Background and importance 

Patients who use recreational drugs frequently co-ingest ethanol, which is considered a central nervous system (CNS) depressant. The clinical relevance of this in acute toxicity involving other CNS depressants is not well described.

Objective 

To assess the clinical impact of ethanol co-use in patients presenting to the emergency department (ED) with acute toxicity involving the use of CNS depressant drugs.

Design, settings and participants 

A retrospective multicentre study using data from the Euro-DEN Plus database from January 2014 to December 2019.

Outcomes measure and analysis 

Comparison of epidemiologic and clinical characteristics, ED and hospital management of patients with CNS depressant intoxication with or without ethanol co-use.

Main results 

Although 7644 (17.5%) of the 43 633 presentations were included, ethanol was co-ingested in 3811 (49.9%). In total 53.3% required medical treatment, 14 patients died. Patients with ethanol co-use more frequently presented with a Glasgow Coma Scale (GCS) ≤8 (34.1% vs. 22.4%; P < 0.001), vomiting (8.1% vs. 4.6%; P < 0.001), anxiety (12 % vs. 6.4%; P < 0.001), agitation/aggression (22% vs. 14.7%; P < 0.001), seizures (3.8% vs. 2.4%; P < 0.001) and hypotension (7.5% vs. 4.6%; P < 0.001). They more often required ambulance transport (85.5% vs. 76.5%; P < 0.001), medical treatment (57.3% vs. 48.0%; P < 0.001), hospitalization (27.7% vs. 18.9%; P < 0.001), and admission to intensive care (12.2% vs. 4.0%; P < 0.001). Subgroup analysis showed that GCS ≤8 was particularly common in patients who combined ethanol with opioids or gamma-hydroxybutyrate (GHB)/gamma-butyrolactone (GBL).

Conclusion 

Co-use of ethanol with CNS-depressant drugs appears to increase the risk of adverse effects and is associated with a higher need for medical treatment, especially when ethanol is combined with opioids or GHB/GBL.