall trend expressed as an average annual percentage change (AAPC). The relationship between the ASR of drug poisoning deaths and prescription data for benzodiazepines and antidepressants was examined using linear regression. Analyses were stratified by sex.

Results: There has been an increase in the ASR of drug poisoning deaths in Ireland, from 6.86 per 100,000 in 2004 to 8.08 per 100,000 in 2017. This increase is mainly driven by deaths among men. For men, drug poisoning deaths involving cocaine (AAPC 7.7% [95% CI: 2.2–13.6]); benzodiazepines (AAPC 7.2% [95% CI: 2.9–11.6]); antidepressants (AAPC 6.1% [95% CI: 2.4–10.0]); and prescription opioids (AAPC 3.5% [95% CI: 1.6–5.5]) increased significantly between 2004 and 2017.

For women, drug poisoning deaths involving antidepressants (AAPC 4.2% [95% CI: 0.2–8.3]); benzodiazepines (AAPC 3.3% [95% CI: 0.1–6.5]); and prescription opioids (AAPC 3.0% [95% CI: 0.7–5.3]) increased significantly between 2004 and 2017, with a significant increase in drug poisoning deaths involving cocaine (albeit from a low baseline number of deaths), observed in the latter part (2011–2017) of the study period. While the ASR of drug poisoning deaths involving alcohol decreased among women (AAPC –4.0% [95% CI: –5.8 to –2.1]), there was no significant change observed among men.

A significant increase in two or more central nervous system (CNS) depressant drugs involved in drug poisoning deaths is reported among both men (AAPC 5.6% [95% CI: 2.4–8.8]) and women (AAPC 4.0% [95% CI: 1.1–6.9]).

Conclusions: The authors conclude that there was an increase in overall drug poisoning deaths in Ireland from 2004 to 2017. The increasing trend of two or more CNS depressant drugs implicated in drug poisoning deaths, especially the more recent significant increase among women, is of concern. The findings from this study highlight the need for an increased understanding among prescribers, people who use drugs, and policymakers of the physiological differences between men and women, how this affects drug activity in the body, and the associated risks with consumption of multiple CNS depressant drugs.

A significant decrease in drug poisoning deaths involving alcohol was reported for women. However, no significant change was reported for deaths involving alcohol among men. The authors highlight that alcohol is a CNS depressant and suggest that prescribers should assess for and advise on alcohol use when prescribing CNS depressant drugs.

Benzodiazepines were the most common drug group in deaths involving two or more CNS depressants. The decreasing rate of benzodiazepines dispensed through the PCRS appears to correspond with the introduction of stricter prescribing regulations. Given the increased availability of illicit benzodiazepines,3 this change in prescribing regulations may have partially resulted in an increased use of high-potent illicit benzodiazepines. The authors state that advocates for people who use drugs should be consulted on and contribute to policy decisions around drug use. In addition, increased focus on treatment provision for misuse of benzodiazepines should be considered. The authors suggest that harm reduction initiatives, along with treatment interventions, which include pharmaceutical combined with psychosocial assistance, need to focus on the range of problematic drugs. Furthermore, reducing stigma associated with drug use and drug poisoning deaths, aligned with actions to target economic deprivation, are required.

1   European Monitoring Centre for Drugs and Drug Addiction (EMCDDA) (2021) European drug report 2021: trends and developments. Luxembourg: Publications Office of the European Union. Available online at: https://www.drugsandalcohol.ie/34349/

2   Lynn E, Cousins G, Lyons S and Bennett KE (2021) Trends in drug poisoning deaths, by sex, in Ireland: a repeated cross-sectional study from 2004 to 2017. BMJ Open, 11(9): e048000.
https://www.drugsandalcohol.ie/34812/

3   Duffin T, Keane M and Millar SR (2020) Street tablet use in Ireland: a Trendspotter study on use, markets, and harms. Dublin: Ana Liffey Drug Project. https://www.drugsandalcohol.ie/31872/