Acute Poisonings from Synthetic Cannabinoids - 50 U.S. Toxicology Investigators Consortium Registry Sites, 2010-2015

Abstract

Recent reports suggest that acute intoxications by synthetic cannabinoids are increasing in the United States (1,2). Synthetic cannabinoids, which were research compounds in the 1980s, are now produced overseas; the first shipment recognized to contain synthetic cannabinoids was seized at a U.S. border in 2008 (3). Fifteen synthetic cannabinoids are Schedule I controlled substances (3), but enforcement is hampered by the continual introduction of new chemical compounds (1,3). Studies of synthetic cannabinoids indicate higher cannabinoid receptor binding affinities, effects two to 100 times more potent than Δ(9)-tetrahydrocannabinol (the principal psychoactive constituent of cannabis), noncannabinoid receptor binding, and genotoxicity (4,5). Acute synthetic cannabinoid exposure reportedly causes a range of mild to severe neuropsychiatric, cardiovascular, renal, and other effects (4,6,7); chronic use might lead to psychosis (6,8). During 2010-2015, physicians in the Toxicology Investigators Consortium (ToxIC) treated 456 patients for synthetic cannabinoid intoxications; 277 of the 456 patients reported synthetic cannabinoids as the sole toxicologic agent. Among these 277 patients, the most common clinical signs of intoxication were neurologic (agitation, central nervous system depression/coma, and delirium/toxic psychosis). Relative to all cases logged by 50 different sites in the ToxIC Case Registry, there was a statistically significant association between reporting year and the annual proportion of synthetic cannabinoid cases. In 2015, reported cases of synthetic cannabinoid intoxication increased at several ToxIC sites, corroborating reported upward trends in the numbers of such cases (1,2) and underscoring the need for prevention.

FIGURE 1. Toxicology Investigators Consortium (ToxIC)* registry cases caused by all agents and by synthetic cannabinoid,^† by U.S. registry site location^§ — January 1, 2010–November 30, 2015

*ToxIC is a select, volunteer network and thus not geographically representative of the United States or the cities where participating sites are located; many sites joined ToxIC after its establishment in 2010 by the American College of Medical Toxicology. ^†As primary agent or part of multiagent exposure. ^§As of November 2015, there were active ToxIC registry sites in 41 U.S. cities, with a few cities (e.g., Boston and New York City) having multiple sites.

FIGURE 2. Percentage of reported ToxIC* registry cases^† caused by synthetic cannabinoids, by U.S. Census region — 2010, 2014, and 2015

*ToxIC is a select, volunteer network and thus not geographically representative of the United States or the cities where participating sites are located; many sites joined ToxIC after its establishment in 2010 by the American College of Medical Toxicology. ^†Includes only cases from sites that reported any synthetic cannabinoid cases.