Comprehensive toxicology testing and clinical outcomes of ED patients with unregulated drug poisoning

Unregulated drugs place a significant burden on individuals and the healthcare system, yet relatively little is known about the mix of substances implicated in the current polydrug crisis and their clinical effects. The current study aims to describe the toxicology and clinical outcomes of unregulated drug poisoning.

We conducted a cross-sectional study at a tertiary hospital in Vancouver, British Columbia. Eligible patients were those presenting to the emergency department (ED) with suspected unregulated drug overdose and residual blood samples available for analysis. Chart review was performed to extract relevant clinical data, and liquid chromatography-tandem quadruple mass spectrometry was applied to blood samples to detect a broad panel of substances beyond routine ED toxicology screens.

From 148 eligible patients, we randomly selected 69 for toxicology testing (mean age 43 years; 74% male). Amphetamines (94%), fentanyl or analogues (67%), and unregulated benzodiazepines (64%) were most prevalent. Polysubstance exposure was nearly universal, with 91% positive for three or more drug classes, 83% for four or more, and nearly half (49%) for six or more concurrently. Clinical interventions were frequent, with naloxone administered to 59% of patients, 25% requiring-assisted ventilation (including two who required intubation). Twenty-eight percent of patients were admitted to hospital, with 4% admitted to intensive care. Complications included loss of consciousness (55%), hypoxia (22%), seizures (9%), severe agitation (6%) and rhabdomyolysis (3%).

Unregulated drug poisoning in Vancouver, British Columbia was characterized by polysubstance exposure and frequent complications. Detailed toxicological analysis revealed high rates of unregulated benzodiazepines and stimulant co-detection with opioids, underscoring risks beyond opioid toxicity alone. Clinicians should be aware that unregulated drug poisoning involves multiple substances and may therefore have atypical presentations and/or incomplete response to standard therapy.