Although an understanding of the adverse effects that occur when new drugs become available or their availability increases—such as with the legalization of recreational cannabis use—is important, few studies have assessed the relative harms of edible and inhalable cannabis products. To describe and compare adult emergency department (ED) visits related to exposure to such products, Andrew A. Monte, MD, PhD, conducted a retrospective chart review analysis of patients presenting to the busiest ED in Colorado between January 2012 and December 2016 with cannabis-related ICD-9 or ICD-10 codes. Results were published in Annals of Internal Medicine.

“We hoped to determine if edibles lead to more ED visits when controlled for the amount of products in our community,” says Dr. Monte. “The total ED volume during the study period was >440,000 visits, and we reviewed almost 10,000 records individually.” Patient demographic characteristics, route of exposure, dose, symptoms, length of stay, disposition, discharge diagnoses, and attribution of visit to cannabis were captured.

Among the 9,973 visits assessed, 25.7% were at least partially attributable to cannabis, among which 9.3% were related to edible cannabis. Whereas inhaled cannabis-attributable visits were more likely to be for cannabinoid hyperemesis syndrome (18.0% vs 8.4%), edible cannabis-attributable visit were more likely to be due to acute psychiatric symptoms (18.0% vs 10.9%), intoxication (48% vs 28%), and cardiovascular symptoms (8.0% vs 3.1%). “When controlled for product availability via product sales data, edible cannabis products lead to approximately 30 times more ED visits per milligram of tetrahydrocannabinol than inhaled cannabis,” explains Dr. Monte. Indeed, edibles accounted for 10.7% of cannabis-attributable visits during the study period but represented only 0.32% of total cannabis sales in Colorado.

With the study limited by a retrospective design, being conducted at a single academic center, using self-reported exposure data, and having limited availability of dose data, Dr. Monte hopes to see prospective cohort studies of cannabis users and non-users in order to determine the medical benefits and risks associated with use. In the meantime, he says “We must educate cannabis users about the risks of cannabis edible products. Specifically, there are more acute psychiatric visits and more cardiovascular-related visits in edible versus inhaled cannabis-attributable ED visits.”