Evolution of clinical characteristics and outcomes of synthetic cannabinoid receptor agonist exposure in the United States: analysis of National Poison Data System data from 2010 to 2015

Abstract

Background and aims: New synthetic cannabinoid receptor agonists (SCRAs) are synthesized each year to evade US governmental regulation and sold for recreational use. Our aim was to estimate the changes in the clinical effects and patient disposition associated with SCRA exposure from 2010 to 2015.

Design: A retrospective observational cohort study.

Setting: National Poison Data System that collects data on reports of poisonings from US poison centers.

Participants: A total of 19 388 isolated SCRA cases between 1 January 2010 and 31 December 2015 were identified. The mean age was 24.6 years and 77.8% were male.

Measurements: Primary outcome was the change in the trend of patient disposition, i.e. treated and released versus hospitalization (e.g. non-critical care, critical care unit or psychiatry) between 2010 and 2015. Secondary outcomes included the trends in the clinical effects and their duration, and therapeutic interventions nationally and regionally.

Findings: Reports of SCRA exposure peaked in 2011 (n = 5305) and 2015 (n = 5475). The majority of patients required supportive care and were treated and released from an emergency department. Hospitalization increased by annual percentage change in the log odds (APCO) of 21.0% (P < 0.0001) during the 6 years, with significant increases in admissions to critical care units and non-critical care units. Overall, tachycardia (32.1%), agitation/irritation (25.6%) and drowsiness/lethargy (20.4%) were the most frequently reported clinical effects from SCRA exposure. Clinical effects resolved within 2-8 hours in 52.8% of cases, but their duration increased markedly by 2015. Regionally, the largest number of SCRA cases was reported in the South (n = 9374, 48.6%). SCRA cases in the Northeast were hospitalized more frequently (27.4%), with cases in the Midwest being admitted more frequently to critical care units (15.3%). However, there were no significant differences in clinical toxicity or disposition among the regions.

Conclusion: Hospitalization resulting from toxicity from synthetic cannabinoid receptor agonists exposure in the United States increased significantly between 2010 and 2015.

Keywords: Drug abuse; epidemiology; national poison data system; novel psychoactive substance; synthetic cannabinoid receptor agonist; synthetic cannabinoid toxicity.